Q235碳素钢应变强化相变的基本特点及影响因素  

HARACTERISTICS OF STRAIN ENHANCED TRANSFORMATION AND ITS INFLUENCING FACTORS IN Q235 PLAIN CARBON STEEL

作　　者：杨平[1] 傅云义[1] 崔凤娥[1] 孙祖庆[2] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]北京科技大学新金属材料国家重点实验室,北京100083

出　　处：《金属学报》2001年第6期592-600,共9页Acta Metallurgica Sinica

基　　金：国家科技部973资助项目G1998061506

摘　　要：在热模拟单向压缩实验中，通过形变参数的变化考察了Ｑ２３５碳素钢应变强化相变的基本规律及铁素体晶粒细化效果．结果表明，铁素体的超细化在热力学上是由于应变强化相变最大限度地提高了相变过冷度，在动力学上是由于形核集中在局部的高应变区，同时在转变过程中形变不断产生新的形核地点并抑制铁素体生长的结果实现铁素体的超细化需要一最小应变量及一定的应变速率，以使转变完毕并抑制铁素体的生长及形变成长条状应变明显削弱了奥氏体晶粒尺寸的差异带来的铁素体尺寸的差异应变造成的铁素体动态再结晶进一步细化了晶粒，这种特征是动态转变所特有的此外。The characteristics of strain enhanced transformation and ferrite grain refinement are investigated under different processing parameters by thermal simulating tests of Q235 plain carbon steel. Results indicate that the ferrite refinement during strain enhanced transformation is due to the strongly increased undercooling of austenite by deformation in the viewpoint of thermodynamics. Repeated ferrite nucleation in localized high strain regions and the prevention of ferrite growth are the dynamic features of strain enhanced transformation. In order to realize ferrite grain refinement a certain amount of strain and a strain rate are needed to provide sufficient nucleation sites and restrain the growth of ferrite grains or their deformation to elongated form. Strain dramatically decreases the influence of initial austenite grain size on the following transformed ferrite grain size. Ferrite dynamic recrystallization can further refine ferrite grain size which is unique in dynamic transformation. The differences between strain enhanced transformation and normal ferrite transformation as well as traditional TMCP are discussed.

关 键 词：碳素钢 应变强化相变 晶粒细化 

分 类 号：TG142.31[一般工业技术—材料科学与工程]