SA738 Gr.C Steel Plate for Pressure Vessels (ASME)
SA738 Gr.C is an American grade of pressure vessel steel plate under the ASME standard. The manufacturing specification is ASME SA-738/SA-738M, and the ultrasonic testing standard is NB/T 47013.3-2015.
This grade is a carbon-manganese pressure vessel steel offering higher elongation and good strength. It is specifically designed for welded pressure vessels and is available in a wide thickness range. SA738 Gr-C Approximate Grade Lookup Table.
SA738 Gr.C steel plates are impact tested upon agreement. Vanadium and niobium can only be added after consultation and agreement between the steel plate manufacturer and the purchasing party.
SA738 Gr.C designation explanation: SA denotes ASME specification, 738 is the specification number, Gr.C denotes Grade C.
Product Overview
SA738 Gr.C Steel Plate is an American grade of pressure vessel steel manufactured in accordance with ASME SA-738/SA-738M. It contains carbon and manganese as primary alloying elements, providing good weldability, strength, and higher elongation for welded pressure vessel applications.
This grade is suitable for a wide range of thickness from thin plate up to 100mm and beyond, with tensile strength 550-690 MPa for thin plate and yield strength 415 MPa for thin plate, decreasing for thicker plate.
Core Advantages
- Higher elongation (≥22%) than Gr.A and Gr.B
- Wide thickness range up to 100mm+
- Customizable: V addition, impact testing
- Good weldability for pressure vessel fabrication
Professional Technical Support and Customization
Comprehensive Knowledge Base: Our sales team is proficient in mainstream domestic and international pressure vessel standards. Whether it's the American ASME standard SA738 Gr.C or other international standards, we can provide accurate technical communication.
Zero Communication Errors: With solid product knowledge, we can avoid all basic errors during the order technical condition confirmation stage, ensuring the accuracy of your order.
Flexible Customization Capabilities: The SA738 Gr.C standard allows vanadium addition after consultation and agreement. If your design has special requirements (e.g., specific hardness, impact testing, HIC/SSC testing), we support customized production.
Applications
Stock Resources
Plates: 6-100mm+ (W:2000-2500, L:11000-12500)
Hot-rolled plates: 6-40mm (W:1800-2500, L:11000-12500)
Coils: 5-16mm (W:1500-2000)
Spot stock size range and supply conditions
Supply Condition: AR, CR, N
SA738 Gr.C Chemical Composition (max %)
| Element | Analysis Type | Thickness | Value |
|---|---|---|---|
| C① | - | ≤0.20 | |
| Mn | Smelting Analysis | ≤1.5in. (40mm) | ≤1.50 |
| >1.5-2.0in. (40-50mm) | ≤1.50 | ||
| >2.0-2.5in. (50-65mm) | ≤1.50 | ||
| >2.5in. (65mm) | ≤1.60 | ||
| Mn | Finished Product Analysis | ≤1.5in. (40mm) | ≤1.62 |
| >1.5-2.0in. (40-50mm) | ≤1.62 | ||
| >2.0-2.5in. (50-65mm) | ≤1.62 | ||
| >2.5in. (65mm) | ≤1.72 | ||
| P① | - | ≤0.025 | |
| S① | - | ≤0.025 | |
| Si | Smelting Analysis | - | 0.15-0.50 |
| Finished Product Analysis | - | 0.13-0.55 | |
| Cu | Smelting Analysis | - | ≤0.35 |
| Finished Product Analysis | - | ≤0.38 | |
| Ni | Smelting Analysis | - | ≤0.50 |
| Finished Product Analysis | - | ≤0.53 | |
| Cr | Smelting Analysis | - | ≤0.25 |
| Finished Product Analysis | - | ≤0.29 | |
| Mo | Smelting Analysis | ≤1.5in. (40mm) | ≤0.08 |
| >1.5in. (40mm) | ≤0.08 | ||
| Finished Product Analysis | ≤1.5in. (40mm) | ≤0.09 | |
| >1.5in. (40mm) | ≤0.09 | ||
| V | Smelting Analysis | - | ≤0.05 |
| Finished Product Analysis | - | ≤0.05 | |
| Nb | Smelting Analysis | - | ... |
| Finished Product Analysis | - | ... | |
| Nb+V | Smelting Analysis | - | ... |
| Finished Product Analysis | - | ... | |
| Ti | - | ... | |
| B | - | ... | |
① Both smelting analysis and finished product analysis are applicable.
