阅读说明：本技术 42CrMo合金结构钢空心轴类锻件热处理方法及其制备的空心轴类锻件 (Heat treatment method for 42CrMo alloy structural steel hollow shaft type forge piece and hollow shaft type forge piece prepared by heat treatment method ) 是由 梁晓捷 陈民涛 胡运宝 鲁玉梅 王凯军 李超越 缪海舟 王超 彭彩霞 王意平 吴 于 2021-07-28 设计创作，主要内容包括：本发明涉及一种42CrMo合金结构钢空心轴类锻件热处理方法及其制备的空心轴类锻件,在淬火冷却步骤中,依次进行第一空冷处理、第一水冷处理、第二空冷处理、获取第一冷却温度、第二水冷处理、第三空冷处理、第三水冷处理以及获取第二冷却温度,上述42CrMo合金结构钢空心轴类锻件热处理方法及其制备的空心轴类锻件,采用清洁资源水作为淬火冷却介质,相比于采用水+快速淬火油或水+快速淬火液(PAG)作为淬火冷却介质,整个生产过程零污染物排放,清洁安全,而且成本更低；淬火冷却周期短,高温待炉时间缩短,降低能耗,使42CrMo合金结构钢空心轴类锻件热处理更为高效,不仅降低了生产成本,而且还提高了生产效率。(The invention relates to a heat treatment method for a 42CrMo alloy structural steel hollow shaft forge piece and a hollow shaft forge piece prepared by the same, wherein in the step of quenching and cooling, a first air cooling treatment, a first water cooling treatment, a second air cooling treatment, a first cooling temperature acquisition, a second water cooling treatment, a third air cooling treatment, a third water cooling treatment and a second cooling temperature acquisition are sequentially carried out; the quenching and cooling period is short, the high-temperature furnace waiting time is shortened, the energy consumption is reduced, the heat treatment of the 42CrMo alloy structural steel hollow shaft forge piece is more efficient, the production cost is reduced, and the production efficiency is improved.)

1. A heat treatment method for a 42CrMo alloy structural steel hollow shaft forging is characterized by comprising a charging step, a quenching and cooling step and a tempering step, wherein in the quenching and cooling step, a first air cooling treatment, a first water cooling treatment, a second air cooling treatment, a first cooling temperature difference acquisition, a second water cooling treatment, a third air cooling treatment, a third water cooling treatment and a second cooling temperature difference acquisition are sequentially carried out,

the air cooling time of the first air cooling treatment is 3-5 min;

the water cooling time of the first water cooling treatment is 15-30 min;

the air cooling time of the second air cooling treatment is 1-5 min;

the step of obtaining the first cooling temperature difference is to measure the temperature inside and outside the hole of the hollow shaft forging before and after the second air cooling treatment to obtain the first cooling temperature difference;

the water cooling time of the second water cooling treatment is 10-20 min;

the air cooling time of the third air cooling treatment is 1-5 min;

the water cooling time of the third water cooling treatment is 10-20 min;

and the second cooling temperature difference is obtained by measuring the temperature inside and outside the hole of the hollow shaft forging before and after the third water-cooling treatment.

2. The heat treatment method according to claim 1, wherein in the quenching step, the quenching conditions are that after the temperature is raised to 650-660 ℃ and kept for 4-6 h, the temperature is raised to 840-860 ℃ and kept for 12-16 h.

3. The heat treatment method according to claim 2, wherein in the quenching step, the rate of temperature rise to 650 ℃ to 660 ℃ is 30 ℃/h to 70 ℃/h, and the rate of temperature rise to 840 ℃ to 860 ℃ is 50 ℃/h to 100 ℃/h.

4. The heat treatment method according to claim 1, wherein in the tempering step, the tempering condition is elevated to 600 to 630 ℃ and kept for 10 to 15 hours.

5. The thermal processing method of claim 1, wherein the thermal processing method is a batch thermal processing.

6. The heat treatment method according to claim 5, wherein the charge amount of the batch heat treatment is 60 t/furnace to 100 t/furnace.

7. The heat treatment method according to any one of claims 1 to 6, wherein in the charging step, a charging stay is provided in accordance with a structure of the hollow shaft-like forging.

8. The heat treatment method according to claim 7, further comprising a temperature return rate obtaining step of obtaining a first stage temperature return rate from the first cooling temperature difference and the air cooling time of the second air cooling treatment and obtaining a final temperature return rate from the second cooling temperature difference and the water cooling time of the third water cooling treatment, before the tempering step.

9. A hollow shaft forging characterized in that it is produced by the heat treatment method of any one of claims 1 to 8.

10. The hollow shaft forging of claim 9, wherein the single piece weight of the hollow shaft forging is 10t to 30t, the length is 3100mm to 3900mm, the maximum diameter is 800mm to 1600mm, and the inner diameter of the central through hole is 280mm to 570 mm.

Technical Field

The disclosure relates to the technical field of alloy structural steel heat treatment, in particular to a heat treatment method for a 42CrMo alloy structural steel hollow shaft type forge piece and the hollow shaft type forge piece prepared by the same.

