The right way to maintain the coil (1) Spiral steel pipe storage products or storage space, should choose clean, smooth drainage area, away from factories and mines harmful gases or dust. On the field, remove weeds and all the debris and keep a clean steel. (2) in the warehouse, not with acid, alkali, salt, cement, steel and other invasive materials stacked together. Different varieties of steel should be stacked separately to prevent confusion and prevent contact with corrosion. 3) large steel, rail, steel shame, large diameter steel pipe, forgings, etc., can be piled open.

1. Thick wall spiral tube forming process, steel deformation even if the residual stress is small, the surface will not have scratches. Steel pipe processing in the diameter and wall thickness range, larger diameter, greater flexibility, especially in the production of high-grade steel thick-walled pipe, especially with large-caliber thick-walled pipe has other advantages of unmatched technology to Meet more users on the pipe specifications;

Spiral processing method is based on the original spiral tube in accordance with the requirements of the product requirements. There are two commonly used spiral tube processing methods. First, the thermal expansion method

Corrosion-resistant insulation pipe with corrosion-resistant steel, with good insulation properties, in the construction has been widely used and promoted, and continue to improve and promote. Corrosion of pipe insulation have different types of processing methods and methods, different processing methods determine the pipeline has different properties and functions, and the use of the range will change. As its name implies, it is to increase the degree of protection of the external thread steel pipe corrosion protection grade, in order to achieve low temperature can be used. Under normal circumstances, the use of two-tube insulation inorganic zinc-rich paint, the temperature ≥ 400 ℃, are corrosion-resistant coating, pipe mouth polyethylene film known as the three-tier PE or cold seal with the previous installation to prevent moisture Into the water or construction.

Forming large diameter straight seam welded pipe molding methods are UOE molding method, a row of roll forming method (CFE), CE molding. For the most part of the molding process is the full-length steel pipe after welding diameter, in order to improve the quality of welded pipe. Large-caliber expanded production is an important process to ensure the quality of finished pipe.

Lateral cracks in the longitudinal seam submerged arc welded pipe appears after rework, in particular: 1. Confirm the defect 100% UT weld inspection of all welds, crack markings location, length, depth and direction. If the entire weld is defective, it is proposed to excavate the entire re-submerged arc welding, manual arc welding of local repair recommendations.

Surface micro-cracks in LSAW steel pipe products have a great impact on quality, from the commutation of sentences, and retirement, especially niobium, vanadium, titanium vertical most prominent, seriously affected the product quality and yield improvement. This not only brought enormous economic losses to the enterprise, but also restricted the development of varieties of sheet metal production lines. Longitudinal surface microcracks are mainly edge cracks, longitudinal cracks, star cracks, the reason for both the rolling process parameters are not properly controlled, but also abnormal casting production, slab cracks, residual element enrichment.

Longitudinal submerged arc welded pipe due to the use of different environmental conditions, and the objective conditions of change over time, coupled with the inherent defects in a certain period of time there will be different forms of damage. Such as hydrogen-containing welded steel pipe, in the high enough stress or residual stress cracking occurs, the form of such damage is commonly referred to as hydrogen induced cracking. Hydrogen-induced cracking of welded steel is due to the diffusion of hydrogen in the metal matrix, forming solid solutions in the form of metal hydrides or metal hydrides, resulting in brittle fracture of the pipe. It is a source of potential pipeline damage. Hydrogen induced cracking can occur in a few weeks even at high stresses or pressures when buried underground.

Longitudinal submerged arc welded pipe due to the use of different environmental conditions, and the objective conditions of change over time, coupled with the inherent defects in a certain period of time there will be different forms of damage. Such as hydrogen-containing welded steel pipe, in the high enough stress or residual stress cracking occurs, the form of such damage is commonly referred to as hydrogen induced cracking. Hydrogen-induced cracking of welded steel is due to the diffusion of hydrogen in the metal matrix, forming solid solutions in the form of metal hydrides or metal hydrides, resulting in brittle fracture of the pipe. It is a source of potential pipeline damage. Hydrogen induced cracking can occur in a few weeks even at high stresses or pressures when buried underground.

1.Confirm the defect 100% UT weld inspection of all welds, crack markings location, length, depth and direction. If the entire weld is defective, it is proposed to excavate the entire re-submerged arc welding, manual arc welding of local repair recommendations.

Lateral cracks in the longitudinal seam submerged arc welded pipe appears after rework, in particular: 1. Confirm the defect 100% UT weld inspection of all welds, crack markings location, length, depth and direction. If the entire weld is defective, it is proposed to excavate the entire re-submerged arc welding, manual arc welding of local repair recommendations.

Surface micro-cracks in LSAW steel pipe products have a great impact on quality, from the commutation of sentences, and retirement, especially niobium, vanadium, titanium vertical most prominent, seriously affected the product quality and yield improvement. This not only brought enormous economic losses to the enterprise, but also restricted the development of varieties of sheet metal production lines. Longitudinal surface microcracks are mainly edge cracks, longitudinal cracks, star cracks, the reason for both the rolling process parameters are not properly controlled, but also abnormal casting production, slab cracks, residual element enrichment.

efficiency.

Longitudinal submerged arc welded pipe due to the use of different environmental conditions, and the objective conditions of change over time, coupled with the inherent defects in a certain period of time there will be different forms of damage. Such as hydrogen-containing welded steel pipe, in the high enough stress or residual stress cracking occurs, the form of such damage is commonly referred to as hydrogen induced cracking. Hydrogen-induced cracking of welded steel is due to the diffusion of hydrogen in the metal matrix, forming solid solutions in the form of metal hydrides or metal hydrides, resulting in brittle fracture of the pipe. It is a source of potential pipeline damage. Hydrogen induced cracking can occur in a few weeks even at high stresses or pressures when buried underground.

2, the quality of welding directly determines the quality of welded pipe, seamless steel pipe welding the biggest difference is. Longitudinal high-frequency welding, straight seam carbon can not be eliminated, the weld and the parent material just connected together, can not be fully integrated into one - can not stand the test of time and pressure. Hot stretch reducing pipe high-frequency welding heating after the whole, the overall annealing temperature of 800 degrees, and then open the process of change, in this series of processes, the weld and the parent organization has the same performance as the complete melting, good from the joints without Transition.

Drainage Pipeline

Analysis of Steel Tube Bending and Deformation Deformation heat treatment principle shows that the heat processing (welding), due to uneven heating temperature, compression plastic deformation caused by high temperature cooling contraction site can also be through other parts (low temperature cooling zone or the first part) block, resulting in residual stress and each Kind of modification Steel pipe heat treatment (steel or thermal expansion) after the market is mainly used for bending steel.

Advantages and disadvantages of welded steel pipe Wall light table average wall thickness (steel appearance, steel grade resolution, brightness) can be any length. Therefore, it is economically and aesthetically accurate, using low pressure fluids.

Large Diameter Seamless Steel Thermoforming Manufacturing Process

Hot-rolled seamless steel pipe defects Separated Located in the vertical distribution of the steel tube surface, a spiral rise, massive metal separation or fracture-like stripping.

Spiral welding production process is simple, high production efficiency, low cost and rapid development. The strength of spiral welded pipe is generally higher than the vertical, you can narrow-billet production of large-diameter steel pipe, you can also use the same width billet production of different diameter steel pipe. However, the length of the weld is 30 to 100% compared to the length of the straight pipe weld and the productivity is low. Therefore, the smaller diameter pipes are mostly straight seam welded, large diameter spiral welded pipe.