阅读说明：本技术 一种焊接式闭式叶轮的热处理方法 (Heat treatment method of welded closed impeller ) 是由 潘峰 于 2020-05-09 设计创作，主要内容包括：本发明公开了一种焊接式闭式叶轮的热处理方法,该方法包括炸盐处理、酸洗处理、一次水洗、热风干燥、固溶处理、一次低温淬火、高温人工时效、二次水洗、二次低温淬火、低温人工时效等步骤。本发明采用高温人工时效、低温人工时效和二次低温淬火处理,并配合两次冷热水交替清洗来保证处理后工件的强度和硬度要求,相较于传统的热处理工艺,本发明具有操作简单、成本低廉、工时短、效率高等优点,且经过处理后的铝合金闭式叶轮在保证尺寸精度的前提下还具备高硬度的要求。(The invention discloses a heat treatment method of a welded closed impeller, which comprises the steps of salt blasting treatment, acid pickling treatment, primary water washing, hot air drying, solid solution treatment, primary low-temperature quenching, high-temperature artificial aging, secondary water washing, secondary low-temperature quenching, low-temperature artificial aging and the like. The invention adopts high-temperature artificial aging, low-temperature artificial aging and secondary low-temperature quenching treatment, and is matched with twice cold and hot water alternate cleaning to ensure the strength and hardness requirements of the treated workpiece.)

1. A heat treatment method of a welded closed impeller is characterized in that: the method comprises the following steps:

(1) and (3) fried salt treatment: taking out the welded aluminum alloy closed impeller workpiece from the salt bath furnace, and putting the aluminum alloy closed impeller workpiece into boiling water at 100 ℃ within 2min for salt blasting treatment, wherein the time is controlled to be 30-50 min;

(2) acid pickling treatment: washing the workpiece subjected to salt explosion treatment by using an acid solution for 20-30 min;

(3) primary water washing: alternately cleaning the pickled workpiece by hot water and cold water;

(4) and (3) hot air drying: drying the workpiece by hot air at the temperature of 60-80 ℃;

(5) solution treatment: preserving the heat of the workpiece at 400-420 ℃ for 2.5-3 h for solution treatment;

(6) primary low-temperature quenching: cooling the workpiece subjected to the solution treatment to 200-230 ℃, soaking the workpiece in distilled water with the water temperature of 15-20 ℃ within 1min after the workpiece reaches the temperature, taking out the workpiece immediately, and cooling the workpiece to room temperature;

(7) high-temperature artificial aging: heating the workpiece subjected to primary low-temperature quenching to 130-145 ℃, and preserving heat for 8-9 hours;

(8) and (3) secondary water washing: cooling the workpiece to room temperature, and then alternately cleaning the workpiece by using hot water and cold water;

(9) secondary low-temperature quenching: soaking the workpiece in distilled water with the water temperature of 15-20 ℃ for 1min for one time, immediately taking out, and then cooling to room temperature;

(10) low-temperature artificial aging: heating the workpiece subjected to the secondary low-temperature quenching to 55-60 ℃, and preserving heat for 2-3 hours;

(11) and (4) detecting and warehousing: and cooling the workpiece to room temperature after low-temperature artificial aging, detecting the hardness, and storing the workpiece with the hardness of more than or equal to 10HB in an oil seal mode.

2. The heat treatment method of a welded shrouded impeller according to claim 1 wherein: the step (3) is divided into the following steps:

(3-1) cleaning the workpiece by using distilled water at the temperature of 70 ℃ for 5-10 min;

(3-2) cleaning the workpiece by using distilled water at the temperature of 15 ℃ for 15-20 min;

(3-3) cleaning the workpiece by using distilled water at the temperature of 45 ℃ for 8-12 min;

and (3-4) cleaning the workpiece by using distilled water at the temperature of 10 ℃ for 20-25 min.

3. The heat treatment method of a welded shrouded impeller according to claim 1 wherein: the step (8) is divided into the following steps:

(8-1) cleaning the workpiece by using distilled water at the temperature of 60 ℃ for 40-45 min;

(8-2) cleaning the workpiece by adopting distilled water at the temperature of 18 ℃ for 60-120 min.

4. The heat treatment method of a welded shrouded impeller according to claim 1 wherein: the step (5) is divided into the following steps:

(5-1) heating the workpiece from room temperature to 120-135 ℃ within 10-20 min, and keeping the temperature for 0.5-1 h;

(5-2) heating the workpiece from 120-135 ℃ to 180-190 ℃ within 3-5 min, and preserving heat for 1-1.5 h;

(5-3) heating the workpiece from 180-190 ℃ to 200-230 ℃ within 8-10 min, and keeping the temperature for 1-1.5 h;

(5-4) heating the workpiece to 400-420 ℃, and preserving heat for 2.5-3 h for solution treatment.

5. The heat treatment method of a welded shrouded impeller according to claim 1 wherein: the acid solution adopted in the step (2) is a hydrogen chloride solution with the concentration of 8-12%.

Technical Field

The invention relates to the technical field of machining and processing, in particular to a heat treatment method of a welded closed impeller.

Background

The closed impeller is used as a key part of turbo machinery, such as a centrifugal machine integral impeller, a ship water jet propeller impeller and the like. The high-power air compressor is widely applied to the fields of aviation, aerospace (liquid rocket pumps), navigation, military, scientific research, precise instruments, high-precision medical equipment and the like, and the quality of the high-power air compressor directly influences the aerodynamic performance and the mechanical efficiency of the high-power air compressor.