Background

The 42CrMo (including 42CrMoA) alloy structural steel is ultrahigh-strength steel, has high strength and high toughness, better hardenability, no obvious temper brittleness, higher fatigue limit and multiple impact resistance after quenching and tempering, good low-temperature impact toughness, and is suitable for manufacturing large and medium-sized dies or devices needing certain strength and toughness.

The traditional heat treatment of the 42CrMo alloy structural steel hollow shaft forging generally uses water and quick quenching oil or water and quick quenching liquid (PAG) as cooling media, the former has toxic substance emission and environmental hazard, and the latter is suitable for single-piece small-batch operation, so that the cost is high and the single-piece treatment efficiency is low.

Disclosure of Invention

The embodiment of the invention provides a heat treatment method for a 42CrMo alloy structural steel hollow shaft type forging and a hollow shaft type forging prepared by the same, and aims to solve the technical problems of toxic substance emission, environmental hazard or high cost and low treatment efficiency in the prior art by using water and rapid quenching oil or water and rapid quenching liquid (PAG) as a cooling medium.

In order to solve the technical problem, the embodiment of the invention discloses the following technical scheme:

the invention discloses a heat treatment method for 42CrMo alloy structural steel hollow shaft forgings, which comprises a charging step, a quenching and cooling step and a tempering step, wherein in the quenching and cooling step, a first air cooling treatment, a first water cooling treatment, a second air cooling treatment, a first cooling temperature difference acquisition, a second water cooling treatment, a third air cooling treatment, a third water cooling treatment and a second cooling temperature difference acquisition are sequentially carried out,

the air cooling time of the first air cooling treatment is 3-5 min;

the water cooling time of the first water cooling treatment is 15-30 min;

the air cooling time of the second air cooling treatment is 1-5 min;

the step of obtaining the first cooling temperature difference is to measure the temperature inside and outside the hole of the hollow shaft forging before and after the second air cooling treatment to obtain the first cooling temperature difference;

the water cooling time of the second water cooling treatment is 10-20 min;

the air cooling time of the third air cooling treatment is 1-5 min;

the water cooling time of the third water cooling treatment is 10-20 min;

and the second cooling temperature difference is obtained by measuring the temperature inside and outside the hole of the hollow shaft forging before and after the third water-cooling treatment.

In one embodiment, in the quenching step, the quenching condition is that after the temperature is raised to 650-660 ℃ and is kept for 4-6 h, the temperature is raised to 840-860 ℃ and is kept for 12-16 h.

In one embodiment, in the quenching step, the temperature rising rate of the temperature rising to 650-660 ℃ is 30-70 ℃/h, and the temperature rising rate of the temperature rising to 840-860 ℃ is 50-100 ℃/h.

In one embodiment, in the tempering step, the tempering condition is that the temperature is raised to 600-630 ℃ and kept for 10-15 h.

In one embodiment, the thermal treatment method is a batch thermal treatment.

In one embodiment, the charging amount of the batch heat treatment is 60 t/furnace to 100 t/furnace.

In one embodiment, in the charging step, a charging support pad is arranged according to the structure of the hollow shaft type forging.

In one embodiment, before the tempering step, a temperature return rate obtaining step is further included, in the temperature return rate obtaining step, a first stage temperature return rate is obtained according to the first cooling temperature difference and the air cooling time of the second air cooling treatment, and a final temperature return rate is obtained according to the second cooling temperature difference and the water cooling time of the third water cooling treatment.

The invention also provides a hollow shaft forging which is prepared by the heat treatment method.

In one embodiment, the weight of each piece of the hollow shaft forging is 10 t-30 t, the length is 3100 mm-3900 mm, the maximum diameter is 800 mm-1600 mm, and the inner diameter of the central through hole is 280 mm-570 mm.

According to the heat treatment method for the 42CrMo alloy structural steel hollow shaft forge piece and the hollow shaft forge piece prepared by the same, clean resource water is used as a quenching cooling medium, and compared with the method that water and rapid quenching oil or water and rapid quenching liquid (PAG) are used as the quenching cooling medium, the whole production process has zero pollutant emission, is clean and safe, and is lower in cost; the quenching and cooling period is short, the high-temperature furnace waiting time is shortened, the energy consumption is reduced, the heat treatment of the 42CrMo alloy structural steel hollow shaft forge piece is more efficient, the production cost is reduced, and the production efficiency is improved.

Further, compared with 42CrMoA hollow shaft forgings, the quenching cracking proportion of the forging is up to 20% in the traditional water cooling production process, and particularly, water cooling is directly adopted as a cooling medium for quenching and cooling after quenching, so that the hollow shaft forgings crack and crack easily, and the products are scrapped after quenching. The cracking rate of the 42CrMo alloy structural steel hollow shaft forging after quenching is reduced to below 0.1 percent.

Furthermore, the traditional method adopts water and rapid quenching oil or water and rapid quenching liquid (PAG) as quenching cooling medium, which can improve the strength of the hollow shaft forging to a certain extent, but simultaneously, the low-temperature toughness of the hollow shaft forging is reduced more and the low-temperature toughness performance is extremely unstable, so that the hollow shaft forging cannot be suitable for working in cold environment. The heat treatment method of the 42CrMo alloy structural steel hollow shaft forging adopts a quenching cooling mode of air cooling and water cooling circulation gradual cooling, so that the strength of the hollow shaft forging can be ensured, the low-temperature toughness of the hollow shaft forging can be improved, the low-temperature impact average value (Akv-30 ℃) is improved to more than 40J, and the working requirement of a product in a cold environment is met.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.

