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Round Bar Delivery Condition: Hot Rolled, Cold Drawn, Forged and Q&T

Two suppliers can quote the same grade, at the same diameter, at very different prices, and both be honest. The difference is the delivery condition, and it decides how much machining you have to do before the bar becomes a part.

Hot rolled bar is the base condition. It arrives with mill scale, a normalised or as-rolled structure, and a diameter tolerance that is generous—typically well over half a millimetre, depending on size and standard. It is the cheapest route and the right one for large diameters that will be roughed out anyway. Order it when your drawing already leaves 2 to 3 mm of machining allowance.

Cold drawn bar is pulled through a die after pickling, so the diameter comes out tight and bright, often within h9 or h11, with a smooth surface and improved straightness. Cold work raises the yield strength a little, which helps on small shafts and pins, but it also leaves residual stress: if the part will be machined heavily or welded, ask for a stress-relieving pass.

Forged bar is chosen for heavy sections and for parts where internal soundness cannot be left to chance—large shafts, rings, tool blocks, pressure-retaining components. A forging ratio breaks down segregation and closes internal porosity, then a normalising or annealing treatment follows. It costs more and takes longer, and it is worth it above roughly 250 mm where rolled bar's core properties start to drift.

Quenched and tempered bar arrives with a hardness range already achieved, typically 28 to 32 HRC or per your drawing. It saves a heat-treat cycle and the distortion that comes with it, but hardness in a large section is not uniform: confirm the hardenability curve for the diameter before you assume the core matches the surface.

What to put on the order: the dimensional standard (EN 10060 for hot rolled, EN 10278 for bright bar), diameter and tolerance class, delivery condition, hardness or mechanical properties, straightness limit such as 2 mm per metre, ultrasonic testing class if the part is critical, and end finish. A bar ordered only as "4140 round bar" will be supplied to the cheapest condition that meets the grade—and it usually is not the one on your process sheet.

We supply hot rolled, cold drawn, forged and quenched and tempered round bar in carbon, alloy and stainless grades, cut to length with mill certificates.

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