杨帅
,
彭云
,
张晓牧
,
田志凌
,
彭展南
宇航材料工艺
采用光学显微镜、扫描电子显微镜以及Thermal-calc计算等方法分析了马氏体时效钢(C300)穿孔型等离子弧焊接(Keyhole-Plasma Arc Welding,K-PAW)过程中结晶裂纹的成因及形貌.研究认为,C300虽然具有良好的焊接性,但也会产生结晶裂纹.本试验条件下,影响高纯净C300产生结晶裂纹的主要因素是应变一温度增长速率,提高预热温度和增加线能量有利于降低结晶裂纹倾向.焊接热源对母材的预热作用有利于已形成结晶裂纹的逐步止裂.具有凸形表面的焊缝以及细小等轴晶的焊缝的结晶裂纹倾向较小.
关键词:
马氏体时效钢
,
等离子弧焊接
,
结晶裂纹
,
临界应变速率
Byung-Hui Choi
,
Byung-Ki Choi
材料科学技术（英文）
As the aircraft and aerospace industry and the automobile industry are developed, the demand of reliable materials with high strength and high toughness is steadily increased. The grain miniature method which improves the ductility and the toughness simultaneously under high strength is the miniature of the casting microstructure. In this paper, the Nb which affects the austenite grain miniature is added by 0.00%, 0.03% and 0.06% in this steel and the ingot is manufactured in a vacuum induction melting furnace (VIM). The casting microstructure and the mechanical property of the maraging steel according to Nb contents are analyzed by conducting the solution annealing and the age hardening after hot rolling. In this result, a specimen containing 0.03% Nb is most miniature. When it does the long time age hardening, the precipitation estimated as the carbide is appeared. The mechanical properties are excellent if a specimen containing 0.06% Nb does the age hardening during 8 h in 482°C.
关键词:
High strength steel
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