steel pipe

　　The machinery industry is a major consumer of steel pipes, mainly including oil, cylinder tubes, tubes for hydraulic parts, tubes for shafts, shafts and rolls, and gas and liquid tubes for mechanical equipment. Seamless steel pipe account for 4% of the steel used in the machinery industry. %, so the amount of steel pipe used in the machinery industry in 2017 was estimated to be 6 million tons. 　　In 2017, China's shipbuilding completion volume may be the same as in 2016, and the hand-held order volume will be less than 90 million DWT. For a 10,000-ton ship, the total length of steel pipes is about tens of kilometers. The marine pipes are mostly water supply and drainage, steam, fuel oil, hydraulic oil pipes, etc. The steel pipe types include seamless steel pipes, straight seam submerged arc welded pipes and high-frequency straight seam welded pipes. The pressure is at least 0.7MPa, the highest is 40MPa, the design temperature is 60°C~300°C, and the pipe diameter is ф114mm~ф610mm...

　　 ERW steel pipe is able to meet the oil, natural gas pipeline. 　　Characteristics of ERW Pipe 　　(1) ERW steel pipe welding mechanism made gratifying achievements, and to the theory as a guide for the optimization of the welding process, all optimized parameters, the computer control, to mention Song of weld quality. 　　(2) weld annealing using fluorescence line positioning technology, so that annealing strictly specified site, so that weld quality further improved. 　　(3) early ERW pipe weld zone the ductile-brittle turn temperature FATT value is much higher than the base metal, the maximum difference of 40-50 degrees. Metallurgical and technological progress, the FATT the value of the pipe base metal can be as low as about -70-80 degrees, so even if the two have some difference, able to meet user requirements. 　　(4) the application of the technology of automated ultrasonic testing, ultrasonic automatic tracking online detection can be achieved, so that the weld formed to fur...

　　Generally, seamless steel pipe defects are crack, fold, double skin, hairline, pinhole, etc... 　　When both ends of the reserved resection margin less, due to the structural reasons of the detection device, both ends of the head and sometimes the lack of effective testing, the end is most likely there are cracks or other defects in the site. End there is a potential crack tendency, the installation of the weld heat affected may also be potential crack propagation. Therefore, it should be noted that the detection of a certain region of the welded seamless steel pipe , the timely detection of defective expansion of the pipe ends. 　　Magnetic particle testing, penetrant testing can be effectively found that the surface crack, fold, double skin, hairline, pinhole surface defects. Ferromagnetic material, should give priority to the use of magnetic particle testing method, because it has a high detection sensitivity; non-ferromagnetic material such as stainless steel seamless pipe penetr...

　　 Seamless steel pipe internal and external surface defects on the performance of high-pressure boiler tubes using have a great influence, for use in the production process, mainly the following measures to control quality. 　　1, the heating of the ingot, billet surface and perforation of the capillary inner and outer surfaces and determined by the money shortage tube outer diameter surface to remove oxide skin, eliminating the resulting scarring and other defects. 　　2, the use of high-quality work, excellent mold and process for lubrication to prevent sticking during rolling of steel, defects, excessive wear and other phenomena, to eliminate the resulting straight, scratching, rolling off, cracks and other defects. 　　3, use of protective gas heat pipe. No shielding gas should be heat-treated steel shot blasting, sanding, etc. Overall, the surface of iron oxide to eliminate defects and improve surface quality and ease of surface inspection.

　　1) Appearance defects such as crack, folding, heavy skin, hair grain, pinhole. Generally magnetic particle testing or soak detection is used. For ferromagnetic material, magnetic powder assay should be adopted preferentially, because it has higher flexibility of detection; for non-ferromagnetic material, such as stainless seamless steel pipe , soak test is used. 　　2) Steel pipe end defects. When obligate excision allowance is fewer, for the structural reasons of detection installation, the two ends sometimes can not get useful testing, which is the most likely to crack or other defects existing sites. If there are latent crack points, the welding heat may also lead to crack propagation. Thus, after butt we should also pay attention to the detection of will surely area of seamless steel pipe, and duly find out defect expansion in steel pipe end. 　　3) Defects such as stress corrosion crack or corrosive pitting. For online use austenitic seamless steel pipe, when shell damaged or th...

