阅读说明：本技术 一种筒件的锻制方法 (Forging method of barrel ) 是由 王佳明 叶文冰 李源 张健 罗祥华 韩涛 戴盛涛 于 2020-04-28 设计创作，主要内容包括：本发明涉及冶金及锻件加工领域,公开了一种筒件的锻制方法,该方法包括如下工艺流程：按配方配料→真空感应炉一次冶炼→真空自耗炉二次冶炼→钢锭高温均质化→镦拔锻造→镦粗冲孔→锻件扩孔→回炉再烧→收孔拔长→热处理→材料测试→评审验收。本发明方法通过采用钢锭高温均质化处理、镦拔锻造、镦粗冲孔、钢锭扩孔、回炉再烧、收孔拔长及热处理,解决了锻制的筒件低倍粗晶及晶粒粗大的问题。(The invention relates to the field of metallurgy and forge piece processing, and discloses a forging method of a cylinder piece, which comprises the following process flows of: proportioning according to the formula → primary smelting in a vacuum induction furnace → secondary smelting in a vacuum consumable electrode furnace → high temperature homogenization of steel ingot → upsetting-drawing forging → upsetting-punching → reaming of forge piece → remelting and reburning → drawing of hole → heat treatment → material testing → acceptance and review. The method solves the problems of low-power coarse grains and large grains of the forged cylinder by adopting high-temperature homogenization treatment of steel ingots, upsetting-drawing forging, upsetting-punching, steel ingot chambering, furnace returning and reburning, hole-closing drawing-out and heat treatment.)

1. The forging method of the barrel is characterized by comprising the following process flows:

proportioning according to the formula → primary smelting in a vacuum induction furnace → secondary smelting in a vacuum consumable furnace → high temperature homogenization of steel ingot → upsetting-drawing forging → upsetting-punching → reaming of forge piece → remelting furnace again → drawing of hole → heat treatment → material testing → acceptance and review,

wherein the chemical components of the steel ingot are controlled as follows by taking the total weight of the steel ingot as 100 percent: less than or equal to 0.1 percent of C, less than or equal to 0.2 percent of Si, less than or equal to 0.2 percent of Mn, less than or equal to 0.025 percent of S, less than or equal to 0.025 percent of P, 0.2-1.5 percent of Ti, 16-20 percent of Ni, 3.5-6.5 percent of Mo, 8-13 percent of Co, 0.05-0.15 percent of Al, and the balance of inevitable impurities and Fe.

2. A method for forging a barrel according to claim 1, wherein said ingot has a diameter of 600mm or less.

3. Forging method of a cartridge according to claim 1, characterized in that the temperature of the high temperature homogenization of the ingot is 1200-1250 ℃.

4. The method for forging a cylindrical member according to claim 1, wherein the upsetting forging is performed at a start forging temperature of 1050 ℃ or higher, a finish forging temperature of 850 ℃ or higher, and a holding time of 1 to 3 hours.

5. The method of forging a cylinder according to claim 1 or 4, wherein the reduction rate of the upsetting is not more than 50% and the number of the upsetting is not less than 2.

6. The method for forging a cartridge according to claim 1, wherein the specific steps of reaming the forging comprise: reaming is carried out by using a first core rod, and then primary drawing is carried out by using a second core rod;

wherein the diameter of the second core rod is smaller than the diameter of an inner hole of the forged piece after broaching,

preferably, the difference between the diameter of the second core rod and the diameter of the inner hole of the forged piece after hole expansion is 10-20 mm.

7. The method of forging a cartridge of claim 1, wherein the inner bore diameter of the forged part after broaching is greater than the inner bore diameter of the forged part after punching;

preferably, the difference between the diameter of the inner hole of the forged piece after broaching and the diameter of the inner hole of the forged piece after punching is more than or equal to 80 mm.

8. The method for forging a cartridge according to claim 1, wherein the conditions for the returning and the reburning are as follows: the reheating temperature is 1000-1100 ℃, and the reheating time is 1-3 h.

