304 stainless steel pipe surface pretreatment

The outer galvanized and inner plastic-coated steel pipe of 304 stainless steel pipe is the same as the plastic-coated steel pipe. It is based on steel pipe. According to the needs of users, choose plastic or galvanized layer, or other coating materials.

Therefore, Wuxi Shengtianxiang 304 stainless steel pipe with galvanized outside and plastic coated inside should be surface pretreated for the base pipe first. The specific treatment steps are as follows:

1. Before blasting and rust removal, Wuxi Shengtianxiang 304 stainless steel pipe should be preheated to remove moisture. The preheating temperature is 40℃～60℃;

2. The rust removal should reach the Sa2.5 level in GB/T8923 "Steel surface corrosion level and rust removal level before painting", and the depth of the anchor pattern on the surface of Wuxi Shengtianxiang 304 stainless steel pipe is 40μm-100μm;

3. The rust and dust remaining on the surface of the 304 stainless steel pipe should be removed;

4. Spraying should be carried out within 4h after surface pretreatment.

In addition, the methods of galvanizing the surface of 304 stainless steel pipes mainly include hot-dip galvanizing and electro-galvanizing. Hot-dip galvanizing includes wet method, dry method, lead-zinc method, redox method, etc.

The main difference between the different methods of hot-dip galvanizing is how to activate the surface of the pipe body to improve the quality of galvanizing after the Wuxi Shengtianxiang 304 stainless steel pipe is acid-leached and cleaned. Dry method and redox method are mainly used in production.

The surface of the electro-galvanized zinc layer is very smooth and compact, with uniform organization; it has good mechanical properties and corrosion resistance; the zinc consumption is 60% to 75% lower than that of hot-dip galvanizing. Electro-galvanizing is technically complicated to a certain extent, but this method must be used for single-sided plating, double-sided plating with different inner and outer surface plating thicknesses, and galvanizing of 304 stainless steel pipes.