冷轧和退火对纯镍拼焊接头组织和力学性能的影响

Effects of cold rolling and annealing on microstructure and mechanical properties of pure nickel welded joints

对纯镍板拼焊接头进行冷轧,然后进行800~1100℃退火,通过对比分析,研究了冷轧和退火工艺对纯镍板材的组织和力学性能的影响。结果表明,经过75%变形量的冷轧加工后,拼焊接头的晶粒破碎,微观组织沿轧制方向呈线性纤维状,其抗拉强度约611 MPa,伸长率约5.6%。在800℃退火时,显微组织发生部分再结晶,但仍然存在大量拉长的线性纤维组织,抗拉强度为387.9 MPa,伸长率为20.4%;在900℃退火时,大部分线性纤维组织发生再结晶,抗拉强度为363.5 MPa,伸长率为23.7%;1000℃退火时,冷轧形成的线性纤维组织完全消失,微观组织发生完全再结晶,抗拉强度为357.5 MPa,伸长率为32.3%;在1100℃退火时,与1000℃退火时相比,微观组织变化不明显,力学性能也无明显变化,抗拉强度为355.3 MPa,伸长率为30.9%。由力学性能和微观组织综合比较可知,1000℃为最佳的中间退火温度。

Welded joints of pure nickel sheets were cold rolled and annealed between 800-1100 ℃.The effects of cold rolling and annealing processes on microstructure and mechanical properties of pure nickel sheets were studied.The results show that after cold rolling with 75% deformation,the grains of the welded joints are broken,and the microstructure is linear and fibrous along the rolling direction,the tensile strength is about 611 MPa and the elongation is about 5.6%.When annealed at 800 ℃,the microstructure is partially recrystallized,but there are still a large number of elongated linear fibers,the tensile strength is 387.9 MPa and the elongation is 20.4%.When annealed at 900 ℃ most of the linear fibers recrystallized,the tensile strength is 363.5 MPa and the elongation is 23.7%.When annealed at 1000 ℃,all the linear fibers disappeared,and the microstructure is completely recrystallized,the tensile strength is 357.5 MPa and the elongation is 32.3%.When annealed at 1100 ℃,the change of microstructure and mechanical properties are not obvious compared with annealed at 1000 ℃,the tensile strength is 355.3 MPa and the elongation is 30.9%.Compared with the mechanical properties and microstructure,1000 ℃ is the best intermediate annealing temperature.