ASME SA724 Grade C Steel Plate | SA724 Gr.C QT Layered Vessel Plate
What is ASME SA724 Grade C Steel?
ASME SA724 Grade C, also written ASME SA724 GR.C, is carbon-manganese-silicon steel plate, quenched and tempered, under ASME SA-724/SA-724M. The specification covers three grades only: A, B and C. Grade C shares the Grade A tensile table — 485 MPa yield and 620–760 MPa tensile — but it is not Grade A. Grade C carbon is higher. Silicon is a range, not only a cap. Grade C may be produced with a boron addition. Current practice also gives Grade C the thicker window, normally to about 50 mm, while Grade A and Grade B stay near 22 mm. As Direct Mill Supply by SHH STEEL, the plate is produced to ASME SA-724/SA-724M.
Buyers search and write the same product many ways: ASME SA724 Grade C, ASME SA724 GR.C, SA724 Grade C, SA724 Gr.C, SA724GRC, SA-724 Grade C, SA724 C and SA 724 Gr C. ASTM A724 Grade C is the companion product spec. There is no Class and no Type. A purchase order that invents “SA724 Grade C Class 1” is mixing this book with SA537 or SA841.
This page is not SA537 Cl.1. SA537 is heat-treated C-Mn-Si for conventional vessels. ASME SA724 Grade C / ASME SA724 GR.C is QT plate written for welded layered pressure vessels. It is not SA517 Gr.E alloy QT. It is not SA841 TMCP. It is not ASME SA516 normalized carbon and not ASME SA387 Cr-Mo.
Temper for Grade C is also different. Grade A and Grade B temper at not less than 595 °C. Grade C tempers at not less than 620 °C. Dual marking SA724 / A724 Grade C is available. Certificates can be EN 10204 3.1 or 3.2. Company scope: China steel Mill Agent-SHH STEEL.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Grade | ASME SA724 Grade C / ASME SA724 GR.C | Confirmed |
| Product Specification | ASME SA-724/SA-724M | Applied |
| Companion Spec | ASTM A724 Grade C | Dual cert available |
| General Requirements | ASME SA-20 / ASTM A20 | Applied |
| Process | Quenched and tempered | Confirmed |
| Grain practice | Killed, fine austenitic grain | Applied |
| Boron | May be added on Grade C | When specified |
| Intended use | Welded layered pressure vessels | As specified |
| Usual thickness practice | About 50 mm for Grade C | Confirm on order |
| Certification | EN 10204 3.1 or 3.2 / third-party | As ordered |
This plate sits in the pressure vessel steel plates family. It does not sit with carbon steel plates that are only as-rolled or normalized, and it does not sit with structural steel plates or ASTM A36/A36M.
SA-20 still governs marking, testing location, retests and repair rules. Quench and temper does not cancel SA-20. If boron is used, it belongs on the certificate, not only in a mill conversation.
Chemical Composition
ASME SA724 Grade C / ASME SA724 GR.C has its own heat and product columns. Do not copy the Grade A table and change the title.
Heat Analysis and Product Analysis — ASME SA724 Grade C
| Element | Heat Analysis (%) | Product Analysis (%) |
|---|---|---|
| Carbon (C), max | 0.22 | 0.26 |
| Manganese (Mn) | 1.10 – 1.60 | 1.02 – 1.72 |
| Phosphorus (P), max | 0.025 | 0.025 |
| Sulfur (S), max | 0.025 | 0.025 |
| Silicon (Si) | 0.20 – 0.60 | 0.18 – 0.65 |
| Copper (Cu), max | 0.35 | 0.38 |
| Nickel (Ni), max | 0.25 | 0.29 |
| Chromium (Cr), max | 0.25 | 0.29 |
| Molybdenum (Mo), max | 0.08 | 0.09 |
| Vanadium (V), max | 0.08 | 0.09 |
| Boron (B) | May be added (commonly ≤ 0.005 when used) | Report when added |
Grade C carbon heat max is 0.22% versus 0.18% on Grade A and 0.20% on Grade B. Manganese heat starts at 1.10%, not 1.00%. Silicon is a range, 0.20–0.60% heat. Grade A and Grade B only cap silicon. Boron is a Grade C option. If the purchase order says “no boron,” the mill must not treat boron as automatic.
