冷却方式对不锈钢板翅结构强度和微观组织的影响  

Effect of Cooling Method on Microstructure and Tensile Strength for 304 Stainless Steel Plate-fin Structure

作　　者：蒋文春[1,2] 巩建鸣[2] 涂善东[2] 

机构地区：[1]中国石油大学(华东)机电工程学院,山东东营257061 [2]南京工业大学机械与动力工程学院,江苏南京210009

出　　处：《压力容器》2009年第11期16-20,49,共6页Pressure Vessel Technology

基　　金：国家自然科学基金资助项目(10472043);江苏省自然科学基金(BK2004214);江苏省普通高校研究生科研创新计划(2007)

摘　　要：对采用镍基钎料BN i-2的304不锈钢板翅结构进行真空钎焊试验,讨论冷却方式对结构强度和微观组织的影响。利用扫描电镜(SEM)对钎焊接头微观组织进行观察;利用能谱分析(EDS)对接头化学成分进行研究。研究结果表明,在其它钎焊工艺参数不变的情况下,冷却方式对304不锈钢板翅结构的强度影响很大。采用现有文献使用的充氮快速冷却的方式,导致钎焊接头产生了较多的裂纹和孔洞,使得强度降低;采用改进的缓慢冷却方式,即从钎焊温度到620℃,让其自由冷却,当炉中温度降到620℃时,向炉内充氮气并同时启动风机快速冷却。利用高温蠕变松弛原理,释放部分钎焊残余应力,减少了裂纹等缺陷的产生,极大提高了304不锈钢板翅结构的强度。The vacuum brazing experiment of 304 stainless steel plate fin structure was carried out. The effect of cooling method on microstructure and tensile strength is investigated. The scanning electron microscope （SEM） and Energy -dispersive X -ray spectrometer （EDS）tests were carried out to reveal the microstructure and chemical components in the brazed joint. The results show that the cooling method has great effect on strength and microstructure for 304 stainless steel plate - fin structure. A lot of cracks and voids are generated in the brazing joint using quick cooling method, which decrease the strength greatly. The improved slow cooling method includes two steps. The first step is the self-cooling in vacuum furnace from 1050 -620 ℃ ,and the second step is the quick cooling by dry nitrogen and wind cooling. The residual stress is relaxed by creep and the flaws are decreased, which increase the strength greatly.

关 键 词：不锈钢板翅结构 真空钎焊 快速冷却 缓慢冷却 

分 类 号：TG111.8[金属学及工艺—物理冶金]