Thin plates of 21% Cr ferritic stainless steel welded by pulsed gas tungsten arc welding at different pulse frequencies were investigated for the microstructure characteristics and hardness behavior.The welds contained columnar grains in the outer part and fine equiaxed grains in the central region due to the pulsed process. Thin plates of 21% Cr ferritic stainless steel welded by pulsed gas tungsten arc welding at different pulse frequencies were investigated for the microstructure characteristics and hardness behavior. The welds contained columnar grains in the outer part and fine equiaxed grains in the central region due to the pulsed process.