Precautions in the Production Process of Stellite Alloy

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    Stellite is a hard alloy that is resistant to all types of wear and corrosion and high temperature oxidation. The so-called cobalt-based alloy, stellite was invented by the Americans in 1907. Stellite Alloy contain cobalt as a main component and contain a considerable amount of nickel, chromium, tungsten and a small amount of alloying elements such as molybdenum, niobium, tantalum, titanium and niobium, and occasionally iron. According to the different composition of the stellite alloy, they can be made into welding wire. The powder can be used for hard surface surfacing, thermal spraying, spray welding and other processes, and can also be used for casting and forging parts and powder metallurgy parts.


    What should we pay attention to during the production process of stellite alloy?


    The wear of the alloy workpiece is largely affected by the contact or impact stress of the surface. Surface wear depends on the interaction of dislocation flow and contact surfaces under stress.


    For stellite alloy, this feature has a lower stacking fault energy with the matrix and the matrix structure is transformed from a face-centered cubic to a hexagonal close-packed crystal structure under the influence of stress or temperature, and has a hexagonal close-packed crystal structure. Metal materials, wear resistance is superior. In addition, the content, morphology and distribution of the second phase of the alloy, such as carbides, also have an effect on wear resistance.


    Since the alloy carbides of chromium, tungsten and molybdenum are distributed in the cobalt-rich matrix and some of the chromium, tungsten and molybdenum atoms are solid-solubilized in the matrix, the alloy is strengthened to improve wear resistance. In cast stellite alloys, the carbide particle size is related to the cooling rate, and the carbide particles are relatively fine when cooled.


    In the sand casting, the hardness of the Stellite Alloy 12 is lower and the carbide particles are coarser. In this state, the abrasive wear resistance of the alloy is significantly better than that of the graphite casting (the carbide particles are fine), and the adhesive wear resistance is both There is no significant difference, indicating that coarse carbides contribute to improved abrasive wear resistance.



     

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