Abstract: The material of heating coil of one heating pipe set is BFe10-1-1 copper alloy. The leakage of equipment occurred after use for several years. The failure reasons for heating coil were analyzed by optical metallographic microscope (OM) and scanning electron microscope (SEM).The failure mode and reason were found. The failure mode for heating coil of heating pipe set was bolt-like corrosion of nickel-removal corrosion occurred at the weld seam. There were two reasons for failure. The dendrite segregation existed in the metallographic structure of weld seam of heating pipe coil, and the dendrites were preferentially corroded by nickel-removal corrosion and then oxidized. The inner surface of the weld seam of heating coil was uneven and the condensate water was easily to be retained. Once the corrosion hole was formed, the condensate water containing corrosive elements (S and Cl) was more easily stored and enriched, which aggravated the corrosion.