含硫易切削模具钢高温热塑性行为探讨  

Discussion of high temperature ductility behavior of sulfur-containing free-cutting die steel

作　　者：陈登国[1] 廖桑桑[2] 徐李军 仇圣桃[3] 冯小明[2] CHEN Deng-guo;LIAO Sang-sang;XU Li-jun;QIU Sheng-tao;FENG Xiao-ming(The Second Steel Plant,Xinyu Iron and Steel Group Co.,Ltd.,Xinyu 338001,Jiangxi,China;Technology Center,Xinyu Iron and Steel Group Co.,Ltd.,Xinyu 338001,Jiangxi,China;National Engineering Research Center of Continuous Casting Technology,CISRI,Beijing 100081,China)

机构地区：[1]新余钢铁集团有限公司第二炼钢厂,江西新余338001 [2]新余钢铁集团有限公司技术中心,江西新余338001 [3]钢铁研究总院连铸技术国家工程研究中心,北京100081

出　　处：《中国冶金》2020年第5期58-64,共7页China Metallurgy

摘　　要：为研究易切削模具钢高温热塑性,利用热膨胀仪分析了该材料在不同冷速下的微观组织转变规律及相变点,并绘制了CCT曲线;利用Gleeble-3800试验机模拟研究材料高温拉伸断裂行为,结合断口形貌分析材料热塑性规律。试验结果表明,该材料高温热塑性存在明显的3个区域,分别为第3脆性区、韧性区和第1脆性区。试验钢在950~1 150℃范围内变形性能最优,为高温塑性区;950℃以下为第3脆性区,断口形貌为韧窝和解理,且随着变形温度的升高,韧窝数量增多,伸长率增加,直至950℃拉伸后断口形貌基本上全为韧窝;1 300℃及以上为第1脆性区,伸长率随变形温度升高而下降。提高冷却速率,会增加冷却过程中奥氏体内部的热应力,导致在相同温度下变形时伸长率较低冷却速率时小。In order to study the high temperature hot plasticity, the microstructure evolution and transformation point under different cooling rates for free cutting die steel were investigated using a dilatation equipment to draw CCT curve. The high-temperature tensile fracture behavior was carried out using a Gleeble-3800 hot simulation testing machine. Combined with the fracture morphology, the hot ductility rules were investigated. The experiment results showed that there were three zones for the hot ductility curves, which were the Ⅰ brittle zone, the hot ductility zone and the Ⅲ brittle zone, respectively. The tensile property for the experimental steel deformed at 950-1 150 ℃ was best, which was in the hot ductility zone. Below 950 ℃, it was the Ⅲ brittle zone. The fracture morphology was dimples and cleavages. With the increase of temperature, the dimple quantity increased and the ductility turned better. Until to 950 ℃, the fracture morphology was whole dimples. When the temperature range was above 1 300 ℃, it was the Ⅰ brittle zone, the elongation rate decreased with temperature. Increasing the cooling rate, the stress formed in the austenite during cooling increased, which caused the elongation decreased compared to the lower cooling rate.

关 键 词：易切削模具钢 高温热塑性 CCT曲线 冷速 

分 类 号：TG142.1[一般工业技术—材料科学与工程]