Effects of deep cryogenic treatment on microstructure and properties of WC-11Co cemented carbides with various carbon contents

The effects of deep cryogenic treatment on the microstructure and properties of WC-11 Co cemented carbides with various carbon contents were investigated.The results show that after deep cryogenic treatment,WC grains are refined into triangular prism with sound edges via the process of spheroidization,but WC grain size has no evident change compared with that of untreated alloys.The phase transformation of Co phase from α-Co（FCC） to ε-Co（HCP） is observed in the cryogenically treated alloys,which is attributed to the decrease of W solubility in the binder（Co）.Deep cryogenic treatment enhances the hardness and bending strength of the alloys,while it has no significant effects on the density and cobalt magnetic performance.

等离子弧喷焊镍基合金对喷焊层硬度的影响

以提高基体材料喷焊层的硬度及耐磨性为目的,使用等离子弧喷焊技术对基体材料(Q345C低合金钢)进行焊接,对于DG.Ni60B镍基合金粉末,选用100,150 A转移弧电流对其进行喷焊。而对于DG.Ni60WC25镍基合金粉末,则在100,150,170,200 A转移弧电流下进行喷焊。结果表明,当使用同一种镍基合金粉末喷焊时,喷焊层最大硬度值和耐磨性随转移弧电流增大而降低。在相同转移弧电流条件下,添加硬质复合材料(碳化钨,WC)镍基合金粉末DG.Ni60WC25焊层的硬度和耐磨性明显高于未添加硬质复合材料镍基合金粉末DG.Ni60B的焊层。试验得出:等离子弧喷焊时,随着转移弧电流的增大,会使喷焊层表面耐磨性减小。但在DG.Ni60B镍基合金粉末中加入硬质相WC之后,对其复合合金粉末进行喷焊,可使转移弧电流对焊层表面耐磨性的影响程度降低。同时,在喷焊层和基体材料结合界面之间出现较大的硬度值,甚至在界面处可获得硬度的最大值。

层片状堆焊材料的研制

为了研制一种柔性比较好的层片状堆焊材料,用来修复易磨损的零件表面和小型的管材类零件等,选择有机硅密封胶、聚乙烯醇、环氧树脂、水玻璃为粘结剂,与硬质材料Ni60H进行混合,做成层片状堆焊材料;另外再加入WC(碳化钨)作为硬质相,利用TIG焊在Q235钢基体上进行堆焊.结果表明:以有机硅密封胶、有机硅密封胶与环氧树脂1∶1为粘结剂的堆焊材料具有良好的柔韧性,可以任意弯折.以有机硅密封胶与环氧树脂1∶1为粘结剂的堆焊材料加入WC和CaF2后的焊接组织均匀、无缺陷,且堆焊层具有良好的耐磨性能,其洛氏硬度值为HRC43.83.

WC+Cr_3C_2增强铁基合金激光熔覆涂层磨损性能

利用CO2激光器,在用KF311+27%Fe901+10%Ni45配制的基体铁基合金粉末中加入WC+Cr3C2硬质增强相,在45钢表面制备了激光熔覆涂层。研究了WC+Cr3C2对熔覆层显微组织和磨损性能的影响。结果表明,添加WC和Cr3C2的熔覆层硬度较基体粉熔覆层硬度高、耐磨性好。当WC和Cr3C2含量分别为8%和4%时,硬度可以达到52 HRC,熔覆层组织主要为由γ-(Fe,Ni)相与(Cr,Fe,W)23C6相组成的共晶。