ASME SA203 Grade A: 2.25% nickel at the lower official strength minima
Gangsteel produces and exports ASME SA203 Grade A nickel-alloy plate for welded pressure-vessel orders. Grade A sits in the 2.25% nominal-nickel family with ASME SA203 Grade B. Official public ASME SA-203 tables were not read. Official ASTM A203 Grade A Scope minima for the counterpart designation are yield 37 ksi [255 MPa] and tensile 65 ksi [450 MPa], with nominal nickel 2.25%. An ASTM certificate is not by itself SA-203 or ASME Code acceptance, and an SA203 certificate is not by itself ASTM A203 acceptance.
What is official for an SA203 Grade A order
The current listed edition of ASME Section II, Part A on the official store is BPVC.II.A-2025. That store page does not name SA-203/SA-203M, does not print SA-203 tables, and does not state which ASTM A203 edition is adopted. Official SA-203 chemistry, tensile, heat-treatment and thickness-cap clauses therefore stay blank as official ASME cells. Official ASTM A203/A203M-23 public Scope is cited only as counterpart facts. Do not treat the two designations as automatic substitutes, and do not invent a construction Code year for a job.
Chemistry: three labelled carbon bands in the 2.25% nickel family
Both chemistry tables below are labelled steelspecs ASME SA203 Grade A compilation data dated 14 September 2026, not official SA-203 Table 1 and not official ASTM Table 1. Percentages are by mass. The dated page prints three heat-carbon bands, including a >100 mm row. Manganese entries are separate maxima—not a range between the thin and thick values.
| Plate thickness | Heat C max, % | Heat Mn max, % | Product Mn max, % |
|---|---|---|---|
| ≤50 mm | 0.17 | 0.70 | 0.78 |
| >50–100 mm | 0.20 | 0.80 | 0.88 |
| >100 mm | 0.23 | 0.80 | 0.88 |
| Element | Heat analysis, % | Product analysis, % | Current official table |
|---|---|---|---|
| Si | 0.15–0.40 | 0.13–0.45 | |
| Ni | 2.10–2.50 | 2.03–2.57 | |
| P | 0.025 max | ||
| S | 0.025 max | ||
| C | See thickness table |
Official public ASTM Scope states only the 2.25% nominal nickel content for the counterpart grade. The heat band 2.10–2.50% and the product band 2.03–2.57% are labelled compilation figures, not official Table 1. Do not publish the 3.50% family product band 3.18–3.82% as Grade A nickel. Blank product C, P and S cells are not zero; confirm the product check under SA-20/SA-203 and the order. Official chemistry cells stay unfilled because official SA-203 text was not read.
Mechanical properties: official SA-203 cells stay blank
| Requirement | Official SA-203 | Official ASTM A203/A203M-23 counterpart Scope | Dated SA203 compilation |
|---|---|---|---|
| Tensile minimum, ksi [MPa] | 65 [450] | 65 [450] | |
| Tensile maximum, ksi [MPa] | 85 [585] | ||
| Yield minimum, ksi [MPa] | 37 [255] | 37 [255] | |
| Elongation minimum, 8 in. [200 mm], % | 19 | ||
| Elongation minimum, 2 in. [50 mm], % | 23 |
The dated compilation therefore gives tensile strength 65–85 ksi [450–585 MPa], with the same mechanical set on both sides of 50 mm. Official ASTM Scope 1.2 for counterpart Grade A is not thickness-split. Official SA-203 upper tensile limits and official elongation stay blank, as do the official ASTM upper and elongation cells. Gauge length is not a thickness band; inch-pound and SI values in the ASTM counterpart Scope belong to independent unit systems. The dated compilation describes Grade A as normally normalized. If a cooling rate faster than air cooling and a temper of not less than 595 °C are agreed, that compilation also calls for Charpy testing; confirm the test temperature and energy in the order. Those heat-treatment notes are labelled, not official SA-203 clauses. Do not apply quench-and-temper practice from Grade F to Grade A.
Equivalent and comparable materials for a Grade A order
A replacement should be checked against the drawing’s nickel family, official strength minima, carbon limits, delivery basis and the acceptance standard named on the order. Matching room-temperature strength does not make two designations interchangeable.
| Material considered | What to compare | Direct substitute? |
|---|---|---|
| ASTM A203 Grade A | Related counterpart designation under A203/A203M-23. Official ASTM Scope minima coincide with the figures shown above, but official SA-203 text was not read and dual certification is not automatic. | Not automatically. ASTM and ASME are not interchangeable in either direction. |
| ASME SA203 Grade B | Same 2.25% nickel family, but official ASTM counterpart minima are higher (40 / 70 ksi) and the labelled carbon and elongation figures differ. | No. Grade B is not equivalent to Grade A. |
| ASME SA203 Grade D | Official ASTM counterpart minima coincide (37 / 65 ksi), but Grade D is the 3.50% nickel family. Carbon and nickel limits differ. | No. Grade D is not equivalent to Grade A. |
| ASME SA203 Grade E | A later-wave 3.50% nickel designation with higher official ASTM counterpart minima (40 / 70 ksi). | No. |
| ASME SA203 Grade F | Same later-wave 3.50% family, with thickness-split official ASTM counterpart minima and a different delivery route in the dated compilations. | No. Grade F is not a normalized Grade A substitute. |
Check chemistry, strength, delivery, testing and the named acceptance standard before approving any alternative.
Related specifications to compare
Review ASME SA203 Grade B for the higher-strength 2.25% nickel designation, ASME SA203 Grade D and ASTM A203 Grade D for the 3.50% nickel family at the same official ASTM strength minima, or ASTM A203 Grade A and ASTM A203 Grade B when the order names the ASTM counterpart. These links are navigation, not substitution approval or technical sources from unremediated sibling pages.
Buyer questions
Does an ASTM A203 Grade A certificate satisfy SA-203 or Code acceptance?
No. The designations are related, not automatic substitutes. Name the acceptance standard, the edition and any Code year the job actually requires; do not invent a Code year here.
Is official SA-203 identical to A203/A203M-23?
That official statement was not read. The official store listing for BPVC.II.A-2025 does not print SA-203 text or name the adopted ASTM year, so this page does not claim identity.
Can we supply Grade A as Grade B because both are 2.25% nickel?
No. Same nickel family is not equivalence. Official ASTM counterpart minima and the labelled carbon and elongation figures differ, and a change of designation needs the purchaser’s approved specification.
Is 3.18–3.82% the nickel band for Grade A?
No. That product band belongs to the 3.50% nickel family. Grade A compilation product nickel is 2.03–2.57%, labelled, not official Table 1.
Is 150 mm the official SA-203 thickness limit?
No official SA-203 thickness cap was read. Official ASTM counterpart Scope limits thickness by the composition’s ability to meet mechanical requirements. A compilation supply range is not an official cap.
Send a Grade A production enquiry
Ask Gangsteel to review your export order. Include Grade A, the contractual SA-203 edition, SA-203 or SA-203M unit system, the Code year the job actually requires, thickness × width × length, quantity, delivery condition, tests, inspection-document requirements and destination.