65Mn钢丝超细晶粒形变热处理工艺及其性能

Proccss and Propeyties of Ultra-Fine Grained LTMT 65Mn Spring Steel Wire

采用超细晶粒与形变热处理复合工艺,研究了原始组织为铅淬索氏体、冷拔变形为50%—78%的65Mn钢丝进行形变热处理时的工艺,以及各项工艺参数对钢丝力学性能的影响。试验证明:工艺参数中起控制作用的为预冷变形度、热拉丝形变度、加热速度和回火温度。奥氏体化温度及分级冷却时间可在较大范围内变化而不影响性能。处理后钢丝(φ≤3.0mm)的性能可达σ_b≥2 000MPa,?≥50%超高强韧水平,相应高出国标规定550MPa和7%,与瑞典Garphyttan公司OTEVA-31规定相比,σ_b和?也分别高出300—400MPa和2%。这时钢丝的相应晶粒度为11—13级。

The influences of the process parameters of the combination process of ultra-finegrained and low temperature thermal mechanical treatment(LTMT) on the mechanicalproperties of 65 Mn steel wire fine pearlitic structure after 50%-78% cold drawn havebeen studied. Testing results show that the controlling parameters are degrees ofdeformation of cold drawing and hot drawing during LTMT, heating speed and tem-pering temperature. Austenitizing temperature and immersion time during martemperingshow minor influence. The 65Mn steel wire (dia.≤3mm) after trcatment is of σ_b≥2000MPa ψ≥50%, Which exceed the oil tempering treated wire (domestic standard)～500MPa and 7%, and in comparison with OTEVA-31 OF GARPHYTTAN WIRE OFSWEDENσ_b and ψ% exceed 300-400 MPa and 2% corraspondingly. Grain size of thetreated wire is ASTM 11-13 grade.