不锈钢硫酸—硫酸铜晶间腐蚀结果评定方法探讨

通过对硫酸-硫酸铜晶间腐蚀后弯曲产生裂纹或断裂的奥氏体不锈钢基体、双相不锈钢基体、不锈钢堆焊复层及不锈钢焊接接头试样进行金相、扫描或透射电镜微观分析,表明用GB4334-2008 E法评定操作性存在问题,参照此法判断试验材料是否有晶间腐蚀倾向,判断结果存在争议;硫酸-硫酸铜晶间腐蚀标准(GB4334-2008 E法)中结果评定方法应在现基础上细化、补充,评定方法中金相法如何操作和如何评定应详细说明,适当可以补充图片指导,结果有争议时,不只限于150～500倍的光学显微镜下观察,根据需要,可在扫描电镜下、甚至是在透射电镜下进行观察分析;在高倍显微镜下准确判断出晶间腐蚀所致裂纹和非晶间腐蚀所致裂纹试样,总结出其低倍形貌特征并补充于标准评定方法中,对于提高标准的操作性具有重要意义。

Study in the Methods of Result Assess of Intergranular Corrosion in Stainless Steels

The bending area of austenitic stainless steel,duplex stainless steel,stainless steel weld overlay and stainless steel welded joint which had crack or fracture after intergranular corrosion testing were studied by metallographic,electronic scanning and transmissiom microscope.The results show that the test evaluation methods among GB4334-2008 E or ASTM262-E standards are difficult manipulative,which will lead to disputed assessment results frequently.The test evaluation methods among the standards should be more detailed than the existing,one telling how to evaluate the results in words or pictures.It is necessary to analyze the cracks or fractures by means of 100～500 times metallographic microscope,or even SEM and TEM if the results are disputed.It is important to summarize low power failure morphology characteristics in the base of high power micro analysis for easy use of the standards.