GlossaryKind of term: Manufacturing termMaterial specification
What is a material specification?
A material specification states which material a part is made from: designation, standard and condition, such as EN AW-6082 T6 or 1.4404, not just ‘aluminium’.
A material specification is the full designation of the required material, usually in the title block or a note. It consists of the material name or number, the condition and, where needed, the standard, the product form and requirements such as a certificate: EN AW-6082 T6, 1.4404, 42CrMo4+QT, POM-C. ‘Aluminium’ or ‘stainless’ is not a specification but a material family. Comparable materials carry their own names in different standards, such as 1.4404 and the American designation 316L, and the limits on composition and properties can differ from one standard to another.
What does the standard say about the material specification?
The designation follows the standard for the material. For wrought aluminium, EN 573 gives the alloy (EN AW-6082) and EN 515 the temper (T6, H111). For steel, EN 10027-1 and EN 10027-2 give the name (42CrMo4) and the material number (1.7225). Condition symbols such as +QT or +A are also given in EN 10027-1; which conditions can be supplied follows from the product standard, such as EN 10083-3 for alloy quenched and tempered steels. Stainless steels are covered by EN 10088. A designation is only unambiguous with its condition: 6082 in T6 has a different strength and machinability from 6082 in T4.
How does the material specification work in practice?
The material affects route and cost in several places. Price per kilo, available sizes and minimum order quantity shape the material cost. Cutting data and tool life shape the machining time: stainless steel generally machines more slowly than aluminium. Finishing is affected too: not every aluminium alloy anodises equally well, and a steel that is hardened or nitrided later may need finishing allowance and a different sequence. An incomplete specification is a question for the customer. Substitute a material only with the customer's approval.
What is the material specification often confused with?
A material specification is not the stock: the specification says which material in which condition, the stock which bar, plate or block you buy. Nor is it the material certificate: that is the document supplied with a delivered batch to show that it meets the specification.
How do you see the material specification in Blake?
The material from the drawing sits in Blake as a proposal on the part. Once you confirm or correct it, who made the choice and when stays visible. The material line calculates with your own purchase prices, with source and history, from one catalogue for metals and plastics. Market references sit alongside with source and date, for comparison and not as a purchase price. More on materials.
Frequently asked questions
What do you do when the drawing only says ‘aluminium’?
Ask the customer which alloy and condition are meant. Price per kilo, cutting data and suitability for anodising depend on it. If you must assume, state the assumption in the quote so the customer can confirm it.
Does the material condition matter for the price?
Yes. The same alloy annealed or quenched and tempered machines differently and can carry a different purchase price. The condition can also set the route: hardening after roughing and finishing afterwards is a different estimate from machining stock that is already quenched and tempered.
Is 1.4404 the same as 316L?
Comparable, not identical by definition. The designations come from different standards, and the limits on composition and properties can differ slightly. If the customer asks for a particular standard or a certificate against it, that designation applies.