退火和平整工艺对08Al钢冷轧包芯线用冷轧薄带力学性能的影响

试验研究了退火工艺(820℃连续退火,670℃罩式退火和730℃罩式退火)和平整延伸率(0.8%,1.2%和1.5%)对包芯线用08Al钢(0.07%C,0.05%Al,0.0040%N)0.4 mm冷轧薄带组织和性能的影响。结果表明,连续退火薄带组织为铁素体+珠光体,屈服强度(300 MPa)和屈强比(0.78)高,延伸率(35%)较低,塑性差,不适合压制成形;730℃罩式退火薄带晶粒粗大,不均匀,成形性能差;670℃罩式退火薄带组织为再结晶铁素体和呈点链状的游离渗碳体,屈服强度(252 MPa)和屈强比(0.69)低、延伸率(48%)较高,成形性能好;随平整延伸率的增加,屈服强度和屈强比先降低后升高,延伸率下降。合适的平整率应控制在1.2%左右,成形性能最佳,应用效果良好。

Influence of Annealing and Flattening Process on Mechanical Properties of Steel 08Al Cold-Rolled Thin Sheet for Clad Wire

The influence of annealing processes ( continuous annealing at 820 ℃, bell type annealing at 670 °C and at 730 °C ) and flattening elongation (0.8% , 1.2% and 1.5% ) on structure and mechanical properties of 0.4 mm cold- rolled thin sheet of 08Al steel (0. 07% C, 0.05% Al, 0.004 0% N) for clad wire has been tested and studied. Results show that the structure of continuous-annealed thin sheet is ferrite + pearlite, it has higher yield strength (300 MPa) and strength-yield ratio (0. 78) , lower elongation (35% ) and poor plasticity, not suitable to press and shape; of bell type annealed at 730 °C the grains are coarse and uneven with poor shaping performance ； of bell type annealed at 670 °C the structure of thin sheet is recrystallized ferrite and particle- or chain-shaped free cementite, it has lower yield strength (252 MPa) and strength-yield ratio ( 0. 69) , higher elongation (48% ) and nice shaping performance; with increasing flattening elongation the yield strength and strength-yield ratio decrease first and then increase, and the elongation decreases, the suitable flatting elongation is about 1. 2% with nice shaping performance and better application results.