舵杆用Q345D钢热处理工艺对组织和性能的影响

Effect of Heat Treatment Process on Structure and Mechanical Properties of Steel Q345D for Rudder Stock

试验研究了Q345D级钢(%:0.18C、0.41Si、1.34Mn、0.05Nb、0.08V、0.024A1)Φ280 mm锻材淬-回火处理和正火处理后的组织和性能。结果表明,经890℃空冷200 s,水冷+570℃回火后的钢抗拉强度R_m≥630MPa,屈服强度R_e≥455 MPa,-20℃冲击功A_(KV) 28～40 J;910℃空冷正火后R_m≥575 MPa,R_e≥390 MPa,-20℃A_(KV)42～59 J,均满足舵杆产品对力学性能的要求;淬-回火工件距表面30 mm的组织为回火索氏体+粒状贝氏体,中心组织为珠光体+少量粒状贝氏体,正火处理后工件表面与心部均为珠光体+铁素体组织。

The structure and properties ofΦ280 mm forgings of steel Q345D（%：0.18C,0.41Si,1.34Mn, 0.05Nb,0.08V,0.024Al） after quenching ＋ tempering treatment and normalizing treatment have been tested and studied. Results show that with 890℃air cooling for 200 s,then water cooling ＋ 570℃tempering the steel tensile strength R_m is≥630 MPa,yield strength R_e is≥455 MPa and impact energy A_（KV） at -20℃is 28～40 J;with normalizing at 910℃air cooling,the R_m,R_e and -20℃A_（KV） of steel are respectively≥575 MPa,≥390 MPa and 42～59 J,all the mechanical properties meet the requirement for rudder stock product;the structure at depth 30 mm from surface of quenched-tempered rudder stock piece is tempered sorbite ＋ granular bainite,at center it is pearlite ＋ minor granular bainite,and all the structure at surface and center of normalized rudder stock piece is pearlite ＋ ferrite.