ASTM A387 Grade 22L Class 1: confirm the specification before production
Gangsteel produces and exports A387 Grade 22L Class 1 plate against an agreed specification and edition. For this low-carbon Cr-Mo designation, the edition must be settled before we confirm a production order—not inferred from the grade name alone.
Grade 22L: confirm the specification first
The current public Scope of ASTM A387/A387M-25 does not list 22L or 21L. Its abstract still names both, but Scope takes precedence. The historical A387/A387M-17 Scope lists 22L at nominal 2.25% Cr and 1.00% Mo, Class 1 only. This is not evidence of current-edition coverage, a successor specification or a 22L Class 2 option.
Chemical composition: heat and product analysis
The following is the steelspecs 22L Class 1 compilation dated 29 September 2026, not official Table 1. Confirm these limits in the ordered edition; carbon 0.12 and silicon 0.50 are maxima, not production targets.
| Element | Heat analysis | Product analysis | Current official table |
|---|---|---|---|
| C | 0.12 max | 0.12 max | |
| Mn | 0.30–0.60 | 0.25–0.66 | |
| Si | 0.50 max | 0.50 max | |
| Cr | 2.00–2.50 | 1.88–2.62 | |
| Mo | 0.90–1.10 | 0.85–1.15 | |
| P | 0.025 max | 0.025 max | |
| S | 0.025 max | 0.025 max | |
| Ni, V, Nb, B, N, Al, W |
Blank cells are unconfirmed, not zero. No tighter heat-carbon maximum is assumed.
Class 1 mechanical properties and delivery
| Requirement | Official public value | Dated compilation |
|---|---|---|
| Tensile strength, ksi [MPa] | 60–85 [415–585] | |
| Yield strength min, ksi [MPa] | 30 [205] | |
| Elongation min, 8 in. [200 mm], % | ||
| Elongation min, 2 in. [50 mm], % | 18 |
The same dated compilation describes annealing, normalizing and tempering, or accelerated cooling followed by tempering for Class 1; annealed plate is Class 1 only. These are compilation routes, not verified official 22L heat-treatment clauses. The official abstract says killed and thermally treated. Agree the route for the ordered edition. No official tempering temperature, reduction-of-area value or numerical thickness cap is supplied here; Scope limits thickness by composition capability to meet mechanical requirements. Inch-pound and SI systems are independent; elongation lengths are specimen gauge lengths, not plate thicknesses.
Equivalent and comparable materials: what can we accept?
When a drawing or enquiry offers another grade beside 22L Class 1, compare the actual purchase requirement—carbon cap, chromium level, tensile class and acceptance basis—before changing the production designation.
| Material considered | What to compare | Direct substitute? |
|---|---|---|
| A387 Grade 22 Class 1 | Labelled carbon bands are 0.05–0.15% heat and 0.04–0.15% product, versus 22L’s 0.12% maximum in both analyses. Matching Class 1 strength does not remove that difference. | No. Grade 22 is not a direct substitute. |
| A387 Grade 22 Class 2 | A separate strength class from Class 1. | No. Class 1 and Class 2 are not equivalent. |
| A387 Grade 21L Class 1 | Historical Scope gives nominal 3.00Cr–1.00Mo, not 22L’s 2.25Cr–1.00Mo. | No. The chromium level is different. |
| A203 nickel-alloy plate | A different alloy family from this Cr-Mo plate. | No. It cannot directly replace 22L. |
| SA-387 / ASME Code acceptance | Certificate designation, approved delivery condition and tests must satisfy the order. | Not automatically. An A387 certificate alone does not establish SA-387 or Code acceptance, and the reverse is not automatic. |
We need the purchaser’s approved specification before quoting any alternative.
Related pressure-vessel plate pages
A203 Grade A and A203 Grade B are nickel-alloy comparisons, not equivalents or technical sources for 22L.
Buyer questions
Can an enquiry simply say “latest A387, 22L”?
No. Name an edition that supports the designation and agree its acceptance basis.
Can we order 22L Class 2 instead?
No confirmed 22L Class 2 requirements are available here; the historical Scope specifies Class 1 only.
Does the blank 200 mm elongation mean zero?
No. An independently confirmed value is unavailable; none is inferred from the 50 mm result.
Is normalizing and tempering the only delivery route?
Not in the labelled Class 1 compilation. Confirm the contractual treatment rather than assuming one.
What should accompany the plate schedule?
Edition, unit system, dimensions, quantity, delivery condition, testing and required inspection documents.
Discuss a 22L production and export order
Send Gangsteel your plate schedule with the drawing designation, accepted edition and destination. We will review the production specification and export enquiry without silently changing the grade or class.