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The effect of Zirconium addition on the ductility of the low interstitial ferritic stainless steel overlay welds has been investigated. Zirconium addition up to about 0.3% to the first layer of ferritic stainless steel overlay welds with chromium content ranging 15 to 30% on a low alloy steel improved their bend ductility. The bend ductility of the overlay welds was also improved by decreasing the chromium content in the first layer of the welted metal. A composition of l9Cr-2Mo-0.25Zr-Fe was recommended for the filler rod for the first layer of 30Cr-2Mo steel overlay welding on a low alloy steel in order to ensure a good weld ductility without deteriorating the carrot ion resistance of the weld surface. SEM and TEM observations revealed that the amount of film-like intergranular M_<23>C_6 which caused the weld embrittlement decreased when adding zirconium or decreasing the chromium content in the weld metal. In addition, grain coarsening in the weld metal which seemed another cause for the weld embrittlement was prevented by addition of zirconium. These facts were deduced to be responsible for the improving effect of the weld ductility when a zirconium-containing l9Cr-2Mo steel filler cod was used for the first layer of 30Gr-2Mo steel overlay welding on a low alloy steel.