PURPOSE: To reduce weight and to posse excellent characteristics, such as wear resistance and corrosion resistance, by forming an Al-Cu alloy padding layer by TIG welding on the base material of an aluminum alloy cast.
CONSTITUTION: A plurality of padding layers 2 of an Al-Cu alloy are formed on a base material 1 of an Al alloy cast to constitute a liquid contact member 3. Further, after the base material 1 of an aluminum alloy cast is molten, the base material 1 of the Al alloy cast is preheated and the Al-Cu alloy padding layers 2 are formed on the base material 1 by TIG welding. This way prevents the occurrence of breakage during welding of the Al-Cu alloy padding layers 2 and improves quality of the liquid contact member 3. Thus, the weight of a pump casing in a complicated shape to which breakage is apt to occur, namely, a pump casing in a complicated shape having diffuse vane formed of a base material of an aluminum alloy cast is reduced and excellent characteristics, such as wear resistance and corrosion resistance, are possessed.
TAMAKI YUKIO
MIURA AKIO
KUBOTA KK