Weld decay-resistant austenitic stainless steel by grain boundary engineering
Weld decay-resistant austenitic stainless steel by grain boundary engineering
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DOI：
10.1007/s10853-005-6511-6
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发表时间：
2005-02
影响因子：
4.5
通讯作者：
H. Kokawa
中科院分区：
文献类型：
--
作者：
H. Kokawa
本文介绍了利用晶界工程提高奥氏体不锈钢的晶间耐蚀性和耐焊蚀性的一个实例。透射电镜（TEM）和扫描电镜（SEM）观察表明，304型奥氏体不锈钢焊接衰减区重合点阵（CSL）界面具有较强的抗晶间析出和抗腐蚀能力。为提高304奥氏体不锈钢的抗晶间腐蚀性能，对GBE进行了热处理。用取向成像显微镜（OIM）研究了晶界特征分布（GBCD）。热处理降低了对晶间腐蚀的敏感性，并在小滚压下达到最小值。CSL边界的频率在小滚降时达到最大值。在长时间敏化作用下，热处理试样的腐蚀速率比基材小得多。优化后的热处理使材料的CSL晶界出现频率高，腐蚀随机晶界网络具有明显的不连续性，具有较高的抗晶间腐蚀能力，阻止了晶间腐蚀从表面扩散。优化后的304不锈钢在弧焊过程中表现出优异的抗焊缝腐蚀性能。
This paper presents an example of grain boundary engineering (GBE) for improving intergranular-corrosion and weld-decay resistance of austenitic stainless steel. Transmission and scanning electron microscope (TEM and SEM) observations demonstrated that coincidence site lattice (CSL) boundaries possess strong resistance to intergranular precipitation and corrosion in weld decay region of a type 304 austenitic stainless steel weldment. A thermomechanical treatment for GBE was tried for improvement of intergranular corrosion resistance of the 304 austenitic stainless steel. The grain boundary character distribution (GBCD) was examined by orientation imaging microscopy (OIM). The sensitivity to intergranular corrosion was reduced by the thermomechanical treatment and indicated a minimum at a small roll-reduction. The frequency of CSL boundaries indicated a maximum at the small roll-reduction. The corrosion rate was much smaller in the thermomechanical-treated specimen than in the base material for long time sensitization. The optimum thermomechanical treatment introduced a high frequency of CSL boundaries and the clear discontinuity of corrosive random boundary network in the material, and resulted in the high intergranular corrosion resistance arresting the propagation of intergranular corrosion from the surface. The optimized 304 stainless steel showed an excellent resistance to weld decay during arc welding.