Fig. 1 is a schematic structural view of a hollow shaft forging according to an embodiment of the present invention.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the heat treatment method for the 42CrMo alloy structural steel hollow shaft type forging according to the embodiment of the present invention includes a charging step, a quenching and cooling step, and a tempering step.

In the quenching and cooling step, a first air cooling treatment, a first water cooling treatment, a second air cooling treatment, a first cooling temperature difference acquisition, a second water cooling treatment, a third air cooling treatment, a third water cooling treatment and a second cooling temperature difference acquisition are sequentially carried out,

the air cooling time of the first air cooling treatment is 3-5 min;

the water cooling time of the first water cooling treatment is 15 min-30 min;

the air cooling time of the second air cooling treatment is 1-5 min;

the first cooling temperature difference is obtained by measuring the temperature inside and outside the hole of the hollow shaft forging before and after the second air cooling treatment;

the water cooling time of the second water cooling treatment is 10 min-20 min;

the air cooling time of the third air cooling treatment is 1-5 min;

the water cooling time of the third water cooling treatment is 10 min-20 min;

and the second cooling temperature difference is obtained by measuring the temperature inside and outside the hole of the hollow shaft forging before and after the third water cooling treatment.

According to the heat treatment method for the 42CrMo alloy structural steel hollow shaft forge piece and the hollow shaft forge piece prepared by the same, clean resource water is used as a quenching cooling medium, and compared with the method that water and rapid quenching oil or water and rapid quenching liquid (PAG) are used as the quenching cooling medium, the whole production process has zero pollutant emission, is clean and safe, and is lower in cost; the quenching and cooling period is short, the high-temperature furnace waiting time is shortened, the energy consumption is reduced, the heat treatment of the 42CrMo alloy structural steel hollow shaft forge piece is more efficient, the production cost is reduced, and the production efficiency is improved.

Further, compared with 42CrMoA hollow shaft forgings, the quenching cracking proportion is up to 20% in the traditional production process, and particularly, water cooling is directly adopted as a cooling medium for quenching cooling after quenching, so that the hollow shaft forgings are prone to cracking, cracks are generated, and products are prone to being scrapped after quenching. The cracking rate of the 42CrMo alloy structural steel hollow shaft forging after quenching is reduced to below 0.1 percent.

Furthermore, the traditional method adopts water and rapid quenching oil or water and rapid quenching liquid (PAG) as quenching cooling medium, which can improve the strength of the hollow shaft forging to a certain extent, but simultaneously, the low-temperature toughness of the hollow shaft forging is reduced more and the low-temperature toughness performance is extremely unstable, so that the hollow shaft forging cannot be suitable for working in cold environment. The heat treatment method of the 42CrMo alloy structural steel hollow shaft forging adopts a quenching cooling mode of air cooling and water cooling circulation gradual cooling, so that the strength of the hollow shaft forging can be ensured, the low-temperature toughness of the hollow shaft forging can be improved, the low-temperature impact average value (Akv-30 ℃) is improved to more than 40J, and the working requirement of a product in a cold environment is met.

The heat treatment method can be used for heat-treating the hollow shaft type forging piece, the weight of a single piece is 10 t-30 t, the length is 2200 mm-2200 mm, the maximum diameter is 1200 mm-3600 mm, and the inner diameter of a central through hole is 240 mm-700 mm. The hollow shaft type forging belongs to a large forging product and has the characteristics of large volume, heavy weight and large thickness.

As an optional implementation mode, in the quenching step, the quenching condition is that after the temperature is raised to 650-660 ℃ and the temperature is kept for 4-6 h, the temperature is raised to 840-860 ℃ and the temperature is kept for 12-16 h. Specifically, optionally, in the quenching step, the step heat preservation time is adaptively adjusted within the heat preservation time range according to the size of the workpiece, when the workpiece is larger and thicker, the heat preservation time is preferably appropriately prolonged, and when the workpiece is smaller and thinner, the heat preservation time is preferably appropriately shortened. The austenitizing heating temperature and the heat preservation time are determined according to the phase transition critical point of steel, the austenitizing is insufficient due to too low heating temperature or too short heat preservation time, and austenite grains are coarsened due to too high heating temperature or too long heat preservation time, which are not beneficial to obtaining good structure and performance. In this embodiment, in order to avoid deformation due to excessive thermal stress, quenching is performed by a step-heating process, and the heating conditions are further controlled as follows: the heating rate of heating to 650-660 ℃ is 30-70 ℃/h, the heating rate of heating to 840-860 ℃ is 50-100 ℃/h, and by further controlling the heating rate, on one hand, the thermal stress can be eliminated to avoid the deformation or cracking of the forge piece, and on the other hand, the forge piece can be fully austenitized, and the forge piece has good tissue structure and mechanical property.

