Stainless steel has a unique corrosion resistance, it can react with oxidants, forming a thin and dense oxide film, to prevent the oxidation reaction to further occur. For other types of metal pipe, almost no passivation function, which is stainless steel pipe material corrosion resistance than general metal pipe is one of the main reasons.
Stainless steel pipe fittings are recognized as healthy materials and widely used in food processing pipelines, including pharmaceutical industry, beverage, brewing, etc.. The performance of the stainless steel tube material is superior, effectively reduce the transportation cost, scale, no node in the long-term transportation process while delivering a smooth inner wall, low energy consumption, is by far the lowest cost of conveying pipe materials.
Classification and application of stainless steel pipe fittings
1. Classification of stainless steel pipe fittings
A stainless steel pipe belongs to a pipe, it is made of stainless steel so that it includes: stainless steel pipe fittings, stainless steel elbow, stainless steel three, stainless steel four, stainless steel different diameter pipe, stainless steel pipe cap,
According to the connection method can be divided into socket type stainless steel pipe fittings, threaded stainless steel pipe fittings, flange stainless steel pipe fittings and welded stainless steel pipe four kinds. Stainless steel elbow pipe fitting for the turning point; flange for the pipe and pipe interconnected parts, connected to the pipe end, three stainless steel pipe for three pipe collection; four stainless steel pipe for four pipes together place; for two pipes of different diameters are connected to the local stainless steel different diameter pipe.
2, stainless steel pipe fittings
Stainless steel fittings can be plated with paint or resistant metals such as zinc, nickel and chromium to ensure the surface of carbon steel, but, as everyone knows, this kind of protection is only a film. If the protective layer is destroyed, the steel will begin to rust, corrosion resistance of air, steam, water and other weak corrosive medium and acid, alkali, salt and other chemical corrosive medium corrosion of steel.
The most part of stainless steel pipe fittings is the pressure vessel and the chemical industry. The general refinery equipment plant has a large demand. Other aspects, such as chemicals, food, beverages, pharmaceuticals and other industries, can be applied. It is mainly used in petroleum, chemical, medical, food, light industry, machinery, instrument and other industrial pipeline and mechanical structure parts.
Two, stainless steel pipe features
Stainless steel pipe has the longest service life. From the analysis of the use of stainless steel abroad, the life of stainless steel pipe can reach 100 years, at least 70 years, as long as the life of the building.
2, corrosion resistance
Stainless steel pipe is one of the most prominent advantages of its excellent corrosion resistance, in a variety of pipe is the best. Because stainless steel passivation can occur with the oxidant, forming a layer of dense tough chromium oxide protective film on the surface of Dr2O3, to effectively prevent the occurrence of oxidation reaction. Other metal pipes, such as galvanized water pipes and copper tubes, have very little passivation ability. This is the key reason why the corrosion resistance of galvanized copper tubes is far lower than that of stainless steel pipes.
Stainless steel does not uniform corrosion like carbon steel, without the protection of coating; stainless steel pipe, chemical composition of water is not restricted, because the corrosion resistance of stainless steel is very good in both PH and hardness of various oxygen content, temperature, water; stainless steel pipe can withstand high velocity, even if the flow rate is greater than 40 m / second, still maintain a very low corrosion rate, less than 0.003 mm / year, especially for high-rise water supply.
3 、 heat resistance and heat preservation
The thermal conductivity of the stainless steel tube is 1/25 of the copper tube, 1/4 of the common steel tube, especially suitable for hot water transportation. The most common stainless steels used in the water industry are 304 and 316 stainless steel, which meet most of the water treatment and transmission conditions.
The strength of the material determines whether the pipe is firm and collision resistant, safe and reliable. And safe and reliable is the most important requirement of building water supply. In the case of external impact, the possibility of leakage of stainless steel pipe water is minimal. The work pressure of high-rise water supply system is generally greater than 0.6Mpa; the pressure requirements of the pipe are higher. Because of its good mechanical performance, the thin-wall stainless steel pipe can bear high water supply pressure, and can reach more than 10Mpa, which is especially suitable for water supply in high-rise buildings.
Three, how to distinguish genuine and fake stainless steel pipe fittings?
1. Compare the teeth distance and tooth distance:
2, standard eyes to see sharp teeth, teeth evenly and bright.
3, feel: tooth front smooth, processing depth specifications, the core wall evenly, the flow of smooth.
4, before leaving the factory after mechanical treatment, surface without clamps, sundries.
5, low carbon content, corrosion resistance, oxidation resistance, toughness, strong resistance to stress.
6, rough, tooth front is unfavorable and thick, the distance between teeth is not standard, tooth front damage, easily leaking
7, the thread can not see the luster, gray, bad feel,
8, the core is crooked, the wall thickness is uneven, after the fluid is easy to block.
9, rough, surface untreated, easy to be oxidized
10. High carbon content, no corrosion resistance, poor toughness and weak tensile resistance.
Four 、 installation skills of stainless steel pipe fittings
The installation skills of stainless steel pipe fittings are mainly following 9 matters needing attention:
1, stainless steel materials shipped, and other metals can not be directly contact, should be padded with wood or rubber panels and other non-metallic materials.
2, pipe cutting is not allowed to use ordinary grinding wheel slice cutting, stainless steel grinding wheel or plasma cutting should be used.
3, stainless steel pipe and pipe fittings positioning welding, welding seam should be filled with argon protection.
4, the arc and arc, arc welding method with back arc, should fill craters. The arc must be completed in the groove, prohibit arc in pipes and pipe fittings base material surface and arc. If cracks and other defects were found and timely treatment should be clean at the arc arc.
5, stainless steel pipe, pipe fittings, stainless steel pipes and pipe fittings and non stainless steel pipes and pipe fittings connection, butt joint welding backing welding internal tube and cavity filled with argon prior protection to argon tungsten arc welding.
6, multi multilayer welding arc, arc should be staggered.
7, stainless steel continuous welding, the temperature between the layer is not more than 60 degrees.
8, the pipe welding seam at the mouth, after welding for pickling and passivation treatment.
9, stainless steel pipe pressure test on water temperature and water quality requirements, the water temperature may not be less than 5; the content of chlorine in water has to be greater than 25Pmm.