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文章用插销试验方法研究了WB36(15NiCuMoNb5)钢热影响区的冷裂纹敏感性,预热对热影响区淬硬程度和临界断裂应力的影响,并分析了冷裂纹断口特征。研究结果表明:WB36钢的热影响区有一定的淬硬和冷裂倾向;大拘束度条件下焊接时,需要预热到120℃以上才能防止冷裂纹;避免HAZ冷裂纹的临界最高硬度值为350HV;冷裂纹断口形貌为沿晶和氢致准解理穿晶并存,晶界与晶内都出现了二次裂纹,呈典型的氢致脆性断裂特征。
The influence of cold crack susceptibility of WB36 (15NiCuMoNb5) heat affected zone, preheating on the degree of hardening and the critical fracture stress in heat affected zone (HAZ) were studied by means of plug test method. The fracture characteristics of cold crack were analyzed. The results show that: the heat-affected zone of WB36 steel has some tendency of quenching and cold cracking; when welding under large restraining conditions, it needs to be preheated to above 120 ℃ to prevent cold crack; the critical maximum hardness of HAZ cold crack is 350HV. The morphology of the cold crack fracture was intergranular and hydrogen-induced quasi-cleavage. The secondary cracks appeared in the grain boundary and in the grain boundary, showing a typical hydrogen-induced brittle fracture.