ASTM A203 Grade D: 3.50% nickel at Grade A’s official strength minima
Gangsteel produces and exports ASTM A203 Grade D nickel-alloy plate for welded pressure-vessel orders. Grade D belongs to the 3.50% nominal-nickel family. Its official strength minima coincide with A203 Grade A, but the two designations are not equivalent and must not be substituted on nickel content alone.
Grade D requirements for the enquiry
The current public edition is A203/A203M-23. Official Scope gives Grade D nominal nickel of 3.50%, 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. Agree the contractual delivery route before production.
Chemistry: two labelled carbon bands, not a copied Grade A schedule
Both chemistry tables below are labelled steelspecs Grade D compilation data dated 14 September 2026, not official Table 1. Percentages are by mass. The dated page prints only two heat-carbon bands, through 100 mm. A third band is not filled from Grade A. 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 |
| Element | Heat analysis, % | Product analysis, % | Current official table |
|---|---|---|---|
| Si | 0.15–0.40 | 0.13–0.45 | |
| Ni | 3.25–3.75 | 3.18–3.82 | |
| P | 0.025 max | ||
| S | 0.025 max | ||
| C | See thickness table |
The official public Scope states only the 3.50% nominal nickel content. The heat band 3.25–3.75% and the product band 3.18–3.82% are labelled compilation figures, not official Table 1. Blank product C, P and S cells are not zero; confirm the product check under A20/A203 and the order. Official chemistry cells stay unfilled because the public Scope does not reproduce Table 1. A chemistry table headed “Element A203 Grade A” does not identify Grade D.
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 Scope 1.2 for Grade D is not thickness-split. 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. If a cooling rate faster than air cooling and a temper of not less than 595 °C are agreed, the dated compilation also calls for Charpy testing; confirm the test temperature and energy in the order. That note is labelled, not an official Scope clause.
Equivalent and comparable materials for a Grade D order
A replacement grade should be checked against the drawing’s nickel family, official strength minima, carbon limits and delivery basis. Matching room-temperature strength does not make two nickel families interchangeable.
| Material considered | What to compare | Direct substitute? |
|---|---|---|
| A203 Grade A | Official strength minima coincide (37 / 65 ksi), but Grade A is the 2.25% nickel family. Carbon and nickel limits differ. | No. Grade A is not equivalent to Grade D. |
| A203 Grade B | A 2.25% nickel grade with higher official minima: yield 40 ksi [275 MPa], tensile 70 ksi [485 MPa]. | No. |
| A203 Grade E | Same 3.50% nominal nickel family, but official minima are higher (40 / 70 ksi). Its labelled heat-carbon maxima are also different. | No. Grade E is not equivalent to Grade D. |
| A203 Grade F | Same nickel family, with thickness-split official minima and a different delivery route in the dated compilation. | No. Grade F is not a normalized Grade D substitute. |
| 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. |
Check chemistry, strength, delivery and testing before approving any alternative.
Related specifications to compare
Review A203 Grade E for the higher-strength 3.50% nickel designation, A203 Grade F for the thickness-split official minima, or A203 Grade A and A203 Grade B for the 2.25% nickel family. These links are navigation, not substitution approval or technical sources.
Buyer questions
Because the official minima match Grade A, can we produce Grade D as Grade A?
No. The official nickel families differ. A change of designation needs the purchaser’s approved specification.
Is 100 mm the ASTM thickness ceiling?
No. Official Scope limits thickness by the composition’s ability to meet mechanical requirements. A compilation supply range is not an official cap.
Is the 3.18–3.82% nickel band official Table 1?
No. Official public Scope gives only the 3.50% nominal content. The heat and product bands above are labelled compilation figures to confirm in the ordered edition.
Can Grade A’s carbon maximum above 100 mm be copied onto this page?
No. The dated Grade D compilation does not print a third carbon band, so that cell stays blank here.
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 D production enquiry
Ask Gangsteel to review your export order. Include Grade D, the contractual edition, A203 or A203M unit system, thickness × width × length, quantity, delivery condition, tests, inspection-document requirements and destination.