Control method for inhibiting hydrogen-induced cracks in welding of ultrahigh-strength steel without heat treatment

By adjusting the composition of welding materials and process parameters, a dual-phase microstructure of martensite and retained austenite with a low phase transformation temperature is formed, solving the problem of hydrogen-induced cracking in ultra-high strength steel welding. This achieves efficient and low-cost welding, and is suitable for preheating-free welding of ultra-high strength steel with a strength of 1300MPa and above.

CN121491497APending Publication Date: 2026-02-10TIANJIN UNIV
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Patent Information

Application Number
CN202512022828.8
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-12-30
Publication Date
2026-02-10

AI Technical Summary

Technical Problem

Existing technologies are insufficient to effectively address hydrogen-induced cracking in ultra-high-strength steels of 1300MPa and above without preheating or post-weld heat treatment. Traditional methods are costly, inefficient, and have limited applicability.

Method used

By synergistically controlling the composition of welding materials and welding process parameters, under a specific dilution rate window, the weld metal can obtain a dual-phase structure with low phase transformation temperature characteristics and retained austenite. Welding is carried out using gas metal arc welding (GMAW) process, and the welding heat input and dilution rate are controlled to form a dual-phase structure of martensite and retained austenite.

Benefits of technology

It enables efficient welding of ultra-high strength steel without preheating or post-heat treatment, reduces manufacturing costs, effectively inhibits hydrogen-induced cracking, and ensures that the strength of the welded joint matches that of the base material. It is suitable for welding in the field or large structural components.

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Abstract

The invention discloses a heat-treatment-free control method for inhibiting hydrogen-induced cracks in ultrahigh-strength steel welding, which belongs to the technical field of welding, and enables weld metal to obtain a low-phase-transition-temperature characteristic and a double-phase structure containing retained austenite under a specific dilution rate window by cooperatively regulating and controlling components of a welding material and welding process parameters. Therefore, preheating-free and post-heat-treatment-free efficient welding of the ultrahigh-strength steel is achieved. According to the method, the volume expansion effect generated by low-temperature martensite phase transformation of weld metal is utilized to actively counteract restrained tensile stress formed by welding cooling shrinkage; on the other hand, the effect of the retained austenite serving as an efficient'hydrogen trap 'is fully played, migration and enrichment of hydrogen to crack sensitive areas such as a heat affected zone or a fusion line are effectively blocked, and finally effective inhibition of hydrogen-induced cracks in ultrahigh-strength steel welding is achieved; the obtained welding joint is free of hydrogen-induced cracks and has the mechanical property level well matched with base metal.
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