Effect of Cr/Ni equivalent ratio on ductility-dip cracking in AISI 316L weld metals
Effect of Cr/Ni equivalent ratio on ductility-dip cracking in AISI 316L weld metals
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DOI：
10.1016/j.matdes.2010.06.016
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发表时间：
2011-01-01
影响因子：
8.4
通讯作者：
Lee, H. W.
中科院分区：
文献类型：
--
作者：
Jang, A. Y.;Lee, D. J.;Lee, H. W.
研究了 AISI 316L 不锈钢焊缝金属的延展性倾角裂纹 (DDC) 敏感性。改良药芯电弧焊 (FCAW) 填充焊丝采用不同的铬和镍含量制成。凝固模式和δ铁素体含量由铬和镍当量比（Cr-eq/Ni-eq）确定。延展性倾斜裂纹通过晶界滑动机制发生在焊缝金属再加热区域的铁素体晶界和枝晶边界（AF模式）中，DDC形成的主要过程与直线迁移晶界（MGB）形态有关。由于蠕虫型铁素体（FA 模式）/针状铁素体和连续奥氏体网络（F 模式）焊缝金属的连续网络中δ铁素体的钉扎效应，在曲折的 MGB 中没有观察到 DDC。三相点或 MGB 交点处的 DDC 表现出蠕变形态。在强约束条件下，在延性下降温度范围内产生晶界滑动时，通过形成微孔观察到严重的局部热塑性变形。 Crown 版权所有 (C) 2010 由 Elsevier Ltd 出版。保留所有权利。
The ductility-dip cracking (DDC) susceptibility of AISI 316L stainless steel weld metals was examined. Modified flux cored arc welding (FCAW) filler wires were fabricated with various chromium and nickel contents. The solidification mode and delta-ferrite content were determined from the chromium and nickel equivalent ratios (Cr-eq/Ni-eq). Ductility-dip cracking occurred through a grain boundary sliding mechanism in the reheated region of the weld metal in the ferrite at cell and dendrite boundaries (AF mode), and the primary course of DDC formation was associated with the straight migrated grain boundary (MGB) morphology. No DDC was observed in the tortuous MGB due to the pinning effect of delta-ferrite in the continuous network of vermicular type of ferrite (FA mode)/acicular ferrite and continuous austenite network (F mode) weld metals. The DDC at the triple point or the intersection of the MGB showed a creep-like morphology. Severe localized and thermal plastic deformation was observed through the formation of micro-voids when grain boundary sliding was generated in the ductility-dip temperature range under strong restraint conditions. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.