After, we should prevent the surface damage of the plate. The parts with serious scars must be grinded to make transition, and there is no domestic standard at present. Therefore, the inspection is mainly aimed at the thickness and weld quality.
The process of heating the whole thick wall coil or welding area before welding is called preheating. For the steel with high welding strength grade, it has hardening trend, material, especially good thermal conductivity, weldment and large thickness. When the ambient temperature around the welding area is too low, it is necessary to preheat the weldment before welding.
.During cold sizing, not only deformation but also a small amount of plastic deformation occurs at the end of thick wall coiled pipe. After sizing, there may be differences in the transition zone between expanding and non expanding. At the same time, there may also be internal and external surface scratches caused by punch and sizing ring, resulting in slight stress corrosion. Therefore, the dimensional accuracy of hot-rolled steel pipe should be improved as much as possible to avoid adopting method.
The products are widely used in petroleum, chemical industry, natural gas transportation, heating, gas supply and other projects. The wall thickness of the hot-rolled thick wall coil of retailers generally exceeds 20mm, and the outer diameter range is 450-3000mm. The hot-rolled thick wall coil is rolled, welded, formed, de reinforced flaw detected and delivered under the state of steel plate heating. Sometimes the wall with special thickness needs secondary heating. It is characterized by small outer diameter tolerance and uniform wall thickness. The main thing is that the hot-rolled thick wall quality management coil will not damage the performance of raw materials. The disadvantages of hot-rolled thick wall coil are long processing time and the diameter of thick wall coil is generally above dn450.
.During pipe rolling, the surface damage of steel plate shall be prevented. The parts with serious scratches must be polished for transition, and the wall thickness of the polished parts shall not be less than the design wall thickness.
It is to preheat rather than increase the line energy. Reel needs quality, honest business! Let's talk about our productivity.
The wall thickness of coiled pipe like coiled pipe is under 20mm and the outer diameter is 450-3000mm. It is made of steel plate by direct rolling, welding, forming, butt joint and rebar removal. Coil pipe has the characteristics of short processing time, rapid delivery and low cost. The rolling pipe is mainly used for pipes, billboards, columns, etc.
When the nominal diameter is greater than or equal to 600mm, back welding shall be carried out in the pipe.
Purpose of steel plate rolling: steel plate rolling is mostly used in large-scale steel structure construction as the main support part, such as bridge piling, seabed piling and high-rise building piling. Its material: Q345C. Q345D and Q345E are also used in low temperature areas.
Thick wall coiled pipe is made of steel plate. Thick wall coiled pipe can be divided into coiled pipe and thick wall coiled pipe. The wall thickness of coiled pipe is 20mm and the outer diameter is 450-3000mm. It is rolled, welded, formed, butted, removed and reinforced directly from the steel plate. Coil pipe processing time is short and delivery is fast Low cost. The rolling pipe is mainly used for pipes, columns, etc.
wholesaler.The convex hull on the surface of the crimp roll shall be treated. Before repeated processing, the equipment surface shall be treated to prevent the convex hull steel plate with abnormal roll surface from causing pits.
1 carbon structural steel: q215-a, q215-a. & middot; F,Q215-B· F,Q235-A,Q235-B· F. Q235-c ordinary carbon steel: B2 BY2 B2F by2f B3 by3 B3F by3f a2ay2 a2f ay2f A3 ay3 A3F ay3f2 high quality carbon steel: 10 15 20 transmission shaft steel 3 low alloy structural steel: 123mn 16Mn 19mn 08ti 10ti15ti4 special purpose steel plates are stacked in the open air to prevent rain from causing steel plates. The oxide scale falling off the surface of steel plates is easy to turn into blocks or clusters and adhere to steel plates or crimping rollersQ235-B, When repeatedly pressed, the coiled pipe forms pit defects.
Flame cutting and plasma cutting are commonly used for sheet metal blanking in our factory. The equipment used includes manual cutting, copier, semi-automatic cutting machine and NC cutting machine. Manual blanking is arbitrarily large compared to other cuts Flexible and convenient, no special supporting cutting equipment is required.
For external welding, a larger welding current is used. However, under the condition of high welding current, the stirring effect of molten pool is enhanced, and the melting amount of welding wire increases accordingly, resulting in the increase of weld reinforcement, the deterioration of weld formation and poor edge transition.
Latest quotation.The thickness of thick wall coiled pipe is generally greater than 20mm, and the outer diameter range is 450-3000mm. The thick wall coiled pipe is rolled under the condition of steel plate heating Welding, forming, rib, defect detection, factory. Sometimes the wall thickness is relatively thick and secondary heating is required. The feature is that the outer diameter tolerance is small Uniform wall thickness.
