ASTM A203 Grade A: start from the edition, thickness and delivery condition
Gangsteel produces and exports ASTM A203 Grade A nickel-alloy plate for welded pressure-vessel orders. To compare our offer with your drawing, start with the required edition, plate thickness and delivery condition—not just the nominal nickel content.
Grade A requirements for the enquiry
The current public edition is A203/A203M-23. Its Scope gives Grade A nominal nickel of 2.25%, minimum yield 37 ksi [255 MPa] and minimum tensile strength 65 ksi [450 MPa]. These are minimum requirements, not a complete tensile table. The official abstract requires killed, fine-grain steel and says Grades A, B, D and E shall be normalized as required.
Chemistry: choose the correct thickness band
Both chemistry tables below are labelled steelspecs Grade A compilation data dated 14 September 2026, not official Table 1. Percentages are by mass. 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, % |
|---|---|---|
| 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 |
Blank product C, P and S cells are not zero or permission to copy heat limits; confirm the product check under A20/A203 and the order. Official chemistry cells remain unfilled because the public Scope does not reproduce Table 1.
Mechanical properties: official minima versus reference limits
| Requirement | Official public Scope | Dated 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 compilation therefore gives tensile strength 65–85 ksi [450–585 MPa], with the same mechanical set on both sides of 50 mm. Official upper tensile and elongation cells stay blank. Gauge length is not a thickness band; inch-pound and SI values belong to independent unit systems.
Equivalent and comparable materials for a Grade A order
A replacement grade should be checked against the drawing’s nickel family, official strength minima, carbon limits and acceptance basis. We do not change the production designation simply because a proposed replacement looks similar or is stronger.
| Material considered | What to compare | Direct substitute? |
|---|---|---|
| A203 Grade B | Shares nominal 2.25% nickel but has higher official minima: yield 40 ksi [275 MPa], tensile 70 ksi [485 MPa]. Its compilation also allows higher heat-carbon maxima and gives lower elongation. | No. Grade B is not equivalent to Grade A. |
| A203 Grade D | Nominal 3.50% nickel at Grade A’s official strength minima. Detailed chemistry has not been verified here. | Not automatic. Examine it as a separate designation if the drawing requires 3.50% nickel. |
| A203 Grade E | Has Grade B’s official minima in the 3.50% nickel family. Detailed chemistry has not been verified here. | Not automatic. |
| A203 Grade F | Has thickness-dependent official minima. Detailed chemistry has not been verified here. | Not automatic. |
| A387 Grade 22L Class 1 | Cr-Mo plate, not a nickel-alloy material. | No. It is not a nickel-alloy replacement. |
| SA-203 / ASME Code acceptance | Governing acceptance basis, certificate designation, delivery condition and tests must be identified. | Not automatically. ASTM and ASME are not interchangeable in either direction; an A203 certificate alone does not establish Code acceptance. |
Check chemistry, strength, delivery and testing before approving any alternative.
Related specifications to compare
Review A203 Grade B for the higher-strength nickel-alloy designation or A387 Grade 22L Class 1 for the separate Cr-Mo family. These links are navigation, not substitution approval or technical sources.
Buyer questions
Is 150 mm the ASTM thickness ceiling?
No. Scope limits thickness by the composition’s ability to meet mechanical requirements, not a fixed 150 mm cap.
Does 2.25% nickel mean a fixed production target?
It is the official nominal content; compare actual analysis against the applicable ordered limits.
Can I combine different thicknesses in one enquiry?
Yes. List each size separately so its carbon and manganese limits can be reviewed.
Are impact temperature and energy fixed by this page?
No. State the required test conditions; no default Charpy value or alternative cooling route is promised.
Are these tables the full purchased standard?
No. Public Scope and labelled compilation references are distinguished; paid ASTM/ASME full texts were not read.
Send a Grade A production enquiry
Ask Gangsteel to review your export order. Include Grade A, the contractual edition, A203 or A203M unit system, thickness × width × length, quantity, delivery condition, tests, inspection-document requirements and destination.