Color difference problem of seamless steel pipe

Seamless steel pipes are mainly caused by the strong reaction of iron and zinc. The violent reaction of the alloy layer makes the complete coating composed of the alloy layer and the pure zinc layer become only the alloy layer without the pure zinc layer. Gray or dark gray is the color of iron-zinc alloys. Furthermore, if the quality of the zinc solution becomes poor, the iron content in the zinc solution will increase.

And due to the iron content, the pure zinc layer on the surface after galvanizing will appear gray, causing color difference, the specific reason: d The material of the electroplated parts contains more carbon, silicon, sulfur and phosphorus elements. The electrochemical reaction between iron and zinc is attributed to the inert electricity formed by these elements, and the relative potential becomes high, which leads to the intensification of the iron and zinc reaction.

The content of metallic elements such as aluminum in the zinc bath is relatively small. For the galvanizing of active steel and other materials, the iron-zinc reaction cannot be effectively suppressed, and the iron content in the zinc solution increases, which reduces the quality of the zinc solution. Improvement measures: select the appropriate galvanizing temperature according to the material, and adjust the zinc solution. composition to control the content of aluminum and nickel within a suitable range.