Q450耐酸钢的相变及耐蚀性能

针对含0.09%Bi的铁路敞车用新型耐酸钢,通过热模拟试验,绘制了动态CCT曲线,进行实验室轧制,利用全浸试验方法和电化学试验方法对其耐硫酸腐蚀性能进行了研究。结果表明:随着冷速提高,显微组织由珠光体+铁素体逐渐完全转变为贝氏体,同时组织细化。在实验室热轧后水冷至622 ℃,石棉卷取保温冷至室温,得到的组织为铁素体+少量贝氏体;经全浸腐蚀试验,腐蚀后表面腐蚀产物平整,腐蚀较轻,其力学性能和耐硫酸腐蚀性能均满足Q/ASB 174—2016要求。电化学试验研究表明,试验钢自腐蚀电位、自腐蚀电流和腐蚀速率均优于Q345B钢,表面富含Cu₂S的致密腐蚀产物氧化膜对耐蚀性提高作用明显。

Phase transformation and corrosion resistance of Q450 acid-resistant steel

A new type of acid-resistant steel containing 0.09%Bi for railway open car was developed. The dynamic CCT curve was drawn through thermal simulation test, and the sulfuric acid corrosion resistance of the steel was studied by means of full immersion test and electrochemical test. The results show that with the increase of cooling rate, the microstructure changes from pearlite+ferrite to bainite and is refined. After hot rolling in the laboratory, water cooling to 622 ℃, and then asbestos coil cooling to room temperature, the microstructure obtained is ferrite and a small amount of bainite. After full immersion corrosion test, the corrosion products on the surface of the steel is smooth and the corrosion is light, and the mechanical properties and sulfuric acid corrosion resistance of the steel meet the requirements of Q/ASB 174—2016 standard. The electrochemical corrosion test show that the self-corrosion potential, self-corrosion current and corrosion rate of the steel are better than that of the Q345B steel, and the oxide film with dense corrosion products rich in Cu₂S on the surface significantly improves the corrosion resistance.