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A production method of austenitic stainless steel special-shaped integral large forging

A technology for austenitic stainless steel and large forgings, applied in the field of stainless steel processing, can solve problems such as grain size control, achieve the effects of refining the structure of forgings, inhibiting abnormal growth, and improving surface quality

Active Publication Date: 2016-04-27
CENT IRON & STEEL RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a production method for austenitic stainless steel special-shaped integral large forgings, which solves the problem of grain size control in the production of AP1000 main pipes and similar austenitic stainless steel special-shaped integral large forgings. Can be controlled at level 4 and above

Method used

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  • A production method of austenitic stainless steel special-shaped integral large forging
  • A production method of austenitic stainless steel special-shaped integral large forging
  • A production method of austenitic stainless steel special-shaped integral large forging

Examples

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Effect test

Embodiment 1

[0053] Example 1: Effects of electroslag ingot surface grinding and forging blanking on the thermal processing performance of steel ingots

[0054]The 3# electroslag ingot has not undergone surface grinding and forging blanking, and is directly heated at 1220 ° C for upsetting. The upsetting deformation ratio is 1.7:1, and serious cracks appear in the steel ingot; 2# electroslag ingot has not undergone surface grinding , heated at 1180°C for 11% deformation of the billet forging, and then returned to the furnace to heat upsetting at 1220°C, the upsetting deformation ratio was 1.9:1, and no cracks appeared; after surface grinding of 9# electroslag ingot, it was It was heated at 17% for open billet forging, and then returned to the furnace at 1220°C for upsetting. The upsetting deformation ratio was 2.8:1, and no cracks appeared. The results show that the surface grinding of electroslag ingot and forging billet can improve the hot workability of steel ingot.

Embodiment 2

[0055] Example 2: Influence of upsetting and elongation with large amount of deformation on the grain size of special-shaped forgings

[0056] The upsetting deformation ratio of the 7# forging is 1.5:1, and the grain size of the special-shaped forging is 3.5 (attached Figure 4 ), the upsetting deformation ratio of 2# forging is 1.9:1, and the grain size reaches 4.5 grades (attached image 3 ); the upsetting deformation ratio of 1# forging is 2.3:1, and the grain size reaches grade 5.0 (attached figure 2 ). The results show that increasing the upsetting deformation ratio can refine the grain size of forgings. Example 3: Influence of integral forging return heating temperature and deformation amount on the grain size of special-shaped forgings

Embodiment 3

[0057] The upsetting deformation ratio of 8# forging and 1# forging is basically the same, 2.2:1 and 2.3:1 respectively. The main difference is that the overall forging heating temperature and deformation are different. The heating temperature of the 8# forging is 1180°C, the deformation is 15%, and the grain size is 2.5 (attached Figure 5 ); the heating temperature of 1# forging is 1120°C, the deformation is 30%, and the grain size is 5.0 (attached figure 2 ). The results show that reducing the reheating temperature and increasing the forging deformation can refine the grain size of the forging.

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Abstract

The invention discloses a production method of an integral special-shaped heavy forging made of austenitic stainless steel, and belongs to the technical field of stainless steel machining. The process comprises the following steps of smelting which combines an electric furnace, AOD (argon oxygen decarburization) and electroslag remelting, hammer cogging, upsetting, stretching, remelting heating and forging, heat treatment, machining, cold bending or hot bending machining, heat treatment and the like. Electroslag ingot surface quality is improved through surface grinding, and an electroslag ingot casting-state structure is broken through hammer cogging, so that the hot-working character of billet steel is improved, the electroslag ingot is restrained from hammer cogging, and conditions are provided for following large-deformation upsetting and stretching. The steel ingot crystal grain size is refined through repeated large-deformation upsetting and stretching processes, recrystallized grains are restrained from abnormal growth through controlling of last flame path remelting heating temperature, forging deformation and final heat treatment process, coarse crystals and mixed crystals are avoided, the forging structure is refined, and the crystal grain size reaches a 4.0 grade or high.

Description

technical field [0001] The invention belongs to the technical field of stainless steel processing, and in particular relates to a production method of austenitic stainless steel special-shaped integral large forgings. Background technique [0002] The main pipeline is a nuclear first-class pipeline, which has an important impact on the operation function and safety of the nuclear reactor. The conventional main pipeline is welded to connect the main pipeline straight pipe, elbow and tee to form a circuit, so as to realize the function of the main pipeline. Generally speaking, the plasticity, toughness and corrosion resistance of the weld are lower than those of the base metal, and stress corrosion is prone to occur due to the existence of welding thermal stress. The welded structure of conventional main pipes reduces the safety of nuclear reactors. In order to improve safety, the AP1000 main pipeline of the third-generation nuclear power plant adopts integral forging to pro...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B21J1/02C21D8/00
Inventor 陈海涛郎宇平荣凡屈华鹏
Owner CENT IRON & STEEL RES INST
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