ERW Steel Pipe

　　Inner fold of hot rolled seamless steel pipe refers to spiral rendered in the steel pipe inner surface, the semi-helical or irregular distribution of the zigzag folding, some rendered as linear warping. Below are details: 　　1.An inner flap: presenting a straight line, a spiral or a semi-helical sawtooth defect on the inner surface of the steel pipe. 　　2. Inside scarring: scars in the steel pipe inner surface, generally easily peel off. 　　3. Warping: a straight line or intermittent small nail-like tilt leather. Often seen in the capillary head, and easy to peel. 　　4. Inside straights: a straight shape scratch with a certain width and depth. 　　5. Inner edge: a straight shape protrusion with a certain width and depth. 　　6. Inner drum kits: a super and regular protrusion and outer surface is not damaged. 　　7. Pull pits: a regular or non-regular pit and the outer surface without damage. 　　8. Internal thread (this defect produced only at Accel units): spiral traces often s...

　　We cannot ignore the last step for the final steel pipe. And it is the transmission. How to transport steel pipe, like ERW steel pipe and seamless steel tube safely would be an important lesson for us to learn. 　　Here is a kind of method of transport for the square steel pipe I’ve seen on my way home. From the picture, can you tell us the right and wrong points? 　　As far as I’m concerned, here are some points we need to pay attention to. 　　First of all, there is no protection for pipe’s end. We should use plastic plugs in both ends to make quality of each end. 　　Then, for the method of packaging, it may not so proper. Hexagonal bundles of max is necessary for these square steel pipes. Of course, with several steel strips are also okay. 　　What’s more, wrapped these steel pipes in waterproof paper may be important. What should we do to keep the high quality of pipes if we meet the rain day? 　　In general, there are so many points we need to focus on for the transportation o...

　　Longitudinal seam steel pipe widely used in water engineering, petrochemical industry, chemical industry, power industry, agricultural irrigation, urban construction, it is one of 20 key product development of our country. For the transport of liquids: water supply, drainage. For gas transportation: gas, steam, liquefied petroleum gas. For structural purposes: as piling pipe, as bridges; piers, roads, pipes and other building structures. Longitudinal mechanical expanding the expanding use of the split-side portion of the segments radially expand, so the tube along the longitudinal direction in a stepwise manner to achieve the full length of the tube segments of plastic deformation process. 　　Longitudinal mechanical expanding there are five big stages: 　　1. Full circle phases: the segments open until all the segments are exposed to Longitudinal wall, this time within the range Longitudinal steps at various points within the radius of the tube are almost identical, Longitudinal pre...

　　Large diameter spiral pipe wrong side generated reason: 　　Large diameter spiral steel pipe production, the wrong side have occurred, many influencing factors. In the production practice, often the wrong side of the ultra-poor leaving dry pipe downgrade. Therefore analyze the causes and prevention of large diameter spiral pipe produced the wrong side is necessary. 　　1, the strip camber is caused by the wrong side of the main factors pipe. In forming the spiral welded pipe, steel strip camber angle will constantly change shape, leading to changes in the weld gap, resulting in open seams, wrong side or even take sides. Seriously affecting the quality of steel, so the observation camber steel strip coil-after by controlling the vertical roll can be cut to make the disc as well as the continuous removal of part of camber angle control and corrective shaping is to reduce the camber of the strip in the production process effective way to produce the wrong side. 　　2, due to the poor w...

　　Currently, double-sided spiral pipe is widely used submerged arc welding technology, following the formation and characteristics of what the submerged arc welding. 　　Principle of submerged arc welding: submerged arc welding is performed by arc welding heat, and manual arc welding is different: submerged arc welding wire is bare, no paint above, submerged arc flux is indeed to be welded in advance shop Department, submerged arc welding wire extends into the flux, the arc is burning in flux. 　　SAW formation process like this: the wire in contact with the workpiece, press the start button and instantly after pressing, welding wire and workpiece energized wire Withdrawing arc ignition, welding carriage forward, under continuous wire to transport, maintain Arc burning at the solder layer, formed under the arc weld pool. In an arc around the solder melts to form a cavity. This empty and the pool continues to advance, but the pool behind the metal solidified, forming a continuous weld. ...

　　According to the technological requirements of different manufacturers, precision tubes length measurement systems with a variety of length measurement methods. There are the following: 　 　1, The grating length measurement 　　The basic principle is: the outer ends of precision tubes are provided two fixed length of the grating, the use of rodless cylinder driven grating near precision tubes ends, using light interference to achieve precise measurement of the length of the tube. 　　It is characterized by high accuracy. But the scale is expensive and difficult to maintain, the impact of dust and vibration is very sensitive site. 　　2, The camera length measurement. 　　Camera length measurement is the use of image processing to achieve precision tubes length measurement, the principle is equidistant series of photoelectric switches installed in the precision roller conveyor tube a certain period, the increase in light and camera on the other section. When precision tubes through t...

　　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...

　　The strength and hardness of the precision seamless steel pipe material increase, the plastic deformation recrystallization temperature, but the plasticity and toughness decrease. Also known as cold work hardening. The reason is that during the plastic deformation process of the precision seamless steel pipe, the grain is slipped, the dislocation entanglement, the slender, broken and fibrillated grain, and the residual stress generated by the internal precision seamless steel pipe. The degree of processing and processing of the surface layer and the depth of the hardened layer are usually expressed as compared to the hardness of the quenching. 　　Cold work hardening is a way to strengthen the precision seamless steel pipe and alloy with the process method (after the cold working, the strength is obviously improved after the decay or alloy), and then the cold stamping process is possible, which is beneficial to the formation and processing of the stainless steel pipe. Alloy gold is n...

