不锈钢板翅结构钎焊残余应力对蠕变的影响
Effect of brazing residual stress on creep for stainless steel platefin structure
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摘要: 利用有限元法,对微小尺寸的镍基钎焊不锈钢板翅结构进行600℃下的蠕变有限元分析,讨论钎焊残余应力对蠕变变形的影响。结果表明,由于镍基钎料BNi-2和不锈钢母材SS304力学性能的差异以及钎焊夹具的约束作用,钎焊后在接头处产生了较大的残余应力,对不锈钢板翅结构高温下的蠕变行为产生很大影响,在强度设计中不能忽略。初始应力和蠕变应变的分布规律具有一致性。隔板和翅片具有不同的应力应变分布特征,隔板侧的蠕变开裂的倾向比翅片大。钎角处蠕变应力和应变集中,易萌生蠕变裂纹。研究结果为不锈钢板翅结构钎焊接头的高温强度设计提供参考。Abstract: The effect of residual stress on creep for microminiaturized nickel base brazed stainless steel plate-fin structure was analyzed by finite element method with ABAQUS code.The results show that because of mismatch of mechanical properties between filler metal and base metal, the welding residual stress was generated inevitably, which has great influence on the creep deformation and life.The residual stress can not be ignored in the strength design and should be controlled during the manufacture of plate-fin structure. The stress and strain is concentrated in the fillet where the creep crack will initiate, propagate and result in the failure.The strain and stress in plate is larger than that in fin, so the cracking susceptibility of plate is lager than that of fin.The present work provides a reference for strength design at high temperature for plate-fin structure.
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