In this study, effect of filler steel type on hardness of weld metal which was developed on to cold-work tool steel SKD11 has been investigated. Filler rod of SKD11 reduced hardness of weld metal to 300-400 HV which is half of hardness of base steel. Mean hardness was increased up to 520 HV by welding with filler rod for mild steel. Relation between mean hardness and retained austenite was observed. As the amount of retained austenite increased, the hardness decreased. By using mild steel rod for the first layer and hot-work tool steel SKD61 for the 2nd and 3rd layers, weld metal whose hardness was equivalent to that of base steel was obtained.

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