ASME SA724 Grade B Steel Plate | SA724 Gr.B QT Layered Vessel Plate
What is ASME SA724 Grade B Steel?
ASME SA724 Grade B, also written ASME SA724 GR.B, 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 B is the higher-strength line. Grade A and Grade C share 485 MPa yield. Grade B steps up to 515 MPa yield and 655–795 MPa tensile. The plates are intended for welded layered pressure vessels. 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 B, ASME SA724 GR.B, SA724 Grade B, SA724 Gr.B, SA724GRB, SA-724 Grade B, SA724 B and SA 724 Gr B. ASTM A724 Grade B is the companion product spec. There is no Class and no Type. A purchase order that invents “SA724 Grade B Class 2” is mixing this book with SA537 or SA841.
This page is not SA537 Cl.2. SA537 is heat-treated C-Mn-Si for conventional vessels. ASME SA724 Grade B / ASME SA724 GR.B is QT plate written for layered construction. It is not SA517 Gr.B alloy QT. It is not SA841 TMCP. It is not ASME SA516 normalized carbon and not ASME SA387 Cr-Mo.
Current practice normally limits Grade A and Grade B to about 22 mm. Grade C is the thicker option, normally to about 50 mm, and may carry boron. If the inquiry is 40 mm ASME SA724 GR.B, stop and read the practice limit before booking a slab. Dual marking SA724 / A724 Grade B 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 B / ASME SA724 GR.B | Confirmed |
| Product Specification | ASME SA-724/SA-724M | Applied |
| Companion Spec | ASTM A724 Grade B | Dual cert available |
| General Requirements | ASME SA-20 / ASTM A20 | Applied |
| Process | Quenched and tempered | Confirmed |
| Grain practice | Killed, fine austenitic grain | Applied |
| Intended use | Welded layered pressure vessels | As specified |
| Usual thickness practice | About 22 mm for Grade B | 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. Layered-vessel cutting lists still need vessel-plate identification, not structural heat numbers.
Chemical Composition
ASME SA724 Grade B / ASME SA724 GR.B has its own heat and product columns. Grade A carbon is lower. Grade C carbon is higher and may include boron. Do not print one table for all three grades.
Heat Analysis and Product Analysis — ASME SA724 Grade B
| Element | Heat Analysis (%) | Product Analysis (%) |
|---|---|---|
| Carbon (C), max | 0.20 | 0.24 |
| Manganese (Mn) | 1.00 – 1.60 | 0.92 – 1.72 |
| Phosphorus (P), max | 0.025 | 0.025 |
| Sulfur (S), max | 0.025 | 0.025 |
| Silicon (Si), max | 0.50 | 0.55 |
| 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) | Not specified for Grade B | Not specified for Grade B |
Grade B is still C-Mn-Si. Carbon heat max is 0.20% versus 0.18% on Grade A. Silicon heat max is 0.50% versus 0.55% on Grade A. Nickel, chromium and molybdenum remain residuals with tight maxima. If the ladle sits in a Cr-Mo window, the plate belongs under SA387 Gr.11 Cl.2 or SA387 Gr.22 Cl.2. If boron is required, that is Grade C language, not ASME SA724 GR.B.
SHH STEEL reports heat analysis on every certificate and product analysis when SA-20 requires it.
Mechanical Properties
Grade B is the high line in SA-724. Grade A and Grade C share the lower table.
Tensile Requirements — ASME SA724 Grade B / ASME SA724 GR.B
| Property | Requirement |
|---|---|
| Yield strength, min | 515 MPa (75 ksi) |
| Tensile strength | 655 – 795 MPa (95 – 115 ksi) |
| Elongation in 50 mm, min | 17% |
| Density | 7.85 g/cm³ |
| Hardness | Not a default Table 2 line |
Grade A is 485 MPa yield, 620–760 MPa tensile and 19% elongation. Do not stamp Grade A as Grade B because a coupon came in high. Do not stamp Grade B as Grade C because someone wants boron and extra thickness. Density is 7.85 g/cm³. Typical QT hardness on ASME SA724 GR.B 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 thin, highly restrained and welded. Write the temperature, energy, location and orientation.
Do not treat 515 MPa yield as permission to substitute ASTM A36 steel plate, ASTM A572 or high strength low alloy plates.
Material Comparison
| Grade | Route | Strength idea | Swap? |
|---|---|---|---|
| SA724 Grade A | QT C-Mn-Si, layered | 485 MPa / 620–760 MPa | No |
| ASME SA724 GR.B | QT C-Mn-Si, layered | 515 MPa / 655–795 MPa | This page |
| SA724 Grade C | QT C-Mn-Si, may add B | Same tensile as A, thicker practice | No |
| SA537 Cl.2 | Heat-treated C-Mn-Si | Not layered-vessel spec | No |
| SA517 Gr.B | QT alloy | Different chemistry | No |
| SA516 Gr.70 | Fine-grain carbon | Not QT layered | No |
| SA533 Type A Class 2 | QT Mn-Mo | Different family | No |
SA299 Gr.B, SA225 Gr.D, SA455 and SA285 Gr.C are also vessel plates. None of them is ASME SA724 Grade B.
