低碳钢焊接热裂纹形成温度区的研究

STUDY OF THE TEMPERATURE RAGES OF HOT CRACKING FORMATION IN THE WELD METAL OF LOW-CARBON STEEL

低碳钢焊缝金属凝固冷却过程存在三个脆性温度区。第一个为结晶裂纹形成温度区BTRs。硫是影响BTRs大小的最主要元素,对试验用钢存在下列关系:BTRs(℃)=25+927(%S)-28(%Mn)。第二个为失塑裂纹形成温度区,各试验钢基本都在1100～800℃。提出了“富硫失塑”的形成机制。第三个脆性温度区约在600℃以下,其形成机制有待进一步研究。

There exist three brittle temperature ranges during the course of solidification and cooling process in the weld metal of Low-carbon steel. The first range is the solidification brittle temperature range (BTR_s). Sulfur is the principal element to widen the BTRs. A relationship among the sulfur and manganese in the world metal and the BTRs has been established as follows.BTR_s(℃)=25+927(%S)-28(%Mn)The second range is the ductility-dip brittle temperature range (BTR_D), which is about 1100～800℃ for the tested materials. A mechanism of the formation of BTR_D is proposed. The third BTR is below 600℃ . Its formation mechanism needs further investigation.