【摘要】 利用热模拟压缩变形试验研究了应变速率、形变温度和应变量对Ｑ２３５级别低碳２０钢过冷奥氏体形变强化相变的组织演变规律，探讨了奥氏体晶粒控制对形变强化相变的影响，分析了组织细化的原因、结果表明，形变强烈促进过冷奥氏体相变，过冷奥氏体在８００～７４０℃温度范围名义变形量为７０％，应变速率为１ｓ－１时,可获得平均截径为２～３μｍ及小于２μｍ的铁素体细晶与珠光体混合组织；还观察到在局部细小铁素体晶粒的晶界上渗碳体以离异珠光体形式析出的现象．适当控制奥氏体晶粒尺寸有利于形变强化细晶组织的获得．更多还原

【Abstract】 The microstructure evolution during deformation enhanced transformation of undercooled austenite of a plain low carbon steel has been investigated by means of hot compression simulation experiment under the conditions of various strain rate, deformation temperature and strain. The effect of austenite grain size on the strain enhanced ferrite transformation has been studied. The experimental results showed that deformation dramatically enhanced the transformation of undercooled austenite. The microstructure with fine ferrite grain of 2-3μm and pearlite can be obtained by deformation of undercooled austenite within the temperature range of 800-740℃ and at nominal reduction of 70%. As the deformation temperature is decreased down to 740℃ the ferrite grain size is reduced to ２μm. The carbon in ferrite was supersaturated in experiment conditions. In the areas with very fine grains Fe3C was precipitated isolately at the grain boundaries. The experimental results confirmed that fine austenite grains benefit the refinement of ferrite.更多还原