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.

研究了硬度和焊缝的硬度和晶粒尺寸及其焊缝对熔融锌（L MEC）中液体金属含量破裂的裂缝应力和灵敏度的影响。使用商业焊接结构钢进行了实验，并在熔融锌中进行了持续的载荷测试（SLT），其加热范围为430゜C-470゜C。研究了热浸入液体中的液体金属金属抗热区（HAZ）钢（HAZ）的液体金属覆盖区域（HAZ）。使用JIS G 3444 STK55的合成HAZ进行实验，并在370°C-470°C的加热范围内进行液体（熔融）和固体锌的持续负载试验。熔融锌中钢和焊缝的LMEC行为是热活化过程的，裂缝是晶间（Ig）类型的女巫，对应于热浸镀锌中的实际LMEC。通过测量Vicker的硬度和晶粒尺寸来获得熔融锌中钢和焊缝断裂应力的估计，这些估计值与测试结果相对应。 LMEC的敏感性受钢的硬度影响，WEDS.LMEC行为是热活化过程，LMEC敏感性受HAZ硬度的影响。 HAZ中的粗粒区域显示出最高的LMEC敏感性。钢的界面能量被锌的程度恢复。钢的反应速率过程LMEC受锌的晶界扩散控制。由于锌的晶界扩散，钢中LMEC的成核和钢中LMEC的繁殖可能与界面能量的降低有密切的关系。