difference between hot chamber and cold chamber die casting difference of lsaw and ssaw - articlesfactory.com

by:Hanway     2019-08-19
The metallurgical properties of the material saw steel pipe are produced and through the heat-rolled coil.The unit hot rolling process has many advantages and has obtained the pro...The metallurgical properties of the material LSAW steel pipe are produced and passed through the heat-rolled coil.
The hot rolling process of the unit has many advantages and has achieved high productionMetallurgical process capacity of quality pipeline.For example, an output bracket with a water-cooled system can accelerate cooling, which allows the use of low-alloy components to achieve a specific level of strength and low-temperature toughness to improve the welding properties of steel.But there is basically no steel production plant in this system.
The alloy content coil (carbon equivalent) is usually lower than the similar nameplate, which also improves the welding properties of the spiral welded pipe.It is more important to note that because the rolling direction ratio of the spiral welded steel coil is perpendicular to the axial direction (depending on the spiral angle of the steel clamp solution) and perpendicular to the straight seam steel pipe rolling direction in the direction of the pipe shaft, therefore, the anti-spiral crack performance of this material is better than that of straight seam welded steel pipe.Welding process from welding process, welding straight seam steel spiral welded pipe and coherent practice, but inevitablyWelding, so the probability of welding defects has been greatly improved, the welding residual T weld stress is large, and the weld metal is often in the thirdThe dimensional stress state increases the possibility of cracks.
In addition, according to the provisions of the submerged arc process, each weld should have an arc at the welding site and extinguished, but in each longitudinal seam welding ring, conditions cannot be met, which may have more welding defects in the extinguishing.When the pressure in the pipe is subjected, the strength feature usually produces two main stresses on the wall, namely, radial and axial stress Δy Δx.Weld force Δ= Δy (l/4sin2α cos2 α) 1/2, of which the weld angle of α spiral welded pipe.
The spiral angle of spiral welded pipe is generally 50-75 degrees, so the stress generated by the Spiral weld is 60-85% longitudinal principal stress.Under the same working pressure, the spiral welded pipe with the same diameter ratio and longitudinal wall thickness can be reduced.According to the above features, we can see:?When the spiral welded pipe occurs during explosion, the weld is subjected to stress and the resulting stress is relatively small.
the blasting Port generally does not originate from the Spiral weld, and its safety and longitudinal direction are relatively high.B.When parallel to the Spiral weld near the defect, because the Spiral weld force is small, the risk of expansion is not as high as the straight weld.C.When the maximum load is sustained due to radial stress, the maximum stress on the pipe exists, so the vertical stress of the weld in this direction exists.
The straight welds bear the maximum load, the weekly welds bear the minimum load, between the spiral welds.Water pressure blasting strength through the relevant comparative test, it is verified that the measured values of spiral welded pipe and longitudinal yield pressure and blasting pressure are basically the same as the theoretical value, and the deviation is close.However, the yield stress and burst pressure are not as low as the longitudinal spiral welded pipe.
The blasting test also shows that the blasting deformation rate of the circular spiral welded pipe is significantly greater than that of the longitudinal port.It is confirmed that the longitudinal superior plastic deformation of the spiral welded pipe is generally limited to one spacing, which is caused by the strong binding effect of the Spiral weld on the expansion gap.· Trends in toughness and fatigue strength in developmentDiameter pipe, high strength.
With the increase of the diameter of the pipe, the steel grade increases, resulting in a tendency of stable expansion of the toughness fracture tip.According to the test of American research institutions, although the spiral welded pipe and the longitudinal are the same level, the spiral welded pipe has a high impact toughness.Since the output volume of the conveyor line has changed in actual operation, the steel is subjected to random alternating loads.
Understanding the low-cycle fatigue strength of steel is of great significance to judge the life of the pipeline.According to the measurement results, the fatigue strength of spiral welded pipe, seamless steel pipe and ERW pipe is the same as the distribution and resistance of seamless steel pipe in the same area, while the longitudinal submerged arc is higher than the average.On-site welding is mainly determined by the dimensional tolerance of steel and ports.
Taking into account the requirements of steel pipe installation and construction, the continuity of steel processing and production and the consistency of shape geometry are particularly important.Spiral welded pipe production is basically stable continuous flow under the same working conditions: the longitudinal production process is segmented, including the whole plate/indenter/pre-Roll/spot/weld/finish/peer groupChannel process.This is an important feature different from the vertical spiral welded pipe production.
