冷旋减薄对镍基合金材料性能的影响

Research on properties of spinning cylinder with Ni-based alloy

针对高性能镍基合金,用冷旋减薄工艺成形的无缝薄壁筒形工件替换传统的卷焊成形,可免除焊缝对其服役性能的弱化,但需要评价冷减薄旋压对镍基合金挤压管性能的影响。对筒形件进行减薄率分别为50%和80%的减薄旋压,通过金相检测、拉伸实验和电化学腐蚀实验分析表明:挤压管坯材料经旋压减薄后,出现高度碎裂的晶粒组织;抗拉强度大幅度提升,延伸率下降;抗腐蚀性能降低。减薄旋压并经固溶退火后,材料晶粒明显细化,排列规则有序;由于消除了残余应力抗拉强度降低,延伸率提升,耐腐蚀性提高,整体性能优于挤压坯料。

In the high-performance nickel base alloy, traditional seamless tubes formed with the roll welding process are replaced by those formed with the spinning process, which can avoid the performance of welded joints having been weakened. However, the assessment of spinning′s impact on the performance of spinning nickel alloy extruded tubes is indispensable during the whole process. The ultra-thin-wall large radius-thickness ratio nickel-based alloy cylinder in this thesis is reduced by 50% and 80%.The results analysis of metallographic test, tensile test and electrochemical corrosion test show that highly-refined crystalline grains appear on the surface of extruded blanks, with an upsurge of the tensile strength and a decrease of elongation and corrosion resistance . While after the annealing process, the crystalline grains are obviously refined and rank in an ordered sequence. Since the remaining stress has been eliminated the tensile strength decreases while the elongation and corrosion resistance is elevated, showing a performance relatively prior to the extruded blanks.