00Cr12Ni双相组织不锈钢焊接接头区域特征与性能

采用熔化极活性气体保护焊(metal active gas arc welding, MAG焊)、等离子弧焊(plasma arc welding, PAW)和高频感应焊接方法获得铁素体+马氏体双相组织不锈钢00Cr12Ni的焊接接头，对其组织区域特征和力学性能进行了研究.典型的焊接接头热影响区(heat affected zone, HAZ)可分为晶粒粗大，铁素体为优势相的高温热影响区(high temperature heat affected zone, HTHAZ)和晶粒细小，马氏体为优势相的低温热影响区(low temperature heat affected zone, LTHAZ).通过测量实际焊接热循环曲线的方法确定了HTHAZ及LTHAZ的温度范围，并采用热模拟研究HAZ不同区域的力学性能.结果表明，HTHAZ的热循环峰值范围为1 200℃至熔点，晶粒粗大呈现为脆性；LTHAZ热循环峰值范围为800～1 200℃，室温组织为非平衡低碳板条马氏体，韧性较好，但低于0℃时呈脆性. MAG焊接头由于奥氏体焊缝为钟罩形，HAZ冲击试验时断面包括奥氏体焊缝，因此冲击性能较好；...

Zone characteristics of microstructure and mechanical properties of welded joints of dual phase stainless steel with 12%Cr

Researches were carried out on the zone characteristics of microstructure and mechanical properties of welding joint of 12%Cr content stainless grade named 00Cr12Ni with dual phases composed of ferrite and martensite, and the joints were welded by metal active gas arc (MAG)welding, plasma arc welding(PAW) and high frequency induction (HFI) welding. Typical HAZ of 00Cr12Ni welding joints is subdivided into high temperature heat affected zone (HTHAZ) and low temperature heat affected zone (LTHAZ). HTHAZ is characterized by predominant coarse ferritic grains while LTHAZ is characterized by predominant fine low carbon martensitic grains. The respective temperature ranges and thermal cycle curves of HTHAZ and LTHAZ were measured through practical MAG welding procedure, and respective mechanical properties of HTHAZ and LTHAZ were acquired by thermal simulation based on the thermal cycle curves measured in practical welding. Results show that peak temperature of HTHAZ ranges from 1 200 ℃ to melting point and that of LTHAZ ranges from 800 to1 200 ℃. HTHAZ exhibits brittle at room temperature for coarse grains and LTHAZ exhibits ductile at room temperature for fine grain non-equilibrium lath martensite, however it exhibits brittle at subzero. The welding seam of MAG welded joint is composed of tough austenite and bell-shaped, so the fracture surface covers austenitic weld seam in impact test hence better impact toughness. The coarse grains in welding joint of PAW can be eliminated through austenization at 1 000 ℃ followed by fast cooling, and fine grain martensite forms thus resulting in toughness improvement. Although welded joint of HFI procedure is composed of fine grain martensite, the toughness at room temperature is low for the joint due to work-hardening during welding. The toughness of HFI joint can be recovered through relief annealing.