Effects of Small Amount of Carbon Addition on the Transformation Texture in Extra-low Carbon Steel Sheets

样品主要为1%Mn-0.035%Ti的超低碳钢冷轧薄板，不含Nb。为了研究碳含量和加热温度对转变行为和转变织构的影响，对板材进行再结晶，然后渗碳至189ppm。(1)从γ区到冰水中淬火形成的相变结构，碳含量为16ppm时为150HV，碳含量为49ppmC时为180HV。相变组织为准多边形铁素体和/或高位错密度的中间相变相，并发育（111）取向（织构）。(2)含碳189ppm钢中板条马氏体的形成促进了（100）和（或）（110）取向的发展，（111）取向的减少。(3)中间相变相亚边界主要由非相干界面组成。(4)锰含量和溶质碳含量的增加如预期的那样加速了转化。（111）相变织构的发育与界面成熟之间的关系是非常令人兴奋的，必须对其进行研究，以阐明（111）织构的发育机制，包括相变机制的重构或位移。这些结果也提示了开发高强度和深拉伸性良好的新型钢板的可能性。

The samples mainly used are 1%Mn-0.035%Ti extra-low carbon steel cold-rolled sheets, which contain no Nb. The sheets are recrystallized and then carburized up to 189ppm, in order to examine the effects of carbon content and heating temperature on the transformation behavior and transformation texture.(1) The transformation structure formed by quenching from γ region into iced water gives 150HV for 16ppm carbon and 180HV for 49ppmC.Moreover, the transformation structure was the quasi-polygonal ferrite and/or intermediate transformation phase having high dislocation density, and the (111) orientation (texture) developed.(2) The formation of the lath martensite in the steel containing 189ppm carbon promoted the development of (100) and/or (110) orientation and the decrease of (111) orientation.(3) The subboundary of intermediate transformation phase is composed of mainly incoherent interface.(4) The increase in manganese content and solute carbon content accelerate transformation as expected.The relationship between the development of (111 ) transformation texture and the mature of interface is very stimulating and must be examined to clarify the mechanism of development of (111) texture with respect to transformation mechanism reconstructive or displacive.These results also suggest the possibility of developing new type of steel sheet having an excellent combination of high strength and good deep-drawability.