关键词: 淬火硬化;电子束焊;真空焊;预热;回火

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