Nb对C38+N2非调质钢组织和力学性能的影响  

Effect of Nb on microstructure and mechanical properties of non-quenched and tempered steel C38+N2

作　　者：余大江[1] 高加强[1] 赵四新[1] YU Da-jiang;GAO Jia-qiang;ZHAO Si-xin(Research Institute,Baoshan Iron and Steel Co.,Ltd.,Shanghai 201900,China)

机构地区：[1]宝山钢铁股份有限公司中央研究院,上海201900

出　　处：《中国冶金》2021年第5期92-97,共6页China Metallurgy

摘　　要：针对曲轴用新型铁素体+珠光体型非调质钢C38+N2锻件组织中铁素体含量往往难以达到用户要求的问题,研究了微量Nb元素(质量分数为0.022%)对其锻造后组织和力学性能的影响规律。结果表明,C38+N2钢中添加微量Nb能够细化晶粒和锻后组织,显著地提高组织中的铁素体含量,模拟曲轴锻造后组织中的铁素体体积分数可达到20%,较未加Nb钢提高了一倍。钢中添加微量Nb后,锻件的强度基本未变或略有提高,但塑韧性得到提高。两种不同锻造工艺的试验结果表明,添加微量Nb元素后的锻造组织受锻造工艺和锻后冷却速度影响的程度较小,可在较宽的工艺窗口下获得满足用户要求的组织和性能。The volume fraction of ferrite in the forged crankshaft of newly developed ferritic + pearlitic non-quenched and tempered steel C38+N2 is often difficult to meet the requirement of customers. Therefore, a small amount(0.022%) of microalloying element Nb was added to the steel and its effect on microstructure and mechanical properties after forging were investigated. The results showed that the addition of Nb can refine the grain size and post-forging microstructure, and significantly increase the ferrite content in the microstructure. The volume fraction of ferrite in the microstructure of simulated crankshaft forging can reach 20%, which was twice as high as that of non-Nb steel. After the Nb addition, the strength of the forged steel was almost unchanged or increases slightly, while the ductility especially the impact toughness were improved. The results of two schedules of simulated forging revealed that the as-forged microstructure of the Nb-added steel was slightly influenced by the changes of forging schedule and post-forging cooling rate, and the microstructure and mechanical properties meeting the requirements of users can be obtained in a wide forging window.

关 键 词：C38+N2非调质钢 NB 控锻控冷 微观组织 力学性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程]