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Photos 1 Features 2 Material 3 Stainless steel pipes classified by production methods 4 The main testing equipment 5 How to distinguish the quality of stainless steel tubes for heating elements 6 Information for orders: 
Customers who bought this product also boughtOur company’s core products are stainless steel and special alloy seamless pipes for industrial use. We utilise the most advanced production facility to process stainless steel, corrosion resistant alloy, titanium alloy, high temperature alloy seamless pipes (hot extrusion/piercing + cold rolling/cold drawing) and welded pipe production lines such as FFX forming and JCO forming. We are committed to providing high-performance, corrosion-resistant, pressure-resistant, temperature-resistant stainless steel pipes for oil and gas, electric power, LNG, energy equipment and petrochemical, chemical, shipbuilding and various other industries.
TOPE provides the highest quality of welded tube, seamless tube, oval tube and strips of stainless steel，our products are widely used in electric heaters, heating elements, superheaters, heat exchangers, condensers, chemical, light industry and other industries, the annual production capacity is 8,000 tons. Our commitment is to shorten lead times，affording greater flexibility. Our customers needs come first so no job is too small.
Stainless steels are classified according to their metallurgical structure: austenitic, ferritic, martensitic, precipitation hardening, and duplex. Austenitic stainless steels contain chromium and nickel. They are hardened only through cold working and are non-magnetic although some may become magnetic by cold working. The materials we supplied are as bellowed.
In order to ensure product quality, the main testing equipment includes WE-100 hydraulic testing machine, pressure testing machine, far-infrared thermometer, stereo microscope, hardness tester and all other measuring tools which meet production needs.
All tubes is 100% Eddy Current Tested and hydraulic tested. We provide the highest quality stainless tube. Rigorous in process inspection and tests assures the highest quality for our customers.
The quality of stainless steel tube is very important to the production of electric heating elements. The material of stainless steel tube is the basis for determining the quality of stainless steel tube. The quality of stainless steel mainly depends on the difference of nickel content. Nickel is a high-quality corrosion-resistant element. Its perfect cooperation with chromium in stainless steel further consolidates the corrosion resistance and acid and alkali resistance, but for low carbon nickel steel, to obtain pure austenite structure, the nickel content must reach 24%, and only when nickel content reach for 27%, it can make the significant change of corrosion resistance of steel in certain media. Therefore, for the heating element tube, if corrosion resistance and high temperature resistance are required, you can choose Alloy 800, Alloy 840, SUS316L and other materials, the nickel content of Alloy 800 tube is 30%, Alloy 840 is 20%, 316L is 10%, But if you use stainless steel 304 tube which contains nickel only 8%, the quality will be too bad.
The advantages of stainless steel heating elements: good heat resistance, dry burning resistance, and relatively low cost. At present, there are many types of stainless steel heating elements, and the price gap of various materials is large. For the same material of stainless steel, the quality and performance are still significant. Therefore, during the purchase of stainless steel pipes for heating elements, we need to test the specific element content to prevent low-quality products at high prices. Stainless steel pipes are difficult to distinguish with naked eye, so how do we identify the material of stainless steel pipes? The following methods can be used:
The magnetism of SUS 316 and SUS 304 is very small.
It is the most intuitive test method to test the corrosion resistance of the substrate through the nitric acid point test. Generally, a good stainless steel pipe will only be slightly corroded during the test, and the stainless steel pipe with the lowest corrosion resistance will have obvious corrosion marks.
It is also called stainless steel tube detection fluid. Make sure the surface of the stainless steel tube is free of stains. After get rid of the coating surface, use a drop of the fluid. Observe the color change of the stainless steel in the test area and compare the color of the stainless steel tube or the time of turning red.
Through the spark and hardness during cutting or welding, the quality of the stainless steel pipe can also be distinguished.
The brighter the brightness, the smoother the surface, and the smaller the oxidized area, the higher the corrosion resistance.
Most of the corrosion of stainless steel pipe starts from the welding line, so the nitrogen protection of the weld can effectively improve the corrosion resistance of the stainless steel pipe.
Although the precision does not have much to do with the corrosion resistance of the stainless steel tube, the higher the precision of the stainless steel tube, the better the process and the higher the quality.
