Prevention of the liquid metal embrittlement in Weldment.

防止焊件中液态金属脆化。

• 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
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-59850123/
• 关键词: Liquid metal embrittlement; Commercial weldable structure steel; Sustained load test; Time dependence fracture; 表面エネルギー; 粒界破壊; 破壊時間の推定法; 液体金属の硬さ依存性

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度对断裂应力和液态金属锌脆裂敏感性的影响。采用工业可焊结构钢，在430 ℃ ~ 470 ℃的锌液中进行持续载荷试验，研究了热镀锌钢热影响区（HAZ）的液态金属脆化开裂。试验采用JIS G 3444 STK 55标准的热影响区，在370 ℃ ~ 470 ℃的加热范围内，在液态（熔融）和固态锌中进行持续载荷试验，结果表明，钢和焊缝在熔融锌中的LMEC行为属于热激活过程，断口为沿晶（IG）型，与实际热浸镀锌的LMEC相对应。通过测定维氏硬度和晶粒度，估算了钢和焊缝在锌液中的断裂应力，估算值与试验结果吻合较好。LMEC的敏感性受钢和焊缝硬度的影响，LMEC行为属于热激活过程，LMEC敏感性受热影响区硬度的影响。焊接热影响区粗晶区的LMEC敏感性最高。锌的存在降低了钢的界面能。钢的LMEC反应速率过程受锌的晶界扩散控制。LMEC在钢中的形核和扩展可能与锌的晶界扩散降低界面能密切相关。

项目成果

鉄と鋼. (1986)

钢铁（1986）

溶接学会論文集. 3-3. (1985)

日本焊接学会会刊 3-3 (1985)。

大阪大学工学報告. 36-1. (1986)

大阪大学工程报告。36-1。

Quarterly J,of The Japan Welding Society. 3,No3. p547 p553 (1985)

日本焊接学会季刊。

Thechnology Reports of The OSAKA University. Vol.36 No1. (1986)

大阪大学的技术报告。