Evaluation of hot cracking in nitrogen-bearing and fully austenitic stainless steel weldments
Evaluation of hot cracking in nitrogen-bearing and fully austenitic stainless steel weldments
复制标题
含氮和全奥氏体不锈钢焊件的热裂纹评估
DOI：
--
复制
发表时间：
1998
期刊：
影响因子：
--
通讯作者：
S. Sundaresan
中科院分区：
文献类型：
--
作者：
V. Shankar;T. Gill;S. Mannan;S. Sundaresan
显示出初级奥氏体凝固模式的不锈钢在焊接期间特别容易发生热裂纹。通常很难预测这种材料的行为，因为裂纹对杂质和微量元素如P、S和N的水平非常敏感。在这项工作中，熔合区和热影响区裂纹行为的含氮AISI型316LN钢和全奥氏体合金D9使用可变约束试验进行了研究。开裂试验的结果与常规的初级铁素体316L组合物的开裂试验的结果进行了比较。裂纹长度测量结果表明，316 LN对熔合区和HAZ裂纹高度敏感，而合金D9则中度敏感。开裂数据的分析表明，总裂纹长度标准提供了一个更好的估计比最大裂纹长度和脆性温度范围标准的可焊性。组成和开裂敏感性的相关性（包括从文献中获得的数据）表明氮和磷之间的相互作用会增强开裂。与316L相比，316LN中产生了高度的母材和焊缝金属HAZ微裂纹，这归因于该合金中的氮的不利影响。热影响区裂纹非常容易发生裂纹扩展，这可能是由于该区域有利的毛细管和热条件所致。
Stainless steels exhibiting a primary austenitic solidification mode are particularly susceptible to hot cracking during welding. It is often difficult to predict the behavior of such materials, since the cracking is extremely sensitive to levels of impurity and minor elements such as P, S and N. In this work, the fusion zone and HAZ cracking behavior of a nitrogen-bearing AISI Type 316LN steel and fully austenitic Alloy D9 were investigated using the Varestraint Test. The results of the cracking tests were compared with that of a conventional primary ferritic 316L composition. The crack length measurements revealed that the 316LN was highly susceptible to fusion zone and HAZ cracking, while Alloy D9 was moderately susceptible. Analysis of the cracking data revealed that the total crack length criterion provided a better estimate of weldability than maximum crack length and brittleness temperature range criteria. Correlation of the composition and cracking susceptibility -including data obtained from the literature- indicated an interaction between nitrogen and phosphorus in enhancing cracking. A high degree of base and weld metal HAZ microfissuring was produced in 316LN, in comparison with 316L, which was attributed to the detrimental effect of nitrogen in this alloy. Heat-affected zone cracks were quite susceptible to backfilling, presumably due to favorable capillary and thermal conditions in this region.