ASME SA302 Grade D: higher-nickel plate ordered for Code acceptance
For an SA-302 Grade D enquiry, the first decision is not simply whether a plate reaches a strength figure. The purchasing documents must identify the ASME material designation and the project’s governing edition. Gangsteel’s enquiry review starts with SA-302 or SA-302M, Grade D, the required dimensions and the acceptance route, so that the quotation is assessed against the vessel specification rather than a generic alloy description.
Grade D belongs to the manganese-molybdenum-nickel pressure-vessel plate family. Its higher nickel band distinguishes it from Grade C; similar tensile requirements do not make the grades interchangeable. This page separates family public references from the documentary requirements that a purchaser must establish for the actual Code order. It does not assign a current Code year or promise certification from a grade name alone.
Start with an acceptance schedule, not an assumed dual certificate
Use a line-item material schedule when different thicknesses, quantities or delivery conditions are required. Include the governing Code year or Section II-A edition before technical review. An ASTM A302 Grade D certificate is not by itself SA-302 acceptance; the reverse is not automatic either. Dual certification must be expressly reviewed and agreed, with evidence meeting both specified requirements. A certificate heading is not a substitute for that review.
| Order item | Information to establish | Acceptance purpose |
|---|---|---|
| Designation and edition | SA-302 or SA-302M, Grade D; governing Code year or Section II-A edition | Avoid an unqualified family designation |
| Unit system and sizes | Inch-pound or SI; thickness, width, length, quantity and drawing reference | Review each line in its chosen system |
| Delivery condition | Required heat-treatment condition and any subsequent fabrication cycle | Define the condition represented by the results |
| Tests and reporting | Required examinations, acceptance criteria, specimen details and report scope | Do not assume extra tests from nickel content |
| Certificate form and traceability | Required document form; plate identification and heat-to-report linkage | Agree the evidence before purchase |
The complete named-Code SA-302 text has not been verified for this page. Family information below uses the official public ASTM A302/A302M-17(2022) Scope and labelled public compilations; it is not an official SA-302 extract for a particular Code year. The project’s specified edition remains the controlling acceptance reference. Establish who reviews documentary deviations before an alternative is considered, rather than leaving the question until plate receipt.
Grade D chemistry: keep the higher nickel band visible
The following reference distinguishes heat analysis from product analysis. Heat/product splits come from a dated Grade D compilation, cross-checked against an undated Grade D compilation whose compressed ranges are product-style, not heat limits. Carbon’s three maxima are stated for both analyses in the compilation note. Phosphorus and sulfur are shown as heat-reference maxima only; unconfirmed product limits remain blank. Confirm all applicable requirements in the named Code edition.
| Element / thickness basis | Heat analysis | Product analysis |
|---|---|---|
| Carbon, max; up to 1 in. [25 mm], inclusive | 0.20 | 0.20 |
| Carbon, max; over 1 to 2 in. [over 25 to 50 mm], inclusive | 0.23 | 0.23 |
| Carbon, max; over 2 in. [50 mm] | 0.25 | 0.25 |
| Manganese | 1.15–1.50 | 1.07–1.62 |
| Silicon | 0.15–0.40 | 0.13–0.45 |
| Molybdenum | 0.45–0.60 | 0.41–0.64 |
| Nickel | 0.70–1.00 | 0.67–1.03 |
| Phosphorus, max | 0.025 | |
| Sulfur, max | 0.025 |
Nickel is a specified range, not a single maximum. Check the analysis type before comparing a reported result: a product-analysis band must not be used as the heat-analysis acceptance band. Grade D’s nickel values were independently checked on Grade D references, not inferred from Grade C. A report bearing another grade requires a complete contractual assessment; matching one element cannot establish acceptance of the entire material.
Strength, gauge length and thickness decisions
| Characteristic | Reference value or condition | Basis / buyer action |
|---|---|---|
| Alloy family | Manganese-molybdenum-nickel | Official ASTM public Scope; family reference here |
| Tensile strength | 80–100 ksi [550–690 MPa] | Official ASTM public Scope; not a named-Code SA extract |
| Yield strength, minimum | 50 ksi [345 MPa] | Grade D public compilations |
| Elongation, minimum; 8 in. [200 mm] gauge | 17% | Grade D public compilations; gauge length, not thickness |
| Elongation, minimum; 2 in. [50 mm] gauge | 20% | Grade D public compilations; separate gauge |
| Thickness coverage | Composition must be capable of meeting the specified mechanical properties | Official ASTM Scope principle; no numerical cap stated here |
| Delivery reference | 2 in. [50 mm] and under normally as-rolled; over that thickness normalized | Compilation restatement only; confirm in the governing Code edition |
Yield and elongation were independently confirmed in Grade D reference columns even where the numbers match Grade C. Inch-pound and SI values are independent unit systems, not exact conversions to combine within one order. Retain the required system throughout dimensional and mechanical review. The elongation result must identify its gauge length; 17% and 20% are not thin-plate and thick-plate bands.
The official ASTM abstract describes killed steel conforming to fine-grain requirements across the family. It does not establish a Grade-D-only process benefit. A dated public compilation restates ordinary delivery as as-rolled at 2 in. [50 mm] and under, with normalizing, stress relieving or both available as ordered, and normalizing above that boundary. This is a compilation restatement, not a verified paid SA-302 clause. Record the agreed condition without assuming a treatment temperature or a default quench-and-temper route.
Keep material identity separate from service approval
Higher nickel does not specify a default impact temperature, impact energy, welding procedure or inspection package. Where the vessel specification requires additional testing, state the method, acceptance criteria and reporting requirements before the order is settled. The plate grade alone does not demonstrate suitability for a particular corrosive environment or fabrication cycle. Keep the designer’s service requirements distinct from the base material description.
For related family enquiries, see ASME SA302 Grade C for the lower-nickel topic, or ASME SA302 Grade B for the Mn-Mo topic. These pages provide related purchasing context, not the technical basis for the figures on this page or automatic substitution approval.
Buyer questions
Can Grade C be accepted against a Grade D order?
Not by assuming that similar strength makes them the same. Grade D’s public-reference nickel is 0.70–1.00% heat and 0.67–1.03% product. Grade C has a different nickel band. Retain the ordered Grade D identity and obtain project approval before considering any change.
Which details should appear in an SA-302 Grade D enquiry?
Specify SA-302 or SA-302M, Grade D, the Code year or Section II-A edition, the unit system, sizes, quantity, delivery condition, tests and certificate form. Include relevant drawing requirements so the review can distinguish mandatory acceptance points from optional requests.
Are 17% and 20% elongation thickness categories?
No. The Grade D public references give 17% in an 8 in. [200 mm] gauge and 20% in a 2 in. [50 mm] gauge. Both are gauge-length minima. The test report must identify the applicable specimen and reporting basis.
Does an ASTM certificate establish ASME acceptance?
Not on its own. The required SA designation and governing Code edition must be supported by the agreed documentation. Dual marking is not automatic, and certificate form is a contract-review item rather than a default promise on this website.
Are additional examinations included merely because this is Grade D?
No additional inspection package is promised here. Write the required examinations, test conditions, acceptance criteria and any witnessing into the purchase requirements. Review their applicability in the governing documents rather than inferring them from the alloy name or nickel content.
Send a Code-specific Grade D enquiry
Provide the material schedule, governing edition, dimensions and acceptance requirements. Identify unresolved document or testing questions so they can be addressed during quotation review, before any material is accepted for the project.