摘要
针对东南亚沿海地区使用的大型轧钢机拉杆(材料为42CrMo钢)易发生腐蚀磨损的问题,采用单热源脉冲离子渗氮炉对拉杆进行氮碳共渗+后氧化复合处理。通过对模拟试样的预氧化工艺、氮碳共渗工艺及后氧化工艺的研究,得到了满足产品要求的复合处理工艺:350℃×2 h预氧化;550℃×24 h氮碳共渗(炉压为260 Pa,NH_(3)∶CO_(2)=20∶1)和520℃×2 h氮氧共渗(炉压为300 Pa,NH_(3)∶O_(2)=6∶1),共渗完毕,关闭电源,同时以0.5 L/min向炉内通入空气,直至炉温降到300℃,打开炉盖,待试样冷至150℃左右,迅速在试样表面均匀涂上防锈油。在此复合工艺下,渗层深度达到0.39~0.41 mm,化合物层达到10~12μm,与同工艺无预氧化试样渗层及化合物层厚度相比均增加;经盐雾试验检测,试样在70 h后出现腐蚀斑,和只经氮碳共渗处理无后氧化处理相比,耐蚀性提高。
Aiming to avoid the corrosion and wear problem of the 42CrMo steel tie rods of large rolling mill used in the coastal areas of Southeast Asia,nitrocarburizing and post-oxidation combined treatment was carried out by using a single heat source pulsed ion nitriding furnace.The research results on the pre-oxidation,nitrocarburizing and post-oxidation processes of the simulated specimen show that,the combined treatment process which meets the product requirements is:firstly pre-oxidation at 350℃for 2 h in air furnace,secondly,nitrocarburizing at 550℃for 24 h(furnace pressure of 260 Pa,NH_(3)∶CO_(2)ratio of 20∶1),thirdly,post-oxidation at 520℃for 2 h(furnace pressure of 300 Pa,NH_(3)∶CO_(2) of 6∶1),then turning the power and penetrating agent off and introducing air into the furnace at a speed of 0.5 L/min until the furnace temperature dropping to 300℃,finally,quickly and evenly coating the surface of the specimen with anti-rust oil when the specimen cooled to about 150℃.Under this combined process,the depth of the infiltration layer reaches 0.39-0.41 mm,the compound layer reaches 10-12μm,which is thicker than that under the same process without pre-oxidation.After salt spray testing,corrosion spots appear on the specimen only until 70 h,and the corrosion resistance is higher than that only undergoing nitrocarburizing treatment without post-oxidation treatment.
作者
房颖
李博
李双喜
Fang Ying;Li Bo;Li Shuangxi(Automotive Engineering Institute,Henan Mechanical and Electrical Vocational College,Zhengzhou Henan 451191,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2023年第5期241-245,共5页
Heat Treatment of Metals
基金
河南省科技攻关(222102220029)。
关键词
大型轧机
拉杆
42CRMO钢
离子氮碳共渗
后氧化
耐蚀性
large rolling mill
tie rod
42CrMo steel
ion nitrocarburizing
post-oxidation
corrosion resistance
