【摘要】 以冷拔20钢薄壁无缝管为研究对象，研究了其在不同退火工艺下的组织演变，并分析了退火处理对其力学性能的影响。结果表明：冷拔态钢管组织由沿变形方向分布的铁素体与片层状珠光体构成；经过退火处理后，珠光体含量减少，晶粒均匀化程度提高。在相同退火时间下，当退火温度为890℃时，晶粒细小且均匀性最佳，退火温度继续升高，晶粒明显长大。在相同退火温度下，随着退火时间增加，晶粒呈现逐渐长大趋势。得到最佳退火工艺为退火温度890℃,退火时间11 min,此时20钢管的抗拉强度为438～449 MPa,屈服强度为272～279 MPa,断后伸长率为34.0%～36.0%。更多还原

【Abstract】 Taking cold-drawn 20 steel thin-walled seamless tubes as the research object, the microstructural evolution under different annealing processes and the effect of annealing treatment on the mechanical properties were investigated and analyzed. The results reveal that the microstructure of the as-cold-drawn tubes consists of ferrite distributed along the deformation direction and lamellar pearlite. After annealing treatment, the content of pearlite decreases, and the degree of grain homogenization improves. When the annealing temperature is 890 ℃ under a fixed annealing time, the grains are fine and the uniformity is optimal, and as the temperature increases, the grain size grows significantly. Under the same annealing temperature, an increase in annealing time leads to a growth of the grain. The optimal annealing process for the 20 steel is determined to be an annealing temperature of 890 ℃ and an annealing time of 11 min, under which the tensile strength ranges from 438 MPa to 449 MPa, the yield strength ranges from 272 MPa to 279 MPa, and the percentage elongation after fracture ranges from 34.0% to 36.0%.更多还原