摘要
研究了RE与Ti变质铸造5CrNiMo模具钢从室温～600℃的磨损行为,采用SEM、EDS和XRD等对磨损表面和截面形貌,以及磨屑形貌与成分进行了分析,探讨了其高温磨损机制。结果表明,随着温度升高,铸造5CrNiMo模具钢的摩擦系数先降低后升高,RE变质与(RE+Ti)复合变质钢在300℃、未变质和Ti变质钢在450℃时摩擦系数出现最小值。变质与未变质铸造5CrNiMo模具钢的磨损失重随温度升高先增加,当温度超过300℃后开始下降;相对于未变质试样,RE变质、Ti变质和(RE+Ti)复合变质试样的最大磨损失重分别下降了14.3%、27.5%和30.5%。高温磨损试样表层氧化产物为Fe_2O_3和Fe_3O_4,疲劳裂纹引起的剥落磨屑为块状及少量长片状氧化物。当温度低于150℃时,(RE+Ti)变质5CrNiMo钢的低温磨损机制为犁削磨损和磨粒磨损,300℃时为粘着磨损和氧化磨损,当温度超过450℃后,磨损机制转变为氧化剥落磨损和疲劳磨损。
The wear behavior of cast 5CrNiMo die steel modified with rare earth （RE） and Titanium （Ti） in from room temperutune to 600℃ was studied, and the morphologies and composition of worn surface, cross-section, and abrasive dusts were examined by using SEM, EDS and XRD. The wear mechanism at high temperature was discussed. The results show that the friction coefficient of cast 5CrNiMo die steel decreases firstly, then increases with the increase of temperature. The friction coefficient of the steels modified with RE or with （RE ＋ Ti） shows the minimum at the temperature of 300℃, while the temperature for the steels unmodified or modified with Ti is 450 ℃. The wear loss of 5CrNiMo cast steel increases with the test temperature, then decreases when the temperature is higher than 300 ℃. Compared with the unmodified steel, the maximum wear loss of the steels modified with RE, Ti or （RE ＋ Ti） decreases by 14.3%, 27.5% and 30.5%, respectively. The oxidation products on the worn surface at high temperature consist of Fe203 and Fe304. The morphology of abrasive dusts stripped by fatigue cracks is mostly block-shaped and a little is in the shape of small flakes. The wear mechanism of 5CrNiMo cast steel modified with （RE ＋ Ti） is ploughing and abrasive wear when the temperature is below 150 ℃, and the wear mechanism is adhesive and oxidative wear at the temperature of 300 ℃. When the temperature was higher than 450 ℃, the wear mechanism transfers to oxidative delamination and fatigue wear.
作者
柯丹
马伟亮
蔡启舟
KE Dan;MA Wei-liang;CAI Qi-zhou(State Key Laboratory of Materials Processing and Die ＆ Mould Technology,Huazhong University of Science and Technology,Wuhan 430074,Hubei,China)
出处
《铸造》
CAS
CSCD
北大核心
2018年第11期988-994,共7页
Foundry
基金
国家重大科技专项资助项目(2012ZX04010-81).
