How To Choose The Diameter Size of Cold-rolled Seamless Pipe?

The materials of cold-rolled seamless pipe are mainly carbon steel, alloy steel, stainless steel, etc. Among them, carbon steel has high strength, good wear resistance and low price, and is a material with high cost performance. Cold-rolled seamless steel pipe is a commonly used steel pipe material, often used in construction, machinery, petrochemical, aviation and other fields. So how to choose its diameter size?

Common diameter range

The diameter size of cold-rolled seamless pipe has a wide range.

1. Small diameter

The small diameter can start from a few millimeters, such as 3mm, 4mm. This kind of small diameter pipe is often used in the hydraulic or pneumatic systems of some precision instruments and small equipment, such as the infusion tube of some medical equipment and the air tube of pneumatic tools.

2. Medium diameter

The medium diameter is generally around 10-50mm. Among them, 10-20mm cold-rolled seamless pipes are widely used in general machinery manufacturing, such as for making transmission shafts of small machinery; 20-50mm pipes are more common in building water supply and drainage systems, general industrial fluid delivery pipelines and other scenarios, such as cooling water circulation pipelines in factories.

3. Large diameter

Large diameter cold-rolled seamless pipes can reach a diameter of more than 100mm, or even several meters. Such large-diameter pipes are mainly used in large industrial pipeline systems, such as the main pipeline for transporting crude oil in the petrochemical industry, and the refrigerant delivery pipeline for central air conditioning in large buildings.

Dimensional accuracy

Cold-rolled seamless pipes have high dimensional accuracy.

1. Outer diameter tolerance

The outer diameter tolerance can generally be controlled between ±0.1-±0.5mm, depending on the pipe diameter and production process. For example, for smaller diameter pipes (less than 10mm), the outer diameter tolerance may reach about ±0.1mm, which enables them to meet application scenarios with extremely high dimensional accuracy requirements, such as hydraulic systems of precision machinery.

2. Inner diameter tolerance

The inner diameter tolerance is also relatively small, which is very important for some fluid delivery pipelines that require precise flow control. For example, in chemical production, reagent delivery pipelines with high flow accuracy requirements require precise inner diameter dimensions to ensure the accurate delivery of reagents.

Factors affecting the selection of diameter size

1. Flow rate and flow rate of the conveying medium

If a large amount of fluid is to be transported and there are certain requirements for the flow rate, a larger diameter pipe is required. For example, the main pipeline for transporting urban domestic water usually has a larger diameter to meet the water needs of a large number of residents.

2. Pressure to bear

For pipelines that withstand high pressure, larger diameter pipes tend to disperse pressure better under the same material. For example, in high-pressure natural gas transmission pipelines, the selection of pipe diameter size should consider the internal pressure that the pipeline can withstand.

3. Size of other connected components

If standard flanges, valves and other components are connected to the pipe, the pipe diameter must match the interface size of these components. For example, when connected to a standard industrial flange, the outer diameter of the cold-rolled seamless pipe must meet the inner diameter requirements of the flange to ensure a tight connection.

Summary

Cold-rolled seamless pipes have various diameters and specifications, high dimensional accuracy, and are suitable for various scenarios. In practical applications, the pipe diameter needs to be selected based on factors such as medium characteristics, pressure, and connecting components. With these advantages, it plays a key role in the industrial field and continues to promote the development of the industry.