焊接及热处理对T250马氏体时效钢
薄壁旋压圆筒性能的影响
张黎旭
吴军胡春海
温树斌
（西安航天动力机械厂，西安710025）
邵芬
文摘采用脉冲TIG焊对T250马氏体时效钢薄壁旋压圆简进行焊接，通过优化焊接工艺参数，得到了外观成形良好，内部缺陷达到QJ175一930级标准要求的焊缝。在焊前和焊后对T250马氏体时效钢薄壁旋压固简进行了热处理，研究了热处理对烊接接头金相组织、显微硬度、角变形和力学性能的影响。结果表明：时效处理后，焊缝金属枝晶晶界中存在逆转变奥氏体组织，显微硬度低于母材；熔合线附近焊楼热影响区晶粒长大，最大处晶粒约为基材的6倍；焊前时效处理大幅度减小了焊接接头角变形；在婵后对试样进行500℃时效处理的情况下，焊前时效处理使焊接接头抗拉强度和弯曲角都有所提高；焊前对旋压圆简进行500℃时效处理，焊后进行500℃时效处理，得到了最佳焊楚强初性匹配。
关键调T250马氏体时效钢，时效处理，金相组织，力学性能
中图分类号：TG407
D0I:10.3969/j.isn.10072330.2014.03.023
Infulence of Welding and Heat Treatment on T250 Maraging
Steel Thin-Walled Spinning Cylinder
ZHANGLixu
WUJun
HU Chunhai
WENShubin
(Xi'an Aerospace Power Machine Factory,Xi'an 710025)
SHAOFen
Abstract This paper adopts pulse TIG welding to weld the T250 maraging steel thin-walled spinning cylinder. By optimizing process parameters, weld joints with weld formation and intermal defects meet the requirement of QJ175 93 O grade was obtained. Heat treatment was carried out to T250 maraging steel thin-walled spinning cylinder prior to weld and post weld. The influence of heat treatment on microstructure, microhardness,angular distortion and me-chanical properties of weld joints was studied. The results showed that after aging treatment, reverted austenite exist in dendritic grain boundary in weld metal, microhardness is lower than basic metal. The grain near the fusion lion of welding heat affected zone grow and the largist grain size was 6 times of base metal. Heat treatment prior to weld de-creased the angular distortion greatly. On the premise of 500°C aging treatment post weld, aging treatment prior to weld improve the tensile strength and the bending angle. The best strength and toughness properties was obtained by 500° aging treatment prior to weld and 500°C aging treatment post weld.
Key wordsT250 maraging steel, Aging treatment,Microstructure,Mechanical properties
0引言
马氏体时效钢是超高强度钢，具有良好的成形性、时效处理变形小、时效处理后有高强韧性等优点，是要求高强度、高精度的新一代固体火箭发动机壳体的理想选材。
马氏体时效钢通常采用钨极氩弧焊和真空电子收稿日期：2014-0321
束焊焊接，为了提高焊接接头的强韧性，目前国内外主要通过焊后热处理改善焊接接头组织和性能，在焊后时效处理前对焊接接头进行高温均质化处理或固溶处理，可以得到良好的焊缝强韧性匹配，但由于温度高，热处理过程中变形严重，难以满足固体火箭发动机等形状精度高的产品的要求。此外，T250马氏
作者简介：张黎旭，1984年出生，硕士，主要从事超高强度钢焊接技术研究。E-mal：xuxu353@sina.com
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