With the dissolution of the steel coil surface, the contents of iron, nickel and chromium in the solution will gradually increase. At this time the solution will gradually lose its polishing ability. In any case, increase the temperature, turn on the current and equalize the force. For the analytical solution, if the iron content exceeds 60g / L and the valence chromium content exceeds, it indicates that the solution has been aged. There are two options for the regeneration of polishing solution and the restoration of polishing ability. When the solution is diluted with water to reduce the acidity, impurities such as iron chromium and nickel can be locally precipitated as salt, and the precipitation at the bottom of the tank can be removed, and then heated and evaporated to remove water, so it is cumbersome to restore the original relative density, which requires a large consumption of energy and time. The other is to replace part of the solution, and only 10% is manual cutting; The CNC cutting machine only accounts for part of the total blanking. 10%, of which the proportion of NC plasma cutting is small. In industrial production the thermal cutting of thick wall coiled pipe generally includes gas cutting, plasma cutting, laser cutting and so on. Among them, plasma cutting has a wider cutting range than gas cutting More efficient. Fine plasma cutting technology is close to laser cutting in material cutting surface quality, but the cost is much lower than laser cutting. Therefore, since the successful development of the United States in the mid-1950s, plasma cutting has developed rapidly. Professional hot-rolled steel pipe, large-diameter thick wall rolling pipe thick wall straight seam rolling pipe, steel casing, rolling pipe factory, high pressure rating, good waterproof performance, fire and high temperature resistance, strong overload capacity, corrosion resistance, radiation protection and long service life. With the rapid development of computer and digital technology, NC cutting has also expanded and improved the processing accuracy. It shows great advantages in saving materials and improving labor productivity. This leads to the development of plasma cutting technology from manual or semi-automatic to NC, which has become one of the main directions of NC cutting technology. NC plasma cutting technology is a set of high-tech technologies such as NC technology, plasma cutting technology and inverter power supply technology. Its development is based on the common progress of computer, plasma arc characteristic research, power electronics and other disciplines. The CNC cutting technology began in the 1980s, and the CNC plasma cutting technology was later. However, recently, some domestic universities, research institutes and manufacturers have studied NC plasma cutting technology and gradually developed and produced various specifications of NC plasma cutting equipment, narrowing the gap of foreign advanced technology. The large-scale rolling pipe factory of rolling pipe, flaw detection welding rolling pipe, 16Mn rolling pipe, Q345B rolling pipe and special-shaped rolling pipe, and the t-welded rolling pipe, 16Mn rolling pipe, and shall not be greater than 3mm. 2. The longitudinal joint of joint 200mm away from the pipe end shall not be greater than 2mm. 3. Other parts shall not be greater than 1mm. 4. The vertical deviation between the end face of coiled pipe and the center line shall not be greater than percent of the outer diameter of pipe and shall not be greater than 3mm. The straightness deviation shall not exceed 1mm / m. 5 the weld cannot be double-sided molded coiled pipe. When the nominal diameter is greater than or equal to 600mm, it is recommended to seal and seal in the pipe. In order to obtain better uniform cleanliness and roughness distribution, the particle size and proportion design of rinse agent is very important. The roughness is too large, which may cause the anti-corrosion layer to become thinner at the peak of the cloud path. At the same time, because the cloud path is too deep, bubbles are easy to form in the process, which seriously affects the performance of the layer.
The second stage is called the complex compensation stage, that is the sector of the coiled pipe will gradually reduce its speed until it reaches the required position, which is the inner circumference position of the steel pipe before complex required by the process design. The second stage is the pressure maintaining and stability stage: the sector block remains stationary at the inner circumference of the steel pipe before re assembly, which is the pressure maintaining and stability stage required by the equipment and expanding process.
The process of thick wall straight seam coiled pipe is generally rolled. If the diameter required by the customer is particularly large, it is difficult for general machinery and equipment, so it is necessary to use coiled pipe. First, after the steel plate is rolled, then weld the two rolled steel pipes. The weld is also called T-welding. Sometimes, the large diameter thick wall straight seam steel needs to roll and weld the two steel plates, Therefore, there may be two welds on a pipe body, also known as double welds. Thick wall straight seam coiled pipe has a wide range of materials. As long as it is a steel plate that can be ordered in a steel plant, it is basically OK. The main problem of the product is the welding quality. The welding quality directly determines the quality of the product, which is the main step in the thick wall rolling pipe. It is suitable for columns for bearing steel structures such as buildings, bridges, dams and offshore platforms, super long-span building structures and electric pole tower and mast structures requiring wind resistance and earthquake resistance.