Identification method and installation technique of stainless steel pipe fittings
Stainless steel has a unique corrosion resistance, it can react with the oxidizing agent, forming a thin and dense oxide film, used to prevent the oxidation reaction into further. For other types of metal pipe, there is almost no passivation function, which is one of the main reasons for the corrosion resistance of stainless steel pipe fittings.
Stainless steel pipe fittings are recognized as a healthy material, widely used in food processing and transportation pipeline, including the 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, stainless steel pipe fittings classification
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 fittings four categories. 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, the use of stainless steel pipe fittings
Stainless steel pipe fittings can be used to ensure the carbon steel surface, such as paint or oxidation resistant metal (e.g., zinc, nickel and chromium), but, as people know, this protection is only a thin film. If the protective layer is damaged, the following steel began to rust, the resistance of air, steam, water and other corrosive medium and weak acid, alkali, salt and other chemical etching medium corrosion of steel.
Stainless steel pipe fittings with the most place is the pressure vessel and chemical aspects. There are a large number of refinery equipment plant needs. Other aspects, such as chemical, food, beverage, pharmaceutical and other industries can be applied. It is widely used in petroleum, chemical, medical, food, light industry, machinery and instruments and other industrial transportation pipeline and mechanical components, etc..
Two, the characteristics of stainless steel pipe fittings
1, life
Stainless steel pipe has the longest service life. Analysis of the use of stainless steel from abroad, the service life of stainless steel pipes can be 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 pipe is 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. And other metal pipes, such as galvanized steel pipe, copper pipe passivation ability is very small, this is the galvanized steel pipe corrosion resistance performance is far less than the key reasons for stainless steel pipe.
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 and thermal insulation
The heat conductivity of the stainless steel tube is the 1/25 of the copper pipe, and the 1/4 of the common steel pipe is especially suitable for the hot water transportation. Stainless steel, the most commonly used in water industry, is 304 and 316 stainless steel, which can meet most of the water treatment and transportation conditions.
4, strength
The strength of the material determines whether the water pipe is solid and durable, safe and reliable. Safety and reliability is the most important requirement of building water supply. In the case of external impact, the possibility of leakage of stainless steel water pipes is very small. High water supply system of high water supply system is generally greater than 0.6Mpa; the pressure on the pipe is higher. Thin wall stainless steel pipe due to excellent mechanical properties, can withstand high water pressure, up to 10Mpa, especially suitable for high water supply.Three, how to distinguish between true and false stainless steel pipe fittings
1, the comparison of the project of tooth front and tooth pitch:
2, the standard of the naked eye to see the sharp teeth, the teeth are evenly and bright.
3, feel: tooth front smooth, processing depth specification, the core wall is uniform, smooth flow.
4, before leaving the factory after mechanical treatment, the surface no clip, debris.
5, low carbon content, corrosion resistance, oxidation resistance, toughness, strong resistance to pressure.
6, rough made, the tooth front is disadvantageous and thick, the tooth distance is not standard, the tooth front has the damage, easy to leak.
7, the thread can not see the luster, gray feel bad,
8, core wall crooked, uneven thickness, fluid after blockage.
9, rough made, the surface is not processed, easy to be oxidized
10, high carbon content, corrosion resistance, poor toughness, tensile strength.
Four, stainless steel pipe fittings installation skills
The installation technique of stainless steel pipe fittings mainly has the following 9 matters needing attention:
1, stainless steel material lifting, can not be directly contact with other metals, should be padded with wood or rubber sheet, etc..
2, the pipe cutting is not allowed to use ordinary grinding wheel piece cutting, should adopt the stainless steel special grinding wheel piece or the plasma cutting.
3, stainless steel pipe and pipe fitting position welding seam inside 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.
8, pipe connection welding mouth of the weld, after welding, pickling and passivation treatment to be carried out.
9, stainless steel pipe fittings water pressure test for water temperature and water quality have certain requirements, the water temperature is not less than 5 degrees Celsius; the chloride ion content in the water had to be greater than 25Pmm.