低合金耐海水腐蚀钢的开发

Development of Low Alloy Seawater Corrosion Resistant Steel

设计、冶炼了Cu-Mo和Cu-Mo-Cr系的3种成分的耐海水腐蚀钢,并轧制成20mm厚钢板,然后测试了设计钢种的力学性能、耐海水腐蚀性能及焊接性能。96,240,336和500h盐雾加速腐蚀试验结果表明:与普通碳素钢(SM490A)相比,3种设计钢的耐海水腐蚀性能均有明显提高,且随着腐蚀时间的延长优势更明显。设计钢种的耐腐蚀性能随Cr含量增加而增加,当Cr质量分数为0.85%时,耐腐蚀性能比对比钢提高59.1%。Cr元素在内锈层的均匀富集有效阻碍了Cl-的侵蚀,提高了耐腐蚀性能。Gleeble热模拟结果表明:不预热和焊后热处理,在焊后冷却速度为5-60℃/s时,焊接粗晶区的KV≥57J,揭示了设计钢种良好的焊接性能。

Three kinds of Cu-Mo and Cu-Mo-Cr alloyed steels were designed and melted, and then hot rolled into 20mm thick plates, and finally mechanical property, seawater corrosion resistance and weldability of the rolled plates were evaluated. Salt spray tests with 96, 240, 336 and 500 hours were conducted, and all tested steels shows improved corrosion resistance as compared to SM490A, and the superior corrosion resistance is more pronounced with elongation of testing period. Corrosion resistance increases with increasing Cr content, and the corrosion resistance of the steel with 0. 85% Cr increases 59.1% as compared to SM490A. The Cr enriched at inner rust layer can effectively withstands diffusion of Cl- , and thus improves corrosion resistance. Gleeble simulation was executed to evaluate steel weldability without preheating and postweld heat treatment, and the impact toughness of the simulated CGHAZ ≥ 57J with cooling rates of 5-60 ℃/s, which implies the good weldability of the designed steel.