40SiMnV非调质钢强韧性的研究

RESEARCH ON STRBNGTH AND TOUGHNESS OF THE MICROALLOYED MEDIUM CARBON STEEL 40SiMnV

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，疲劳特性等力学性能的影响。研究表明，本钢具有与４０Ｃｒ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，建立了力学性能与微观组织参数间的数学模型。最后，本文对非调质钢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力学性能的热加工工艺优化原则。

AbstractThis article deals with the hot-working effects on the microstructure,ordinary mechanical properties,foracture toughness and fatigue feature of the microalloyed medium carbon stee1 40Simnv.It is found on research that tbe strength,fatigue limit and many times impact resistance with low energy of this steel are similar to that of 40Cr steel under the state of quenching and tempering,but the toughness much lower than that of 40Cr.The strength and toughness of mi- croalloyed medium carbon steel could be controlled by the quantily of pearlite or pro-eutectoid ferrite,the grain size and the precipitating ability of pro-eutectoid ferrite,while the microstruc- ture factors of pro-eutectoid ferrite depend on the prior austenite grain diameter, cooling rate and hot-working ways(rolling, forging and normarlizing).The math modal between the me- chanical proprties and microstructure factors could be established. The property characteristic and the application of microalloyed medium carbon steel are discussed, the optimizing principles of hot-working technologies by whiche better overall mechanical properties could be obtai- ned are proposed in the end.