What is precision seamless tubing？

The concept of precision seamless tubing.

Precision seamless tube is a high-precision metal material processed through cold drawing or cold rolling. With no oxide layer on its inner and outer walls, it can withstand high pressure without leakage. It boasts advantages such as high precision, high cleanliness, no deformation during cold bending, and resistance to expansion, flattening, and cracking. Mainly utilized in the production of pneumatic or hydraulic components, such as cylinders or oil cylinders for mechanical applications.

Compared to solid steel materials like round steel, precision seamless steel tubes are lighter while maintaining comparable mechanical properties. They are an economical cross-sectional steel material widely used in the manufacturing of structural components and mechanical parts.

The major distinction between precision seamless steel tubes and ordinary seamless steel tubes lies in the difference in precision and surface quality. Essentially, precision seamless steel tubes are products of further processing based on ordinary hot-rolled pipes.

2. The production process of cold-rolled precision seamless steel tubes.

The cold processing methods for steel pipes include cold rolling and cold drawing, primarily used for the production of high-precision, special material, sized, and high-strength pipes. Cold-rolled seamless steel pipes exhibit features such as smooth surface, precise dimensions, excellent performance, diverse cross-sectional shapes, and high metal utilization, making them widely utilized in defense, military, machinery, mining, chemical, power, agricultural machinery, and other fields. The process of cold-rolling steel pipes is developed based on the cold-drawing process, addressing issues such as low deformation in each pass, numerous passes, high metal consumption, and poor deformation conditions associated with cold drawing.

The primary advantage of cold-rolled steel pipes lies in their significant reduction in cross-sectional area, particularly strong wall-thinning capabilities, and the ability to correct the unevenness observed in hot-rolled seamless pipes. For carbon steel, the cross-sectional area reduction rate can reach 80% to 83% in a single pass, while for alloy steel, it can reach 72% to 75%. The main drawback is the difficulty in mold replacement, resulting in lower production efficiency. Cold rolling is not only directly used to produce some high-precision cold-rolled pipes but is often combined with the cold drawing method to prepare blanks for cold drawing. This approach maximizes the wall-thinning capabilities of cold rolling while leveraging the ease of mold replacement in cold drawing tools, facilitating improved productivity, expanded product range, and enhanced surface quality of the steel pipes.

When the rolling mill and rolls are in the original position A, the hole size is at its maximum (slightly larger than the billet’s outer diameter). Upon reaching the travel limit position B, the hole size is slightly larger than the finished product’s outer diameter. Before reaching position B, the hole size is at its minimum, equal to the finished product’s outer diameter. At the original position A, the pipe material is fed in, with a feed amount ranging from 3 to 30 mm, depending on the size of the rolling mill. At position B, the pipe material is flipped, rotating 60° to 90° each time to facilitate the smooth rolling of the pipe wall when the rolls return. After returning to the original position A, the pipe material is fed in again to start the next cycle of rolling. This process is repeated to repeatedly roll and shape the pipe material until the desired dimensions of the cold-rolled steel pipe are achieved.

The product specifications for cold-rolled steel pipes are as follows: outer diameter ranging from 4.0 to 450 millimeters, and wall thickness from 0.04 to 60 millimeters. In comparison to the cold drawing method, the periodic cold-rolling tube method has the advantages of a significant reduction in cross-sectional area, no need for a difficult initial pass, and a high yield of finished products. However, its drawbacks include a slower production speed, expensive tool costs, and relatively high intermediate processing expenses. This method is primarily used in the production of stainless steel pipes.

3.production process

Raw Material Preparation: Firstly, suitable raw materials, typically steel billets or steel tubes, need to be prepared.

Pre-treatment: The steel billets undergo pre-treatment, including cleaning, (pickling, phosphating, saponification), or other pre-processing steps to remove surface oxides, rust, and impurities, ensuring material purity.

Cold Rolling: The heated steel billets are rolled through a cold rolling mill. During this process, the billets undergo a series of deformation through roller rolling, ultimately forming the shape of cold-rolled steel pipes. Cold rolling offers advantages in achieving higher dimensional accuracy and surface quality.

Heat Treatment (Optional): Some cold-rolled steel pipes may undergo heat treatment to improve their mechanical properties and organizational structure.

Inspection and Quality Control: The finished products undergo inspection and quality control to ensure compliance with relevant standards and specifications.

Packaging and Transport: Qualified cold-rolled steel pipes are packaged and prepared for shipment to customers or entry into the market.

4.Characteristics

High Precision: Possesses a high level of precision, reducing material loss for users during mechanical processing.

Diverse Specifications: Offers a variety of specifications, capable of manufacturing to international standard dimensions, with a wide range of applications.

High-Precision Cold Rolling: Cold-rolled products exhibit high precision, excellent surface quality, and straightness.

Hexagonal Inner Diameter: The steel pipe’s inner diameter can be designed in a hexagonal shape, enhancing design flexibility.

Superior Performance: The pipes exhibit superior performance with a higher metal density.

5.Summary

Cold-drawn precision seamless tubes inherit the advantages of seamless steel pipes while having their distinct characteristics.

The use of these precision tubes for manufacturing circular components can improve material utilization, simplify manufacturing processes, and save on materials and processing time. Precision steel tubes are widely used in the manufacturing of components such as rolling bearing sleeves and hydraulic jack casings.

The extensive application of precision seamless tubes is significant for conserving steel, enhancing processing efficiency, reducing processing steps, or equipment investments. This can lead to cost savings, shorter processing times, increased output, and improved material utilization. Furthermore, it contributes to enhancing product quality and reducing costs, playing a crucial role in improving economic efficiency.

Industries with higher precision requirements generally opt for precision seamless tubes, while those without such precision requirements mostly use seamless tubes. After all, the prices of precision seamless tubes of the same specifications are generally higher than those of seamless tubes.

6.Applications

Cold-drawn precision seamless tubes are widely used across various industries, including hydraulic systems, injection molding machines, hydraulic presses, shipbuilding, EVA foam hydraulic machinery, precision hydraulic cutting machines, shoemaking machinery, hydraulic equipment, high-pressure oil pipes, hydraulic oil pipes, card sleeve joints, steel pipe joints, rubber machinery, forging machinery, die-casting machinery, engineering machinery, concrete pump high-pressure steel pipes, sanitation vehicles, automotive industry, shipbuilding, metal processing, military, diesel engines, internal combustion engines, air compressors, construction machinery, agricultural and forestry machinery, and more.

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Cold-rolled precision seamless pipe