Q345BLarge diameter spiral steel pipeThe material is Q345B, which is a type of steel material. It is a low-carbon alloy steel (c<0.2%) with good comprehensive performance, good low-temperature performance, good cold stamping performance, welding performance, and machinability. Widely used in bridges, vehicles, ships, buildings, pressure vessels, etc. Q represents the yield of this material, and the following 345 refers to the yield value of this material, which is around 345MPa. And it will decrease in yield value as the thickness of the material increases..

The main standard for Q345B large-diameter spiral steel pipes is 5037, but there are some projects that require strict quality standards such as 9711.

The most common specifications for Q345B large-diameter spiral steel pipes are 219mm-3020mm, with a wall thickness ranging from 6mm to 18mm.

Q345B large-diameter spiral steel pipe is applied in water engineering, petrochemical industry, chemical industry, power industry, agricultural irrigation, urban construction, and is one of the twenty key products developed in China. Used for liquid transportation: water supply and drainage. Used for gas transportation: coal gas, steam, liquefied petroleum gas. Used for structural purposes: as pile driving pipes, as bridges; Pipes for docks, roads, building structures, etc.

The main standard for Q345B large-diameter spiral steel pipes is GB/T9711-1997 petroleum and natural gas industry transportation steel pipes, which includes GB/T9711.1 (representing A-grade steel) and GB/T9711.2 (representing B-grade steel). GB9711.2 includes quality and testing requirements that are generally higher than those specified in GB9711.1. GB9711.2 is generally applicable to steel pipes used for transporting flammable fluids and is not suitable for cast pipes.

GB/T9711 Part 1 specifies the technical delivery conditions for non alloy steel and alloy steel (excluding stainless steel) seamless steel pipes and welded steel pipes used in the petroleum and natural gas industry for transporting flammable and non flammable fluids (including water) based on basic quality and testing requirements (Class A).

This standard includes threaded and heavy-duty threaded steel pipes; Non threaded, extra light heavyweight non threaded, ordinary heavyweight non threaded, extra heavy heavyweight (XS) non threaded, and extra heavy heavyweight (XXS) non threaded steel pipes; And socket and insertion steel pipes. The dimensional requirements, measurement method regulations, gauge technical requirements and calibration, and instruments and methods for inspecting threads and thread gauges are given in GB/T9253.4, GB/T9253.7, and SY/T5994, and are applicable to the products involved in this standard.

This standard includes steel grades L175, L210, L245, L290, L320, L360, L390, L415, L450, L485, and L555, as well as intermediate steel grades between L290 and higher grades listed in Table 2. The ordinary heavyweight unthreaded phase ultra light heavyweight unthreaded steel pipes shown in Tables 9A and 9B, as well as threaded steel pipes with nominal dimensions greater than 12 (see Table 6), are marked with outer diameter dimensions. For other steel pipes, the size marking is the nominal size of the steel pipe.

In each chapter of the main text of this standard, where the size boundary line (or size range) of the steel pipe is indicated, except for the nominal size indicated, it refers to the outer diameter size. These outer diameter dimension lines and ranges also apply to the corresponding nominal dimensions.

Main materials of large-diameter spiral steel pipes

Q235A、Q23b、Q345、 L245、L290、X42、 X46、X70、 X80。