If the ladle sits in a Cr-Mo window, the plate belongs under SA387 Gr.11 Cl.1 or SA387 Gr.22 Cl.1. SHH STEEL reports heat analysis on every certificate, including boron when it is added, and product analysis when SA-20 requires it.
Mechanical Properties
Grade C shares the tensile table with Grade A. Grade B is the higher line.
Tensile Requirements — ASME SA724 Grade C / ASME SA724 GR.C
| Property | Requirement |
|---|---|
| Yield strength, min | 485 MPa (70 ksi) |
| Tensile strength | 620 – 760 MPa (90 – 110 ksi) |
| Elongation in 50 mm, min | 19% |
| Density | 7.85 g/cm³ |
| Hardness | Not a default Table 2 line |
Grade B is 515 MPa yield, 655–795 MPa tensile and 17% elongation. Same tensile numbers as Grade A do not make Grade C into Grade A. Thickness practice, silicon range, carbon cap, temper floor and boron option are different.
Density is 7.85 g/cm³. Typical QT hardness on ASME SA724 GR.C sits above normalized SA516 Gr.70. Print hardness only when the order sets a limit.
Charpy is not automatic. Layered-vessel specifications often add impact because the plate is restrained and welded. Write the temperature, energy, location and orientation.
Do not treat 485 MPa yield as permission to substitute ASTM A36 steel plate, ASTM A572 or high strength low alloy plates.
Material Comparison
| Grade | Route | What changes | Swap? |
|---|---|---|---|
| SA724 Grade A | QT C-Mn-Si, layered | Same tensile, ~22 mm practice, no B | No |
| SA724 Grade B | QT C-Mn-Si, layered | 515 MPa / 655–795 MPa | No |
| ASME SA724 GR.C | QT C-Mn-Si, layered | Same tensile as A, ~50 mm, B optional | This page |
| SA537 Cl.1 | Heat-treated C-Mn-Si | Not layered-vessel spec | No |
| SA517 Gr.C family | QT alloy | Different chemistry | No |
| SA516 Gr.70 | Fine-grain carbon | Not QT layered | No |
| SA533 Type A Class 1 | QT Mn-Mo | Different family | No |
SA299 Gr.A, SA225 Gr.C, SA455 and SA285 Gr.C are also vessel plates. None of them is ASME SA724 Grade C.
Layered Vessel Service
ASME SA724 Grade C / ASME SA724 GR.C is selected when the layered vessel wants the Grade A strength window but needs the thicker practice grade, the Grade C silicon range, the higher temper floor, or a boron addition. Allowable stress comes from ASME Section II Part D after the Code lists SA-724 Grade C.
Typical use is thicker layer shells, wrapper courses and related QT plate in multilayer construction up to about 50 mm. It is not nickel low-temp plate like SA203 Gr.D. It is not TMCP plate like SA841. Stainless inquiries belong on ASME SA240/SA240M, ASTM A240/A240M or stainless steel sheets and plates.
Do not form this plate as if it were as-rolled SA285 Gr.A. Quench-and-temper properties are the product. A later high-temperature cycle has to be planned and, when required, simulated on coupons.
Weldability
SA724 Gr.C is killed, fine-grain, quenched-and-tempered C-Mn-Si. Welding is Code welding for layered construction.
Qualify procedures to ASME Section IX. Use low-hydrogen consumables. Carbon heat max is 0.22%. Manganese heat starts at 1.10%. Boron, when added, changes HAZ behaviour. Calculate carbon equivalent from the actual ladle and say on the WPS whether boron is present.
Preheat depends on thickness, restraint, hydrogen and the WPS. After welding, many shops want a temper or PWHT discussion. Grade C mill temper is not less than 620 °C, with soak not less than half an hour after quench from 870–925 °C. That temper floor is higher than Grade A and Grade B. Shop cycles should not walk past the qualified WPS.
Do not copy a SA387 Gr.12 Cl.1 procedure or a SA533 Type B Class 1 procedure onto ASME SA724 GR.C without review. The fabricator owns the WPS.
