合金元素对针阀体用钢淬火组织及性能的影响

Effect of Alloying Elements on Microstructure and Properties of Needle Valve Body Steel

为了提高针阀体的服役性能,在18Cr2Ni2钢的基础上分别添加微量Nb元素和适量Mo元素,采用DIL805A型热膨胀仪,表征、分析了合金元素对18Cr2Ni2钢870~1020℃淬火后组织性能的影响。研究结果表明:18Cr2Ni2钢作为本质细晶粒钢,添加微量Nb后原奥氏体晶粒轻微细化,细晶强化使淬火硬度及强韧性提高;添加适量Mo后,原奥氏体晶粒明显细化,Mo元素的固溶及细晶强化显著提高了针阀体的淬火硬度和强韧性。

Influences of Nb/Mo on microstructure and properties of hardened 18Cr2Ni2 steel were studied in order to optimize the service performance of needle valve body.The Nb/Mo modified steel specimens were quenched at 870-1020℃with DIL805 Athermal dilatometer.The results show that the original austenite grain is slightly refined by a little Nb addition and its strength and toughness are also slightly improved as compared with that of 18Cr2Ni2 intrinsic fine grained steel.An appropriate amount Mo addition remarkably refines original austenite grain of the needle valve body steel.Both hardness and toughness are increased obviously due to the grain refinement and Mo element solid solution.