Haihao Group recently completed the production and shipment of a custom 20# steel tube for a customer in South Africa. Unlike standard steel pipe orders, this project required the tube to be manufactured strictly according to the customer’s engineering drawing, including the outside diameter, inside diameter, finished length, chamfer dimensions and bore inspection requirements.
The order called for a smooth-bore drawn tube made from 20# mild steel. The finished component was designed for a specific mechanical application, so dimensional accuracy was more important than simply supplying a standard pipe size.
Custom 20# Steel Tube Specifications
The supplied tube has an outside diameter of 26.20 mm, an inside diameter of 22.20 mm, and a finished length of 67 mm. The drawing identifies the material as #20 mild steel and specifies a smooth-bore drawn tube configuration.
| Product | Type | Outside Diameter | Inside Diameter | Length | Material | Standard |
| Steel Tube | Smooth Bore Drawn Tube | 26.20 mm | 22.20 mm | 67 mm | 20# Mild Steel | Customer Drawing |
The drawing also specifies a 0.50 × 45° chamfer at the tube ends. These details are important because the product is used as a machined component rather than as a conventional pipeline pipe.
Manufacturing to a Drawing, Not Just a Pipe Size
For a 20# steel tube produced for a specific assembly, nominal pipe dimensions are not enough. Haihao Group followed the customer’s drawing throughout the manufacturing process and paid particular attention to the finished bore.
The drawing requires the internal diameter to be checked after machining and deburring using a 22.05 mm GO gauge. This provides a practical dimensional check of the bore after finishing and helps ensure that the tube meets the customer’s assembly requirements.
Key drawing requirements include:
- Outside diameter: 20 mm
- Inside diameter: 20 mm
- Finished length: 67 mm
- End chamfer: 50 × 45°
- Material: 20# / #20 mild steel
- Tube type: Smooth bore drawn tube
- Bore inspection: 05 mm GO gauge
- Dimensions: Millimeters
- Manufacturing basis: Customer-approved drawing
This type of project requires closer coordination between material preparation, drawing or sizing, cutting, end finishing and final inspection.
Custom 20# drawn steel tube manufactured to customer drawing with 26.20mm OD and 22.20mm ID
Dimensional Control for Small-Bore Components
Although this 20# steel tube is only 67 mm long, its relatively small diameter and specified bore make dimensional control important. A small deviation in the ID, OD or end condition can affect the fit of the finished component.
Haihao Group therefore treats drawing-based orders differently from standard stock pipe requirements. The engineering drawing is used as the primary reference for production and inspection, while critical dimensions are verified before shipment.
The drawing indicates general unspecified tolerances of ±0.1 mm, ±0.05 mm and ±0.02 mm according to the number of decimal places. For a component with a specified bore inspection requirement, maintaining consistency during cutting, machining and deburring is particularly important.
20# Mild Steel for Drawn Tube Applications
20# mild steel is commonly used for components where a combination of machinability, strength and cost efficiency is required. In this project, the material was specified by the customer together with the drawn-tube construction.
The final product is therefore not simply a short piece of generic steel pipe. It is a drawing-controlled steel tube component with defined dimensional and finishing requirements.
For customers requiring similar products, Haihao Group can work from engineering drawings and production specifications to manufacture steel tubes and other pipeline components according to the required dimensions and inspection criteria.
Haihao Group: Custom Steel Tube Manufacturing
This South African order demonstrates Haihao Group’s ability to handle small-diameter, drawing-based steel tube production as well as conventional pipeline products. Our manufacturing process can be coordinated around customer drawings, material requirements, dimensional tolerances and inspection methods.
If you have a 20# steel tube requirement with non-standard dimensions, short finished lengths or drawing-specific machining details, send us your drawing and specifications. Our team can review the requirements and provide a suitable manufacturing solution.
