Classification of stainless steel pipes: stainless steel seamless steel pipes and stainless steel welded steel pipes (seam steel pipes) are two basic categories. According to the outer diameter of the steel pipe, it can be divided into round pipes and special-shaped pipes. Round steel pipes are widely used, but there are also some square, rectangular, semicircular, hexagonal, equilateral triangle, octagonal and other special-shaped steel pipes.
For steel pipes under fluid pressure, hydraulic tests and radiographic inspections are required to check their pressure resistance and quality. No leakage, soaking or expansion under the specified pressure is qualified. Some steel pipes must be carried out according to standards or requirements of the buyer. Crimping test, flaring test, flattening test, etc.
Seamless stainless steel pipe, also called stainless steel seamless pipe, is made of steel ingots or solid tube billets through perforation to make capillaries, and then hot rolled, cold rolled or cold drawn. The specifications of seamless steel pipes are expressed in millimeters of outer diameter * wall thickness.
The full name of 304 stainless steel pipe is SUS304 stainless steel pipe.
SUS304 stainless steel pipe is a stainless steel pipe made of American grade material. The domestic grade is equivalent to 0Cr19Ni9 stainless steel pipe, and it is usually replaced by 0Cr18Ni9.
The mechanism of stainless steel rust prevention is that alloy elements form a dense oxide film, which isolates oxygen from contacting and prevents continued oxidation. So stainless steel is not "stainless".
The rust of 304 material may have the following reasons:
1. There are chloride ions in the use environment.
Chloride ions are widespread, such as salt, sweat, sea water, sea breeze, soil and so on. Stainless steel corrodes quickly in the presence of chloride ions, even more than ordinary low carbon steel.
Therefore, there are requirements for the use environment of stainless steel, and it needs to be wiped frequently to remove dust and keep it clean and dry.
316 and 317 stainless steel (see below for the properties of 317 stainless steel) are molybdenum-containing stainless steels. The content of molybdenum in 317 stainless steel is slightly higher than that in 316 stainless steel. Due to the molybdenum in steel, the overall performance of this steel is better than 310 and 304 stainless steel. Under high temperature conditions, when the concentration of sulfuric acid is lower than 15% and higher than 85%, 316 Stainless steel has a wide range of uses. 316 stainless steel also has good chloride corrosion properties, so it is usually used in marine environments.
With the development of social economy, the application of stainless steel pipe has also become more and more popular. It will surely bring about a brand-new improvement in all fields.
Theoretical weight of the stainless steel pipe: W = outer diameter-wall thickness x wall thickness x 0.02491.
Since the invention of stainless steel at the beginning of this century, stainless steel has combined the image of modern materials and its excellent reputation in architectural applications, making its competitors envy. Stainless steel will not produce corrosion, pitting, rust or wear. Stainless steel is also one of the strongest materials among metal materials for construction. Because stainless steel has good corrosion resistance, it can make structural components permanently maintain the integrity of engineering design. The chromium-containing stainless steel also combines mechanical strength and high extensibility, easy to process and manufacture parts, and can meet the needs of architects and structural designers.