ASTM A537 Class 3 Steel Plate | A537CL3 Pressure Vessel Plate
What is ASTM A537 Class 3 Steel Plate?
As a professional steel plate supplier and China Mill-Direct Exporter, SHH STEEL is pleased to present ASTM A537 Class 3 Steel Plate (also known as A537CL3 or SA537 Class 3).
ASTM A537 Class 3 is a quenched and tempered (Q&T) carbon-manganese-silicon steel plate designed for welded pressure vessels and boilers. Compared with Class 2, Class 3 requires a higher minimum tempering temperature (not less than 620°C), which generally provides a better balance of strength and toughness. SHH STEEL sources this material directly from leading Chinese steel mills, ensuring competitive mill-direct pricing, stable quality and shorter lead times.
We supply ASTM A537 Class 3 steel plate in thicknesses from 6 mm to 150 mm, widths up to 3000–4000 mm, and lengths up to 12000–18000 mm. Custom cutting, ultrasonic testing and third-party inspection are available. All plates are delivered with full Mill Test Certificates (EN 10204 3.1).
Material Specification
ASTM A537 Class 3 steel plate is produced in accordance with ASTM A537/A537M and ASME SA-537.
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Primary Standard | ASTM A537 / ASME SA-537 Class 3 | Full compliance |
| Heat Treatment | Quenched and Tempered | Confirmed (Tempering ≥ 620°C) |
| Product Form | Steel Plate | Available |
| Thickness Range | 6 mm – 150 mm | Custom sizes available |
| Width / Length | Up to 3000–4000 mm / 12000–18000 mm | Custom cutting supported |
| Certification | EN 10204 3.1 / 3.2 | Available |
Chemical Composition
The chemical composition of ASTM A537 Class 3 is controlled to the same limits as Class 1 and Class 2 to ensure good weldability and toughness after quenching and tempering.
| Element | Content (%) | Standard Limit | Role |
|---|---|---|---|
| Carbon (C) | ≤ 0.24 | 0.24 max | Strength |
| Manganese (Mn) | 0.70 – 1.60 | Depending on thickness | Strength and hardenability |
| Silicon (Si) | 0.15 – 0.50 | 0.15 – 0.50 | Deoxidation |
| Phosphorus (P) | ≤ 0.025 – 0.035 | 0.035 max | Impurity control |
| Sulfur (S) | ≤ 0.025 – 0.035 | 0.035 max | Cleanliness |
| Copper (Cu) | ≤ 0.35 | 0.35 max | Optional |
| Nickel (Ni) | ≤ 0.25 | 0.25 max | Toughness |
| Chromium (Cr) | ≤ 0.25 | 0.25 max | — |
| Molybdenum (Mo) | ≤ 0.08 | 0.08 max | — |
Mechanical Properties
ASTM A537 Class 3 is supplied in the quenched and tempered condition with the following mechanical properties:
| Property | ≤ 65 mm Thickness | > 65 – 100 mm Thickness | Test Method |
|---|---|---|---|
| Yield Strength | ≥ 380 MPa (55 ksi) | ≥ 345 MPa (50 ksi) | ASTM A370 |
| Tensile Strength | 550 – 690 MPa | 515 – 655 MPa | ASTM A370 |
| Elongation in 50 mm | ≥ 22% | ≥ 20–22% | ASTM A370 |
| Density | 7.85 g/cm³ | 7.85 g/cm³ | — |
The higher minimum tempering temperature of Class 3 ( ≥ 620°C ) generally results in improved toughness compared with Class 2. Impact testing (Charpy V-Notch) at low temperatures can be provided according to project requirements.
Delivery Conditions
SHH STEEL, as a China Mill-Direct Supplier, supplies ASTM A537 Class 3 steel plate in the quenched and tempered condition.
