ABSTRACT

In the current article, the influence of titanium on the hot ductility of peritectic-microalloyed steels, in the temperature range 600°C to 950°C, was investigated by tensile testing. The morphology of the fracture and the behaviour of precipitates, inclusions and microstructures near the fracture surface were observed and discussed. It was found that within the test temperature range, the reduction in area values of titanium-bearing steels were almost greater than 40%, which were much larger than those of titanium-free steels. This improvement was due to the formation of (Ti_xNb_1-x)(C_yN_1-y) precipitates and titanium-aluminium oxides with high titanium content that could act as the nucleation sites for dimples to promote the occurrence of ductile fracture. In addition, the austenite grain was refined and more uniform in size. The thickness together with the maintain temperature range of the ferrite films which distribute only along austenite grain boundaries were reduced.

摘要

在本文中，通过拉伸试验研究了钛对包晶微合金钢在 600°C 至 950°C 温度范围内的热延展性的影响。观察和讨论了断口的形貌和断口附近的析出物、夹杂物和显微组织的行为。发现在试验温度范围内，含钛钢的面积减少量几乎大于40%，远大于无钛钢。这种改进是由于 (Ti _x Nb _1-x )(C _y N _1-y) 析出物和钛含量高的钛铝氧化物，可作为凹坑的成核位点，促进韧性断裂的发生。此外，奥氏体晶粒细化，尺寸更均匀。仅沿奥氏体晶界分布的铁素体薄膜的厚度和维持温度范围都减小了。