ER50-6焊丝钢拉拔过程中轴向铁素体织构演变

Ferrite axial texture evolution of ER50-6 steel wire during drawing process

采用DIL805A热膨胀仪研究了ER50-6焊丝钢的奥氏体连续冷却转变曲线(CCT曲线),并利用EBSD技术分析比较了五种拉拔变形量下沿轴向铁素体织构的演变规律及各织构组分变化情况。结果表明,ER50-6焊丝钢的相变点温度分别为Ac 1=732℃,Ac3=865℃,在现场实际冷却速度情况下ER50-6焊丝钢是由'铁素体(F)+珠光体(P)+贝氏体(B)'三相组成,随着拉拔变形量的增加,铁素体晶粒沿轴向发生转动,立方{100}【001】取向和旋转立方{100}【011】为较为稳定的取向,在形变过程中基本维持了晶粒的形状和百分含量;{111}面上的{111}【1 10】,{111}【11 2】及{110}【1 10】取向随着拉拔变形量的增加织构组分随之增加。各拉拔道次样品相邻晶粒间取向差主体为0°~5°之间的小角度晶界,随着拉拔道次的增加,相邻晶粒晶界间取向差角分布基本维持不变,非相邻晶粒间取向差主要分布在45°~50°范围之内,随着拉拔道次的增加非相邻晶粒间取向差分布逐渐向更大角度过渡。

DIL805A dilatometer was used to study the continuous cooling transformation curve( CCT curve) of ER50-6 welding wire steel,and EBSD was used to analysisthe changes of evolution rule and the texture component of the ferrite after five drawing pass along the axial deformation. The results show that,the phase transition point temperatures of ER50-6 welding wire steel is Ac1= 732 ℃,Ac3= 865 ℃,andthe three phase composition of ' ferrite( F) + bainite( B) + pearlite( P) ' will be get under the process conditions in this paper,ferrite grains to rotate axially with the increase of the drawing deformation,{ 100} < 001 > orientation and { 100} < 011 > orientation are relatively stable orientations,the grain shape,size and the percentage content are maintained after deformation process; the component of{ 111} < 1 10 >,{ 111} < 11 2 > which on { 111} planesand { 110} < 1 10 > texture increase with drawing pass. The misorientation between neighboring grains of each drawing samples subject to 0°-5° is the small-angle grain boundaries,with the increase of drawing pass. The misorientation between adjoining grains essentially unchanged,Non adjacent grain misorientation mainly distributed within the range of 45°-50°,the increase in non adjacent grain misorientation distribution transits to a greater angle after drawing passes.