40SiMnV非调质钢强韧性的研究

本文研究了热加工工艺对40SiMnV非调质钢的金相组织、常规力学性能、断裂韧性、疲劳特性等机械性能的影响。研究表明,这种非调质钢具有与40Gr调质态相近的强度、缺口疲劳极限及小能量多冲抗力,但韧性指标较低。非调质钢的强韧性取决于金相组织中珠光体与先共析铁素体的相对含量、先共析铁素体的晶粒大小及沉淀硬化能力。先共析铁素体的组织参数受原奥氏体晶粒直径、冷却速度及热加工方式(轧制、锻造、正火)的控制。通过回归分析,建立了机械性能与微观组织参数间的数学模型。对非调质铜的性能特点及应用前景进行了讨论,并提出了获得良好的综合机械性能的热加工工艺优化原则。

Controlling Over Strength and Toughness on the Microalloyed Medium Carbon Steel 40SiMnV

This paper deals with the hot-working effects on the microstructure, general me- chanical properties, fracture toughness and fatigue feature of microalloyed medium carbon steel 40SiMnV. The results indicated that the strength, fatigue limit and multiple impact re- sistance with low energy of this microalloyed medium carbon steel are similar to those of 40Cr steel under the quenching and tempering states, but the toughness is much lower than that of 40Cr. The strength and toughness of microalloyed medium carbon steel are controlled by the quantity of pearlite or proeutectoid ferrite, the grain size and the precipitation ability of proeutectoid ferrite. The microstructure factors of procutectoid ferrite are controlled by the previous austenite grain diameter, cooling rate and hot working approaches (rolling, forging and normarlizing). The mathematical model between the mechanical properties and microstructure factors is established. The performances and future applications of mieroalloyed medium carbon steel are discussed thereby to present the optimizing principles of hot-working technologies by which the overall mechanical properties are obtained.