Q345—J圆筒裂纹分析

Analysis on Q345-J Barrel Cracking

对不同厚度规格的Q345—J圆筒上的两种裂纹缺陷试样进行了金相等分析。结果表明,40mm规格的圆筒端部焊接处存在严重的夹渣是弯制圆筒过程中产生裂纹的主要原因。36mm规格的圆筒在弯制过程中产生裂纹则是由于端部冷剪切面存在严重的剪切缺陷(台阶、小裂纹及尖角等)、残余应力以及硬度偏高造成的。

Metallographical examination has been made on two different types of samples having cracking defects taken from Q345-J barrels of two different gauges.Results show that extremely serious slag carry-over existing at the welded joint of 40?mm barrel end is the primary cause to the cracking occurring in the process of bending the barrel while cracking of 30?mm barrel taking place in bending results mainly from the severe shearing defects(terrace,tiny crack and sharp angle...etc.)at the cold shearing face of the barrel end,the residual stress and higher hardness.