9. A method of forging a cartridge according to claim 1, wherein in said reducing hole elongation, a core rod diameter < an inner hole diameter after forging broaching is used.

10. The method of forging a cartridge of claim 1, wherein said heat treatment process is a cyclic phase transition fine grain heat treatment;

the circulating phase-change fine grain heat treatment comprises primary air cooling, secondary air cooling and third air cooling;

preferably, the temperature of the first air cooling is 930-.

Technical Field

The invention relates to the field of metallurgy and forge piece processing, in particular to a forging method of a cylinder piece.

Background

The forged cylinder piece has small anisotropy of performance, and is widely applied to the fields of pressure-bearing dies, containers and the like. At present, steel ingots are usually manufactured by upsetting, drawing, reaming and drawing-out forming processes when cylinder parts are forged in China, and the problems of low-power coarse grains, coarse grains and the like can occur during low-power inspection of some cylinder parts. Because the high-end compression dies in some special fields bear alternating stress of loading, unloading and reloading for a long time in the use process, the problems of low-time coarse grains, coarse crystal grains and the like of the cylinder can cause the cylinder to be scrapped and even cause serious safety accidents. Therefore, high-end barrels in some special fields require that coarse grains and coarse grains are not allowed.

Disclosure of Invention

The invention aims to overcome the problems of coarse grains and coarse grains of a forged cylinder in the prior art, and provides a method for forging a cylinder.

In order to achieve the above object, the present invention provides a method for forging a barrel, which comprises the following process flows:

proportioning according to the formula → primary smelting in a vacuum induction furnace → secondary smelting in a vacuum consumable furnace → high temperature homogenization of steel ingot → upsetting-drawing forging → upsetting-punching → reaming of forge piece → remelting furnace again → drawing of hole → heat treatment → material testing → acceptance and review,

wherein the chemical components of the steel ingot are controlled as follows by taking the total weight of the steel ingot as 100 percent: less than or equal to 0.1 percent of C, less than or equal to 0.2 percent of Si, less than or equal to 0.2 percent of Mn, less than or equal to 0.025 percent of S, less than or equal to 0.025 percent of P, 0.2-1.5 percent of Ti, 16-20 percent of Ni, 3.5-6.5 percent of Mo, 8-13 percent of Co, 0.05-0.15 percent of Al, and the balance of inevitable impurities and Fe.

Preferably, the diameter of the steel ingot is less than or equal to 600 mm.

Preferably, the temperature for high temperature homogenization of the steel ingot is 1200-1250 ℃.

Preferably, in the upsetting forging, the initial forging temperature is more than or equal to 1050 ℃, the final forging temperature is more than or equal to 850 ℃, and the heat preservation time is 1-3 h.

Preferably, the upsetting reduction rate is less than or equal to 50 percent, and the upsetting frequency is more than or equal to 2 times.

Preferably, the forging reaming method specifically comprises the following steps: reaming is carried out by using a first core rod, and then primary drawing is carried out by using a second core rod; the diameter of the second core rod is smaller than the inner hole diameter of the forged piece after broaching, and more preferably, the difference between the diameter of the second core rod and the inner hole diameter of the forged piece after broaching is 10-20 mm.

Preferably, the diameter of the inner hole of the forged piece after broaching is larger than the diameter of the inner hole of the forged piece after punching; more preferably, the difference between the diameter of the inner hole of the forged piece after broaching and the diameter of the inner hole of the forged piece after punching is more than or equal to 80 mm.

Preferably, the conditions of the furnace returning and the reburning are as follows: the reheating temperature is 1000-1100 ℃, and the reheating time is 1-3 h.

Preferably, in the shrinkage hole drawing, the diameter of the core rod used is less than the inner hole diameter of the forged piece after hole expansion.

Preferably, the heat treatment process is a cyclic phase transition fine grain heat treatment; the circulating phase-change fine grain heat treatment comprises primary air cooling, secondary air cooling and third air cooling; preferably, the temperature of the first air cooling is 930-.