- Surface: As-rolled, shot-blasted, or primed upon request
- Cutting: Flame cutting, plasma cutting available
- Ultrasonic testing (UT) according to ASTM A435 / A578 available
- Third-party inspection (SGS, BV, TUV, etc.) can be arranged
Tolerances
Dimensional tolerances for ASTM A537 Class 3 steel plate follow ASTM A6/A6M and ASTM A20.
- Thickness, width and length tolerances meet ASTM A6 requirements.
- Flatness is controlled according to standard specifications.
- Edge conditions: Mill edge or cut edge (flame / plasma).
Tighter tolerances can be provided upon request.
Weldability
ASTM A537 Class 3 offers good weldability when proper welding procedures are followed. Common processes such as SMAW, SAW, GMAW and FCAW can be used. Low-hydrogen consumables are recommended. Preheating and interpass temperature control are important, especially for thicker plates. Post-weld heat treatment (PWHT) is frequently required for pressure vessel applications in accordance with ASME Code rules.
Equivalent Material Grades
| Grade | Standard | Notes |
|---|---|---|
| ASTM A537 Class 3 | ASTM A537 / ASME SA-537 | — |
| SA537 Class 3 | ASME | Identical |
| Related Q&T grades | EN / Other | High-strength pressure vessel steels |
| Approximate Chinese | GB | Q&T pressure vessel grades |
Applications
ASTM A537 Class 3 is selected when a good combination of high strength and enhanced toughness is required for pressure-containing equipment. Typical applications include:
| Application Area | Typical Components / Uses (Keywords) |
|---|---|
| Pressure Vessels | Reactors, separators, high-pressure vessels – A537 Class 3 Pressure Vessel |
| Boilers | Boiler components requiring higher toughness – A537CL3 Boiler |
| Oil & Gas | Process vessels, critical pressure equipment – A537 Class 3 Oil Gas |
| Petrochemical | Columns, heat exchangers – A537CL3 Petrochemical |
| Storage Tanks | High-pressure or low-temperature storage – A537 Class 3 Storage Tank |
| Power Generation | Pressure parts – A537CL3 Power |
Why Choose SHH STEEL
SHH STEEL is a China Mill-Direct Exporter. We maintain long-term strategic cooperation with major Chinese steel mills and act as a first-level (primary) agent. This direct mill supply model allows us to offer:
- Competitive mill-direct pricing
- Faster delivery times
- Stable and traceable quality
- Full Mill Test Certificates (EN 10204 3.1 / 3.2)
- Professional export service and technical support
Customers benefit from reliable supply, short lead times and cost-effective solutions for high-strength pressure vessel projects worldwide.
FAQ
- What is the main difference between ASTM A537 Class 2 and Class 3?Both Class 2 and Class 3 are quenched and tempered. The key difference is the minimum tempering temperature: Class 2 ≥ 595°C, while Class 3 ≥ 620°C. The higher tempering temperature of Class 3 generally provides better toughness while still delivering high strength.
- What is the heat treatment of A537 Class 3?ASTM A537 Class 3 is supplied in the quenched and tempered condition, with the tempering temperature not less than 620°C (1150°F).
- What is the density of ASTM A537 Class 3?7.85 g/cm³.
- Can SHH STEEL supply cut-to-size A537 Class 3 plates?Yes. As a China Mill-Direct Supplier, we provide flame cutting, plasma cutting and other processing services according to customer drawings.
- Do you provide impact test results for Class 3?Yes. Charpy impact testing at specified low temperatures can be arranged according to project requirements.
Conclusion
ASTM A537 Class 3 (A537CL3) Steel Plate from SHH STEEL offers a balanced combination of high strength and enhanced toughness through quenching and tempering at a higher minimum temperature. As a China Mill-Direct Exporter, we provide competitive pricing, fast delivery and consistent quality backed by full mill certifications. Trust SHH STEEL for your ASTM A537 Class 3 pressure vessel steel plate requirements.
Contact SHH STEEL today for stock availability, pricing and technical support.
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