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为找出4130X气瓶钢管生产过程内壁圈状裂纹产生的原因,通过裂纹缺陷分析、坯料低倍组织对比分析、穿管加热工艺对比试验、热塑性模拟试验等多方面研究,发现裂纹产生机制是:坯料中聚集的热应力、组织应力在铸坯中间柱状晶和中心等轴晶的环形交接界面叠加,当叠加到一定值且达到该值的温度正处于材料热脆温度区间时,就使坯料产生环形裂纹,穿孔时,环形裂纹内部区域由于在轴向延伸变薄,而在径向由内往外扩张,最终在管内壁留下径向圈裂缺陷,然后通过减少应力和避开应力叠加的办法加以解决。
In order to find out the reason of inner wall ring crack in 4130X gas cylinder steel tube production process, the crack generation mechanism was found through the analysis of crack defects, comparative analysis of billet microstructure, comparison test of wear tube heating process and thermoplastic simulation test. The thermal stress and the tissue stress accumulated in the billet are superimposed on the ring-shaped interface of the central columnar crystal and the equiaxed center of the billet. When the temperature that is superimposed to a certain value and reaches this value is in the range of the material hot embrittlement temperature, the billet is generated Ring crack, perforation, the inner ring crack due to the axial extension of the thinning, and in the radial expansion from the inside out, leaving the radial wall rupture defects in the pipe wall, and then by reducing the stress and avoid stress superposition approach To be solved.