I. Classification of pipes 1, according to the production method classification (1) seamless pipe - hot-rolled pipe, cold-rolled pipe, cold-drawn pipe, extruded pipe, pipe jacking (2) welded pipe (a) according to the process - arc welded pipe, resistance welded pipe (high-frequency, low-frequency), gas welded pipe, furnace welded pipe (b) according to the welding seam - straight seam welded pipe, spiral welded pipe. Welded pipe (b) according to the weld seam - straight seam welded pipe, spiral welded pipe 2, according to the section shape classification (1) simple cross-section of the steel pipe - round steel pipe, square steel pipe, oval steel pipe, triangular steel pipe, hexagonal steel pipe, rhombus, octagonal steel pipe, semicircle (2) complex cross-section steel pipe - unequal hexagonal steel pipe, five-petal plum-shaped steel pipe, double convex steel pipe, double concave steel pipe, melon shaped steel pipe, conical steel pipe, corrugated steel pipe, case steel pipe, other 3, according to the classification of thick-walled - thin-walled 4, according to the use of classification - pipeline steel pipe, steel pipe for thermal equipment, steel pipe for the mechanical industry, oil, geological drilling steel pipe, container steel pipe, steel pipe for the chemical industry, special-purpose steel pipe, other two, seamless steel pipe is a kind of hollow cross-section, there is no peripheral seams of the long strip of steel. Steel pipe has a hollow cross-section, used in large quantities as a pipeline for the transportation of fluids, such as pipelines for the transportation of oil, natural gas, gas, water and certain solid materials. Compared with solid steel such as round steel, steel pipe is lighter in weight when the bending and torsion strength is the same, and it is a kind of economic cross-section steel, which is widely used to make structural and mechanical parts, such as oil drilling rods, automobile drive shafts, bicycle frames and steel scaffolding used in building construction. Steel pipe manufacturing ring-shaped parts, can improve material utilization, simplify the manufacturing process, save materials and processing time, such as rolling bearing rings, jack sets, etc., has been widely used in the manufacture of steel pipe. Steel pipe or a variety of conventional weapons indispensable materials, gun barrels, gun barrels, etc. to steel pipe to manufacture. Steel pipe according to the shape of the cross-sectional area of different can be divided into round pipe and shaped pipe. Since the circular area is the largest under the condition of equal perimeter, more fluid can be transported with circular pipe. In addition, the circular cross-section is more uniformly stressed when subjected to internal or external radial pressure, therefore, the vast majority of steel pipes are round pipes. However, the round tube also has certain limitations, such as under the conditions of plane bending, round tube is not as strong as the square, rectangular tube bending strength, some agricultural equipment skeleton, steel and wood furniture, etc. are commonly used square, rectangular tube. According to different uses also need to have other cross-section shape of the shaped steel pipe. 1. Seamless steel pipe for structural use (GB/T8162-1999) is a seamless steel pipe used for general structure and mechanical structure. 2. Seamless steel pipe for fluid transportation (GB/T8163-1999) is a general seamless steel pipe used for transportation of water, oil, gas and other fluids. 3. Seamless steel pipe for low and medium pressure boiler (GB3087-1999) is hot-rolled and cold-drawn (rolled) seamless steel pipe of high-quality carbon structural steel used for manufacturing superheated steam pipe, boiling water pipe for low and medium pressure boiler of all kinds of structure, superheated steam pipe for boilers of locomotives, large smoke pipe, small smoke pipe, and arch brick pipe. 4. High-pressure boiler seamless steel pipe (GB5310-1995) is used to manufacture high-quality carbon steel, alloy steel and stainless heat-resistant steel seamless steel pipe for high pressure and above pressure water pipe boiler heating surface. 5. High-pressure seamless steel pipe for chemical fertilizer equipment (GB6479-86) is a high-quality carbon structural steel and alloy steel seamless pipe for chemical equipment and pipelines with working temperature of -40~400℃ and working pressure of 10~30Ma. 6. Seamless steel pipe for petroleum cracking (GB9948-88) is seamless steel pipe for furnace pipe, heat exchanger and pipeline of petroleum refinery. 7. Steel pipe for geological drilling (YB235-70) is a steel pipe used for core drilling in geological department, which can be divided into drill pipes, drill collars, core pipes, casing pipes and precipitation pipes according to the usage. 8.Seamless steel pipe for diamond core drilling (GB3423-82) is seamless steel pipe for diamond core drilling drill pipe, core pipe and casing. 9. Oil drilling pipe (YB528-65) is a seamless steel pipe used for oil drilling with thickening inside or outside at both ends. There are two kinds of steel pipes, car-wire and non-car-wire, car-wire pipes are connected with joints, and non-car-wire pipes are connected with tool joints by butt-welding method. 