As an optional embodiment, in the tempering step, the tempering condition is that the temperature is raised to 600-630 ℃ and is kept for 10-15 h. Specifically, optionally, in the tempering step, the tempering heat preservation time is adaptively adjusted within the heat preservation time range according to the size of the workpiece, when the workpiece is larger and thicker, the heat preservation time is preferably appropriately prolonged, and when the workpiece is smaller and thinner, the heat preservation time is preferably appropriately shortened. By carrying out high-temperature tempering treatment on the hollow shaft type forge piece, the residual stress generated in the quenching step or the quenching and cooling step can be eliminated, the forge piece is prevented from being deformed and cracked, the hardness, the strength, the plasticity and the toughness of the forge piece can be adjusted by matching with quenching, and the requirement on good service performance is met.

As an alternative embodiment, the heat treatment process is a batch heat treatment process. Namely, a plurality of hollow shaft forgings are quenched or quenched and cooled in batches, so that the heat treatment efficiency is improved, and the energy consumption is reduced. Further optionally, the charging amount of the batch heat treatment is 60 t/furnace to 100 t/furnace.

In the prior art, when large forgings are subjected to heat treatment, a single-piece heat treatment mode is generally adopted, or a 2-4 piece/furnace heat treatment mode can be adopted. In the embodiment of the invention, the batch heat treatment mode of the large forgings is realized, and the furnace charging amount reaches 100 t/furnace. For example, when the weight of a single hollow shaft forging is 20t, 5 hollow shaft forgings can be subjected to heat treatment simultaneously, so that the production period of the heat treatment can be shortened, the energy consumption of a quenching furnace can be effectively reduced, and the heat treatment cost is greatly reduced.

As an optional embodiment, in the charging step, a charging support pad is arranged according to the structure of the hollow shaft type forging. For example, as shown in fig. 1, according to the structural characteristics of the hollow shaft forging, charging support pads matched with the main shafts A, B, C and D are respectively arranged at the main shafts A, B, C and D, specifically, in this embodiment, the charging support pad height at a is 70mm, the charging support pad height at B is 470mm, the charging support pad height at C is 580mm, and the charging support pad height at D is 600 mm.

As an optional implementation manner, before the tempering step, a temperature return rate obtaining step is further included, in the temperature return rate obtaining step, a first stage temperature return rate is obtained according to the first cooling temperature difference and the air cooling time of the second air cooling treatment, and a final temperature return rate is obtained according to the second cooling temperature difference and the water cooling time of the third water cooling treatment. In the embodiment, the first temperature return rate and the final temperature return rate are tracked and calculated to ensure that the final cooling temperature of the core of the product is controlled within the range of 280-320 ℃, so that the quenching cracking caused by microcracks generated by overlarge stress of the core structure due to the overlow final cooling temperature is prevented. And predicting the final cooling temperature of the workpiece according to the first temperature return rate and the final temperature return rate so as to enable the final cooling temperature to be in the range of 280-320 ℃, and if the final cooling temperature predicted according to the first temperature return rate and the final temperature return rate is too high or too low, adjusting the water cooling time of the first water cooling treatment, the water cooling time of the second water cooling treatment and the water cooling time of the third water cooling treatment in the water cooling time range so as to change the temperature return rate, so that the final cooling temperature of the workpiece is ensured to be in the range of 280-320 ℃.

The heat treatment method for the 42CrMo alloy structural steel hollow shaft forging and the performance of the prepared hollow shaft forging are described in more detail with reference to specific embodiments.

Example 1

In the embodiment, the heat treatment is carried out on the large-flange hollow long-shaft forging, the product has the weight of 20t in one piece, the length dimension of 4400mm, the maximum diameter of the flange of 2400mm and the inner diameter of a central through hole of 470mm, and belongs to a large forging product.

Before the step of charging, performing surface quality detection on the large-flange hollow long shaft forging, avoiding surface defects such as black skin, cracks, scars, sharp corners and the like, and if the surface defects exist, polishing local edges and corners and then charging; checking whether the software data of the product is complete and whether the chemical composition meets the requirements, and marking the workpiece information on the outer end face of the workpiece flange by using the anti-oxidation coating. In the charging step, 5 large flange hollow long shaft forgings subjected to the inspection and marking are charged into a quenching furnace, the charging amount is 100 t/furnace, as shown in fig. 1, each large flange hollow long shaft forging is provided with a corresponding charging support pad, wherein the charging support pad height at the position A is 70mm, the charging support pad height at the position B is 470mm, the charging support pad height at the position C is 580mm, and the charging support pad height at the position D is 600mm, and the central shaft of the large flange hollow long shaft forging is ensured to be in a horizontal state by arranging the charging support pads. And after the charging is finished, marking the specific charging position of each large flange hollow long shaft forging in a charging position diagram. After charging, closing a quenching furnace door for quenching, firstly, gradually heating to 650 ℃ at a heating rate of 50 ℃/h for heat preservation, wherein the heat preservation time is 5 h; and then gradually heating to 840 ℃ at the heating rate of 70 ℃/h for heat preservation, wherein the heat preservation time is 15 h. And after quenching is finished, discharging the large flange hollow long shaft forge piece out of the furnace, carrying out first air cooling treatment for 4min, feeding water, moving the large flange hollow long shaft forge piece along the hole direction, carrying out first water cooling treatment for 20min, carrying out second air cooling treatment on the discharged water for 3min, measuring the temperature inside and outside the hole to obtain a first cooling temperature, carrying out second water cooling treatment on the fed water for 15min after temperature measurement, carrying out third air cooling treatment on the discharged water for 3min, feeding water again, carrying out third water cooling treatment for 15min, measuring the temperature inside and outside the hole to obtain a second cooling temperature, and finishing quenching and cooling. And (3) putting the quenched and cooled large-flange hollow long shaft forging into a quenching furnace for tempering, gradually heating to 600 ℃, keeping the temperature for 13h, discharging, and cooling to room temperature.

