Postweld thermal treatment process for forge pieces

A post-weld heat treatment and post-forging heat treatment technology, applied in heat treatment furnaces, heat treatment equipment, manufacturing tools, etc., can solve the problems of huge internal stress, unstable stress state, and easy cracking of temperature distribution workpieces, and achieve small deformation tendency, Refinement and uniformity of the matrix structure, the effect of reducing the tendency of welding cracks

Inactive Publication Date: 2016-10-26
ANHUI RUIJIE FORGING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Repair welding is a common process in the forging workshop, but due to the uneven temperature distribution of the weldment caused by welding, huge internal stress is generated inside the workpiece, which is prone to cracks; and the residual stress is an unstable stress state

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] Post-weld heat treatment process for forgings, which includes the following steps:

[0013] 1) During the furnace loading process, the forgings should be placed in the effective heating zone of the heating furnace, leaving a gap between the workpieces, and the influence of different forging placement methods on deformation should also be considered, such as cylindrical forgings should be placed flat; Pad iron should be placed at the bottom of the shaft forgings, and square forgings should be placed vertically;

[0014] 2) For the repair welding of forgings, it should be covered with thermal insulation cotton in time after welding to reduce temperature loss and thermal stress;

[0015] 3) The specific steps of post-forging heat treatment of block forgings are as follows:

[0016] Before the first normalizing, the temperature of the forging is at 600°C, keep it warm for 7 hours, then start the first normalizing by raising the temperature; raise the temperature to 950°C f...

Embodiment 2

[0019] Post-weld heat treatment process for forgings, which includes the following steps:

[0020] 1) During the furnace loading process, the forgings should be placed in the effective heating zone of the heating furnace, leaving a gap between the workpieces, and the influence of different forging placement methods on deformation should also be considered, such as cylindrical forgings should be placed flat; Pad iron should be placed at the bottom of the shaft forgings, and square forgings should be placed vertically;

[0021] 2) For the repair welding of forgings, it should be covered with thermal insulation cotton in time after welding to reduce temperature loss and thermal stress;

[0022] 3) The specific steps of post-forging heat treatment of block forgings are as follows:

[0023] Before the first normalizing, the temperature of the forging is at 650°C, keep it warm for 7 hours, then start the first normalizing by raising the temperature; raise the temperature to 910°C f...

Embodiment 3

[0026] Post-weld heat treatment process for forgings, which includes the following steps:

[0027] 1) During the furnace loading process, the forgings should be placed in the effective heating zone of the heating furnace, leaving a gap between the workpieces, and the influence of different forging placement methods on deformation should also be considered, such as cylindrical forgings should be placed flat; Pad iron should be placed at the bottom of the shaft forgings, and square forgings should be placed vertically;

[0028] 2) For the repair welding of forgings, it should be covered with thermal insulation cotton in time after welding to reduce temperature loss and thermal stress;

[0029] 3) The specific steps of post-forging heat treatment of block forgings are as follows:

[0030] Before the first normalizing, the temperature of the forging is at 630°C, keep it warm for 7 hours, then raise the temperature and start the first normalizing; raise the temperature to 940°C fo...

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PUM

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Abstract

The invention discloses a postweld thermal treatment process for forge pieces. The postweld thermal treatment process for the forge pieces includes the following steps that in the charging process, the forge pieces should be put in an effective heating region of a heating furnace, gaps are reserved between workpieces, and influences of different forge piece placing manners on deformation need to be considered, for example, the cylinder type forge pieces should be put flatly, a sizing block should be placed at the bottom of each shaft type forge piece, and the square block type forge pieces should be vertically placed; for repair welding of the forge pieces, the forge pieces should be covered with thermal insulation cotton in time after weld, the temperature loss is reduced, and therefore thermal stress is reduced; and for the situation that grain refinement is insufficient, for the thick pipe plate forge pieces, due to the smelting condition and serious segregation, internal grains are relatively coarse, one-time normalizing and one-time supercooling are needed, a base body structure is more refined and uniform, and structure preparation is made for follow-up thermal treatment and machining. Through high-temperature tempering after weld, the weld crack generation tendency is lowered greatly, the structure is stabilized, and the deformation tendency after finish machining is small.

Description

technical field [0001] The invention relates to a plate heat treatment process, in particular to a post-weld heat treatment process for forgings. Background technique [0002] Repair welding is a common process in forging workshops, but due to the uneven temperature distribution of weldments caused by welding, huge internal stress is generated inside the workpiece, which is prone to cracks; and the residual stress is an unstable stress state. When the forging is subjected to external force, it interacts with the residual stress, causing some parts of the forging to be plastically deformed, and the internal stress of the section is redistributed; when the external force is removed, the entire forging is deformed. Therefore, the residual stress obviously affects the accuracy of forgings after machining. [0003] The most common method to eliminate residual stress is high-temperature tempering, that is, heating the weldment to a certain temperature and holding it for a certain...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/28C21D1/18C21D9/50
CPCC21D1/28C21D1/18C21D9/50
Inventor 吕美莲刘春超冯宝倪吕俊吕诚
Owner ANHUI RUIJIE FORGING
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