　　OCTG casing and tubing is a kind of popular steel pipe in the steel industry, but there occurs decarburization phenomenon for the OCTG tubing and casing. Then what do we take the measures to avoid decarburization for them? 　　Generally, there are two ways to avoid decarburization for OCTG casing and tubing. One is the common and simple way: make full use of nitrogen protective to sustain the pressure inside the furnace. According to proportion, workers can join or inject into the neutral nitrogen to the furnace, which will not only prevent the outside air decomposing into oxygen and water vapor into the debris but also disperse the gas existing oxidation in furnace effectively. Without reaction medium with the surface of carbon, decarburization would not happen and the area of the decarburization also can be reduced generally. 　　Another way is to make the balance to control furnace carbon dioxide levels according to the OCTG tubing and casing workpiece. Expert research if the bala...

　　In some high-intensity work environment, large-diameter seamless steel pipe may deform. So how to straighten large diameter seamless steel pipes? The best way is to use steel pipe straightening machine. Steel pipe straightening machine is used for metal profiles, bars, tubes, wire, etc. Here we will introduce operations and attentions of steel pipe straightening machine to correct large diameter seamless steel pipes. 　　1. Before starting, check the hydraulic oil box, gear box is full or not. 　　2. Before starting the main motor, adjust the hydraulic system pressure. 　　3. Lubricate every smooth point and ensure the work of the mechanical transmission is sensitive. 　　4. After the oil pressure reaches stable. The straightening rollers should be lifted to the initial position. 　　5. Put the large diameter seamless steel pipe on the third straightening roller. 　　6. Start the main motor, large diameter seamless steel pipe will rotate with straightening. 　　7. Stop the motor and...

　　Tips for choosing good quality seamless steel pipes . 　　1. As for good quality seamless steel pipes, its cross section should be smooth and even. If you see there is burr or uneven cross section, do not pick up these defective seamless steel pipes. 　　2. You need to know the percent of impurities. Weight the pipes and measure its density. If it is low density, light seamless steel pipes will be poor quality. 　　3. Check trademark. There will be standard trademark and words on seamless steel pipe from good quality seamless steel pipes manufacturers. 　　4. Check the shape of seamless steel pipes. As for poor quality pipes, you will find oval shape on the side of it. 　　5. Check the surface of seamless steel pipes. Bad rolling technology produce rough surface seamless steel pipes. Do not choose poor surface seamless steel pipes.

　　In the non-destructive testing of ultrasonic welding of straight seam welded pipes, there are commonly used: ultrasonic flaw detection, X-ray inspection, film inspection. There are single-sided double-sided flaw detection, double-sided double-side flaw detection, and single-sided one-sided flaw detection. When selecting the flaw detection method, it is determined according to the wall thickness of the straight seam welded pipe and the width of the weld seam. The thick and wide weld seam is suitable for single-sided double-side flaw detection or double-sided double sides. 　　Execution standards for straight seam welded pipe inspection: 　　GB11345-89, GB/T11345-2013 Non-destructive inspection of flaw detection, primary and secondary inspection, select three-level inspection for structural piping with low requirements. 　　The welded steel pipe shall be subjected to mechanical performance test, flattening test and flare test after the finished product is completed. It is also necessar...

　　Large diameter LSAW steel pipe suit for conveying sea and land oil and gas, oil and natural gas, coal and ore oar medium pipeline , particularly appropriate Currently being built in our country "west to east gas pipeline project", can also be used for exports and replace imported. Here are its production process: 　　1. Plate probe: used to manufacture large diameter submerged arc welded steel pipe joints straight after entering the production line, the first full-board ultrasonic testing; 　　2. Milling: Milling machine through the two-sided edge of the milling plate, so as to meet the requirements of the plate width, the plate sides parallel to the groove shape and degree; 　　3. Pre-curved side: the use of pre-bending machine pre-bending plate edge, the edge of the plate has to meet the requirements of curvature; 　　4. Forming: in the first half of JCO molding machine after the pre-bending step after several stamped steel, pressed into a "J" shape, and then th...