GlossaryKind of term: Manufacturing termMaterial certificate
What is a material certificate?
A material certificate is the inspection document with a delivered batch of material, giving heat number, composition and properties, usually to EN 10204.
Besides the heat number and the chemical composition, it gives mechanical values such as tensile strength and hardness, and the standard and condition of delivery. The material's producer issues it; a stockholder passes it on and keeps the batch traceable. Which type of certificate is needed is stated on the drawing, in the purchasing terms or in the order. In English it is often called a mill certificate or mill test report.
What does the standard say about a material certificate?
EN 10204 defines the types of inspection document for metallic products. Type 2.1 is a declaration that the product complies with the order, without test results; type 2.2 gives results of non-specific inspection, from production in general. Type 3.1 gives results of specific inspection on the delivered batch, validated by the producer's inspection representative, who is independent of the manufacturing department. With 3.2 a representative of the purchaser, or an inspector designated by regulations, validates it as well. Which tests appear follows from the product standard and the order, not from EN 10204.
How does a material certificate work in practice?
A certificate requirement changes purchasing and paperwork. You buy from a supplier who can provide the type asked for, sometimes at a surcharge and, for 3.2, often with a longer lead time. The heat number has to stay traceable from purchase to delivery: at the saw, on the job paperwork and on offcuts returned to stock. Offcuts whose batch can no longer be established cannot be used for such an order. If a certificate is required but not included in the price, you bear the surcharge and paperwork yourself.
What is a material certificate often confused with?
A material certificate is not a material specification: the specification says what the drawing asks for, the certificate shows what a batch has. Nor is it a certificate of conformity: that is issued by the maker of the part about the delivered part, while the material certificate covers the material.
Frequently asked questions
What is the difference between a 3.1 and a 3.2 certificate?
With 3.1 the producer's inspection representative, independent of manufacturing, validates the test results for the batch. With 3.2 a representative of the purchaser or a designated inspector validates them as well. A 3.2 usually costs more and takes longer.
May I use material from stock when a certificate is required?
Only if the heat number of that piece is established and the certificate for that batch is on file and of the type required. An offcut without traceability is not an option for such an order, however good the material.
Does EN 10204 also apply to plastics?
The standard is written for metallic products. Suppliers of plastic stock shapes often issue comparable document types, but what is to be supplied should be stated in the order.