At present, the processing modes of the closed impeller mainly include the following three types:

1. the integral casting molding is that investment casting is adopted for molding, although the process is simple and large, the material structure of the finished part is loose, the strength is poor, and the bearing capacity is low;

2. the impeller has certain limitations on the impeller structure, such as the flow channel is not too narrow, the torsional rate of the blade cannot be too large, and the like, otherwise, a cutter cannot enter, and naturally, cutting processing cannot be carried out;

3. the welding forming is a main means for processing the existing closed impeller, is less influenced by the width of the blade and the flow channel, and can weld the closed impeller with the narrowest flow channel width of 0.6 mm. The welding mode mainly adopts salt bath brazing, and the impeller welded by the mode often has certain influence on the hardness of the material, and the original hardness value of the material is difficult to ensure after welding. The hardness values of the parts after salt bath brazing in the past are all obtained by heat treatment: the method has the advantages that the quenching, tempering and aging are ensured, the processing quality of the part is difficult to control, if the quenching is easy to cause the crack or the desoldering phenomenon of the part material, in addition, the processing period of the part is long, the cost is high, and the requirement of the high-speed development of the existing military products is difficult to meet.

Disclosure of Invention

The invention aims to provide a heat treatment method of a welded closed impeller, which aims to solve the problems that the quenching easily occurs during the heat treatment of the closed impeller, so that the part material is easy to crack or has a desoldering phenomenon, the processing period is long, the processing cost is high, the hardness cannot meet the requirement, and the like.

The invention is realized by the following technical scheme:

a method of heat treating a welded shrouded impeller, the method comprising the steps of:

(1) and (3) fried salt treatment: taking out the welded aluminum alloy closed impeller workpiece from the salt bath furnace, and putting the aluminum alloy closed impeller workpiece into boiling water at 100 ℃ within 2min for salt blasting treatment, wherein the time is controlled to be 30-50 min;

(2) acid pickling treatment: washing the workpiece subjected to salt explosion treatment by using an acid solution for 20-30 min;

(3) primary water washing: alternately cleaning the acid-cleaned workpiece by adopting hot water and cold water, wherein the preferable alternate cleaning frequency is 2 times;

(4) and (3) hot air drying: drying the workpiece by hot air at the temperature of 60-80 ℃;

(5) solution treatment: preserving the heat of the workpiece at 400-420 ℃ for 2.5-3 h for solution treatment;

(6) primary low-temperature quenching: cooling the workpiece after the solution treatment to 200-230 ℃, soaking the workpiece in distilled water with the water temperature of 15-20 ℃ within 1min after the workpiece reaches the temperature, taking out the workpiece immediately, and cooling the workpiece to room temperature;

(7) high-temperature artificial aging: heating the workpiece subjected to primary low-temperature quenching to 130-145 ℃, and preserving heat for 8-9 h;

(8) and (3) secondary water washing: cooling the workpiece to room temperature, and then alternately cleaning the workpiece by adopting hot water and cold water, wherein the preferable alternate cleaning frequency is 1 time;

(9) secondary low-temperature quenching: soaking the workpiece in distilled water with the water temperature of 15-20 ℃ for 1min for one time, immediately taking out, and then cooling to room temperature;

(10) low-temperature artificial aging: heating the workpiece subjected to the secondary low-temperature quenching to 55-60 ℃, and preserving heat for 2-3 h;

(11) and (4) detecting and warehousing: and cooling the workpiece to room temperature after low-temperature artificial aging, detecting the hardness, and storing the workpiece with the hardness of more than or equal to 10HB in an oil seal mode.

Preferably, the step (3) is divided into the following steps:

(3-1) cleaning the workpiece by using distilled water at the temperature of 70 ℃ for 5-10 min;

(3-2) cleaning the workpiece by using distilled water at the temperature of 15 ℃ for 15-20 min;

(3-3) cleaning the workpiece by using distilled water at the temperature of 45 ℃ for 8-12 min;

and (3-4) cleaning the workpiece by using distilled water at the temperature of 10 ℃ for 20-25 min.

Preferably, the step (8) is divided into the following steps:

(8-1) cleaning the workpiece by using distilled water at the temperature of 60 ℃ for 40-45 min;

(8-2) cleaning the workpiece by adopting distilled water at the temperature of 18 ℃ for 60-120 min.

Preferably, in the step (5), the temperature is raised from normal temperature to 400-420 ℃ before solid solution, and the method is divided into a plurality of temperature raising stages, and specifically comprises the following steps:

(5-1) heating the workpiece from room temperature to 120-135 ℃ within 10-20 min, and keeping the temperature for 0.5-1 h;

(5-2) heating the workpiece from 120-135 ℃ to 180-190 ℃ within 3-5 min, and preserving heat for 1-1.5 h;

(5-3) heating the workpiece from 180-190 ℃ to 200-230 ℃ within 8-10 min, and preserving heat for 1-1.5 h;

(5-4) heating the workpiece to 400-420 ℃, and preserving heat for 2.5-3 h for solution treatment.

Preferably, the acid solution used in the step (2) is a hydrogen chloride solution with a concentration of 8-12%.

The beneficial effects of the invention are as follows:

compared with the prior art, the heat treatment method of the welded closed impeller provided by the invention adopts high-temperature artificial aging, low-temperature artificial aging and secondary low-temperature quenching treatment, and is matched with twice cold and hot water alternate cleaning to ensure the strength and hardness requirements of the treated workpiece.

Detailed Description

The present invention will be further described with reference to the following examples, but it should not be construed that the scope of the subject matter of the present invention is limited to the following examples, and various modifications, substitutions and alterations made based on the knowledge and conventional practices of the ordinary skill in the art without departing from the technical spirit of the present invention as described above are included in the scope of the present invention.