模具材料表面等离子喷焊层的制备及性能研究

发布时间：2018-04-03 08:39

  本文选题：模具材料　切入点：等离子喷焊　出处：《西华大学》2017年硕士论文

【摘要】：模具是用来制作成型物品的工具,现已成为制造业的重要核心部分。其种类繁多,如冲压模具、塑料模具、压铸模具、玻璃模具等,应用也十分广泛。模具在服役过程中会受到高温、高压、交变热应力等影响,特别是模具的成型零件与制品之间产生摩擦磨损,这些因素会造成模具零件,特别是成型零件的失效或报废。如何修复模具,提高模具耐磨性能,延长模具使用寿命等工作是模具领域的重要研究课题。本文以等离子喷焊技术为手段,选择45钢、H13热作模具钢、HT250灰口铸铁为基材,选用镍基合金粉末Ni45A和Ni60B,制备45钢-Ni45A、45钢-Ni60B、H13-Ni45A、HT250-Ni45A喷焊试样。研究等离子喷焊层制备的工艺参数,喷焊层与基材的结合情况,微观组织,力学性能,以及摩擦磨损性能。主要研究内容和结论如下:1.对等离子喷焊层的微观组织研究表明:45钢-Ni45A和45钢-Ni60B喷焊层的显微组织主要为胞状晶和树枝晶,H13-Ni45A和HT250-Ni45A喷焊层的显微组织主要为胞状晶和柱状晶。经EDS分析发现,合金元素在喷焊层与基材之间相互扩散,喷焊层与基材形成明显的结合区。经SEM分析发现,各喷焊层中均存在白色和灰色相,在45钢-Ni60B和HT250-Ni45A喷焊层中还存在黑色相。通过XRD分析得出,各喷焊层中均含有富Ni的γ-Ni、FeNi3等基体相和M7C3(Cr7C3、(Cr,Fe)7C3)、M23C6(Cr23C6、(Cr,Fe)23C6)等硬质相,其中(Cr,Fe)7C3、(Cr,Fe)23C6分别是以Cr7C3、Cr23C6为基础,溶有Fe原子的碳化物。白色相主要为含Ni、Fe的化合物,灰色相主要为M7C3碳化物,黑色相主要为M23C6碳化物。2.力学性能研究表明:等离子喷焊层的显微硬度均明显高于基材,Ni60B喷焊层的显微硬度高于Ni45A喷焊层的显微硬度。细小的M23C6、M7C3等碳化物能提高抗拉强度和屈服强度。3.对等离子喷焊层的摩擦磨损性能研究表明:随摩擦磨损时长和载荷的增加,45钢-Ni45A和45钢-Ni60B喷焊层的摩擦系数减小,磨损量增加。45钢-Ni45A喷焊层的摩擦系数能达到0.15,45钢-Ni60B喷焊层的摩擦系数能达到0.11,均明显低于基材45钢的摩擦系数(约0.7)。45钢-Ni60B喷焊层较45钢-Ni45A喷焊层的耐磨性好。在摩擦磨损前期,45钢-Ni45A喷焊层磨损面出现少量的粘着颗粒,45钢-Ni60B喷焊层磨损面为轻微磨损,磨损机制主要为粘着磨损。随摩擦时长和载荷的增加,45钢-Ni45A喷焊层磨损面出现磨损凹坑,45钢-Ni60B喷焊层磨损面出现犁沟,甚至有较大的剥落坑,磨损机制主要为磨粒磨损和疲劳磨损。4.本文研究表明:在45钢、H13、HT250基材上喷焊Ni45A、Ni60B合金粉末制备喷焊层以修复模具材料是可行的,喷焊层与基材可以达到冶金结合。
[Abstract]:Molds are tools used to make moulding objects and have become an important core part of manufacturing.Its variety, such as stamping die, plastic mold, die-casting mold, glass mold, and so on, is also widely used.The die will be affected by high temperature, high pressure and alternating thermal stress during service, especially the friction and wear between the molded parts and the products. These factors will lead to the invalidation or scrapping of the mould parts, especially the molded parts.How to repair the mould, improve the wear resistance and prolong the service life of the die is an important research topic in the field of mould.Based on plasma spray welding technology, 45 steel H13 hot working die steel / HT250 gray cast iron was selected as base material, and Ni-base alloy powder Ni45A and Ni60B were used to prepare 45 steel -Ni45AH13-Ni45A H13-Ni45A HT250-Ni45A spray welding specimen.The process parameters of plasma spray welding coating, the bonding between the coating and the substrate, the microstructure, the mechanical properties and the friction and wear properties were studied.The main contents and conclusions are as follows: 1.The microstructure of plasma spray welding layer shows that the microstructures of the spray-welding coatings are mainly cellular crystal and dendritic H13-Ni45A and HT250-Ni45A spray welding layer, which are mainly cellular crystal and columnar crystal in the spray-welding layer of% 45 steel -Ni45A and 45 steel -Ni60B. The microstructure of the coating is mainly cellular crystal and dendritic H13-Ni45A layer and HT250-Ni45A spray welding layer is mainly cellular crystal and columnar crystal.By EDS analysis, it was found that the alloy elements diffused between the spray welding layer and the substrate, and the bonding zone between the spray welding layer and the substrate was obvious.It was found by SEM analysis that white and gray phases existed in all spray welding coatings and black phases were also found in 45 steel Ni60B and HT250-Ni45A spray welding coatings.閫氳繃XRD鍒嗘瀽寰楀嚭,鍚勫柗鐒婂眰涓�鍧囧惈鏈夊瘜Ni鐨勎，

本文编号：1704448