Stable production conditions are easy to control and the geometry ensures the welding quality.Due to the reasonable structure of the Spiral welding pipe and uniform Weld, the Spiral welding pipe has a very good ellipse and end verticality relative to the longitudinal direction, ensuring the accuracy of the on-site steel welding group.The effect on the flow properties of the transmission medium pressure drop is proportional to the length of the transmission line in the pipeline, the viscosity coefficient of the fluid, the fluid speed, the fluid resistance coefficient, and is inversely proportional to the inner diameter of the tube.
The fluid resistance coefficient is related to both the Reynolds number and the roughness of the surface wall.Determining the factors that affect the surface roughness of the pipe wall is that the local uplift of the area (such as a spiral or longitudinal weld, even including the inner-week Weld) has been hit ten timesProduction and Management of spiral welded steel pipe production to reflect the advantages of high quality and high efficiency.The production unit of spiral welded pipe is equivalent to 5-8 vertical station equipment, how to make multiple volume control equipment and production lines meet the same production standards, ie unified production process specification and quality assurance system, to meet the quality requirements of welding production and the grade of pipe manufacturing will be a difficult task.
The production potential for a long time is higher than the quantity of project management and engineering quality supervision.The multi-roller straight seam welded pipe rolling mill and corresponding devices, the operation skills, quality awareness, poor distribution points and control procedures of its operators, will bring about production management, progress, inspection and acceptance, many difficulties in coordinating other aspects of delivery can easily lead to tight quality, management and push prev coordination by manufacturers and construction units.According to the provisions of the spiral welded steel pipe for the main inspection/control items, the quality assurance spiral welded pipe production standards include: Size: pipe diameter, wall thickness, ellipse, bending, pipe end flat, length appearance quality: weld steel bar, wrong side, steel surface, layering, inclusion, welding defect determination of chemical composition of welded joint tensile test water pressure test etching test non-destructive test there is no corresponding production standard in the longitudinal direction.
The ordinary spiral welded pipe production line adopts the method of continuous test to ensure the quality of the weld, which is another important feature that the spiral welded pipe production is different from the vertical production.Continuous monitoring tests conducive to welding defects, welding quality and stability, welding grade assurance.Due to the limitation of production process, it is extremely difficult to achieve uninterrupted inspection in vertical direction.
This will increase the probability of welding hidden quality problems, and even affect the overall reliability of pipeline operation in the future.· Spiral welded pipe production enterprises shall hold industrial production licenses issued by the state.The licensing requirements of the manufacturer of spiral welded pipe shall first review the assessment of the national accreditation body and be equipped with appropriate means of production, testing equipment and a good and effective quality assurance system, after confirmation by the National Industrial production license issuing office, the product shall meet the requirements of the national standard level and quality standard.
Spiral welded pipe production enterprises have good performance in quality assurance system, operation process and quality control.Vertical manufacturers do not have industrial production license requirements.Price Analysis due to high technology performance of hot-The material and production process requirements of the coil, so on the one hand, domestic manufacturers meet the standards less than steel plate manufacturers, on the other hand, its production process and quality level determine its market price is also higher than the hot rolled steel plate.
This is the main reason why the market price of spiral welded pipe is higher than vertical.For the composition of the steel pipe sales price, the price of the material is the dominant or even decisive factor.Careful study and the difference in the price of longitudinal spiral welded pipe, the price is slightly higher than the difference in the price of longitudinal spiral welded pipe is caused by the production of primary materials.
However, steel production is only part of the project, but if the overall quality of the project, the total cost of the project and other factors are taken into account, the spiral welded pipe still has an overall advantage.Cut length and price production cut length pipe Wood rate is usually a large cut lower than the length of the tube, the company's proposed fare increase requirements are reasonable.Usually based on the basic price increase of about 10%, the company's increase price is inconsistent.
The length of the cut shall be within the usual length range, and the size is the contractual requirement for a fixed length.But the actual operation is absolutely cut.Length cutting is unlikely, so the standard length that allows a predetermined length is a positive deviation.
If the standard deviation is not the double length and cut margin terms negotiated by both parties and specified in the contract.In the case of the same length, the company will bring a significant reduction in the yield, so the increase proposed by the company is reasonable, and its growth rate is basically the same as the length of the growth rate.In the process of plasma cutting dust, a large amount of metal steam, ozone, nitrogen oxide and soot will be generated during plasma cutting of the workpiece, which will seriously pollute the surrounding environment.
