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以智能耐火钢Q420FRE为研究对象,采用Gleeble3800热模拟试验机对其焊接热影响区组织转变及焊接性进行研究,并对40、60 mm厚的Q420FRE钢板进行了斜Y坡口焊接裂纹试验。结果表明,Q420FRE智能型耐火钢,在较大的冷却速度范围内(3~600 s),组织主要为粒状贝氏体,硬度值HV_(0.2)186.7~207.4,变化不大。在较大的线能量输入焊接,焊接热影响区粗晶区组织稳定,性能稳定。40、60 mm的Q420FRE钢板采用BHG-2焊丝气体保护焊,防止焊接冷裂纹产生的预热温度分别为50、75℃。
Taking the intelligent fire-resistant steel Q420FRE as the research object, the microstructure and weldability of the heat-affected zone (HAZ) were studied by using the Gleeble3800 thermal simulation machine. The crack test of the oblique-Y groove was carried out on the 40 and 60 mm thick Q420FRE steel. The results show that the microstructure of Q420FRE intelligent refractory steel is mainly granular granular bainite with a hardness value of HV 0.218 to 207.4 at large cooling rate (3 ~ 600 s), with little change. In the larger input of energy input welding, heat-affected zone coarse grain crystalline organization, stable performance. 40,60 mm Q420FRE steel with BHG-2 wire gas shielded welding, to prevent welding cold crack preheating temperature was 50,75 ℃.