Special Steel Profile

The estimating problem in this market is that the drawing arrives before the process is decided. A customer sends a cross-section; the mill has to work out whether that shape is hot rolled, cold drawn, hot extruded or laser fused, because each route has different tooling costs, different minimum quantities and different achievable tolerances. The same drawing can be viable on one route and uneconomic on another.

Producers in this market include Montanstahl, which makes stainless profiles by hot rolling, cold drawing and laser fusion, and Siderval, which produces special sections by hot extrusion. The existence of several routes is the point: a shape that is impossible to roll may be straightforward to laser fuse from plate, and a shape that is expensive to extrude in small quantity may be economic at volume.

The decision usually turns on a small number of variables: wall thickness and how it varies across the section, the tightest internal radius, overall envelope, the grade, the tolerance class and the order quantity. Those six are what an experienced estimator reads off a drawing in minutes and what takes a newcomer a day, which is the reason this lane rewards indexed history so heavily.

The production routes, and what each suits

• Hot rolling: high volume, generous radii, standard-ish sections. Tooling cost amortised over long runs.
• Cold drawing: tight tolerances and good surface finish, usually from a hot-rolled or extruded pre-section.
• Hot extrusion: complex sections and thick walls that rolling cannot form. Siderval works this route.
• Laser fusion: built up from plate, so almost any geometry including asymmetric sections; no rolling tooling required. Montanstahl works this route in stainless.
• Which wins: decided by section complexity, wall thickness variation, tolerance class, grade and quantity, not by the shape alone.