Heat Treatment
The steel shall be killed and shall meet fine austenitic grain practice under ASME SA-20. All plates shall be quenched from 870–925 °C (1600–1700 °F). Grade C shall then be tempered at not less than 620 °C (1150 °F). Tempering soak shall be not less than ½ hour.
Do not apply the Grade A/B temper floor of 595 °C to ASME SA724 Grade C. If the layered vessel will see a later thermal cycle, test coupons shall follow a simulated cycle. SHH STEEL reports quench temperature range, temper temperature, soak and boron when added.
Delivery Condition
Usual delivery is quenched-and-tempered ASME SA724 Grade C / ASME SA724 GR.C plate.
The certificate lists ASME SA724 Grade C and, when dual certified, ASTM A724 Grade C; heat number; heat analysis including B when added; product analysis when ordered; tensile results to the Grade C / Grade A table; QT statement with the Grade C temper floor; Charpy results when ordered; and supplementary tests. Certificates may be EN 10204 3.1 or EN 10204 3.2.
Dimensions
Usual supply range from SHH STEEL for SA724 Gr.C QT layered vessel plate:
- Thickness: 6 mm – 50 mm as current practice for Grade C. Grade A and Grade B stay near 22 mm
- Width: 1500 mm – 4000 mm
- Length: 3000 mm – 12000 mm
- Cut-to-length layer courses and nest sizes inside those limits
If the inquiry is 80 mm, this specification’s usual practice is already behind you. Structural sizes belong on EN 10025-2 or JIS G3106. Weathering plate belongs on EN 10025-5 or Corten A/B. Fine-grain structural belongs on EN 10025-3 or EN 10025-4. QT structural belongs on EN 10025-6.
Tolerances
Dimensional limits follow ASME SA-20. Thickness, width, length, flatness and camber are vessel-plate tolerances. QT plate for layered wrapping is sensitive to flatness and camber. Write those extras if the wrapping shop is tight. UT to A435 / A577 / A578 is commonly added on Grade C thicknesses.
Supplementary Requirements
Most export ASME SA724 Grade C / ASME SA724 GR.C orders add extras. SHH STEEL does not assume them.
Boron on or off. Write it. Grade C may include boron. It is not automatic.
Charpy details. Temperature, energy, location and orientation.
Simulated PWHT. Same-heat coupons follow the vessel cycle.
NDE. UT to A435 / A577 / A578.
Restricted P, S / CEV. When specified.
Third-party. EN 10204 3.2.
Equivalent Material Grades
| Designation | Standard | Notes |
|---|---|---|
| ASME SA724 Grade C / ASME SA724 GR.C | ASME SA-724/SA-724M | Code name on this page |
| ASTM A724 Grade C | ASTM A724/A724M | Companion spec |
| SA724 Grade A / Grade B | SA-724 | Other grades |
| EN 10028-6 P460Q / P500Q related | EN | QT comparison only |
| JIS G3115 SPV450 / SPV490 related | JIS | Project comparison |
| GB 713 / GB/T 19189 related | GB | Strength talk only |
| ASME SA537 Class 1 | SA-537 | Heat-treated, not layered spec |
| ASTM A537 Cl.1 | A537 | Same caution |
DIN 17100, ASTM A516, ASME SA515 and ASTM A285 are not ASME SA724 GR.C.
Applications
| Industry | Typical components |
|---|---|
| Layered pressure vessels | ASME SA724 Grade C layer plate and ASME SA724 GR.C wrapper courses |
| Thicker multilayer shells | SA-724 Gr.C QT courses to about 50 mm |
| Dual-certified export | SA724 / A724 Grade C plate |
| Fabrication | SA724 Gr.C cut to nest sizes |
Ship plate inquiries belong on shipbuilding steel plates or BV Rules. Weathering inquiries belong on weathering steel plates. Stainless inquiries belong on stainless steel products, JIS G4305 or AISI stainless.
Other vessel comparisons: SA203 Gr.B, SA302 Gr.A, A516 Gr.70, SA533 Type D Class 1.