10. Carbon steel seamless steel pipe for ships (GB5213-85) is a carbon steel seamless steel pipe used for manufacturing ship class I pressure-resistant pipe system, class II pressure-resistant pipe system, boiler and superheater. Carbon steel seamless steel pipe wall working temperature does not exceed 450 ℃, alloy steel seamless steel pipe wall working temperature exceeds 450 ℃. 11. Automobile half shaft casing seamless steel pipe (GB3088-82) is the manufacture of automobile half shaft casing and drive axle housing axle tube with high quality carbon structural steel and alloy structural steel hot rolled seamless steel pipe. 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. Hydraulic and pneumatic cylinder barrel with precision internal diameter seamless steel tube (GB8713-88) is the manufacture of hydraulic and pneumatic cylinder barrel with precision internal diameter size of cold-drawn or cold-rolled precision seamless steel tubes. 14. Cold-drawn or cold-rolled precision seamless steel tubes (GB3639-83) are cold-drawn or cold-rolled precision seamless steel tubes with high dimensional accuracy and good surface finish for mechanical structures and hydraulic equipment. Selection of precision seamless steel pipe manufacturing mechanical structure or hydraulic equipment, etc., can greatly save machining hours, improve material utilization, while helping to improve product quality. 15. Structural stainless steel seamless steel pipe (GB/T14975-1994) is widely used in chemical, petroleum, textile, medical, food, machinery and other industries, corrosion-resistant piping and structural components and parts of the stainless steel made of hot-rolled (extruded, expanded) and cold-drawn (rolled) seamless steel pipe. 16. Stainless steel seamless steel pipe for fluid transportation (GB/T14976-1994) is used for the transportation of fluids made of stainless steel hot-rolled (extruded, expanded) and cold-drawn (rolled) seamless steel pipe. 17. Shaped seamless steel pipe is in addition to other than round seamless steel pipe cross-section shape of the general term. According to the different dimensions of the cross-section shape of the pipe can be divided into equal wall thickness profiled seamless steel pipe (code D), unequal wall thickness profiled seamless steel pipe (code BD), variable diameter profiled seamless steel pipe (code BJ). Profiled seamless steel pipe is widely used for various structural parts, tools and mechanical parts. Compared with round pipe, shaped pipe generally has larger moment of inertia and section modulus, has larger bending and torsion resistance, can greatly reduce the weight of the structure and save steel. Generally 201 202 304 316 These 202 and 304 used more
316 and 317 stainless steel (317 stainless steel properties see later) is a molybdenum stainless steel. 317 stainless steel molybdenum content is slightly higher than 316 stainless steel. Because of the molybdenum in the steel, the total performance of the steel is better than 310 and 304 stainless steel, high temperature conditions, when the concentration of sulfuric acid is less than 15% and higher than 85%, 316 stainless steel has a wide range of uses. 316 stainless steel also has a good and chloride erosion performance, so it is usually used in marine environments.
316L stainless steel has a maximum carbon content of 0.03, can be used after welding can not be annealed and need maximum corrosion resistance
Corrosion resistance
Corrosion resistance
Corrosion resistance is better than the 304 stainless steel, in the production of pulp and paper production process has good corrosion resistance. And 316 stainless steel is also resistant to marine and aggressive industrial atmospheres.
Heat resistance
In intermittent use below 1600 degrees and in continuous use below 1700 degrees, 316 stainless steel has good oxidation resistance. In the range of 800-1575 degrees, it is best not to continuous role of 316 stainless steel, but in the continuous use of 316 stainless steel outside the temperature range, the stainless steel has good heat resistance. 316L stainless steel resistance to carbide precipitation is better than 316 stainless steel, available in the above temperature range.
Heat treatment
Annealed in the temperature range of 1850-2050 degrees, then annealed rapidly, then cooled rapidly. 316 stainless steel can not be hardened by heat treatment.
Welding
316 stainless steel has good welding properties. All standard welding methods can be used for welding. Welding can be done with 316Cb, 316L or 309Cb stainless steel filler rod or electrodes, respectively, depending on the application. For optimum corrosion resistance, welded sections of 316 stainless steel need to be annealed after welding. If 316L stainless steel is used, no post-weld annealing is required. ( 00Cr17Ni14Mo2 )
Mo2Ti.
Main difference: 316 contains molybdenum
304 contains neither titanium nor molybdenum
Mo2Ti contains both molybdenum and titanium
Performance of 316L is optimal, 321/304 is average