CAST IRON PIPE HAVING FLANGE AND MANUFACTURING METHOD THEREOF

To provide a cast iron pipe having a flange that prevents weld cracks from being generated easily in flange welding and can maintain wear resistance for a long period.SOLUTION: While one portion of a flange 2 projects from a shaft end of a straight pipe part 1 to the outside in an axial direction, an outer welded part 3 is formed between an end face in the inside in an axial direction of the flange 2 and an outer peripheral surface of the straight pipe part 1, and an inner welded part 4 is formed between an inner peripheral surface of a projecting part of the flange 2 and a shaft end face of the straight pipe part 1, thus reducing tensile stress in the radial direction generated in the straight pipe part 1 in welding, and preventing weld cracks from being generated easily in a heat-affected part of the straight pipe part 1. A hard build-up welding part 5 in which a first surface 5a flush with an end face in the outside in an axial direction of the flange 2 and a second surface 5b flush with an inner peripheral surface of the straight pipe part 1 are continuous in the entire periphery is provided, thus flattening an inner surface of a flange junction part with the one having the same configuration and increasing wear resistance, and hence preventing premature wear from occurring easily.SELECTED DRAWING: Figure 3 【課題】フランジ溶接時に溶接割れを生じにくく、かつ長期間にわたって耐摩耗性を維持できるフランジ付鋳鉄管を提供する。【解決手段】フランジ２の一部が直管部１の軸端から軸方向外側にはみ出した状態で、フランジ２の軸方向内側の端面と直管部１の外周面との間に外側溶接部３が形成され、フランジ２のはみ出し部の内周面と直管部１の軸端面との間に内側溶接部４が形成された構成とすることにより、溶接時に直管部１に生じる径方向の引張応力を小さくして、直管部１の熱影響部での溶接割れを生じにくくするとともに、フランジ２の軸方向外側の端面と面一となる第１の表面５ａと、直管部１の内周面と面一となる第２の表面５ｂとが全周にわたって連続した硬化肉盛溶接部５を設けることにより、同じ構成のものとのフランジ接合部の内面が平坦で耐摩耗性の高いものとなり、早期摩耗が生じにくくなるようにした。【選択図】図３