Strengthening and toughening treatment method of steel and iron material

Abstract

The invention provides a strengthening and toughening treatment method of a steel and iron material. Subcritical quenching and subzero treatment are combined, the steel and iron material is subjectedto subcritical quenching treatment, a microstructure is a ferrite and martensite biphasic structure, then, tempering treatment is carried out, quenching stress can be reduced, meanwhile, the effect ofprecipitation of certain carbide can be achieved, the subzero treatment is carried out, a ferritic structure can be refined, the ferrite-martensite orientation relationship can be improved, the phenomenon that in the use process of the steel and iron material, due to a rough and uneven structure, the use property of a workpiece is reduced can be avoided, the toughness of the steel and iron material can be effectively improved, the subzero treatment is carried out after tempering, the influence of the subzero treatment on supersaturated martensite decomposition in the tempering treatment process can be avoided, meanwhile, through the shrinkage effect of crystal lattices at the low temperature, precipitation of carbide particles can be further promoted, and the strength and the hardness ofthe steel and iron material can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of material processing technology, in particular to a method for strengthening and toughening steel materials. Background technique [0002] Combining high strength and high toughness is essential for most structural steel materials. However, usually, the strength and toughness of steel materials are a pair of contradictions, that is, improving one is at the expense of the other. The purpose of strengthening and toughening steel is to coordinate and unify this pair of contradictions, so that steel materials can obtain higher strength and toughness at the same time. [0003] Ferrite has good toughness and plasticity, and a certain amount of ferrite in steel can hinder the initiation and propagation of cracks and play the role of toughening materials. Based on this, sub-temperature quenching is to heat the steel to the two-phase region for quenching, and retain 15% to 20% of undissolved ferrite in the micros...

AI Technical Summary

Problems solved by technology

[0005] However, the above method does not directly combine sub-temperature quenching and cryogenic treatment in the process, it mainly focuses on the refinement of martensite structure, and does not involve the optimization of ferrite structure, and the existence of ferrite has great influence on the quality of steel materials. The toughening effect is more obvious

Therefore, this method does not give full play to the technological advantages of sub-temperature quenching

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