The forging method of the cylinder part solves the problems of low-power coarse crystals and coarse grains of the forged cylinder part by adopting high-temperature homogenization treatment of steel ingots, upsetting-drawing forging, upsetting-punching, hole expanding of forged pieces, furnace returning and reburning, hole contraction drawing and heat treatment.

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides a forging method of a cylinder, which comprises the following process flows of:

proportioning according to the formula → primary smelting in a vacuum induction furnace → secondary smelting in a vacuum consumable furnace → high temperature homogenization of steel ingot → upsetting-drawing forging → upsetting-punching → reaming of forge piece → remelting furnace again → drawing of hole → heat treatment → material testing → acceptance and review,

wherein the chemical components of the steel ingot are controlled as follows by taking the total weight of the steel ingot as 100 percent: less than or equal to 0.1 percent of C, less than or equal to 0.2 percent of Si, less than or equal to 0.2 percent of Mn, less than or equal to 0.025 percent of S, less than or equal to 0.025 percent of P, 0.2-1.5 percent of Ti, 16-20 percent of Ni, 3.5-6.5 percent of Mo, 8-13 percent of Co, 0.05-0.15 percent of Al, and the balance of inevitable impurities and Fe.

In the method, the technological parameters of the primary smelting of the vacuum induction furnace and the secondary smelting of the vacuum consumable electrode furnace are not particularly limited as long as the excellent comprehensive performance of the obtained steel ingot can be ensured.

In the method of the invention, the diameter of the steel ingot is not particularly limited as long as the excellent performance of the forging piece can be ensured, and the diameter of the steel ingot is preferably less than or equal to 600 mm. Specifically, it may be, for example, 100mm, 200mm, 300mm, 400mm, 500mm, or 600 mm.

In the method of the present invention, the high temperature homogenization temperature of the steel ingot is 1200-1250 ℃. Specifically, the temperature may be 1200 ℃, 1210 ℃, 1220 ℃, 1230 ℃, 1240 ℃ or 1250 ℃, for example.

The steel ingot is subjected to high-temperature homogenization treatment, and the main purpose is to ensure that atoms such as Ti, Mo, Ni and the like in the steel ingot move violently through high temperature so as to achieve the purposes of uniform chemical components, reduce the segregation of the chemical components in the steel ingot and ensure the uniform internal structure of a finished product.

In the method, during upsetting forging, the initial forging temperature is more than or equal to 1050 ℃, the final forging temperature is more than or equal to 850 ℃, and the heat preservation time is 1-3 h. Specifically, the heat preservation time can be 1h, 1.5h, 2h, 2.5h or 3 h.

In the method, the upsetting reduction rate is less than or equal to 50 percent, and the upsetting frequency is more than or equal to 2 times. Specifically, the reduction rate of the upsetting may be, for example, 10%, 20%, 30%, 40%, or 50%. Specifically, the number of times of upsetting may be, for example, 2 times, 3 times, or 4 times.

In the method, the upsetting reduction rate is the ratio of the height of the forged piece after each upsetting to the height of the forged piece before each upsetting, and the upsetting times are the upsetting times of the forged piece and the upsetting times of the forged piece.

In the upsetting forging, the steel ingot needs to be cooled from the homogenization temperature to 1050 ℃, and then heated to the forging temperature 1170 ℃, so as to homogenize the internal temperature of the steel ingot. The steel ingot is upset and pulled for more than or equal to 2 times, the steel ingot is upset and pulled for multiple times by using an upsetting plate, the multiple upsetting and pulling can ensure that the steel ingot is fully and thoroughly forged, the steel ingot is upset and pulled in place at one time by using higher temperature and higher forging force in the upsetting and pulling process, the pulling length adopts an FM method, so that the full breaking of the cast structure of the steel ingot and the welding of gaps are ensured, the axial deformation and the radial deformation of the steel ingot are basically consistent after the multiple upsetting and pulling, at the moment, the steel ingot is converted into the forged structure from the cast structure, and the internal defects in the steel billet can be repaired by preserving the heat.