Why Choose SHH STEEL
SHH STEEL works as a China Mill Direct Exporter for plates to ASME SA-724/SA-724M. On ASME SA724 Grade C / ASME SA724 GR.C that means mill pricing, dual SA724/A724 marking, Grade C chemistry, boron reported when added, recorded quench and temper at the Grade C floor, tensile results at 485 MPa yield and 620–760 MPa tensile, the usual 50 mm practice respected, 3.1 as standard and 3.2 when specified.
We keep the grade on the order. Grade C is not Grade A and is not Grade B. SA724 is not SA516 Gr.55. SA724 is not SA387 Gr.91 Cl.2. SA724 Gr.C is not SA533 Type C Class 1. If the drawing names conventional heat-treated carbon, we point the inquiry to SA537. If it names 12 mm layered plate at Grade B strength, we will not ship Grade C and call it close. If the shop plans a 595 °C temper as if this were Grade A, we will say Grade C tempers at not less than 620 °C.
Company scope: China steel Mill Agent-SHH STEEL.
FAQ
- What names are used for ASME SA724 Grade C / ASME SA724 GR.C?Buyers write ASME SA724 Grade C, ASME SA724 GR.C, SA724 Grade C, SA724 Gr.C, SA724GRC, SA-724 Grade C, SA724 C and SA 724 Gr C. SHH STEEL prints the wording on the purchase order.
- Is ASME SA724 Grade C the same as ASTM A724 Grade C?Chemistry and tensile limits match. ASME SA-724 is the Code version. ASTM A724 is the product spec. As China mill-Direct Supply, SHH STEEL dual-certifies both names when the vessel must be stamped.
- What is the yield strength of ASME SA724 GR.C / SA724 Gr.C?485 MPa minimum. Tensile is 620–760 MPa. Elongation is 19% in 50 mm. That table is shared with Grade A.
- How is ASME SA724 Grade C different from SA724 Grade A and Grade B?Same tensile as Grade A. Higher carbon, silicon as a range, optional boron, usual thickness to 50 mm, and temper not less than 620 °C. Grade B is the stronger tensile line at 515 MPa yield.
- Does ASME SA724 GR.C always contain boron?No. The specification says Grade C may be produced with a boron addition. Write boron on or off on the order. SHH STEEL reports it when it is added.
- Is ASME SA724 Grade C the same as SA537 Class 1?No. Both can be heat-treated C-Mn-Si. ASME SA724 Grade C is written for welded layered vessels. SA537 is a different specification.
- What thickness of ASME SA724 GR.C can SHH STEEL supply?Current practice for Grade C is about 50 mm. Grade A and Grade B stay near 22 mm.
- What is the heat treatment for ASME SA724 Grade C?Quench from 870–925 °C, then temper at not less than 620 °C for at least half an hour.
- Can welding of SA724 Gr.C be qualified to ASME Section IX?Yes. Use a low-hydrogen WPS written for QT layered vessel plate, and state whether boron is present. The fabricator owns the procedure.
- Can SHH STEEL issue EN 10204 3.2 for ASME SA724 Grade C?Yes. EN 10204 3.1 is standard. EN 10204 3.2 is arranged when written on the order.
Conclusion
ASME SA724 Grade C Steel Plate, also searched as ASME SA724 GR.C, is quenched-and-tempered C-Mn-Si plate under ASME SA-724/SA-724M for welded layered pressure vessels. Whether the inquiry says ASME SA724 Grade C, ASME SA724 GR.C, SA724 Gr.C or SA724GRC, SHH STEEL supplies plate with Grade C chemistry, optional boron reported when used, recorded QT delivery at the Grade C temper floor, 485 MPa yield, and EN 10204 3.1 or 3.2 certification.
As a China mill Distributor, SHH STEEL provides ASME SA724 Grade C / ASME SA724 GR.C QT Layered Vessel Plate for ASME Section VIII layered-vessel work.
Contact SHH STEEL for mill rolling, dual SA724/A724 marking, 3.2 inspection or a quotation.
ASME SA724 Grade C Steel Plate, ASME SA724 GR.C, SA724 Gr.C, SA724GRC, SA-724 Grade C, QT layered vessel plate, Direct Mill Supply by SHH STEEL
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