Effect of processing temperatures on characteristics of surface layers of low temperature plasma nitrocarburized AISI 204Cu austenitic stainless steel

The influence of processing temperatures on the surface characteristics of AISI 204Cu austenitic stainless steel was investigated during a low temperature plasma nitrocarburizing.The resultant layer was a dual-layer structure,which comprises a N-enriched layer on the top of C-enriched layer.The surface hardness and the layer thickness increase up to about HV 0.05 1000 and 20μm with increasing temperature.The specimen treated at 400°C shows a much enhanced corrosion resistance compared to the untreated steel.A loss in corrosion resistance was observed for specimens treated at temperatures above 430°C due to the formation of Cr2N.

稀土元素Ce对204Cu奥氏体不锈钢耐腐蚀性能的影响

200 Cu奥氏体不锈钢（/%：0.125-0.131C,0.32-0.34Si,8.51-8.73Mn,0.002-0.006S,0.035-0.007P,16.40-16.64Cr,2.53-2.72Ni,2.33-2.38Cu,0.257-0.271N,0-0.064Ce）由10 kg真空感应炉熔炼,锻成25 mm×25 mm方坯,并进行1 150℃2 h水冷的固溶处理。利用重量法和电化学法的交流阻抗和极化曲线技术研究了0-0064%Ce对204Cu不锈钢在25℃3.5%NaCl溶液中耐腐蚀性能的影响。结果表明,200Cu不锈钢中加入一定量的稀土元素Ce,200Cu不锈钢的阳极极化电位值正移,降低腐蚀电流密度,增加极化电阻,可以显著提高其耐腐蚀性能,当向钢中加入0.029%Ce时,204Cu不锈钢可以获得最佳的耐腐蚀性能。

稀土铈对204Cu不锈钢晶间腐蚀的影响研究

冶炼了不同稀土Ce含量的204Cu不锈钢,进行650℃下保温2 h的敏化处理。采用能谱分析和化学浸蚀等方法研究了不同含量的稀土Ce对204Cu不锈钢耐晶间腐蚀性的影响。结果表明:向钢中加入稀土Ce可使晶界处的Cr含量提高,改善耐晶间腐蚀性能,降低腐蚀沟槽宽度。当Ce含量高于0.029%时,试样的耐晶间腐蚀性降低。向钢中加入0.029%的稀土Ce可使204Cu不锈钢获得最佳的耐晶间腐蚀性。