I. classification of pipes
1. Classification by production method
(1) seamless tube -- hot rolled tube, cold rolled tube, cold drawn tube, extrusion tube and push tube
(2) pipe welding
(a) by process -- arc welding pipe, resistance welding pipe (high frequency, low frequency), gas welding pipe, furnace welding pipe
(b) by weld - straight welded pipe, spiral welded pipe
2. Classification by section shape
(1) simple steel tubes -- round steel tubes, square steel tubes, oval steel tubes, triangle steel tubes, hexagonal steel tubes, diamond steel tubes, octagonal steel tubes, semicircular steel tubes and others
(2) steel tubes with complex sections -- hexagonal steel tubes with unequal sides, quintuple plum shaped steel tubes, double convex steel tubes, double concave steel tubes, melon seed shaped steel tubes, conical steel tubes, corrugated steel tubes, case steel tubes, and others
3. Classification by wall thickness -- thin-wall steel pipe, thick-wall steel pipe
4. Classification by purpose -- pipe for pipe, pipe for thermal equipment, pipe for mechanical industry, pipe for petroleum, pipe for geological drilling, pipe for container, pipe for chemical industry, pipe for special purpose and others
Practical knowledge of steel
Two, seamless steel pipe
Seamless steel tube is a kind of strip steel with hollow section and no joints around.Steel pipe has a hollow section and is widely used as a pipe for conveying fluid, such as oil, natural gas, gas, water and some solid materials.Steel pipe and round steel and other solid steel compared, in the bending and torsion strength at the same time, the weight is lighter, is an economic section of steel, widely used in the manufacture of structural parts and mechanical parts, such as oil drilling pipe, car shaft, bicycle frame and construction of steel scaffolding.Using steel pipe to make annular parts can improve the material utilization rate, simplify the manufacturing process, and save materials and processing time, such as rolling bearing rings, jack sleeves, etc., which have been widely used to make steel pipe.Steel pipe is also an indispensable material for all kinds of conventional weapons.Steel pipe can be divided into circular pipe and shaped pipe according to the different shape of cross section area.Since the area of the circle is the largest under the condition of equal perimeter, more fluid can be transported through the circular tube.In addition, when the ring section is subjected to internal or external radial pressure, the force is more uniform, so the vast majority of steel tubes are round.However, the circular pipe also has certain limitations. For example, under the condition of plane bending, the circular pipe is not as strong as the bending strength of square and rectangular pipes. Some agricultural machinery and tools, steel and wood furniture, etc. are commonly used square and rectangular pipes.Special steel tubes of other section shapes are required for different purposes.
1.Seamless steel tubes for structural purposes (GB/ t8162-1999) are seamless steel tubes for general and mechanical applications.
2. Seamless steel tube for fluid transport (GB/ t8163-1999) is a general seamless steel tube for water, oil, gas and other fluids
3.Seamless steel tube for low and medium pressure boiler (gb3087-1999) is a kind of high quality carbon structural steel hot-rolled and cold-drawn (rolled) seamless steel tube, which is used for manufacturing superheated steam pipe, boiling water pipe and superheated steam pipe, large smoke pipe, small smoke pipe and arch brick pipe for various low and medium pressure boiler structures.
4.Seamless steel tubes for high pressure boilers (gb5310-1995) are high quality carbon steel, alloy steel and stainless heat resistant seamless steel tubes for the heating surface of water tube boilers with high pressure and above.
5. Fertilizer equipment with high-pressure seamless steel tube (GB6479-86) is applicable to the working temperature for - 40 ~ 400 ℃, the working pressure of 10 ~ 30 ma chemical equipment and pipeline of high quality carbon structural steel and alloy steel seamless steel tube.
6.Seamless steel tubes for petroleum cracking (gb9948-88) are suitable for furnace tubes, heat exchangers and seamless steel tubes for pipelines in petroleum refineries.
7. The steel pipe for geological drilling (yb235-70) is the steel pipe for the geological department to conduct core drilling, which can be divided into drill pipe, drill collar, core pipe, casing pipe and sedimentation pipe, etc.
8.Seamless steel tube for diamond core drilling (gb3423-82) is a seamless steel tube for drill pipe, core rod and casing used in diamond core drilling.
9. Oil drilling pipe (yb528-65) is a seamless steel tube used for both ends of oil drilling for internal or external thickening.Steel pipe is divided into two types, turning wire and non-turning wire.
10. Ship with carbon steel seamless steel tube (GB5213-85) is the manufacturing of ship class I pressure piping, pressure piping Ⅱ, boiler and overheating for carbon steel seamless steel tube.Carbon steel seamless steel tube wall temperature does not exceed 450 ℃, the alloy steel seamless steel tube wall temperature over 450 ℃.
11.Automobile semi-axle tube seamless steel tube (gb3088-82) is the manufacture of automobile semi-axle tube and drive axle shell shaft tube of high quality carbon structural steel and alloy structural steel hot-rolled seamless steel tube.
12. High-pressure oil pipe for diesel engine (gb3093-86) is a cold-drawn seamless steel pipe for manufacturing high-pressure pipe for diesel engine injection system.
13. Precision seamless steel tube with inner diameter for hydraulic and pneumatic cylinder (gb8713-88) is a cold-drawn or cold-rolled precision seamless steel tube with precise inner diameter for manufacturing hydraulic and pneumatic cylinder.
14. Cold-drawn or cold-rolled precision seamless steel tube (gb3639-83) is used for mechanical structure, hydraulic equipment of high dimensional accuracy and good surface finish cold-drawn or cold-rolled precision seamless steel tube.Precision seamless steel pipe manufacturing machinery structure or hydraulic equipment, etc., can greatly save machining time, improve material utilization rate, and is conducive to improving product quality.
15.Stainless steel seamless steel tubes for structure (GB/ t14975-1994) are hot-rolled (extruded, expanded) and cold-drawn (rolled) seamless steel tubes made of stainless steel of corrosion-resistant pipes and structural parts and parts widely used in chemical, petroleum, textile, medical, food and machinery industries.
16.Seamless stainless steel tubes for fluid transport (GB/ t14976-1994) are hot-rolled (extruded, expanded) and cold-drawn (rolled) seamless steel tubes made of stainless steel for fluid transport.
17.Special-shaped seamless steel tube is the general term for seamless steel tubes of other section shapes except circular tubes.According to the different shape and size of steel tube section, it can be divided into isopolaric seamless steel tube (code D), isopolaric seamless steel tube (code BD) and variable diameter isopolaric seamless steel tube (code BJ).Profiled seamless steel pipe is widely used in various structural parts, tools and mechanical parts.Compared with the round pipe, the special-shaped pipe generally has a greater moment of inertia and section modulus, has a greater resistance to bending and torsion, can greatly reduce the weight of the structure, save steel.