steel tube

　　Welded pipe is generally divided into straight seam welded pipe and spiral welded pipe two types. 　　 Strength characteristics 　　When the pressure in the pipe withstand, usually two main stress on the wall, that the radial and axial stress stress δ. Synthetic weld stress δ, where α is the helix angle of the spiral weld pipe. Spiral welded seam degree helix angle is generally so synthetic, and spiral weld Longitudinal stress is the main stress. Under the same operating pressure, spiral pipe of the same diameter than the Longitudinal wall thickness can be reduced. 　 　Hydrostatic burst strength 　　By the relevant comparison test to verify the spiral welded pipe and Longitudinal yield pressure and burst pressure measured and theoretical values ??match, the deviation closer. But whether it is the yield stress or burst pressure, were lower than the Longitudinal spiral welded. Burst test also shows that the rate of deformation ring spiral welded pipe bursting Longitudinal significant...

　　The solution temperature is mainly determined by chemical composition. In general, the solution temperature should increase for those containing many kinds of alloy elements or with high alloy. Especially for those that contains high steel, like manganese, molybdenum, nickel, silicon. Only by increasing the solution temperature can we dissolve and soften them. But for stabilized steels such as 321 stainless steel pipe , when the solution temperature is high, the carbide of the stabilizing elements are fully dissolved in the austenite and precipitate in the grain boundary with the form of Cr23C6 after cooling. That can cause intergranular corrosion. We often adopt the lowest solution temperature for carbide(Tic and NbC) of the stabilizing elements which can't be dissolved or treated by solid solution. 　　For seamless stainless steel pipe, the three elements of the solution treatment are temperature, holding time and cooling rate. What is the role of solution treatment of seamless...

　　We know that steel pipe surface treatment is one of the key factors determine the service life of the pipeline corrosion, it is a precondition for whether the anti-corrosion layer and steel tube can be combined. It is verified by the research institutions that the life of the coating depends on the quality of coating types, coating quality and environmental factors such as construction. The steel tube surface treatment effects on coating life accounted for about 50%, therefore, we should be strictly accordance with the specification on the coating on the surface of steel pipe requirements, continuously explore and summary, continuously improve steel pipe surface treatment. 　 　1. Cleaning 　　Using solvent and emulsion to clean the steel surface, to remove oil, grease, dirt, lubricants, and similar organic matters, but it cannot remove rust, scale, such as welding flux on the surface of the steel, so only as auxiliary in the anti-corrosion production. 　 　2. Rust cleaning by tools ...

　　Transverse cracks will affect the finished product rate just after rolling. Increase billet cleanup time, both great harm. The slab temperature is brittle zone of 700-900 ℃. The reason the lower surface cracks is 1050-1100 ℃, transverse cracks on the surface of the reason is the billet surface by a large segment straightening straightening stress. Niobium nitride in the austenite grain boundaries reduces the binding force, the grain boundary precipitation. At this point in the curved section slab junction arc poor, resulting in a lower surface cracks. Vertical cracks and chemical composition, mold cooling water temperature, mold equipment, the chemical composition of the slag, continuous casting machine precision secondary cooling system related. Related prevention measures: 　　1. Control steel composition. Try to prevent wC is 0.12% -0.16% D36 steel carbon content in the smelting process control method according to the upper limit. Can effectively reduce the cracks. Peritectic reac...

　　Seamless steel tube is the combination of machining and metal pressure processing, processing many ways, within the scope of machining and the like, are common stamping, forging method, roller processing method, rolling method, bulging method, stretching , bending method, and a combination of processing methods, to understand in detail below under: 　　1, Bulging method: one is placed in the seamless steel pipe rubber, with the top punch compression, so that the sub-convex shaped seamless steel pipe; Another method is forming a hydraulic bulging in the middle of seamless steel tubes filled with liquid child, by fluid pressure seamless steel sub-drum into the desired shape, like we used corrugated seamless steel pipe production is most used in this way. 　　2, Forging method: using a swaging machine seamless steel pipe end or part of the child to be rushed stretch, reducing the outer diameter, often have a rotary swaging machine, link type, roller. 　　3, Roller method: Place the cor...

　　High-pressure alloy pipe deformation strengthening is using the method of deformation of steel reinforcement. Also known as the strain hardening or work hardening. The strength of the material at the macro (or a whole) the ability to resist deformation (or flow stress). Hardness is the ability of the material to resist plastic deformation localized (whether micro-hardness, Vickers hardness, Rockwell hardness or Brinell hardness). Both have similar corresponding relationship in many cases. Strength of the material, the greater the resistance to plastic deformation, the higher the hardness value. Conversely, the higher the hardness of the material, the material may be due to increased brittleness, its strength is not fully reflected in such strength index value is not high. 　　For longer subjected to heat treatment, and the use of the material in temperatures well below the recrystallization temperature of the high-pressure alloy pipe steel pipe material (such as low-carbon low-alloy...

