喷射成形H13钢的耐腐蚀行为

Corrosion behavior of sprayed-formed H13 steel

采用电化学测试和浸泡实验研究了喷射成形H13钢与铸造H13钢的耐腐蚀性能,通过OM、SEM和TEM分析了材料组织对耐蚀性的影响以及腐蚀机理。结果表明:喷射成形H13钢在1050℃淬火后600℃回火时自腐蚀电位最高,耐腐蚀性能最好;喷射成形H13钢的点腐蚀由夹杂物引起,点腐蚀产物在夹杂物周围沉积,造成溶液局部p H下降,加速了腐蚀过程;与铸造H13钢相比,由于喷射成形H13钢组织中存在孔洞,晶界、位错密度大,容易成为点蚀的诱发源,回火后在晶界和马氏体边界析出的大量碳化物造成基体贫Cr,增加了阴阳极的电位差,导致喷射成形H13钢的耐蚀性与铸造H13钢相比稍差。

The corrosion resistance of spray-formed H13 steel and as-cast H13 steel was studied by electrochemical measurement and immersion test. Effect of microstructure on corrosion resistance and corrosion mechanism of the steel was analyzed by means of OM、SEM and TEM. The results show that the corrosion resistance of pray-formed H13 steel is the best when the sample is quenched at 1500 ℃ and tempered at 600 ℃. The pitting corrosion is induced by inclusion,and the corrosion products can be deposited around the inclusion which reduces the solution p H,and increase the corrosion rate. Compared with cast H13 steel,because of the high density of the grain boundary and dislocation of spray-formed H13 steel,and the precipitation carbides around the grain boundary and martensite result in lacking of Cr on the basis,the corrosion resistance of spray-formed H13 steel is slightly inferior.