The detection position of the large-flange hollow long shaft forging is shown in figure 1, and after the large-flange hollow long shaft forging is cooled to room temperature, sampling detection is carried out at a position 73mm away from the surface layer at the Z5 position. According to GB/T228.1-2010 part 1 of the tensile test of metallic materials: testing the tensile strength Rm, the lower yield strength ReH, the elongation A after fracture and the reduction of area Z of a sample according to a room temperature test method; measuring the impact absorption energy AKW (-30 ℃) of the sample according to GB/T229-; according to GB/T231.1-2018 Brinell hardness test part 1 of metal materials: test method "determines the brinell hardness HBW of a sample. The results are shown in Table 1.

Table 1 results of mechanical property measurements of large flange hollow long shaft forgings after heat treatment in example 1

The detection results in table 1 show that the mechanical properties of all parts of the large flange hollow long shaft forging after heat treatment in the embodiment are balanced and stable, the low-temperature toughness performance is improved while the strength is improved, the performance is stable, and the large flange hollow long shaft forging can meet the working requirements in a cold environment.

The large-flange hollow shaft forging with the specification is processed in batch by the heat treatment method of the embodiment, compared with the traditional single-piece heat treatment, the production period is shortened by about half, and meanwhile, a large amount of fuel and cooling medium can be saved. The method is calculated by producing 1000 products per year, the cost of natural gas is saved by 150 ten thousand yuan per year, the consumption cost of rapid quenching oil is saved by about 32.5 ten thousand yuan per year, and the toxic substance emission in the quenching process is reduced to zero.

The longer the heat preservation time of the large-flange long-shaft forging product at high temperature, the longer the production period, the larger the energy consumption, compared with the traditional quenching cooling time, the cooling time is generally more than 125min, the high-temperature treatment time of the subsequent workpiece in the furnace is longer, the cooling time of the embodiment is shortened to 60min, the high-temperature treatment time of the subsequent workpiece in the quenching furnace is greatly reduced, and the energy consumption can be reduced through effective heat treatment.

Example 2

In the embodiment, the heat treatment is carried out on the large-flange hollow long-shaft forging, the product has the weight of 20t in one piece, the length dimension of 4400mm, the maximum diameter of the flange of 2400mm and the inner diameter of a central through hole of 470mm, and belongs to a large-size hollow shaft forging product.

Before the step of charging, performing surface quality detection on the large-flange hollow long shaft forging, avoiding surface defects such as black skin, cracks, scars, sharp corners and the like, and if the surface defects exist, polishing local edges and corners and then charging; checking whether the software data of the product is complete and whether the chemical composition meets the requirements, and marking the workpiece information on the outer end face of the workpiece flange by using the anti-oxidation coating. In the charging step, 5 large flange hollow long shaft forgings subjected to the inspection and marking are charged into a quenching furnace, the charging amount is 100 t/furnace, as shown in fig. 1, each large flange hollow long shaft forging is provided with a corresponding charging support pad, wherein the charging support pad height at the position A is 70mm, the charging support pad height at the position B is 470mm, the charging support pad height at the position C is 580mm, and the charging support pad height at the position D is 600mm, and the central shaft of the large flange hollow long shaft forging is ensured to be in a horizontal state by arranging the charging support pads. And after the charging is finished, marking the specific charging position of each large flange hollow long shaft forging in a charging position diagram. After charging, closing a quenching furnace door for quenching, firstly, gradually heating to 650 ℃ at the heating rate of 30 ℃/h for heat preservation, wherein the heat preservation time is 5 h; and then gradually heating to 850 ℃ at the heating rate of 50 ℃/h for heat preservation for 15 h. And after quenching is finished, discharging the large flange hollow long shaft forging out of the furnace, carrying out first air cooling treatment for 5min, introducing water, moving the large flange hollow long shaft forging along the hole direction, carrying out first water cooling treatment for 30min, carrying out second air cooling treatment on the discharged water for 5min, measuring the temperature inside and outside the hole to obtain a first cooling temperature, introducing water after temperature measurement, carrying out second water cooling treatment for 20min, discharging water again, carrying out third air cooling treatment for 5min, introducing water again, carrying out third water cooling treatment for 20min, measuring the temperature inside and outside the hole to obtain a second cooling temperature, and finishing quenching and cooling. And (3) putting the quenched and cooled large-flange hollow long shaft forging into a quenching furnace for tempering, gradually heating to 610 ℃, keeping the temperature for 13h, discharging, and cooling to room temperature.

