Characteristics of Cobalt Alloys for Welding Rods

Cobalt Chrome Alloy electrode base material casting cobalt-based superalloy is largely dependent on carbide strengthening. Pure cobalt crystals are densely packed hexagonal (hcp) crystal structures below 417 ° C and converted to fcc at higher temperatures.

In order to avoid this transformation of the cobalt alloy during use, virtually all of the cobalt alloy is alloyed with nickel to stabilize the structure from room temperature to melting point temperature. Cobalt alloy has a flat fracture stress-temperature relationship, but it exhibits excellent hot corrosion resistance at temperatures above 1000 °C, which may be due to the higher chromium content of the alloy, which is one of these alloys. feature.

In cast Cobalt Alloy Plate , 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 alloy 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.

The main carbides in cobalt alloys are MC, M23C6 and M6C. In cast Cobalt Alloy , M23C6 precipitates between grain boundaries and dendrites when slowly cooled. In some alloys, fine M23C6 can form a co-crystal with the matrix γ. The MC carbide particles are too large to directly affect the dislocations, so the strengthening effect on the alloy is not obvious, and the finely dispersed carbides have a good strengthening effect. The carbides located on the grain boundaries (mainly M23C6) can prevent the grain boundary from slipping and improve the permanent strength. The microstructure of the cobalt alloy HA-31 (X-40) is a dispersed strengthening phase (CoCrW) 6 C type. carbide.

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