1. Calculation formula for theoretical weight of square steel pipes
The theoretical weight of galvanized square pipes can be calculated by a calculation formula: 4*wall thickness*(side length-wall thickness)*7.85=weight per meter (g/m). The side length and wall thickness are both in millimeters. Substitute the values directly into the above formula to get the weight of a square pipe per meter in grams. For example, for a 30*30*2.5 mm square pipe, the weight per meter can be calculated according to the above formula: 4*2.5*(30-2.5)*7.85=275*7.85=2158.75 grams, which is about 2.16 kilograms.
When the wall thickness and side length are in millimeters, 4*wall thickness*(side length-wall thickness) calculates the volume of the square tube per meter in cubic centimeters, and then multiplies it by the specific gravity of iron, 7.85 grams per cubic centimeter, to get the weight of the square steel tube per meter in grams.
2. Process characteristics of galvanized steel pipes
Galvanized steel pipes adopt the sulfate electroplating zinc-iron alloy process. The production line slots are perforated and straight through without any solution carryover or overflow. Each process of the production process consists of a circulation system. The solutions in each tank, namely acid and alkali solution, electroplating solution, and light and passivation solution, are only recycled and reused without leakage or discharge to the outside of the system. The production line has only 5 cleaning tanks, which are recycled and discharged regularly, especially since no wastewater is generated after passivation without cleaning. The characteristics of galvanized steel pipes are: the current efficiency of the sulfate electroplating zinc-iron alloy process is as high as 100%, and the deposition rate is fast, which is unmatched by any galvanizing process. The running speed of fine tubes is 8-12m/min, and the average coating thickness is 2m/min, which is difficult to achieve with continuous galvanizing. The coating is bright, delicate, and pleasing to the eye. According to the national standard GB/T10125 “Artificial atmosphere test-salt spray test” method, the coating is intact and unchanged after 72 hours. After 96 hours, a small amount of white rust appears on the surface of the coating.
Galvanized steel pipes only retain the main salt zinc sulfate of sulfate zinc plating. The remaining components such as aluminum sulfate and alum (potassium aluminum sulfate) can be removed by adding sodium hydroxide during the plating solution treatment to generate insoluble hydroxide precipitation. For organic additives, powdered activated carbon is added for adsorption and removal. Experiments have shown that aluminum sulfate and potassium aluminum sulfate are difficult to completely remove at one time, and they have an impact on the brightness of the coating, but it is not serious and can be consumed as they are carried out. At this time, the brightness of the coating can be restored by solution treatment, and the content of components required by the new process can be supplemented to complete the conversion.
Post time: Jan-20-2025