② Vanadium and niobium can only be added after consultation and agreement between the steel plate manufacturer and the purchasing party.
SA738 Gr.C - Alloying Elements and Roles
per ASME SA-738Influences strength and hardness. Applicable to both smelting and finished product analysis.
Enhances strength and toughness. Varies by thickness and analysis type.
Deoxidizer, increases strength. Smelting 0.15-0.50%, finished 0.13-0.55%.
Harmful element, reduces toughness.
Harmful element, causes hot shortness.
Enhances toughness. Smelting ≤0.50%, finished ≤0.53%.
Improves corrosion resistance and hardness. Smelting ≤0.25%, finished ≤0.29%.
Vanadium is limited to ≤0.05% for both smelting and finished product analysis. Niobium is not specified (marked as "...") for this grade.
SA738 Gr.C Mechanical Properties
| Property | Thickness | Value |
|---|---|---|
| Tensile Strength (MPa) | ≤1.5in. (40mm) | 550-690 |
| >1.5in. (40mm) - 2.0in. (50mm) | 550-690 | |
| >2.0in. (50mm) - 2.5in. (65mm) | 550-690 | |
| >2.5in. (65mm) - 4in. (100mm) | 515-655 | |
| >4in. (100mm) | 485-620 | |
| Yield Strength (MPa), ≥ | ≤1.5in. (40mm) | 415 |
| >1.5in. (40mm) - 2.0in. (50mm) | 415 | |
| >2.0in. (50mm) - 2.5in. (65mm) | 415 | |
| >2.5in. (65mm) - 4in. (100mm) | 380 | |
| >4in. (100mm) | 315 | |
| Elongation (2in./50mm), % ≥ | ≤1.5in. (40mm) | 22 |
| >1.5in. (40mm) - 4in. (100mm) | 22 | |
| >4in. (100mm) | 20 |
① Not allowed. ② For adjustments to elongation, please refer to the A20/A20M standard.
SA738 Gr.C vs SA738 Gr.B vs Q345R
| Item | SA738 Gr.C | SA738 Gr.B | Q345R |
|---|---|---|---|
| Standard | ASME SA-738 | ASME SA-738 | GB/T 713.2 |
| Yield Strength (≤40mm) | ≥415 MPa | ≥415 MPa | ≥345 MPa |
| Tensile Strength (≤40mm) | 550-690 MPa | 585-705 MPa | 510-640 MPa |
| Elongation | ≥22% (2in.) | ≥20% (2in.) | ≥21% |
Scenario-Based Recommendation - Grade Comparison
SA738 Gr.B
Elongation ≥20%
SA738 Gr.C
Elongation ≥22%
Q345R
Charpy 0 C
Quality Control and Inspection
Customizable Specification Range for SA738 Gr.C
Delivery Condition
AR as rolled - CR controlled rolled - N normalized
Additional Requirements
- Simulated post-weld heat treatment (PWHT)
- Brinell hardness requirements
- HIC / SSC testing
- V addition per agreement
Other customized technical conditions are also negotiable.
The above ranges represent our standard customizing capability.
Frequently Asked Questions
What is SA738 Gr.C steel plate used for?
SA738 Gr.C steel plate is mainly used for welded pressure vessels, boilers, heat exchangers, storage tanks, and general pressure equipment manufactured under ASME standards.
What is the difference between SA738 Gr.B and Gr.C?
SA738 Gr.C has higher elongation (≥22% vs ≥20%) and slightly lower tensile strength (550-690 MPa vs 585-705 MPa for thickness ≤65mm). Gr.C provides improved ductility for forming and fabrication.
Can vanadium and niobium be added to SA738 Gr.C?
Vanadium is limited to ≤0.05% for both smelting and finished product analysis. Niobium is not specified for this grade. Any addition must be after consultation and agreement between the steel plate manufacturer and the purchasing party.
What is the delivery condition for SA738 Gr.C?
SA738 Gr.C is typically delivered in as-rolled (AR), controlled rolled (CR), or normalized (N) condition.
Can you provide SA738 Gr.C steel plates with custom sizes?
Yes. Custom rolling up to 100mm+ thick, 5200mm wide, 18000mm long. Delivery: 15-20 days hot-rolled, 30-35 days normalized.
Request a Quote
Emails go directly to customize@cehesteel.com - reply within 12h.