Prevention of the liquid metal embrittlement in Weldment.

防止焊件中液态金属脆化。

基本信息

批准号：
59850123
负责人：
ARAKI Takao
金额：
$ 3.65万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1984
资助国家：
日本
起止时间：
1984 至 1985
项目状态：
已结题

项目摘要

The effect of hardness and grain size of steels and their welds on fracture stress and sensitivity of Liquid Metal Embrittlement Cracking in molten Zinc (L MEC) was investigated. The experiment was conducted using commercial weldable structual steels and Sustained Load Test (SLT) was conducted in molten Zinc with heating range of 430゜C-470゜C.The liquid metal embrittlement cracking of heat affected zone (HAZ) of steel in hot dip galvanizing was investigated. The experiment was conducted using synthetic HAZ of JIS G 3444 STK55 and Sustained Load Test at 370゜C-470゜C heating range in liquid (molten) and solid Zinc.The LMEC behavior of steels and welds in molten Zinc is of thermal activated process, and fractures are intergranular (IG) type witch corresponds to actual LMEC in hot dip galvanising. Estimation of fracture stress of steels and welds in molten Zinc is obtained by measuring Vicker's hardness and grain size, and these estimation values are correspond with test results. The sensitivity of LMEC is affected by hardness of steels and welds.LMEC behavior is of thermal activated process and LMEC sensitivity is affected by hardness of HAZ. The coarse grain region in HAZ showned the highest LMEC sensitivity. The interfacial enegy of steel is redused by the exsistence of Zinc. The reaction rate process of LMEC of steel is controlled by grain boundery diffusion of Zinc. The nucleation and the propagation of LMEC in steel are likely to have a close relation to the reduction of interfacial energy due to the grain boundery diffusion of Zinc.

研究了钢及其焊缝的硬度和晶粒尺寸对熔融锌中液态金属脆化裂纹 (L MEC) 的断裂应力和敏感性的影响。该实验使用商业可焊接结构钢进行，并进行了持续载荷测试 (SLT)。在加热范围为430°C-470°C的熔融锌中钢热影响区（HAZ）的液态金属脆化开裂该实验使用 JIS G 3444 STK55 的合成热影响区和在液态（熔融）和固态锌中在 370°C-470°C 加热范围内进行的持续负载测试进行了研究。熔融锌采用热激活工艺，裂纹为晶间 (IG) 型，与热浸镀锌中的实际 LMEC 相对应。通过测量维氏硬度和晶粒尺寸来估计钢和焊缝在熔融锌中的断裂应力，这些估计值与测试结果相对应。LMEC 的灵敏度受到钢和焊缝硬度的影响。LMEC 行为为热激活过程和LMEC敏感性受HAZ硬度的影响，HAZ中的粗晶区表现出最高的LMEC敏感性，钢的界面能因存在而减少。钢中 LMEC 的反应速率过程受锌晶界扩散控制钢中 LMEC 的成核和扩展可能与锌晶界扩散引起的界面能降低密切相关。。