LSAW (submerged arc welding) steel pipes have significant differences in wall thickness requirements in different application scenarios. The following are some of the wall thickness requirements in the main applications:

Oil and gas transportation field

1. Long distance oil pipelines

In long-distance oil pipelines, the wall thickness is determined based on factors such as the type of oil being transported and the transportation pressure. For example, for pipelines transporting ordinary crude oil, when the conveying pressure is between 4-8 MPa, LSAW Steel Pipes with a diameter of DN (nominal diameter) 600-1000mm are generally required to have a wall thickness of 10-16mm. This is because crude oil has a certain density and viscosity, and requires sufficient wall thickness to withstand internal pressure and prevent pipeline rupture at higher pressures.

If transporting heavy oil with high pour point and high viscosity, higher pressure and temperature may be required during the transportation process to ensure fluidity. For pipelines of the same diameter, the wall thickness may increase to 14-20mm. At the same time, the pipeline also needs to consider external environmental factors, such as soil pressure and groundwater corrosion that may affect buried pipelines. Adequate wall thickness can enhance the pipeline's corrosion and compression resistance.

2. Natural gas transmission pipelines

For natural gas transmission pipelines, due to the high pressure state of natural gas (such as 10-12 MPa) and the flammability and explosiveness of natural gas, the safety requirements for pipelines are extremely high. For example, for pipes with a diameter of DN800-1200mm, the wall thickness is generally between 12-22mm. This is to ensure that the pipeline can withstand the external forces generated by possible geological disasters (such as earthquakes, landslides, etc.) while withstanding high internal pressure. Moreover, natural gas may contain small amounts of acidic gases such as hydrogen sulfide, and appropriate wall thickness can also help slow down the corrosion rate of pipelines.

In the field of architectural structures

1. Pipe piles for building pile foundations

When LSAW steel pipes are used as pile pipes in building pile foundations, the wall thickness depends on the bearing capacity and depth of penetration of the piles. For example, for pile foundations in general multi story buildings (less than 7 floors), LSAW steel pipe piles with a diameter of 400-600mm may have a wall thickness of 8-12mm. These steel pipe piles mainly bear the vertical load of the building, transferring the weight of the building to the bearing layer deep in the foundation.

For heavy structures such as high-rise buildings (over 10 floors) or large bridge foundations, with large pile diameters (such as 800-1000mm), in order to withstand enormous vertical and horizontal loads, the wall thickness may reach 14-20mm. Moreover, in some areas with soft soil foundations or high seismic requirements, increasing the wall thickness will also be considered to improve the bending and shear resistance of piles.

2. Steel pipes supporting the building frame structure

When LSAW steel pipes are used as supporting components for building frame structures, such as in steel frame structures of some industrial plants or large venues, the wall thickness depends on the span and load conditions of the structure. For steel pipe columns with a span of 20-30m and bearing roof and wall loads, LSAW steel pipes with a diameter of 300-500mm generally have a wall thickness of 6-10mm. This wall thickness ensures that the steel pipe has sufficient stability and load-bearing capacity when subjected to axial pressure and possible eccentric loads.

Mechanical manufacturing field

1. Manufacturing of pressure equipment (such as boilers, etc.)

In boiler manufacturing, LSAW steel pipes are used as materials for components such as drums or headers, and have strict wall thickness requirements. Taking medium pressure boilers (pressure range of 3.8-5.8MPa) as an example, LSAW steel pipes with a diameter of 200-400mm are used for the drum, and the wall thickness is generally 10-18mm. This is because the interior of the boiler is a high-temperature and high-pressure water vapor environment, and the steel pipes need to withstand high internal pressure, while also considering the effects of thermal stress and corrosion. Under such harsh working conditions, sufficient wall thickness can ensure the strength and sealing of the steel pipe, preventing safety accidents such as leaks and even explosions.

2. Mechanical transmission shafts and other components

When LSAW steel pipes are used to manufacture mechanical transmission shafts, the wall thickness is determined based on factors such as the shaft's torque, speed, and the weight of the connected components. For example, in the transmission shaft of some large cranes, LSAW steel pipes with a diameter of 150-300mm may have a wall thickness of 6-12mm. This wall thickness can ensure that the shaft has sufficient torsional strength when transmitting torque, and can withstand the weight of the shaft itself and the forces of external connecting components, ensuring the normal operation of the machinery.