合金设计对高强HFW焊管用钢强度和韧性的影响

通过对0.08%～0.15%的C-Cr-Mo-B系以及0.15%～0.20%C-Cr-Mo系试验钢组织和性能研究,得到高强HFW焊管用钢合金设计的基本特征——低碳、超低碳的多元微合金设计,着重分析了C含量对组织和性能的影响以及Nb,Mo和B等元素的作用。结果表明,C含量对高强HFW焊管用钢的组织和性能有较大的影响,能够显著提高强度,但会使组织中具有较多的碳化物,对韧性非常不利;Nb,Mo和B等元素具有提高淬透性、实现固溶强化、析出强化和细化晶粒的明显作用。低碳设计是提高韧性的重要因素,通过优化合金设计可以得到P110和Q125高强韧性HFW焊管用钢。

Effect of Alloy Design on Strength and Toughness of High Strength HFW Welded Pipe Steels

Based on the research of microstructure and properties of 0.08%-0.15% C-Cr-Mo-B series and 0.15%-0.20% C-Cr-Mo series of tested steels, the basic characteristics of alloy design of high strength HFW welded pipe steels is gained, which is low carbon content and ultra carbon content, muhi-microalloying design. The influence of carbon content on microstructure and properties, the roles of Nb, Mo and B are emphasized analyzed. The result showed that carbon content on the microstructure and properties of high strength HFW welded pipe steels has a great influence. The carbon element can remarkably improve the strength, but will lead to more carbides exist in microstructure, is very adverse to toughness. The elements of Nb, Mo and B have several obvious effects, such as improving hardenability, realizing solid solution strengthening, precipitation strengenthing and refining grain. Low carbon content design is the important factor to improve toughness. And through optimization of alloy design, the high strength and toughness I-IFW welded pipe steels of P110 grade and Q125 grade can gained.