ERW Carbon steel square tube 25x25x1.5mm ASTM A513 Grade 1010 Welded Hollow Section Stock

ASTM A513 is the specification buyers reach for when the tube has to be machined, bent or threaded rather than simply welded into a frame. This 25 x 25 x 1.5 mm ERW carbon steel square tube is made to Grade 1010 chemistry, a low carbon grade that machines cleanly on a centre lathe and bends without the orange peel surface that appears on higher carbon hollow sections.

The difference between A513 mechanical tubing and A500 structural tubing is not the shape, it is what is controlled. A513 puts the emphasis on wall uniformity, concentricity and surface condition, because the tube is usually an input to a machining operation where a 0.15 mm wall variation turns into an out of round part. We run this size on a dedicated mill pass with a strip width tolerance of 0.1 mm, and the inside bead is scarfed so that a boring bar or a broach does not catch on the seam.

• Grade 1010 Chemistry: Low carbon steel with 0.08 to 0.13 percent carbon, chosen for machinability and for consistent bend radii without cracking.
• Tight Strip Width Control: Strip is slit to plus or minus 0.1 mm, which is what keeps the finished wall uniform along the 6 m length.
• Scarfed Internal Bead: The inside weld is trimmed flush, so boring, internal threading and insert fitting are not interrupted by a raised seam.
• Machining Friendly: Free of the hard spots and laps that blunt tooling, with a surface that accepts black oxide, zinc plating and powder coating without extra preparation.
• Consistent Mechanical Values: Typical tensile 365 to 450 MPa and yield 235 MPa minimum, with elongation above 25 percent for forming operations.
• Stock and Cut Lengths: Held in stock in 6 m lengths, with cut to length, deburring and mitre service for production runs.

This is a machining and fabrication size rather than a structural one. Typical uses are machine guards, control cabinet frames, conveyor legs and cross members, shelving posts, display fixtures, exercise equipment frames and agricultural implement parts. It is also common in the automotive aftermarket for roof rack bars and light chassis brackets, where the tube is bent on a rotary draw bender and then welded. Because the grade machines well, it is frequently chosen for parts that are drilled, tapped or slotted after cutting.

Bundles of up to 2 tons, three steel straps, waterproof paper and PVC sleeve, with two tags per bundle showing heat number, size and wall. Oil is applied before wrapping to protect the mill finish in transit. Mill test reports to EN 10204 3.1 accompany each lot, and third party inspection can be arranged. We hold ISO 9001, CE and CNAS certification, and short trial lengths are available for machining tests before a production order.

Buyers sometimes order A513 for a welded frame to save cost over A500, and it works, but the weld procedure has to be adjusted. A513 has no minimum yield requirement as high as Grade B, so if the frame carries load, stay with A500 and accept the small price difference.