气体氮化对35CrMo钢表面纳米晶化后CO2腐蚀的影响。

Effect of gas nitriding on CO2 corrosion for 35CrMo steel after surface nanocrystallization.

作者信息

Wang Bingying, Zhou Shengnan, Wang Jingjing, Zhao Bin

出版信息

J Nanosci Nanotechnol. 2014 Oct;14(10):8079-82. doi: 10.1166/jnn.2014.9400.

DOI:10.1166/jnn.2014.9400

Abstract

This paper studies the influence of ultrasonic surface rolling procession (USRP) and gas nitriding on CO2 corrosion for 35CrMo steel. The microstructure of the nanocrystallized surface caused by USRP and the nitrided layer were studied by means of HRTEM and optical microscope, respectively. High temperature high pressure autoclave was adopted to study the CO2 corrosion behavior of 35CrMo steel. The characteristics of CO2 corrosion scales on 35CrMo steel were investigated by the SEM, EDS and XRD techniques. The experimental results show that after USRP about 250 μm rheological layer forms on the metal surface, and the average grain size is 25 nm. USRP thicken the nitrided layer, 10 hours' gas nitriding at 550 degrees C lower the corrosion rate while the combine of gas nitriding and USRP enhances the corrosion resistance furthest; and the surface nanocrystallization increases the content of Cr and changes the corrosion product film from FeCO3 to FeCO3 and Cr2O3, and from loose crystal structure to amorphous flocculent structure. The corrosion resistance of 35CrMo has been improved significantly by USRP and gas nitriding.

摘要

本文研究了超声表面滚压工艺（USRP）和气体渗氮对35CrMo钢CO2腐蚀的影响。分别采用高分辨透射电子显微镜（HRTEM）和光学显微镜研究了USRP引起的纳米晶化表面和渗氮层的微观结构。采用高温高压釜研究了35CrMo钢的CO2腐蚀行为。利用扫描电子显微镜（SEM）、能谱仪（EDS）和X射线衍射仪（XRD）技术研究了35CrMo钢表面CO2腐蚀产物垢的特征。实验结果表明，经USRP处理后，金属表面形成了约250μm的流变层，平均晶粒尺寸为25nm。USRP使渗氮层增厚，550℃下10小时的气体渗氮降低了腐蚀速率，而气体渗氮与USRP相结合则进一步提高了耐蚀性；表面纳米晶化增加了Cr的含量，使腐蚀产物膜由FeCO3转变为FeCO3和Cr2O3，由疏松晶体结构转变为非晶态絮状结构。USRP和气体渗氮显著提高了35CrMo钢的耐蚀性。