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在两种不同的扫描速度下(100 mm/min、300 mm/min),在20钢基体表面激光熔覆钼粉与高铬铸铁复合粉末,利用扫描电子显微镜、维氏硬度计检测了不同钼粉含量时(0.5%、3%、5%、7.5%、10%)熔覆层的显微组织和硬度。结果表明,钼粉与高铬铸铁复合粉末经激光熔覆后,晶粒细化,组织致密,无裂纹、气孔等缺陷;在100 mm/min较低的扫描速度下,加入钼后,能细化晶粒,促进条状珠光体向胞状奥氏体枝晶转变,不同钼含量下熔覆层的平均硬度分别为160、172、193、212和226 HV0.2;在300 mm/min较高的扫描速度下,钼加入后,能抑制碳化物生长,促进长条状的初生合金碳化物向方块状、层片状的碳化物转变,有利于抑制开裂。不同钼含量下熔覆层的平均硬度分别为586、612、637、682和712 HV0.2。
At two different scanning speeds (100 mm / min, 300 mm / min), molybdenum powder and high chromium cast iron composite powders were laser cladded on the surface of 20 steel substrate. The tensile properties of different molybdenum (0.5%, 3%, 5%, 7.5%, 10%) of the cladding layer microstructure and hardness. The results show that the composite powders of molybdenum powder and high chromium cast iron after laser cladding have the characteristics of grain refinement, compact structure, no cracks and pores, etc. At the lower scanning speed of 100 mm / min, The grain size of the lamellar pearlite transformed into cellular austenite dendrite. The average hardness of the cladding layer under different molybdenum contents were 160, 172, 193, 212 and 226 HV0.2, respectively. At 300 mm / min, Of the scanning speed, the addition of molybdenum, carbide growth can be inhibited and promote the strip of primary carbides carbide to lamellar, lamellar carbide, is conducive to inhibiting cracking. The average hardness of the cladding layers at different molybdenum contents were 586, 612, 637, 682 and 712 HV0.2, respectively.