9%～12% Cr钢Ⅳ型开裂与软化区对比实验

Acontrast Experiment of 9%~12% Cr Steel Between Type Ⅳ Cracking and Softening Zone

选用SA335-P92钢管,采取GTAW+SMAW+SAW的焊接方法获取焊接接头,利用SAW的较大热输入,获得了具有较宽热影响区的试验接头。通过高温低应力的持久试验获取发生Ⅳ型开裂的试样,在扫描电镜下确定蠕变孔洞的出现位置,并通过测试整个热影响区显微硬度找出了软化区,比较了二者位置关系。试验表明:高温低应力下产生的Ⅳ开裂主要发生在热影响区的细晶区,其直接原因为蠕变孔洞,与热影响区的软化区没有直接关系。

This article select SA335-P92 steel, and take GTAW ＋ SMAW ＋ SAW welding method to get the welded joints with a wide heat-affected zone based on SAW s larger heat input. The creep test specimens with type IV cracking were prepared, under conditions of high temperature and low stress. By using the SEM, ascertained the position of the creep voids. At the same time, the position of the softening zone was found by the hardness test of the entire HAZ. After the compari- son of the above positional relationship, the following conclusions： type IV cracking under high tem- perature and low stress generated mainly occurred in the FGHAZ, directly caused by the creep voids, and the softening zone in the HAZ is not directly related.