高铁弹条用60Si2Mn弹簧钢腐蚀行为研究

Research on corrosion behavior of 60Si2Mn spring steel for high-speed rail spring bar

为有效够延长弹条在大气腐蚀环境下的服役时间,在常规60Si2Mn弹簧钢的化学成分基础上进行合金成分设计,研究了轧制、热处理工艺对3种实验钢(常规60Si2Mn钢、耐蚀60Si2Mn-1钢和耐蚀60Si2Mn-2钢)显微组织及力学性能的影响,并以0.01 mol/L的NaHSO3溶液为腐蚀介质,使用周期浸润法进行不同周期的腐蚀实验,对比分析了耐蚀60Si2Mn钢和常规60Si2Mn钢在大气环境下的腐蚀行为。结果表明:3种实验钢热轧后的组织均为铁素体和珠光体,耐蚀60Si2Mn钢的珠光体片层间距均小于常规60Si2Mn钢;热处理后3种实验钢的组织均为铁素体和渗碳体,耐蚀60Si2Mn钢经回火后组织中铁素体的回复程度低于常规60Si2Mn钢,热处理后耐蚀60Si2Mn钢的力学性能优于常规60Si2Mn钢;3种弹簧钢的腐蚀速率随腐蚀周期的增加不断下降,相同腐蚀周期下,耐蚀60Si2Mn钢的腐蚀速率低于常规60Si2Mn钢,两者腐蚀速率的差距在腐蚀后期尤为明显。腐蚀后期Cu、Cr、Ni元素富集于耐蚀60Si2Mn钢靠近基体一侧的锈层中,形成更加致密的锈层,显著提高其耐大气腐蚀性能。

In order to effectively prolong the service time of spring bars in the atmospheric corrosion environment, the alloy composition was designed based on the chemical composition of conventional 60Si2Mn spring steel. The effects of rolling and heat treatment processes on the microstructures and mechanical properties of three experimental steels(conventional 60Si2Mn steel, corrosion resistant 60Si2Mn-1 steel and corrosion resistant 60Si2Mn-2 steel) were studied. With 0.01 mol/L NaHSO3solution as the corrosion medium, the periodic immersion method was used to conduct corrosion experiments for different periods. The corrosion behavior of corrosion resistant 60Si2Mn steel and conventional 60Si2Mn steel in atmospheric environment was compared and analyzed. The results show that the microstructure of the three experimental steels after hot rolling is ferrite and pearlite, and the pearlite lamellar spacing of corrosion resistant 60Si2Mn steel is smaller than that of conventional 60Si2Mn steel. The microstructure of the three kinds of experimental steels after heat treatment is ferrite and cementite. The recovery degree of ferrite in the microstructure of the corrosion resistant 60Si2Mn steel after tempering is lower than that of the conventional 60Si2Mn steel. The mechanical properties of the corrosion resistant 60Si2Mn steel after heat treatment are better than that of the conventional 60Si2Mn steel. The corrosion rate of the three spring steels decreases with the increase of corrosion cycle. Under the same corrosion cycle, the corrosion rate of corrosion resistant 60Si2Mn steel is lower than that of conventional 60Si2Mn steel, and the difference between the two corrosion rates is particularly obvious in the later stage of corrosion. At the later stage of corrosion, Cu, Cr and Ni elements are enriched in the rust layer near the substrate of the corrosion resistant 60Si2Mn steel, forming a more dense rust layer, which significantly improves its atmospheric corrosion resistance.