　　Pre-finishing technology is the large diameter welding thick-walled spiral pipe production of oil and gas pipelines in the more advanced technology. 　　The first step in the pre-bonding method using fine production of spiral welded pipe , which was followed by gas welding continuously welded steel strip on the molding machine, pre-weld tube consequent plasma cutting machine cut into a predetermined length of pipe the second step is a pre-welded steel pipe after finish welding production line delivery to internal and external multi-wire submerged arc welding fine. 　　Spiral welded pipe welding two-step pre-finishing production technology Yuan has obvious advantages compared with conventional one-step spiral welded pipe production due to pre-finish welding submerged arc welding speed constraints, the forming and welding separately, an effective solution to the forming and welding problems between mutual interference. full advantage of forming and welding their own characteristics, to...

　　At present, the domestic long-distance pipeline construction usually "under the cellulose type electrode to weld, cellulose type electrode root welding + self shielded flux cored wire semi-automatic welding and STT root pass + self shielded flux cored wire semi-automatic welding" process, welding easy question that arises is: 　　1, Slag 　　Reason: Because they use a long-distance pipeline under flux cored wire semi-automatic welding process to be filled, cover up, when a semi-automatic welding process equipment intermittent fault, often top wire phenomenon, then wear a wire into the bath, when melt instant re-ignited after rapid cooling pool, the weld was often wrapped with metal debris, or slag, produced slag. 　　Measures: Before root weld groove should carefully cleaning, filling, be careful when you clean up the slag cover pass. 　　2, Stomatal 　　Cause: The filling layer porosity is mainly due to self-protection cored semiautomatic welding arc voltage caused by exce...

　　Now everyone is paying attention to environmental protection, and then the seamless steel pipe manufacturers will briefly tell you about the content: 　　Seamless steel pipe is a kind of high precision pipe material, and it has strong mechanical properties. These are its characteristics. Seamless steel pipe is a typical hollow section pipe material, which can be used as an important pipe transportation. Materials, seamless steel pipes can be transported with many materials, including various energy sources, petroleum, liquids, etc. It is different from ordinary solid steel pipes. The weight of this seamless steel pipe is very light, and the price is also cost-effective. That is to say, seamless steel pipe is a very economical pipe material. 　　It is not only widely used in the field of pipeline transportation. In the machinery manufacturing industry, in the automobile manufacturing industry, seamless steel tubes also play an active role. It can be seen that its use is very extensive...

　　To walled Longitudinal rust oil treatment, we must first understand the characteristics and type of anti-rust oil, as well as their respective roles. So when buying such products can not be thrown off balance, indirectly save time. 　 　1. Quick-drying 　　Its biggest advantage is that dry fast, hard shell, use widely welcomed, can be used in harsh environments, and durable. 　 　2. Soft membrane 　　With paraffin oil or heavy oil treatment from rust performance are the three strongest presence, and solvent may be used one kind of washed away. 　 　3. Film type 　　Its relatively nearly rust resistance. But it's working process is very simple. Use can reduce the damage they caused due to friction, reduce costs, indirect guarantee the development of the productive forces. 　　Thus it can be seen, thick-walled Longitudinal Rust oil has a significant role.

　　Cracking principle of petroleum cracking tube : that is cracking under certain conditions, the relative molecular mass larger, higher boiling hydrocarbons break into smaller molecular weight, lower boiling hydrocarbons process. In the catalytic cracking is carried out, also known as catalytic cracking. 　　Pyrolysis oil chemical production process, higher than the cracking temperature (700 ℃ ~ 800 ℃, sometimes even up to 1000 ℃), petroleum fractionation products (including LPG) in the long chain hydrocarbon broken into ethylene, propylene, etc. short-chain hydrocarbon processing. 　　It is a deeper cleavage cracking. Chemical petroleum cracking process is more complex, cracked gas generating composition is a complex mixture of gases, the main products in addition to ethylene, but also propylene, isobutylene and methane, ethane, butane, alkynes, hydrogen sulfide and carbon oxides, etc. . Pyrolysis gas purified and isolated, you can get the required purity ethylene, propylene and other...

　　Under cold conditions a low-carbon steel welding, the cooling rate of the welded joint, which has made cracking tendency to increase, especially in the first weld Heavy structures susceptible to cracking, it is necessary to take the following process steps: 　　1) Do not possible under conditions of low temperature bending, correction and assembly weldments. 　　2) Preheat, 16Mn seamless steel pipe welding process strictly maintained interlayer temperature should not fall below the preheating temperature. 　　3) Hydrogen or ultra-low hydrogen welding. 　　4) The whole seam continuous welding should be completed to avoid interruption. 　　5) When positioning welding to increase the welding current, welding speed slows down, due to increase tack welds cross-sectional area and length, preheated if necessary. 　　6) Not be performed on a base material arc groove surface other than the need to fill the crater when extinction.

　　304 stainless steel thick-walled tube parts to control grain size during heat treatment is necessary, its quality heat-treated 304 stainless steel thick-walled tube has a very important impact. 　　Here's how to control the size of its grain size Method Summary as follows. 　　(1) Choose a reasonable heating temperature 　　Heating temperature is too low, the process of forming austenitic 304 stainless steel thick-walled tube is slow, can not even fully formed, heat treatment can not achieve the requirements. Heating temperature is too high, it is easy to get coarse austenite grains. Cause performance degradation. It should be a reasonable choice of heating temperature varies depending on several aspects of the chemical composition of 304 stainless steel thick-walled pipe, shape and size of parts, any special requirements, changes in cross section and specific technical requirements. 　　(2) Determine a reasonable time and best insulation insulation parts for the purpose of heat ...