　　Seamless precision steel pipe products have problems of uneven eccentric thickness, but what are the reasons? Many people don’t understand, today we will talk about how to produce eccentricity of seamless steel pipes such as cold drawn steel pipes, cold rolled steel pipes and hot rolled steel pipes. Rate, why the concentricity of seamless steel pipes is not so ideal? Eccentric steel pipes are the most easily produced in the production of hot rolled steel pipes, and most of the connecting rods are produced during the hot perforation process. 　　Through the anatomical analysis of the steel pipe after the automatic pipe rolling machine, it is considered that the vertical and horizontal wall thickness distribution of the perforated pipe after the automatic pipe rolling machine is rolled unevenly, and the characteristics of the perforated pipe are basically maintained. The wall thickness of the perforated pipe is unevenly distributed, that is, the pipe wall still has a spiral wall thickn...

　　1. Precision seamless steel pipe is light weight, high strength, easy for transportation and installation. It is only 1/4 of steel, but the circumferential tensile strength is 180 - 300MPa and the axial tensile strength is 60 - 15OMPa, which is similar to alloy steel. Therefore, the strength is 2 to 3 times of gold steel. So that it can meet different requirements of users, designed to various types of pipeline to withstand internal and external pressure. Precision seamless steel pipe is 12 meters per section, it is easy to install which reduce the cost of lifting and improve the installation speed. 　　2. Anti-fouling and anti-boring. Precision seamless steel pipe will not be affected by sewage, fungi and other microbial station fester, reduce maintenance costs. Without these pollution, precision seamless steel pipe can be used for a long time. Due to its smooth wall and excellent corrosion resistance, it will not produce scale and microbial, effectively ensure water quality. 　　3...

　　Smaller diameter pipe mostly straight seam welded, large diameter spiral welded pipe for the most spiral submerged arc welded steel pipe hot-rolled strip in a spiral bending, 　　Performed outside seam and seam welding system with automatic submerged arc welding into a spiral pipe joints. 　　Spiral steel pipe for the following reasons it is widely used in large-diameter spiral pipe production: 　　1) Just change the angle formed, you can use the same strip width of the production of large diameter steel pipe; 　　2) Because it is a continuous bending, so the length of the pipe length is not limited; 　　3) spiral weld uniformly distributed over the entire circumference of the pipe, large diameter steel pipe so high dimensional accuracy, intensity is higher; 　　4) Easy to change size, suitable for small quantity and variety of large-diameter pipe production.

　　The use of spiral thread to the scene to identify the most useful approach to the use of joint foot, this foot is a kind of special tag root diameter of the external thread and internal thread expansion tapered bore diameter caliper, using concise, intuitive and precise. It can also apply directly associated with long-legged steel vernier caliper ruler to measure external thread root diameter, length, thread expanding cone threaded aperture control specification query. 　　Thread upright seen from the front direction can differentiate rising spiral threaded to rise to the right of the right-handed, left to rise for the left-handed. Spiral drill threaded in the production process according to API specification rules mandate the use of thread gauge thread standoff inspection, the inspection cycle by the use of a certain individual tester for drilling screw pitch and taper to be checked. 　　Drilling screw three digits indicate the method is the Ministry of Metallurgical Industry specif...

　　Pipe forming the strip is unequal curvature composite longitudinal deformation process and continuous operation in cross section, and the strip is bent by the force of a multi-directional deformation process. 　　The basic principle of straight seam steel pipe forming theory is by the action of an external force to produce plastic deformation of the steel strip into a desired shape and size tubes. Since the steel pipe in the process of deformation of the main surface in a continuous horizontal and vertical aspects, the binding applied thereon is arranged in two aspects to implement and pass through the mill roll forming, roll passes is to make transverse deformation of steel, the steel sheet rolling mill is arranged to produce longitudinal deformation, the specific operation models and a variety of differences in engineering is a continuous steel deformation process to be implemented in stages, from the corresponding mill (including the roll groove and mill arrangement) to achieve. ...

　　Submerged arc welding is an arc welding under flux layer combustion method. Welding arc between the wire and the weldment burning heat of the arc and arc welding wire ends near the base metal and solder melts, continue feeding the wire, and proceeds along a certain trajectory, an arc weld pool solidified metal is removed to weld the molten solder is solidified into a shell covering the surface of the weld slag, slag of molten pool and weld metal for protection against arcing and the pool by the outside air intrusion. 　　Submerged arc welding arc, wire, wire and shift interrupter such action is usually done by machine, it is known as submerged arc welding. SAW has the following advantages: ① high degree of mechanization, for welders require low skill levels; ② welding current, can be reduced weldments groove, high welding efficiency; ③ can be separated from molten solder metal contact with the air, the protective effect good, high weld quality; ④ covered with arc radiation, better wo...

