摘要
研究了300M超高强度钢电子束焊接接头在油淬、正火1油淬、正火2油淬三种焊后热处理状态下的室温拉伸及冲击性能,并与母材油淬状态下的室温拉伸及冲击性能进行了对比。对三种焊后热处理工艺下的接头组织及冲击断口进行了扫描电镜观察。结果表明:焊后热处理并没有消除焊缝中粗大柱状晶组织,但是正火油淬工艺使柱状晶轮廓及焊缝与热影响区的分界变得模糊。接头正火2油淬状态的强度、塑性和冲击韧度明显优于接头油淬状态。与母材油淬状态相比,正火2油淬状态接头的抗拉强度更高,伸长率及断面收缩率分别达到前者的93.6%和81%,冲击韧度与前者相当。接头油淬状态冲击断口表面沿裂纹扩展方向有大量柱状晶被撕裂并翘起,粗大柱状晶沿晶开裂。
The microstructure, tensile properties and Charpy V-notch impact toughness at room temperature of electron beam welded joints of 300M steel in the oil quenching ＋ tempering （WOQ） , Normalizing 1 ＋ oil quenching ＋ tempering （WN1OQ） and Normalizing 2 ＋ oil quenching ＋ tempering （WN2OQ） conditions have been investigated. And the mechanical properties of post weld heat treated joints were compared with base metal of oil quenching ＋ tempering （ BOQ）. Mierostructure and impact fraetography are investi- gated by SEM. Results indicate that these PWHT processes can＇t eliminate coarse columnar grains in weld metal, but the PWHT processes of WN1OQT and WN2OQ make the columnar grains morphology and the boundaries between weld metal and HAZ indistinctly. Mechanical properties of WN2OQ are significantly improved in comparison with WOQ. WN20Q have higher ultimate tensile strength than BOQ, elongation and reduction of area reach 93.6% and 81% of the latter respectively and impact toughness is not less than BOQ. Impact fractography of WOQ is rough and columnar grains are pulled apart. Crack propagation is along with the columnar grain boundaries in some regions, this is the reason why oil quenched weld joints have a low impact toughness.
出处
《航空材料学报》
EI
CAS
CSCD
北大核心
2012年第5期26-31,共6页
Journal of Aeronautical Materials
关键词
超高强度钢
电子束焊接
焊后热处理
力学性能
ultra-high strength steel
electron beam welding
post-weld heat treatment
mechanical properties
作者简介
张同栋（1987-），男，硕士，主要从事钛合金、超高强度钢电子束焊接接头组织、性能及疲劳断裂行为的研究，（E—mail）zzggdd2010@163．com
通讯作者：杨新岐，男，教授，（E—mail）xqyang@tju．edu．cn。
