steel tube

　　The combination of chromium and nickel forms chromium-nickel stainless steel, which is a better stainless steel. A large amount of nickel is added to such a stainless steel in order to obtain a single austenite structure, thereby improving its corrosion resistance and workability. It has strong plasticity and toughness at normal temperature and low temperature, is not magnetic, and has good resistance to intergranular corrosion. 　　(1) Chromium plays a major role in the corrosion resistance of stainless steel. Chromium is the main element determining the corrosion resistance of stainless steel. Because chromium in steel can make the stainless steel passivate in the oxidizing medium, that is, a thin layer is formed on the surface. The film is enriched in chromium in this film. The higher the chromium content in the steel, the stronger the corrosion resistance. In addition, chromium can enhance the mechanical properties and process properties of steel. 　　(2) The effect of nickel on...

　　The main processes of hot rolling pickling include laser welding, stretch straightening, turbulent pickling, in-line flattening, and trimming. 　　Pickling specifications are generally 1.0 - 6.0 * 800 - 1650mm. Products include low, medium and high strength stamping steel, automotive structural steel , etc., mainly delivered in the form of steel coils. 　 　Process characteristics 　　A beautiful, smooth surface is obtained by removing the scale from the hot rolled steel sheet. 　 　Features 　　Reducing costs and replacing the cold-rolled sheets with pickled sheets can save costs for the company. 　　The surface quality is good. Compared with the ordinary hot-rolled sheet, the hot-rolled pickling plate removes the surface iron oxide scale, improves the surface quality of the steel, and is convenient for welding, oiling and painting. 　　The dimensional accuracy is high, and after flattening, the plate shape can be changed to reduce the deviation of the unevenness. 　　Improves surfa...

　　Manufacturing process 　　High-frequency welding straight seam steel pipe (ERW) production process is simple, a single production specifications. The double-sided submerged arc welding straight seam steel pipe ( LSAW ) production specification is complete, the plate can be customized in various sizes.Double-sided submerged arc welding straight seam steel production process before molding with JCOE process, complex molding process, forming efficiency relative to the low frequency welded pipe, so the manufacturing cost is higher than the high-frequency welding pipe joints straight. Straight double-sided submerged arc welding pipe joints using double-sided welding, ultrasonic plate probe pre-curved edge → Milling → ultrasonic testing of the JCO forming → pre-welding → welding → Weld → X-ray examination → expanding → hydrostatic test → X-ray examination chamfering → ultrasonic detection → Magnetic particle inspection of the pipe end → finished. 　　application 　　The high-frequency weld...

　　1. Complete annealing. It is used to refine the coarse superheated structure of medium and low carbon steel which has poor mechanical properties after casting, forging and welding. The workpiece is heated to a temperature of 30 to 50 ° C above the temperature at which all of the ferrite is transformed into austenite, and is kept for a period of time, and then slowly cooled with the furnace, and the austenite is again transformed during the cooling process, so that the microstructure of the steel is thinned. . 　　2. Spheroidizing annealing. It is used to reduce the high hardness of tool steel and bearing steel after forging. The workpiece is heated to a temperature of 20 to 40 ° C above the temperature at which the steel begins to form austenite, and is slowly cooled after the heat preservation. During the cooling process, the lamellar cementite in the pearlite becomes spherical, thereby lowering the hardness. 　　3. Isothermal annealing. It is used to reduce the high hardness of ce...

　　 Oil casing pipe gas seal detection technology principle and process 　　Principle: The tightness of the oil casing buckle is closely related to the pressure and medium. The pressure and medium molecular size are different, and the permeability is different. The gas is more difficult to seal than the liquid. 　　The principle of gas seal detection technology is to use the low molecular gas medium to test the gas seal performance of the oil casing buckle under the allowed high pressure conditions. 　　Process: 　　Inserting a test tool with a double packer into the column, sealing it up and down at the threaded joint, then injecting high-pressure nitrogen and ammonia mixed gas into the middle sealed space, and detecting it outside the thread with a high-sensitivity helium detector. To determine if a leak has occurred.

　　Spiral steel surface by high velocity and turbulence of the fluid-like impact, along with wear and corrosion damage was known corrosion and wear. Impact corrosion and wear is the primary form of corrosion. Spiral pipe fluid at high speed impact, protective film damage, break at the bare metal accelerate corrosion. If the fluid contains solid particles, spiral pipe corrosion and wear even more grim. Its surface is characterized by: Locality grooves, ripples, round-shaped valley and generally show directivity. Exposed to the fluid movement of equipment such as:, tees, valves, blowers, centrifuges, impellers, heat exchangers, exhaust duct, etc. can impact the onset of corrosion. Soft metals such as copper and lead more severe. 　　Spiral pipe impact corrosion-prone zone and preventive measures 　　The impact of corrosion attack more fluid changes in the direction of the site. Such as elbows, tees, cyclones, the container inlet tube relative to the location and. Condensers and heat excha...

　　In the production of seamless steel pipes, the first step to be done is galvanizing, because galvanizing will allow the surface of the seamless steel pipe to be coated with an oxide film. This will play a certain protective role, and can make the seamless steel pipe long-term preservation, so that the hardness of the seamless steel pipe is improved, high temperature resistance and corrosion resistance. 　　It has been confirmed from historical tests and production practices that the temperature of the zinc bath for hot-dip galvanizing of seamless steel tubes is controlled at an optimum temperature in the range of 450 to 460'C. When the temperature is high, it will increase the heat consumption, shorten the service life of the steel zinc pot, accelerate the formation of zinc slag and zinc ash, and affect the quality of the galvanized silkworm plastic layer. When the temperature is low, it will affect the galvanizing ability of the seamless steel pipe, and the zinc layer will be t...