The definition of stainless steel seamless pipes
Stainless steel seamless pipe is a long strip of steel with a hollow section and no joints around it. It is resistant to air, steam, water and other weak corrosive media and acid, alkali, salt and other chemical etch medium corrosion of the steel pipe. It also known as stainless acid resistant steel pipe.
The features of stainless steel seamless pipes
First, the thicker the wall thickness of the product, the more economical and practical it is. The thinner the wall thickness, its processing costs will rise significantly.
Secondly, the process of the product determines its limited performance, and the general precision of seamless steel pipes is low. The wall thickness is uneven, the inner and outer surfaces of the tube have low brightness, the cost of cutting to length is high, and there are pits and black spots on the inner and outer surfaces that are difficult to remove.
Third, its detection and shaping must be processed offline. Therefore, it reflects its superiority in terms of high pressure, high strength, and mechanical structural materials.
The corrosion resistance of stainless steel seamless pipes depends on the alloy elements contained in the steel. Chromium is the basic element that makes stainless steel corrosion resistant. When the chromium content in steel reaches about 12%, chromium interacts with the oxygen in the corrosive medium to form a thin oxide film (self-passivation film) on the surface of the steel. , which can prevent further corrosion of the steel matrix.
In addition to chromium, commonly used alloy elements for stainless steel seamless pipes include nickel, molybdenum, titanium, niobium, copper, nitrogen, etc. to meet the requirements for the structure and performance of stainless steel for various purposes. In addition to chromium, commonly used alloy elements for stainless steel seamless pipes include nickel, molybdenum, titanium, niobium, copper, nitrogen, etc. to meet the requirements for the structure and performance of stainless steel for various purposes.
The type of stainless steel seamless pipes
The rolling methods are divided into hot rolling, hot extrusion and cold drawn (rolled) stainless steel pipes.
According to the different metallographic structures of stainless steel, it can be divided into semi-ferritic and semi-martensitic stainless steel pipes, martensitic stainless steel pipes, austenitic stainless steel pipes, austenitic-ferritic stainless steel pipes, etc.
The application of stainless steel seamless pipes
1. Stainless steel seamless pipes for structural use (GB/T8162-1999) are seamless pipes used for general structures and mechanical structures.
2. Stainless steel seamless pipes for fluid transportation (GB/T8163-1999) are general seamless pipes used to transport fluids such as water, oil, gas, etc.
3. Stainless steel seamless pipes for low and medium pressure boilers (GB3087-1999) are used to manufacture superheated steam pipes, boiling water pipes for low and medium pressure boilers of various structures, superheated steam pipes, large smoke pipes, small smoke pipes and arch brick pipes for locomotive boilers. High-quality carbon structural steel hot-rolled and cold-drawn (rolled) seamless pipes.
4. Stainless steel seamless pipes for high-pressure boilers (GB5310-1995) are high-quality carbon steel, alloy steel and stainless heat-resistant steel seamless pipes used for the heating surfaces of water tube boilers with high pressures and above.
5. High-pressure stainless steel seamless pipes for fertilizer equipment (GB6479-2000) are high-quality carbon structural steel and alloy steel seamless pipes suitable for chemical equipment and pipelines with working temperatures of -40~400℃ and working pressures of 10~30Ma.
6. Stainless steel seamless pipes for petroleum cracking (GB9948-88) are seamless pipes suitable for furnace tubes, heat exchangers and pipelines in petroleum refineries.
7. Steel pipes for geological drilling (YB235-70) are steel pipes used by geological departments for core drilling. According to their uses, they can be divided into drill pipes, drill collars, core pipes, casings and sedimentation pipes, etc.
8. Stainless steel seamless pipe for diamond core drilling (GB3423-82) is a seamless pipe used for drill pipe, core rod and casing for diamond core drilling.
9. Oil drilling pipe (YB528-65) is a stainless steel seamless pipe with internal or external thickening at both ends for oil drilling. Steel pipes are divided into two types: wired and unthreaded. Threaded pipes are connected with joints, and non-threaded pipes are connected with tool joints by butt welding.