　　Pipe hangers can be divided into three categories: load-bearing hanger, hangers and vibration-limiting bracket spiral welded pipe selection principles are as follows: 　　1. In the selection of spiral welded pipe hangers, should be borne in accordance with anchor size and direction of the load, displacement of the pipe, whether working temperature for cold type, pipe material and other conditions appropriate choice of hanger: 　　2. Design spiral pipe hangers, the card should be used wherever possible standard pipe, pipe supports and pipe hanging; 　　3. The welded pipe bracket, clamp-type pipe hanging over tube holder, steel tube hanging province, and making simple, the construction side cases, therefore, except in the following circumstances, should be adopted in welded pipe and tube inserted hanging; 　　1) tube medium temperature equal to or greater than 400 degrees carbon steel pipe material; 2) low temperature piping; 3) alloy steel pipe; 4) production pipeline maintenance req...

　　Galvanized steel is steel with a protective zinc coating. This coating has many advantages over other methods used to protect steel, and it makes galvanized steel pipe , fittings and other structures more desirable in many situations. Here are nine of the advantages associated with using galvanized steel. 　　1. Low Initial Cost 　　The galvanization process usually costs less than other popular methods of protecting steel. This is because the other methods are often labor intensive, and the cost of labor is always increasing. Galvanization requires less manual labor, and therefore has not been been affected by this increase. 　　2. Long Life 　　The main benefit of galvanized steel is its long life. Galvanized steel pipe, fittings and other structures can last more than 50 years in many rural areas, and more than 25 years in severely exposed urban and coastal environments. 　　3. Toughness 　　The unique metallurgical composition of a galvanized coating makes it very rugged. Therefo...

　　Large diameter seamless steel pipe is over 1000MM, which is made from steel ingot or solid tube, and then processed by hot rolling or cold rolling. Sometimes, the seamless steel pipes is longer or short while using. Short seamless steel pipes can be welded, longer seamless steel pipes can be cut off. Here are three methods of cutting large diameter seamless steel pipes to proper length to meet industry needs. 　　1. By saw machine 　　Saw machine can make neat section which is convenient for welding. The disadvantage is low efficiency. 　　2. By gas cutting 　　Though gas cutting is fast, the disadvantage is presented notched surface which is not good for construction. 　　3. By cnc cutting machine 　　By cnc cutting machine, seamless steel pipes manufacturers will not save a lot cost but also can obtain smooth section of seamless steel pipe which has not much difference from cutting by saw machine. 　　If you are looking for a new range of strong and durable pipes, you have come at...

　　The tubing is a tube that is lowered into the casing pipe of the well, when the well is being produced normally. From the well, the oil flows through the casing pipe into the ground and enters the gathering process. In the coal mining well, the combination of oil pipe, sucker rod and deep well pump (ie “three pumping” equipment) draws oil to the ground and enters the gathering process. The casing is a pipe that is lowered into the well after the drilling is completed. The casing and the well wall are cement-sealed, and then the perforating gun is used to align the perforation of the target layer, so that the oil flows through the rock layer, the cement ring, and the casing into the well. At the bottom, enter the tubing and come to the ground. 　　The main functions are: 1. Reinforce the well wall to prevent the formation from collapsing; 2. Separate different oil layers and water layers to achieve layered mining; 3. Facilitate the implementation of fracturing and acidification operat...

　　 LSAW Steel Pipe to control the quality, in order to safely carry out production operations, but also to protect the operator an essential element of personal safety. The main application areas are: large span grid project, building steel structure project, electric power and EHV transmission and distribution project, mechanical engineering, bridge, bridge, railway station, airport, stadium steel structure project, municipal pipe network, Foundation piling, water gas pipeline and highway construction and other supporting facilities. 　　1, According to the welding process specification review wire and flux specifications are correct, to prevent the wrong use of welding wire and flux caused by welding quality accidents. 　　2, The welding environment to monitor, when the welding environment is not good (temperature below 0 ℃, relative humidity greater than 90%) should be taken after the appropriate measures for welding. 　　3, Before the first test groove size, including the gap, blu...

　　In order to detect the transverse or longitudinal defect of the weld of LSAW longitudinal seam, ultrasonic testing was carried out by jet (water column) coupling. Jet (water column) ultrasonic flaw detection is the probe and the pipe through the jet coupling between the probe issued by the longitudinal wave beam through the water or steel interface into the steel pipe , through the waveform conversion of the steel pipe welds pure shear wave detection. 　　Therefore, the realization of the weld in the pure shear wave detection, the probe angle of incidence must be between the critical angle and the critical angle between the II, can be derived from the law of refraction. The critical angles of the first and second critical angles of incident longitudinal waves from the water to steel are calculated to be 14.5 °and 27.3 °, respectively. 　　Longitudinal welded pipe Ultrasonic Inspection: Nondestructive testing is on-site testing, fast and non-destructive, without the need to arrive at ...