冷变形低碳马氏体钢的回火塑性

Effect of cold deformation and tempering on ductility of low carbon martensite steel

研究回火温度对15钢冷变形低碳马氏体塑性的影响。获得板条马氏体的试样经大量冷拔变形后在200-600℃进行了回火处理并测试了抗拉强度和伸长率。结果表明,随回火温度的提高拉伸强度连续降低,且伸长率在200-500℃范围内始终保持不变,当回火温度超过500℃后伸长率才开始急剧上升。而未冷变形的低碳马氏体钢在同温度范围回火时其伸长率随回火温度的提高连续增长。透射电镜分析结果表明,这种冷变形低碳马氏体的回火特性是,由于马氏体再结晶晶界上大量析出渗碳体所致。

The effect of tempering temperature on the ductility of cold-deformed low carbon martensite steel was investigated. The sample with lath martensite microstructure was heavily cold-drawn first, and then was tempered at 200℃ to 600℃ . The tensile strength and elongation were measured. The results show that the tensile strength of the steel decreases continuously with increase of tempering temperature. The elongation of the steel tempered at 200℃ to 500℃ remains constant and increases dramatically over 500℃ . In comparison, when the non-deformed low-carbon martensite steel is tempered at the same temperature range, its elongation increases continuously with the increase of temperature. It is demonstrated from TEM observation that the precipitated cementites along the grain boundaries of recrystallized martensite are responsible for the tempering characteristics of the deformed martensite.