The key to solving the dust problem is how to put all the inhaled plasma dust into the dust removal device to prevent air pollution.Spiral welded pipe plasma cutting, dust difficulties are: 1. when cutting, the plasma gun nozzle air blows in two opposite directions at the same time, so that the smoke from both ends of the spiral steel pipe, the spiral steel pipe installed in the direction of the air inlet is difficult to recover fine dust.
the cold air around the air inlet enters the air inlet from the outside space, and the air volume is large. in this way, the total amount of spiral pipe smoke and cold air is greater than the effective dust intake air. therefore, it becomes completely impossible to reduce the absorption of soot.
since the cutting site is far away from the dust suction port, the wind force of the dust suction port is difficult to reach the level of pumping smoke.Therefore, the design principle of the dust cover is: 1. the suction dust air volume is greater than the total amount of plasma cutting and pipe smoke generated inside the air, which should be inside the spiral steel pipe of a certain amount of negative pressure chamber, try not to let the outside air pour into the spiral steel pipe so as to effectively absorb the dust into the dust collector.
after the entrance of the smoke blocking, the spiral steel pipe is cut to avoid cold air suction into the spiral steel pipe. the spiral steel pipe in the internal space forms a negative pressure dust baffle installed in the spiral steel pipe with a small car, and place the plasma cutting point gun at about 500mm, and the spiral tube after the stay is cut off to absorb all the dust.Please note that the smoke baffle must be positioned exactly in this position after cutting.
In addition to the coincidence of the supporting smoke-proof baffle rotating with the car and the spiral pipe, we must also allow the wheel angle and roll angle of the car to be taken within a consistent range.For large diameter spiral welded pipe with a diameter of about 800mm, plasma cutting method can be adopted;For pipes with a diameter of less than 800mm, there is no need to install an internal baffle to emit a trail smoke from the direction.However, in the previous dust suction port, the cold air must be blocked to the outer baffle.
Development direction editing due to the increasing bearing pressure of the pipeline and the increasingly demanding use conditions, in order to extend the service life of the pipeline as far as possible, the main development direction of the spiral welded pipe is: (1) large diameter thick-Wall tubes that increase pressure resistance;(2) the design and production of new steel structure, such as double helix welded pipe, welding half of the wall thickness of the steel into double pipe, not only the strength is higher than the single-Pipe, no brittle failure;(3) develop new steel species, improve the level of smelting process, widely adopt the heat treatment process of controlled rolling and post-rolling, and continuously improve the toughness and solderability of the pipe body;(4) develop coated pipes, such as coating on the inner wall of the pipe, not only prolong the life, improve the smoothness of the wall, reduce fluid friction, reduce the accumulated wax and dirt, and reduce the frequency of cleaning the pipe, reduce maintenance costs.SSAWpipe plays an important role in transporting gas and transportation.With the planning and construction of many major pipeline projects at home and abroad, large deformation steel, highStrength level and weight-High temperature elbow tube-Market competition and greater market demand, while domestic enterprises have made relatively slow progress in developing this series of products, they should develop industrial applications with high added value and large deformation pipelines as soon as possible, heating and simbend steel for low added value pipesTemperature steel pipe, X100 straight seam submerged arc welding pipe, hot sim elbow of spiral welded pipe.
Perform standard editing pressure fluid delivery spiral submerged arc welded pipe SY5036-Article 83 is mainly used for the transportation of oil and natural gas pipelines;Pressure fluid delivery of high frequency welded steel pipe SY5038-spiral seam83. high-frequency lap welding method for conveying fluid in high-frequency welded steel pipes in pressure spiral joints.High pressure steel, plastic, easy welding and processing molding;SY5037-spiral submerged arc welding pipe for general low pressure liquid conveying83, use doubleDouble-sided automatic submerged arc welding or welding of generally low-pressure liquid conveying saw pipes such as water, gas, air and steam into the legal system.
Common spiral steel pipe standards are generally divided into: SY/T5037-2000 (standard department, also known as General Fluid pipe with spiral submerged arc welding pipe), GB/t97 11.1-1997 (GB, also known as the oil and gas industry-Part 1 technical delivery conditions for steel pipes: Grade A steel (GB/t97 11 required.Grade 2 B steel), API-5L, also known as the American Petroleum Society;It is divided into two levels PSL1 and PSL2), SY/T5040-92 (spiral submerged arc welding pipe pile ).
Device Editor to Open co: double cone to Open co, removable 32 tons of heavy steel roll.Flat steel cutting machine: 7 flat Roller cutting machines with a thickness of up to 20mm cut: 2000mm * 20mm Roll welding machine can be cut: welding just lead end plate cutting: cutting steel edges to a predetermined size milling machine: the expected groove ≥ 10mm roll edge processed into steel plate means: ensure the delivery of steel delivered along the production line: two roll forming machines used to deliver the main power Guide Rail: ensure that the balance plate enters the forming machine and bridge, output roller, three-bar curved plate, outer roller sizing forming machine, molded pipe 219-
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