Technical Information
Reference notes for buyers: designation systems, what the certificate should contain, the specifications that usually apply to each product form, and the conversion constants used throughout the site.
Designation Systems — Who Names What
| System | What it is | Example |
|---|---|---|
| ASTM | US standards body; material and product specifications written as grade/product standards | ASTM A312 (stainless pipe) |
| ASME | Boiler & Pressure Vessel Code versions of ASTM specs, prefixed SA/SB for code work | ASME SA-312 |
| EN | European Norms; the W.Nr. material number accompanies them | EN 10088 (stainless) |
| UNS | Unified Numbering System — one identifier per alloy across North America | S31603 = 316L |
| W.Nr. | European "Werkstoffnummer" material number | 1.4404 = 316L |
| IS | Indian Standards | IS 2062 (structural steel) |
Trade names (Monel, Inconel, Hastelloy) are proprietary alloy families of their respective producers; the UNS/W.Nr. column on each material page gives the neutral identifiers.
Reading a Mill Test Certificate
- Specification header. The standard the material was produced and tested against must match your order — including the revision.
- Heat number. The number that ties the certificate to the physical piece. Check it against the marking on the material, not just the tag.
- Chemical analysis. Actual heat analysis, element by element, against the specification limits. It should be the real numbers, not the standard's ranges.
- Mechanical results. Actual tensile, yield, elongation — plus any specified impacts or hardness — with the specimen orientation and treatment condition stated.
- Certificate type and signature. EN 10204 3.1 (manufacturer's authorised representative) or 3.2 (with purchaser's/official representative countersignature), signed and dated.
See Quality Assurance for how certification is handled on ACERO ALLOYS orders.
Specifications by Product Form
The commonly applied specifications per product form (material-specific variants noted on each material page):
| Product form | Stainless / nickel | Carbon / alloy steel |
|---|---|---|
| Seamless / welded pipe | ASTM A312, A335 (alloy), B161–B167 (Ni alloys), B462 | ASTM A106, A53, A333, A672 |
| Heat-exchanger tube | ASTM A213, A249, B163, B515/B516 | ASTM A179 |
| Sheet, plate, strip | ASTM A240, B168, B443, B575 | ASTM A516, A285, EN 10029 |
| Bars, rods, sections | ASTM A276, B164, B425, B348 | ASTM A105 (forgings), A29, EN 10083 |
| Butt-weld fittings | ASTM B16.9 with matching grade | ASTM B16.9, MSS SP-75 (welded) |
| Forged fittings | ASTM B564, B462 | ASTM A105, A350, B16.11 |
| Flanges | ASTM A182, B564, B16.5 | ASTM A105, A694, B16.5 |
| Fasteners | ASTM A193 B8/B8M, B325-type nickel specs | ASTM A193 B7, A320, A325/A490 |
Indicative mapping for orientation — the governing specification is always the one stated on your order and its certificate.
Conversion Constants Used on This Site
| From | To | Multiply by |
|---|---|---|
| inch | mm | 25.4 |
| mm | inch | 0.039370 |
| metre | foot | 3.28084 |
| kg | lb | 2.20462 |
| kg/m | lb/ft | 0.671969 |
| kg | metric ton (t) | 0.001 |
| From | To | Multiply by |
|---|---|---|
| MPa | psi | 145.038 |
| psi | MPa | 0.00689476 |
| N/mm² | MPa | 1 |
| bar | psi | 14.5038 |
The unit conversion calculator applies these constants with more figures and both directions at once.
Our Data Discipline
- Composition and property values on this site are indicative published ranges for selection and comparison
- Tables are labelled as indicative, and where a value is approximate it carries the ≈ mark
- Verified values not published as fact — certifications come from the mill with the material
- Geographic, corporate and capability claims are kept to what is verifiable
Frequently Asked Questions
Which specification applies to my material?
The product form decides the family: pipe and tube have their own specifications, sheet and plate another, bars another. Start from the material page for the grade, then the product-form table on this page for the typical specification — and state the exact specification on your enquiry so supply and paperwork match.
What is a UNS number?
The Unified Numbering System is a single North-American identifier for metals and alloys — e.g. S31603 for 316L stainless, N04400 for Monel 400. It removes ambiguity between trade names and national designations.
What does an EN W.Nr. number mean?
The European "Werkstoffnummer" (material number) is the German/European equivalent identifier — e.g. 1.4404 for 316L. Together UNS and W.Nr. let you cross-reference a grade across markets; the material pages list both where they exist.
How accurate are the weight calculators?
They give theoretical weights from the nominal dimensions and nominal density — exactly what is needed for estimation, freight planning and budgeting. The certified weight of a specific lot can differ slightly due to tolerance and actual chemistry; invoicing uses the actual figures.
Ready to Specify?
Run the numbers in the calculators, then send the enquiry with the figures attached.