A204 Gr.B
Data verifiedASTM A204 Grade B is a molybdenum-alloy (0.5Mo) pressure-vessel plate whose Mo addition lifts elevated-temperature strength above the plain-carbon A516 family. The carbon limit rises in steps with plate thickness in the standard; the value shown is for plate up to 25 mm.
Chemical composition
| Element | Content (%) |
|---|---|
| C | ≤0.20 (≤25 mm) |
| Si | 0.15–0.40 |
| Mn | ≤0.90 |
| P | ≤0.025 |
| S | ≤0.025 |
| Mo | 0.45–0.60 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Yield strength | ≥275 MPa |
| Tensile strength | 485–620 MPa |
| Density | 7.85 g/cm³ |
Heat treatment
As-rolled, normalized or normalized and tempered at the mill’s option by thickness; specified for welded boilers and pressure vessels.
Equivalent grades
| Standard | Designation |
|---|---|
| aisi | A204 Gr.B |
Compare side by side: A204 Gr.B vs A302 Gr.B · A204 Gr.B vs P265GH
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Welded boilers, pressure vessels and process equipment for moderately elevated temperatures, steam drums, separators.
Processing: Weldable with Mo-bearing or matching low-hydrogen practice; preheat by thickness and carbon equivalent as for other Cr/Mo-free alloy vessel plates.
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Ask for a quotationVisit NasteelSource: ASTM A204 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.