The effect of chemical constituents of $(Cr,;Fe)_7C_3$ carbide phase on its hardness in the chromium-carbide type Cr white iron hardfacing weld deposits has been investigated. In order to examine $(Cr,;Fe)_7C_3$ carbide phase, a series of filler metals with varying chromium contents was used. The alloys were deposited once or twice on a mild steel plate using the self?shielding flux cored arc welding process. The hardness of $(Cr,;Fe)_7C_3$ carbide phase was measured by the micro-Vickers hardness test. It was shown that hardness of $(Cr,;Fe)_7C_3$ carbide phase increased with increasing Cr content in $(Cr,;Fe)_7C_3$ carbide phase. This behavior of the hardness of $(Cr,;Fe)_7C_3$ carbide phase was explained by the types of chemical bonds that hold atoms together in $(Cr,;Fe)_7C_3$ carbide phase.