An important material widely used in the fields of petroleum, natural gas, automobiles, construction, machinery, electricity, chemical industry, etc. Different from welded pipes, seamless steel pipes are made of perforated round steel and have no welds on the surface, hence the name seamless steel pipe. There are hot rolling, cold rolling, cold drawing, extrusion and jacking production methods.
Seamless steel pipe is an important material widely used in the fields of petroleum, natural gas, automobiles, construction, machinery, electricity, chemical industry, etc. It is different from welded pipes. Seamless steel pipes are made of perforated round steel and have no welds on the surface, so they are named seamless steel pipes. There are hot rolling, cold rolling, cold drawing, extrusion, and jacking production methods.
Common seamless steel pipe materials
There are carbon steel, alloy steel, stainless steel, etc. Carbon steel has good mechanical properties and weldability, but poor corrosion resistance; alloy steel improves strength, hardness and wear resistance by adding other elements. Seamless steel pipes for structures (GBT8162), seamless steel pipes for low and medium pressure boilers (GB3087), seamless steel pipes for high pressure boilers (GB5310), and seamless steel pipes for petroleum cracking (GB9948) are mostly made of carbon steel and alloy steel.
Stainless steel has excellent corrosion resistance, formability and toughness in a wide temperature range. It is widely used in industries such as industry, daily necessities and architectural decoration. Stainless steel can be divided into chromium stainless steel (commonly known as 400 series), chromium-nickel stainless steel/chromium-nickel-molybdenum stainless steel (commonly known as 300 series) and chromium-manganese-nitrogen stainless steel (commonly known as 200 series) according to the main chemical composition of the material.
Selection of seamless stainless steel pipe
Usually, it is necessary to select based on the material characteristics of stainless steel (material chemical composition), pressure and temperature requirements, corrosion resistance requirements, connection methods, specifications and dimensions, surface treatment requirements, etc. First of all, we need to know where seamless stainless steel pipes are used, and determine the appropriate material (steel grade/brand) according to the purpose. For specific reference, please refer to the appropriate standards. Some reference standards are as follows:
For general purposes, please refer to the standard specification for general seamless and welded austenitic stainless steel pipes (ASTM A269)
Stainless steel seamless pipes for fluid transportation (GB/T 14976)
Seamless ferrite and austenitic alloy steel pipes for boilers, superheaters and heat exchangers (ASTM A213)
Seamless steel pipes for pressure (EN 10216)
Diesel engine. High-pressure fuel injection pipe assembly (ISO 13296)
Precision stainless steel seamless pipes for rail transit vehicle braking systems (GB/T 34107)
The above standards are also called production and manufacturing execution standards, covering many aspects of the manufacturer's procurement of raw materials, production and processing, quality inspection, factory packaging, etc., such as steel brand, chemical composition, specifications (outer diameter/wall thickness) and allowable deviation, heat treatment, mechanical properties (hardness/flaring, etc.), non-destructive testing, internal and external surface quality, intergranular corrosion test, etc.