Sampling and detection were carried out in the same manner as in example 1, and the detection results are shown in Table 2.

Example 3

In the embodiment, the heat treatment is carried out on the large-flange hollow long-shaft forging, the product has the weight of 20t in one piece, the length dimension of 4400mm, the maximum diameter of the flange of 2400mm and the inner diameter of a central through hole of 470mm, and belongs to a large forging product.

Before the step of charging, performing surface quality detection on the large-flange hollow long shaft forging, avoiding surface defects such as black skin, cracks, scars, sharp corners and the like, and if the surface defects exist, polishing local edges and corners and then charging; checking whether the software data of the product is complete and whether the chemical composition meets the requirements, and marking the workpiece information on the outer end face of the workpiece flange by using the anti-oxidation coating. In the charging step, 5 large flange hollow long shaft forgings subjected to the inspection and marking are charged into a quenching furnace, the charging amount is 100 t/furnace, as shown in fig. 1, each large flange hollow long shaft forging is provided with a corresponding charging support pad, wherein the charging support pad height at the position A is 70mm, the charging support pad height at the position B is 470mm, the charging support pad height at the position C is 580mm, and the charging support pad height at the position D is 600mm, and the central shaft of the large flange hollow long shaft forging is ensured to be in a horizontal state by arranging the charging support pads. And after the charging is finished, marking the specific charging position of each large flange hollow long shaft forging in a charging position diagram. After charging, closing a quenching furnace door for quenching, firstly, gradually heating to 650 ℃ at a heating rate of 70 ℃/h for heat preservation, wherein the heat preservation time is 45 h; and then gradually heating to 850 ℃ at the heating rate of 100 ℃/h for heat preservation for 15 h. And after quenching is finished, discharging the large flange hollow long shaft forge piece out of the furnace, carrying out first air cooling treatment for 3min, feeding water, moving the large flange hollow long shaft forge piece along the hole direction, carrying out first water cooling treatment for 15min, carrying out second air cooling treatment on the discharged water for 1min, measuring the temperature inside and outside the hole to obtain a first cooling temperature, carrying out second water cooling treatment on the fed water for 10min after temperature measurement, carrying out third air cooling treatment on the discharged water for 1min again, feeding water again, carrying out third water cooling treatment for 10min, measuring the temperature inside and outside the hole to obtain a second cooling temperature, and finishing quenching and cooling. And (3) putting the quenched and cooled large-flange hollow long shaft forging into a quenching furnace for tempering, gradually heating to 620 ℃, keeping the temperature for 13h, discharging, and cooling to room temperature.

Sampling and detection were carried out in the same manner as in example 1, and the detection results are shown in Table 2.

Example 4

In the embodiment, the heat treatment is carried out on the large-flange hollow long-shaft forging, the product has the unit weight of 25t, the length dimension of 4600mm, the maximum diameter of the flange of 2500mm and the inner diameter of the central through hole of 490mm, and belongs to a large forging product.

Before the step of charging, performing surface quality detection on the large-flange hollow long shaft forging, avoiding surface defects such as black skin, cracks, scars, sharp corners and the like, and if the surface defects exist, polishing local edges and corners and then charging; checking whether the software data of the product is complete and whether the chemical composition meets the requirements, and marking the workpiece information on the outer end face of the workpiece flange by using the anti-oxidation coating. In the charging step, 4 large flange hollow long shaft forgings subjected to the inspection and marking are charged into a quenching furnace, the charging amount is 100 t/furnace, as shown in fig. 1, each large flange hollow long shaft forging is provided with a corresponding charging support pad, wherein the charging support pad height at the position A is 70mm, the charging support pad height at the position B is 470mm, the charging support pad height at the position C is 580mm, and the charging support pad height at the position D is 600mm, and the central shaft of the large flange hollow long shaft forging is ensured to be in a horizontal state by arranging the charging support pads. And after the charging is finished, marking the specific charging position of each large flange hollow long shaft forging in a charging position diagram. After charging, closing a quenching furnace door for quenching, firstly, gradually heating to 650 ℃ at a heating rate of 50 ℃/h for heat preservation, wherein the heat preservation time is 5 h; and then gradually raising the temperature to 850 ℃ at the temperature rise rate of 70 ℃/h for heat preservation for 15 h. And after quenching is finished, discharging the large flange hollow long shaft forge piece out of the furnace, carrying out first air cooling treatment for 4min, feeding water, moving the large flange hollow long shaft forge piece along the hole direction, carrying out first water cooling treatment for 20min, carrying out second air cooling treatment on the discharged water for 3min, measuring the temperature inside and outside the hole to obtain a first cooling temperature, carrying out second water cooling treatment on the fed water for 15min after temperature measurement, carrying out third air cooling treatment on the discharged water for 3min, feeding water again, carrying out third water cooling treatment for 15min, measuring the temperature inside and outside the hole to obtain a second cooling temperature, and finishing quenching and cooling. And (3) putting the quenched and cooled large-flange hollow long shaft forging into a quenching furnace for tempering, gradually heating to 630 ℃, keeping the temperature for 13h, discharging, and cooling to room temperature.

