Causes of corrosion perforation of copper-nickel alloy tube in ship cooling system

The failure analysis of BFe10-1.6-1 copper-nickel alloy tube with corrosion perforation failure was carried out by stereomicroscope, metallographic microscope and electronic probe. The results show that there were different degrees of scratches on the inner wall of the failure tube, and the microstructure of the inner wall of the corrosion pit was ‘ripple’, which was consistent with the characteristics of seawater erosion and corrosion. The microstructure of the corrosion zone was ‘ice sugar block’, which was consistent with the characteristics of intergranular corrosion. Sediment deposition in corrosion pits caused pitting of pipelines. Combined with the working conditions of marine copper-nickel alloy tube, it was confirmed that the main causes of corrosion perforation failure of the failure tube were seawater erosion corrosion, intergranular corrosion and pitting corrosion.