Product Specification

Electric-Resistance Welded Carbon Steel Structural Pipe for Automotive Applications

Material

This product is an electric-resistance welded (ERW) carbon steel tube manufactured from hot-rolled or cold-rolled steel strip/coil and welded continuously. It is designed specifically for automotive structural applications, meeting the Japanese standard JIS G3472 for “Electric Resistance Welded Carbon Steel Tubes for Automobile” (automotive structural use).
The material is carbon steel (plain carbon or low alloy) welded tube, offering cost-effective fabrication, high strength, consistent dimensions and suitability for chassis, frame, suspension and other structural parts in vehicles.

Specifications

• Standard: JIS G3472 (latest revision 2018)

• Grades covered: STAM500G, STAM290GA, STAM290GB, STAM340G, STAM40G (automotive structural ERW tube)

• Outside diameter (OD): typically 15.9 mm to 101.6 mm (standard covers this range)

• Wall thickness (WT): typically 1.0 mm to 6.0 mm (depending on OD and grade)

• Manufacturing: Electric resistance welded, possibly hot-finished or cold-finished depending on grade and process.

• Finish: As welded, descaled, or pickled & oiled; ends plain or beveled as per buyer requirements.

• Additional dimensional tolerances and straightness, weld bead removal, internal weld bead treatment, are as per JIS G3472.

Key Features

• High structural strength: The grades deliver a range of tensile and yield strengths tailored to automotive structural demands (see Mechanical Performance section).

• Good formability: The tubes are designed for automotive uses such as bending, flaring, collapse resistance, and often the standard requires flaring (expansion) tests.

• Consistent dimensions and weld quality: Being ERW (electric resistance welded) ensures consistent weld seam, minimal deformation, and reliable mechanical performance.

• Lightweight design suitability: By providing high strength in thin-wall tube form, these products support weight reduction in automotive structures.

• Automotive quality assurance: Conformance to JIS G3472 ensures key requirements such as chemical composition limits, mechanical tests, flaring test, dimensional tolerances, non-destructive testing per purchaser’s specification.

Our Advantages

From a factory-and-supply-chain perspective, we provide the following advantages which address customer concerns:

1. Straightness & dimensional accuracy – Our manufacturing process monitors tube straightness, outer diameter tolerance, wall thickness tolerance and weld seam geometry to meet JIS G3472 requirements, reducing downstream bending or fit-up issues.

2. Controlled tolerances & surface finish – We pay special attention to outer/inner surface condition, weld bead removal or inside bead flattening, internal/external defects, ensuring minimal re-work and cleaner assembly for automotive production.

3. Consistent mechanical properties across runs – Material traceability, heat treatment (where applicable) and mechanical test certification guarantee that each lot meets specified yield/tensile/elongation values, avoiding variability in crash-performance or forming operations.

4. Weld quality & flaring/expansion capability – Per JIS G3472 the “flaring test” (expanding the tube end) must show no crack at specified expansion factor (e.g., 1.15 D for STAM500G). We ensure weld quality and inner bead treatment so this test is reliably passed, which is critical for automotive assemblies requiring flared/mated tube ends.

5. Certified material and automotive grade supply – We supply full test certificate, chemical and mechanical reports, non-destructive testing (UT/ECT) on welds (as per customer’s specs), and support automotive quality systems (e.g., ISO/TS, PPAP documentation).

6. Flexible grade and size availability – Because we stock or produce multiple grades (STAM290GA/GB, STAM340G, STAM500G etc) and a wide range of diameters and wall thicknesses, we can optimize cost for the given strength requirement rather than over-specifying a higher strength (higher cost) grade than needed.

Chemical Composition

Mechanical Performance

Execution / Standard

• Standard: JIS G3472:2018 – “Electric resistance welded carbon steel tubes for automobile”.

• The standard covers manufacturing methods, marking, testing (chemical analysis, tensile, flaring), dimensions/weights, tolerances, external and internal weld bead treatment, etc.

• Typical execution code on tube marking would include: Class (G or H), grade (e.g., STAM290GA), manufacturing method symbol (e.g., E for ERW, G for as welded, H for hot finished, C for cold finished) as defined in Table 1 of JIS.

Application Fields

General Application Field

This welded carbon steel tube is aimed at automotive structural use, particularly where strength, weight-economy and formability are required.

Specific Application Breakdown

• Chassis frame members (cross-members, longitudinal frame rails)

• Suspension components (control arms, member support tubes)

• Cross-bracing and safety cage members

• Seat frame structures and mounting tubes

• Steering column supports, axial tubes

• Prop-shafts, stabiliser bars (for lighter duty)

Q: Are you trading company or manufacturer ?

A: manufacturer,also can do trading.

Q: How long is your delivery time?

A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,

it is according to quantity.

Q: Do you provide samples? is it free or extra ?

A: Yes, we could offer the sample for free charge but need pay the cost of freight.

Q: What is your terms of payment ?

A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.

If you have another question, pls feel free to contact with me.