Stainless steel has a unique corrosion resistance, it can react with the oxidant to form a thin and dense oxide film used to prevent the oxidation reaction into a further occurrence. For other types of metal pipe, almost no passivation function, which is stainless steel pipe material corrosion resistance than the general one of the main reasons for metal pipe.
Stainless steel pipe fittings are recognized as healthy materials, widely used in food processing and transportation pipeline, including the pharmaceutical industry, beverages, brewing and so on. Stainless steel pipe material performance is superior, effectively reduce the cost of transportation, in the long process of transport will not scale, smooth inner wall, while transporting low energy consumption, is the lowest cost of water pipes so far.
First, the classification and use of stainless steel pipe fittings
1, stainless steel pipe fittings classification
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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 categories. Stainless steel elbow for pipe turning place; flange for the pipe and pipe interconnected parts, connected to the pipe end, stainless steel tee for three pipe collection place; stainless steel pipe for four pipe collection Place; stainless steel reducer for the different diameter of the two pipes connected to the place.
2, the use of stainless steel pipe
Stainless steel fittings can be used to ensure carbon steel surfaces by means of paints or oxidation resistant metals (eg zinc, nickel and chromium), but, as is known, this protection is only a film. If the protective layer is damaged, the following steel will start to rust, resistance to air, steam, water and other weak corrosive media and acid, alkali, salt and other chemical erosion medium corrosion of steel.
Stainless steel pipe fittings with the most is the pressure vessel and chemical aspects. General refinery equipment factory has a lot of demand. Other aspects, such as chemical, food, beverage, pharmaceutical and other industries can be applied. Its main widely used in petroleum, chemical, medical, food, light industry, mechanical instruments and other industrial pipelines and mechanical structural components.
Second, the characteristics of stainless steel pipe fittings
1, life expectancy
Stainless steel tubing has the longest service life. Analysis of the use of stainless steel from abroad, stainless steel water pipe life of up to 100 years, at least 70 years, as long as the life of the building.
2, corrosion resistance
One of the most prominent advantages of stainless steel tubing is its excellent corrosion resistance, which is the best in a variety of tubing. Because stainless steel can be passivated with the oxidant, in the surface to form a layer of tough and dense chromium oxide oxide protective film Dr2O3, effectively prevent the further occurrence of oxidation. The other metal pipe, such as galvanized water pipes, brass passivation capacity is very small, which is galvanized copper tube corrosion resistance is far less than the key reason for stainless steel pipe.
Stainless steel does not have the same corrosion as carbon steel, the use of no need to protect the coating; the use of stainless steel water pipes, the chemical composition of water is not limited, because the stainless steel in a variety of oxygen content, temperature, PH and hardness of the water are very good Corrosion resistance; stainless steel water pipes can withstand high flow rates, even if the flow rate is greater than 40 m / s, still maintain a very low corrosion rate, not more than 0.003 mm / year, especially for high-rise water supply.
3, heat and insulation
Stainless steel tube thermal conductivity is brass tube 1/25, is the ordinary steel pipe 1/4, especially for hot water delivery. The most commonly used stainless steel in the water industry is 304 and 316 stainless steel, which meet the vast majority of water treatment and transmission conditions.
The strength of the material determines whether the water pipe is strong and reliable, safe and reliable. And safe and reliable construction of water is the most important requirements. In the case of external shocks, the possibility of leakage of stainless steel water pipes is extremely small. High-rise water supply system working pressure is generally greater than 0.6Mpa; pipe pressure requirements are higher. Thin-walled stainless steel pipe due to excellent mechanical properties, can withstand high water pressure, up to 10Mpa above, especially for high-rise water supply.
Third, how to distinguish between true and false stainless steel pipe fittings
1, compare items tooth front and teeth distance:
2, the standard naked eye to see the front teeth sharp, teeth from the uniform and bright.
3, feel: ivory smooth, deep processing standards, the core is even wall, flow flow.
4, the factory before mechanical processing, the surface without folder, debris.
5, low carbon content, corrosion resistance, oxidation resistance, toughness, strong anti-pressure.
6, rough, tooth front unfavorable and thick, teeth from the non-standard, tooth front damage, easy to leak
7, thread can not see the shiny, dark feel bad,
8, core distortion, wall thickness uneven, easy to plug the fluid after.
9, rough, the surface is not processed, easy to be oxidized
10, high carbon content, not rot, toughness is poor, weak pull resistance.
Fourth, the installation of stainless steel pipe fittings skills
Stainless steel pipe fittings installation techniques are the following nine note:
1, stainless steel material lifting, can not be in direct contact with other metals, should be added to the board or rubber sheet and other non-metallic materials.
2, pipe cutting is not allowed to use ordinary wheel cutting, should be used for stainless steel grinding wheel or plasma cutting.
3, stainless steel pipe and pipe fittings welding should be carried out on the inside of the weld argon protection.
4, starting arc and arc, starting arc using back welding method, the arc should be filled with craters. Arc must be completed in the groove, prohibited in the pipeline, pipe base material arc and arc. If the arc and the arc found at the pores, cracks and other defects should be promptly handled clean.
5, stainless steel pipe, pipe fittings and stainless steel pipe, pipe fittings and non-stainless steel pipe, pipe fittings, welding of the butt joint primer welding before and inside the cavity should be filled with argon protection, in order to TIG welding.
6, multi-channel multi-layer welding from the arc, the arc should be staggered with each other.
7, stainless steel continuous welding, the interlayer temperature does not exceed 60 ℃.
8, pipe connection welds at the weld, after welding to be pickling and passivation treatment.
9, stainless steel pipe water pressure test on the water temperature and water quality have certain requirements, the water temperature shall not be less than 5 degrees Celsius; water chloride content had to be greater than 25Pmm.
Source: China Stainless Steel Pipe Fittings Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)