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Post-forging heat treatment process for nickeliferous dilute alloy round steel

A post-forging heat treatment and low-alloy technology, which is applied in the field of post-forging heat treatment of nickel-containing low-alloy round steel, can solve problems such as incomplete hydrogen expansion, and achieve the effects of eliminating potential safety hazards, improving quality, and eliminating internal stress

Active Publication Date: 2011-09-14
ZHANGJIAGANG CITY GUANGDA MACHINERY FORGING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current post-forging heat treatment process does not fully diffuse the hydrogen in the forging, that is, the hydrogen expansion is not complete, so that the hydrogen content inside the forging after forging heat treatment exceeds the standard. In the actual use of this forging, there is hydrogen. The safety hazard of brittle fracture

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] 1) Air-cool the surface temperature of the forged piece to 300°C;

[0016] 2) Heat it with normalizing fire, heat the surface temperature of the forging to 650°C at a heating rate of 90°C / hour, and keep it warm for 11 hours; then, raise the surface temperature of the forging to 860°C at a heating rate of 60°C / hour ℃, keep warm for 11 hours;

[0017] 3) Hang out the forging, and carry out air cooling and mist cooling at the same time, so that the surface temperature can be cooled to 350°C within 10 minutes;

[0018] 4) Keep the temperature in the furnace to keep the surface of the forging at 350°C for 11 hours;

[0019] 5) Tempering and heating at a heating rate of 60°C / hour, the surface temperature of the forging is raised to 670°C, kept for 32 hours, and then uniformly heated for 3 hours;

[0020] 6) Embed the forgings in a sand pit with a sand thickness of 20 mm to keep warm to further diffuse the hydrogen. The holding time is 3 days, and the temperature of the sand...

Embodiment 2

[0022] 1) Air-cool the surface temperature of the forged piece to 330°C;

[0023] 2) Heat it with normalizing fire, heat the surface temperature of the forging to 650°C at a heating rate of 95°C / hour, and keep it warm for 12 hours; then, raise the surface temperature of the forging to 850°C at a heating rate of 70°C / hour ℃, keep warm for 12 hours;

[0024] 3) Hang out the forging, and carry out air cooling and fog cooling at the same time, so that the surface temperature can be cooled to 315°C within 10 minutes;

[0025] 4) Into the furnace for heat preservation, so that the surface of the forging is maintained at 315 ° C, and heat preservation for 12 hours;

[0026] 5) Tempering and heating at a heating rate of 70°C / hour, the surface temperature of the forging is raised to 660°C, kept for 35 hours, and then maintained for 4 hours;

[0027] 6) Embed the forgings in a sand pit with a sand thickness of 25 mm to keep warm to further diffuse the hydrogen. The holding time is 4 d...

Embodiment 3

[0029] 1) Air-cool the surface temperature of the forged forging to 350°C;

[0030] 2) Heat it with normalizing fire, heat the surface temperature of the forging to 650°C at a heating rate of 100°C / hour, and keep it warm for 13 hours; then, raise the surface temperature of the forging to 840°C at a heating rate of 80°C / hour ℃, keep warm for 13 hours;

[0031] 3) Hang out the forging, and carry out air cooling and fog cooling at the same time, so that the surface temperature can be cooled to 280°C within 10 minutes;

[0032] 4) Keep the temperature in the furnace to keep the surface of the forging at 280°C for 13 hours;

[0033] 5) Tempering and heating at a heating rate of 80°C / hour, the surface temperature of the forging is raised to 650°C, kept for 39 hours, and then uniformly heated for 5 hours;

[0034] 6) Embed the forgings in a sand pit with a sand thickness of 30mm for heat preservation to further diffuse the hydrogen. The heat preservation time is 5 days, and the tem...

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Abstract

The invention discloses a post-forging heat treatment process for nickeliferous dilute alloy round steel, which can enables the hydrogen in a forged piece to fully spread and escape out and comprises the following steps: 1) carrying out air cooling on the surface of the forged piece until the temperature thereof is 300-350 DEG C; 2) utilizing normalizing to heat the forged piece until the temperature thereof is 650 DEG C, carrying out heat preservation for a while, then heating the forged piece until the temperature thereof is 840-860 DEG C, and carrying out heat preservation for a while; 3) lifting out the forged piece, simultaneously carrying out air cooling and fog cooling, rapidly cooling the forged piece until the temperature thereof is 280-350 DEG C; 4) putting the forged piece intoa furnace for heat preservation, keeping the temperature of the forged piece to be 280-350 DEG C; 5) heating the forged piece until the temperature thereof is 650-670 DEG C, carrying out heat preservation for a while, and then carrying out temperature equilibrium for 3-5h; and 6) embedding the forge piece into a sand pit with the sand thickness of 20-30mm for heat preservation for 3-5 days, enabling the hydrogen to further spread, and controlling the temperature of the forged piece which is taken away from the sand to be 100-150 DEG C. The post-forging heat treatment process of the invention can enable the hydrogen in the forge piece to fully spread and escape out, thereby eliminating the potential safety hazard of hydrogen embrittlement fracture of the forged piece and improving the quality of the forged piece.

Description

technical field [0001] The invention relates to a post-forging heat treatment process, in particular to a post-forging heat treatment process for nickel-containing low-alloy round steel. Background technique [0002] In the production process of forgings, the forgings formed by forging have coarser internal grains, greater stress, and greater hydrogen content. It is necessary to refine the grains, eliminate stress and expand hydrogen through post-forging heat treatment, so that Its internal organization has been effectively changed. The current post-forging heat treatment process does not fully diffuse the hydrogen in the forging, that is, the hydrogen expansion is not complete, so that the hydrogen content inside the forging after forging heat treatment exceeds the standard. In the actual use of this forging, there is hydrogen. The safety hazard of brittle fracture. Contents of the invention [0003] The technical problem to be solved by the present invention is to prov...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D8/00
Inventor 范存学
Owner ZHANGJIAGANG CITY GUANGDA MACHINERY FORGING