Multi-stage gradient heat treatment method for high-strength tie rod forgings

By employing a multi-stage gradient heat treatment method, the stress problem caused by temperature gradients in high-strength tie rod forgings was solved, achieving uniform internal structure and stress release, thereby improving product qualification rate and service life.

CN122405949APending Publication Date: 2026-07-17XUANCHENG LONGHU PRECISION TECH CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
XUANCHENG LONGHU PRECISION TECH CO LTD
Filing Date
2026-04-27
Publication Date
2026-07-17

AI Technical Summary

Technical Problem

During the uniform cooling process, high-strength tie rod forgings are prone to longitudinal cracks and local deformation due to the temperature gradient differences between the surface and the core, and between the rod body and the joint. This can affect the product qualification rate and service life, and even cause safety accidents.

Method used

A multi-stage gradient heat treatment method is adopted, including forging pretreatment, differentiated gradient holding and three-stage gradient cooling, combined with a dedicated heat treatment furnace with zoned temperature control and inert gas protection, to precisely control the temperature and cooling rate at each stage, ensuring the uniformity of the internal structure of the forging and stress release.

Benefits of technology

It significantly reduces the incidence of longitudinal cracks in forgings, improves product qualification rate and service life, meets the mechanical performance and stability requirements of high-strength tie rod forgings, and enhances load-bearing stability and operational reliability.

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Abstract

本发明公开了高强度拉杆锻件多段式梯度热处理方法,包括以下步骤:S1、锻件预处理:终锻后30min内将锻件转移至专用热处理炉,转移过程避免锻件表面损伤,采用高压空气吹除、机械打磨或高压水冲洗的一种或组合方式清理锻件表面氧化皮、氧化渣及油污,保证表面无杂质、损伤。本发明三段式梯度降温工艺通过精准控制各阶段的降温速度,完美适配锻件内部的相变规律和应力释放需求,降低了锻件表面与心部、杆身与接头之间的温度梯度,减少了热应力和组织应力的集中,将锻件纵向裂纹发生率降低至0.5%以下,提升了产品合格率,通过应力释放区的缓冷处理,可进一步消除锻件内部的残余应力,避免后续使用过程中因应力释放导致的裂纹扩展,延长锻件的使用寿命。
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