This guide starts after the part designer has narrowed the material family. Its purpose is to turn that choice into an RFQ specification a stamping supplier can price without guessing the grade, condition, thickness or allowed alternatives.
Use the separate material-selection guide to compare steel, stainless, aluminum, copper and other options by function. Use this page to control the engineering-to-purchasing handoff before tooling, samples and repeat production are quoted.
Short answer: what material details belong in the RFQ
State the material family and exact grade or governing standard, temper or hardness when applicable, nominal thickness, surface condition, finish route and whether any substitute is allowed. Link those requirements to one drawing revision.
If the grade is not yet fixed, describe the functional requirement and mark the choice as open for supplier review. Do not mix a mandatory drawing callout with a different purchasing description.
- Material standard and grade, including alloy designation where relevant.
- Temper, hardness, coating or surface condition that can affect forming and contact behavior.
- Nominal thickness and any thickness tolerance that affects assembly or tooling.
- Drawing revision, part function and the features that make the callout critical.
Control required grades and approved substitutes
A supplier can only price an alternative responsibly when the RFQ explains which properties must remain unchanged and who approves the substitution. A similar commercial name does not prove equivalent forming, corrosion, conductivity or finish behavior.
List pre-approved equivalents separately from supplier-proposed options. Tooling and production should not be released on a substitute until the buyer accepts the material and any required sample evidence.
- Required: the drawing grade cannot change without an approved revision or deviation.
- Pre-approved: named equivalent grades may be quoted under the stated conditions.
- Supplier proposal: engineering data and sample review are required before release.
- Record which price and lead-time assumptions depend on the proposed material source.
Connect material condition to stamping and finishing
Temper, hardness, grain direction and precoated surface condition can affect springback, hole quality, bend risk, surface marking and tooling assumptions. Identify the features that need DFM review rather than naming only a broad metal family.
Powder coating, plating, anodizing, passivation, brushing and deburring also depend on the selected base material. Mark visible, conductive, masked and coating-sensitive faces on the drawing.
- State whether inspection is performed before or after plating, coating or anodizing.
- Define burr direction, edge cleanup, masked zones and protected cosmetic faces.
- List dimensions affected by sheet variation or finish buildup.
- Keep the sample material condition representative of intended production.
Define certificates, compliance and incoming evidence
Request only the records the program needs, but request them before pricing. Material certificates, RoHS or REACH declarations and inspection reports can affect sourcing, lot traceability, lead time and shipment documentation.
The RFQ should say whether records are needed with samples, with every production lot or only on request, and which material characteristics the supplier must verify.
- Material certificate or certificate of conformity and the required lot linkage.
- RoHS, REACH or other buyer-specified declarations where applicable.
- Thickness, hardness, coating or conductivity checks when they control function.
- Record-retention and shipment-document expectations for repeat orders.
| Specification field | What to define | Why it matters |
|---|---|---|
| Grade or standard | Exact designation and governing material specification | Prevents pricing a different alloy or steel condition |
| Temper or hardness | Required condition, range or buyer-approved supplier review | Changes springback, forming and contact behavior |
| Thickness | Nominal value and applicable tolerance | Affects tooling, fit, weight and material cost |
| Surface condition | Bare, galvanized, electrolytic, tin-coated, brushed or other condition | Connects forming, corrosion and appearance assumptions |
| Substitute rule | Required grade, pre-approved equivalents and approval owner | Keeps purchasing flexibility under engineering control |
| Finish interface | Plating, coating, anodizing, passivation, masking and visible faces | Avoids incompatible or dimension-changing finish assumptions |
| Certificates | Material certificate, conformity, RoHS, REACH and lot linkage | Makes documentation scope visible in the quote |
| Inspection evidence | Thickness, hardness, coating, conductivity or other required checks | Defines sample and production acceptance |