How bar steel is supplied

Rolled or forged

Up to approx. Ø400, most grades come as hot-rolled bar. Large diameters and short pieces are forged. Same W.Nr. – different material. A Ø80 in 42CrMo4 and a Ø400 in 42CrMo4 are not the same piece: the core of the large bar has seen less deformation and takes hardening less well. That is why we often switch to 34CrNiMo6 as the diameter grows.

+N, +QT and what the drawing forgets

The plus on the drawing is the delivery condition. +N is normalised – uniform ferrite-pearlite, which is what C45N means. +QT is hardened and tempered, the condition 42CrMo4 is most often traded in. Without a plus, the bar is typically as rolled, with mill scale. We state the condition on the quotation and the certificate, so you do not receive rolled material when you were counting on +QT.

• +N – normalised. C45N is C45 in that condition.
• +QT – quenched and tempered. Standard on quenched and tempered steel.
• Rolled / +AR – as it comes from the mill, with mill scale.
• Turned or bright drawn – scale removed, dimensions closer to the finished part.

What sawing does not change

When we cut to length, we cut length. The condition comes with it. A +QT certificate applies to the cut piece. A sawn face is ready for clamping – it does not turn a rolled bar into +N. If the condition has to change, that is heat treatment, not sawing.