冷作形变强化非调质钢紧固件的低温韧性

Low temperature toughness of non-quenched and tempered steel fasteners strengthened by cold deformation

利用金相显微镜、扫描电镜、低温冲击试验方法研究了冷作形变对非调质钢紧固件线材低温韧性的影响。结果表明,随变形量提高,铁素体和珠光体沿拉拔方向伸长;形变减面率从28%提高到37%,韧脆转变温度从-25℃升至-15℃,这主要归因于冷变形引起的亚结构和晶界夹角的变化。

Effect of cold deformation on low temperature toughness of non-quenched and tempered steel for fastener was investigated by metalloscope, SEM and low temperature impact testing method. The results show that ferrite and pearlite extends along the drawing direction with the increase of deformation. It is found that the ductile-brittle transition temperature is increased to - 15 ℃ from - 25 ℃ when the percent reduction in area is increased to 37% from 28%. This is attributed to the appearance of sub-structure and grain boundary angle due to cold deformation.