Welding overlay flange is a kind of composite flange which use carbon steel or alloy steel as the base layer and lined a certain thickness (usually 2-3mm) of stainless steel, titanium, copper, aluminum and other corrosion-resistant alloy on the surface of it’s inside hole and seal face of flange. This special structure can keep the flange have both the characters of pressure resistance of carbon steel and corrosion resistance of stainless steel and low cost compare to stainless steel. Its outstanding cost performance and corrosion resistance make it has a wide range of application prospects in the oil and gas industry , Water supply projects, chemical industry and other industries.