In the method of the present invention, the forging reaming method specifically includes: reaming is carried out by using a first core rod, and then primary drawing is carried out by using a second core rod; the diameter of the second core rod is smaller than the diameter of the inner hole of the forged piece after broaching, and under the optimal condition, the difference between the diameter of the second core rod and the diameter of the inner hole of the forged piece after broaching is 10-20 mm. Specifically, it may be, for example, 10mm, 12mm, 14mm, 16mm, 18mm, or 20 mm.

In the method, after the forging is reamed, a core rod is used for drawing out for the first time, and the drawing-out size is minimum and can meet the length requirement of the barrel part. In the forging process of the barrel, the transverse dimension is firstly processed, and then the longitudinal dimension is processed by a drawing method.

In the method, the diameter of the inner hole of the forged piece after broaching is larger than the diameter of the inner hole of the forged piece after punching; in a specific embodiment, the difference between the diameter of the inner hole of the forged piece after broaching and the diameter of the inner hole of the forged piece after punching is more than or equal to 80 mm.

In the method of the invention, the conditions of the furnace return and the reburning are as follows: the reheating temperature is 1000-1100 ℃, and the reheating time is 1-3 h. Specifically, the furnace-returning and reburning temperature can be 1000 ℃, 1020 ℃, 1040 ℃, 1060 ℃, 1080 ℃ or 1100 ℃, and the reburning time can be 1h, 1.5h, 2h, 2.5h or 3 h.

In the method, the diameter of the used core rod is less than the diameter of the inner hole of the forged piece after hole expansion in the hole closing and drawing process.

The reheating temperature is low, so that generated crystal grains are not easy to grow, and simultaneously, a core rod with the diameter smaller than the diameter of the inner hole of the forge piece is used for low-temperature hole closing and drawing-out after the reheating, and the problem that the inner surface temperature of the forge piece is high due to the fact that the space between the core rod and the forge piece after hole expansion is large and heat dissipation is fast is solved.

In the method, the heat treatment process is a cyclic phase-change fine-grain heat treatment; the circulating phase-change fine grain heat treatment comprises primary air cooling, secondary air cooling and third air cooling; preferably, the first air cooling temperature is 930-. The second air cooling temperature is 880-920 ℃, specifically, 880 ℃, 890 ℃, 900 ℃, 910 ℃ or 920 ℃. The third air cooling temperature is 860 ℃ to 900 ℃, and specifically, it may be 860 ℃, 870 ℃, 880 ℃, 890 ℃ or 900 ℃, for example.

Due to the complex forging process of the forge piece and the adoption of multi-heat forging, the problems of mixed crystals and coarse crystal grains can occur in the internal crystal grains. The high-strength steel adopted by the method belongs to maraging steel taking iron and nickel as a matrix, has a martensite structure at room temperature, and the martensite phase transformation is shear phase transformation, and is characterized in that a large number of microscopic defects including dislocation, stacking fault and the like are generated in the martensite structure in the shear phase transformation process. These defects, which are always present when the martensite heating is transformed back to austenite, increase the stored energy of the material, and recrystallization, which is mainly a process of nucleation and growth at a position with higher energy, is caused by the fragmentation of martensite laths and the increase of dislocation density. The high-strength steel AC3 adopted by the method is about 730 ℃, the solid solution temperature is usually 50-100 ℃ above AC3, and the austenite grains can be effectively and fully refined by adopting the cyclic phase transition fine grain heat treatment process under the condition that the high-strength steel does not need plastic deformation.

The forging method of the cylinder part solves the problems of low-power coarse grains and coarse grains of the forged cylinder part by adopting high-temperature homogenization treatment of steel ingots, upsetting-drawing forging, upsetting-punching, hole expanding of forged pieces, furnace returning and reburning, hole contraction drawing and heat treatment.

The present invention will be described in detail below by way of examples, but the scope of the present invention is not limited thereto.