Sampling and detection were carried out in the same manner as in example 1, and the detection results are shown in Table 2.

Comparative example 1

In the embodiment, the heat treatment is carried out on the large-flange hollow long-shaft forging, the product has the weight of 20t in one piece, the length dimension of 4400mm, the maximum diameter of the flange of 2400mm and the inner diameter of a central through hole of 470mm, and belongs to a large forging product.

Before the step of charging, performing surface quality detection on the large-flange hollow long shaft forging, avoiding surface defects such as black skin, cracks, scars, sharp corners and the like, and if the surface defects exist, polishing local edges and corners and then charging; checking whether the software data of the product is complete and whether the chemical composition meets the requirements, and marking the workpiece information on the outer end face of the workpiece flange by using the anti-oxidation coating. In the charging step, 5 large flange hollow long shaft forgings subjected to the inspection and marking are charged into a quenching furnace, the charging amount is 100 t/furnace, as shown in fig. 1, each large flange hollow long shaft forging is provided with a corresponding charging support pad, wherein the charging support pad height at the position A is 70mm, the charging support pad height at the position B is 470mm, the charging support pad height at the position C is 580mm, and the charging support pad height at the position D is 600mm, and the central shaft of the large flange hollow long shaft forging is ensured to be in a horizontal state by arranging the charging support pads. And after the charging is finished, marking the specific charging position of each large flange hollow long shaft forging in a charging position diagram. After charging, closing a quenching furnace door for quenching, firstly, gradually heating to 650 ℃ at a heating rate of 50 ℃/h for heat preservation, wherein the heat preservation time is 5 h; and then gradually raising the temperature to 860 ℃ at the temperature rise rate of 70 ℃/h for heat preservation, wherein the heat preservation time is 15 h. And (4) discharging the large flange hollow long shaft forge piece out of the furnace after quenching is finished, and carrying out water cooling treatment for 60min to finish quenching cooling. And (3) putting the quenched and cooled large-flange hollow long shaft forging into a quenching furnace for tempering, gradually heating to 600 ℃, keeping the temperature for 13h, discharging, and cooling to room temperature.

Sampling and detection were carried out in the same manner as in example 1, and the detection results are shown in Table 2.

Comparative example 2

In the embodiment, the heat treatment is carried out on the large-flange hollow long-shaft forging, the product has the weight of 20t in one piece, the length dimension of 4400mm, the maximum diameter of the flange of 2400mm and the inner diameter of a central through hole of 470mm, and belongs to a large forging product.

Before the step of charging, performing surface quality detection on the large-flange hollow long shaft forging, avoiding surface defects such as black skin, cracks, scars, sharp corners and the like, and if the surface defects exist, polishing local edges and corners and then charging; checking whether the software data of the product is complete and whether the chemical composition meets the requirements, and marking the workpiece information on the outer end face of the workpiece flange by using the anti-oxidation coating. In the charging step, 5 large flange hollow long shaft forgings subjected to the inspection and marking are charged into a quenching furnace, the charging amount is 100 t/furnace, as shown in fig. 1, each large flange hollow long shaft forging is provided with a corresponding charging support pad, wherein the charging support pad height at the position A is 70mm, the charging support pad height at the position B is 470mm, the charging support pad height at the position C is 580mm, and the charging support pad height at the position D is 600mm, and the central shaft of the large flange hollow long shaft forging is ensured to be in a horizontal state by arranging the charging support pads. And after the charging is finished, marking the specific charging position of each large flange hollow long shaft forging in a charging position diagram. After charging, closing a quenching furnace door for quenching, firstly, gradually heating to 650 ℃ at a heating rate of 50 ℃/h for heat preservation, wherein the heat preservation time is 5 h; and then gradually raising the temperature to 860 ℃ at the temperature rise rate of 70 ℃/h for heat preservation, wherein the heat preservation time is 15 h. And after quenching is finished, discharging the large flange hollow long shaft forging out of the furnace, feeding water, moving the large flange hollow long shaft forging along the hole direction, carrying out first water cooling treatment for 20min, then carrying out first air cooling treatment for 4min, feeding water again, carrying out second water cooling treatment for 15min, then carrying out second air cooling treatment for 3min, feeding water again, carrying out third water cooling treatment for 15min, then carrying out third air cooling treatment for 3min, and finishing quenching and cooling. And (3) putting the quenched and cooled large-flange hollow long shaft forging into a quenching furnace for tempering, gradually heating to 610 ℃, keeping the temperature for 13h, discharging, and cooling to room temperature.

Sampling and detection were carried out in the same manner as in example 1, and the detection results are shown in Table 2.

Comparative example 3

In the embodiment, the heat treatment is carried out on the large-flange hollow long-shaft forging, the product has the weight of 20t in one piece, the length dimension of 4400mm, the maximum diameter of the flange of 2400mm and the inner diameter of a central through hole of 470mm, and belongs to a large forging product.

