4'' Sch 40 Astm-A312-A213-A249-Tp310-Stainless-Steel-Pipe-Tube

Since the invention of stainless steel at the beginning of this century, stainless steel has combined the image of modern materials and the outstanding reputation in architectural applications, which has made its competitors envy. Stainless steel does not produce corrosion, pitting, corrosion or wear. Stainless steel is also one of the highest strength materials in building metal materials. Because stainless steel has good corrosion resistance, it enables structural components to permanently maintain the integrity of engineering design. Chromium-containing stainless steel also integrates mechanical strength and high extensibility, and is easy to process and manufacture components, which can meet the needs of architects and structural designers.

Stainless steel seamless pipe is resistant to air, steam, water and other weak corrosion medium and acid, alkali, salt and other chemical corrosion medium corrosion steel pipe. Also known as stainless acid-resistant steel pipe.

The corrosion resistance of stainless steel seamless tubes depends on the alloying elements contained in the steel. Chromium is the basic element to obtain corrosion resistance of stainless steel. When the chromium content in steel reaches about 12%, chromium acts with oxygen in corrosive medium and forms a thin oxide film (self-passivation film) on the steel surface, which can prevent the steel matrix from further corrosion. In addition to chromium, nickel, molybdenum, titanium, niobium, copper and nitrogen are commonly used in stainless steel seamless pipes to meet the requirements of stainless steel structure and properties for various uses.

Stainless steel seamless pipe is a hollow long circular steel, widely used in petroleum, chemical, medical, food, light industry, mechanical instruments and other industrial transport pipelines and mechanical structure components. In addition, when bending and torsion strength is the same, the weight is lighter, so it is also widely used in the manufacture of mechanical parts and engineering structures. Also often used for the production of a variety of conventional weapons, barrel, shells and so on.

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The rolling method is divided into hot rolling, hot extrusion and cold drawing stainless steel pipe.

According to the metallographic structure of stainless steel, it is divided into semi-ferrite semi-m martensite stainless steel pipe, martensite stainless steel pipe, austenitic iron stainless steel pipe and so on.

Specification quality

• GB14975-94< Stainless Steel Seamless Steel Pipe) The length of hot rolled steel pipe is 1.5~10 m, hot extruded steel pipe equal to and greater than 1 The wall thickness of cold-drawn (rolled) steel pipe is 0.5~1.0 mm ,1.0~7, and 1.5~8 m. if the wall thickness is greater than 1.0
• B, diameter of hot rolled (hot extruded) steel pipe is 54~480 mm and the wall thickness is 4.5~45. The diameter of cold-drawn (rolled) steel pipe is 6~200 mm and the wall thickness is 0.5~21.

C, there shall be no cracks, folding, cracking, cracks, rolling, delamination and scarring defects on the inner and outer surfaces of the steel pipe, these defects shall be completely removed (except for pipes for machining) and the wall thickness and outer diameter shall not exceed the

• negative deviation after removal. Any other minor surface defects not exceeding the allowable negative deviation may not be removed.
• D, straight path allows depth. hot-rolled, hot-extruded steel tubes of not more than 5% of nominal wall thickness with diameters less than and equal to 140 mm, maximum depth not greater than 0.5 mm; cold-drawn (rolled) steel tubes not greater than 4% of nominal wall thickness, maximum depth not greater than 0.3 mm.
• E, both ends of the steel pipe should be cut into right angles and burr removed. Manufacturing process of stainless steel seamless pipe:
• 1. hot rolling (extruded seamless steel pipe): tube billet → heating → perforation → three-roll oblique rolling, continuous rolling or extrusion → pipe removal (or reduction), cooling, straightening → water pressure test (or flaw detection) and storage
• The raw material of rolling seamless pipe is round tube billet. The round tube embryo is cut by cutting machine to process the billet with a growth degree of about 1 meter and sent to the furnace by conveyor belt for heating. The billet is heated into the furnace at a temperature of about 1200 degrees Celsius. The fuel is hydrogen or acetylene. Furnace temperature control is a key problem. After the round tube billet is out of the oven, it must pass through the pressure perforation machine to carry on the empty. The common perforator is conical roller perforator, which has high production efficiency, good product quality, large perforation diameter expansion and can wear many kinds of steel. After perforation, the round tube billet has been three-roll oblique rolling, continuous rolling or extrusion. After extrusion, take off the pipe and set the diameter. The diameter fixing machine rotates into the steel embryo through the conical bit at high speed to form the steel pipe. The inner diameter of the steel pipe is determined by the outer diameter length of the drill bit. After the steel pipe is fixed, it enters the cooling tower and is cooled by water spray. After cooling, the steel pipe will be straightened. The steel pipe is straightened and sent from conveyor belt to metal flaw detector (or hydraulic test) for internal flaw detection. If there are cracks, bubbles and other problems inside the steel pipe, it will be detected. Steel pipe quality inspection but also through strict manual selection. After quality inspection of steel pipe, spray the number, specification, production batch number and so on with paint. And crane into the warehouse.
• 2. cold drawn (rolled) seamless steel pipe: pipe billet → heating → perforation → head → annealing, pickling → oiling (copper plating), multi-pass cold drawing (cold rolling)→ billet tube heat treatment, straightening → water pressure test (flaw detection) marking → storage.
• The rolling method of cold drawn seamless steel pipe is more complicated than that of hot rolled seamless steel pipe. Their production process is basically the same in the first three steps. The difference starts from the fourth step, after the tube blank is empty, to hit the head, annealing. After annealing, special acid liquid should be used for pickling. After pickling, oil. Then followed by a multi-pass cold drawing (cold rolling) billet tube, special heat treatment. After heat treatment, the same treatment as steel pipe cooling process.

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