Abstract: The tendency of cold crack, overheating area embrittlement and HAZ softening of 30Cr3 ultrahigh strength steel in quenching state after vacuum electron beam welding were introduced. A series of measures such as raising vacuum level, increasing acceleration voltage, preheating before welding, choosing suitable welding speed and tempering after welding were presented based on the material property analysis. The results showed that no defect was found through metallographic analysis of weld joint. It also showed that the sample fractured plastically, weld strength factor of the sample reached as high as 0.96 and the bursting pressure of the product was more than 27MPa. Thus, with the effective measures, qualified weld joint of 30Cr3 ultrahigh strength steel in quenching state can be manufactured, which will open a new way to the production of solid rocket motor case.

Key words: Quench hardening;Electron beam welding;Vacuum welding;Preheating;Tempering

摘要： 为解决淬火状态下30Cr3超高强度钢在真空电子束焊接时易产生冷裂纹、过热区脆化及热影响区软化等问题,在对材料性能分析的基础上,采取了提高真空度、提高加速电压、焊前预热、选择合适的焊接速度以及焊后回火处理等措施。结果表明,金相分析未发现缺陷,试样断口为塑性断裂,试片焊缝强度系数达0 96,产品爆破压力pb>27MPa。证明该方法可满足设计要求的焊接接头,为固体火箭发动机壳体的生产提供了新的工艺方法。

关键词: 淬火硬化;电子束焊;真空焊;预热;回火