Before the step of charging, performing surface quality detection on the large-flange hollow long shaft forging, avoiding surface defects such as black skin, cracks, scars, sharp corners and the like, and if the surface defects exist, polishing local edges and corners and then charging; checking whether the software data of the product is complete and whether the chemical composition meets the requirements, and marking the workpiece information on the outer end face of the workpiece flange by using the anti-oxidation coating. In the charging step, 5 large flange hollow long shaft forgings subjected to the inspection and marking are charged into a quenching furnace, the charging amount is 100 t/furnace, as shown in fig. 1, each large flange hollow long shaft forging is provided with a corresponding charging support pad, wherein the charging support pad height at the position A is 70mm, the charging support pad height at the position B is 470mm, the charging support pad height at the position C is 580mm, and the charging support pad height at the position D is 600mm, and the central shaft of the large flange hollow long shaft forging is ensured to be in a horizontal state by arranging the charging support pads. And after the charging is finished, marking the specific charging position of each large flange hollow long shaft forging in a charging position diagram. After charging, closing a quenching furnace door for quenching, firstly, gradually heating to 650 ℃ at a heating rate of 50 ℃/h for heat preservation, wherein the heat preservation time is 5 h; and then gradually raising the temperature to 860 ℃ at the temperature rise rate of 70 ℃/h for heat preservation, wherein the heat preservation time is 15 h. And after quenching is finished, discharging the large flange hollow long shaft forge piece out of the furnace, carrying out first air cooling treatment for 4min, then introducing water, moving the large flange hollow long shaft forge piece along the hole direction, carrying out first water cooling treatment for 20min, introducing quick quenching oil into discharged water, carrying out oil cooling for 100min, and finishing quenching cooling. And (3) putting the quenched and cooled large-flange hollow long shaft forging into a quenching furnace for tempering, gradually heating to 620 ℃, keeping the temperature for 13h, discharging, and cooling to room temperature.

Sampling and detection were carried out in the same manner as in example 1, and the detection results are shown in Table 2.

Comparative example 4

In the embodiment, the heat treatment is carried out on the large-flange hollow long-shaft forging, the product has the weight of 20t in one piece, the length dimension of 4400mm, the maximum diameter of the flange of 2400mm and the inner diameter of a central through hole of 470mm, and belongs to a large forging product.

Before the step of charging, performing surface quality detection on the large-flange hollow long shaft forging, avoiding surface defects such as black skin, cracks, scars, sharp corners and the like, and if the surface defects exist, polishing local edges and corners and then charging; checking whether the software data of the product is complete and whether the chemical composition meets the requirements, and marking the workpiece information on the outer end face of the workpiece flange by using the anti-oxidation coating. In the charging step, 5 large flange hollow long shaft forgings subjected to the inspection and marking are charged into a quenching furnace, the charging amount is 100 t/furnace, as shown in fig. 1, each large flange hollow long shaft forging is provided with a corresponding charging support pad, wherein the charging support pad height at the position A is 70mm, the charging support pad height at the position B is 470mm, the charging support pad height at the position C is 580mm, and the charging support pad height at the position D is 600mm, and the central shaft of the large flange hollow long shaft forging is ensured to be in a horizontal state by arranging the charging support pads. And after the charging is finished, marking the specific charging position of each large flange hollow long shaft forging in a charging position diagram. After charging, closing a quenching furnace door for quenching, firstly, gradually heating to 650 ℃ at a heating rate of 50 ℃/h for heat preservation, wherein the heat preservation time is 5 h; and then gradually raising the temperature to 860 ℃ at the temperature rise rate of 70 ℃/h for heat preservation, wherein the heat preservation time is 15 h. And after quenching is finished, discharging the large flange hollow long shaft forging out of the furnace, feeding oil into the large flange hollow long shaft forging, performing oil cooling treatment for 4min, feeding water, moving the large flange hollow long shaft forging along the hole direction, performing first water cooling treatment for 20min, feeding the discharged water into the oil, performing oil cooling treatment for 3min, measuring the temperature inside and outside the hole to obtain a first cooling temperature, measuring the temperature inside and outside the hole, performing second water cooling treatment for 15min, discharging the water again, feeding the oil, performing oil cooling treatment for 3min, feeding the water again, performing third water cooling treatment for 15min, measuring the temperature inside and outside the hole to obtain a second cooling temperature, and finishing quenching and cooling. And (3) putting the quenched and cooled large-flange hollow long shaft forging into a quenching furnace for tempering, gradually heating to 630 ℃, keeping the temperature for 13h, discharging, and cooling to room temperature.

Sampling and detection were carried out in the same manner as in example 1, and the detection results are shown in Table 2.

Table 2 mechanical property detection results of large flange hollow long shaft forgings of examples and comparative examples after heat treatment

The test results in table 2 show that the hollow shaft forging processed by the heat treatment method of the invention has good mechanical properties, and simultaneously, the low-temperature impact property is obviously improved, and the working requirements of the product in cold environment are met.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for apparatus or system embodiments, since they are substantially similar to method embodiments, they are described in relative terms, as long as they are described in partial descriptions of method embodiments. The above-described embodiments of the apparatus and system are merely illustrative, and the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

The foregoing is directed to embodiments of the present invention, and it is understood that various modifications and improvements can be made by those skilled in the art without departing from the spirit of the invention.