Layered Vessel Service
ASME SA724 Grade B / ASME SA724 GR.B is selected when the layered vessel needs the higher C-Mn-Si QT line. Allowable stress comes from ASME Section II Part D after the Code lists SA-724 Grade B. Do not copy a Grade A allowable onto a Grade B drawing.
Typical use is layer shells, wrapper courses and related thin QT plate in multilayer construction where 515 MPa yield is written. It is not nickel low-temp plate like SA203 Gr.B. 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. Thin layered plate also means wrapping strain. If the shop cold-forms layers tightly, write the forming method on the inquiry so the mill and the fabricator are looking at the same plate.
Weldability
SA724 Gr.B is killed, fine-grain, quenched-and-tempered C-Mn-Si at the higher tensile line. Welding is Code welding for layered construction.
Qualify procedures to ASME Section IX. Use low-hydrogen consumables matched to 655–795 MPa tensile after any shop cycle. Carbon heat max is 0.20%. Manganese sits at 1.00–1.60%. Calculate carbon equivalent from the actual ladle. Layered vessels often mean long seams, high restraint and thin plate. Hydrogen control matters more than the grade name.
Preheat depends on thickness, restraint, hydrogen and the WPS. After welding, many shops want a temper or PWHT discussion. Grade B temper in the mill is not less than 595 °C, with soak not less than half an hour after quench from 870–925 °C. Shop cycles should not walk past the qualified WPS.
Do not copy a SA387 Gr.12 Cl.2 procedure or a SA533 Type B Class 1 procedure onto ASME SA724 GR.B 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 B shall then be tempered at not less than 595 °C (1100 °F). Tempering soak shall be not less than ½ hour.
That is the same temper floor as Grade A. Grade C temper is higher (not less than 620 °C). Do not apply the Grade C temper sentence to ASME SA724 Grade B and call it conservative without checking the order.
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 and soak on the MTC when the mill record carries them.
Delivery Condition
Usual delivery is quenched-and-tempered ASME SA724 Grade B / ASME SA724 GR.B plate.
The certificate lists ASME SA724 Grade B and, when dual certified, ASTM A724 Grade B; heat number; heat analysis; product analysis when ordered; tensile results to the Grade B table; QT statement; 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.B QT layered vessel plate:
- Thickness: 6 mm – 22 mm as current practice for Grade B. Thicker layered plate is normally Grade C, to about 50 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 40 mm, Grade B is the wrong practice grade. 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. Thin 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.
Supplementary Requirements
Most export ASME SA724 Grade B / ASME SA724 GR.B orders add extras. SHH STEEL does not assume them.
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 B / ASME SA724 GR.B | ASME SA-724/SA-724M | Code name on this page |
| ASTM A724 Grade B | ASTM A724/A724M | Companion spec |
| SA724 Grade A / Grade C | SA-724 | Other grades, not this tensile line |
| EN 10028-6 P500Q / P500QL related | EN | QT comparison only |
| JIS G3115 SPV490 related | JIS | Project comparison |
| GB 713 / GB/T 19189 related | GB | Strength talk only |
| ASME SA537 Class 2 | SA-537 | Heat-treated, not layered spec |
| ASTM A537 Cl.2 | A537 | Same caution |
DIN 17100, ASTM A516, ASME SA515 and ASTM A285 are not ASME SA724 GR.B.
Applications
| Industry | Typical components |
|---|---|
| Layered pressure vessels | ASME SA724 Grade B layer plate and ASME SA724 GR.B wrapper courses |
| Multilayer shells | SA-724 Gr.B QT courses to about 22 mm |
| Dual-certified export | SA724 / A724 Grade B plate |
| Fabrication | SA724 Gr.B 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.E, SA302 Gr.B, A516 Gr.70, SA533 Type D Class 2.
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 B / ASME SA724 GR.B that means mill pricing, dual SA724/A724 marking, Grade B chemistry, recorded quench and temper, tensile results at 515 MPa yield and 655–795 MPa tensile, the usual 22 mm practice respected, 3.1 as standard and 3.2 when specified.
We keep the grade on the order. Grade B is not Grade A and is not Grade C. SA724 is not SA516 Gr.55. SA724 is not SA387 Gr.91 Cl.2. SA724 Gr.B is not SA533 Type C Class 1. If the drawing names conventional heat-treated carbon, we point the inquiry to SA537. If it names 40 mm layered plate, we point it to Grade C. If the shop plans a normalize-only delivery, we will say this specification is QT.
Company scope: China steel Mill Agent-SHH STEEL.
FAQ
- What names are used for ASME SA724 Grade B / ASME SA724 GR.B?Buyers write ASME SA724 Grade B, ASME SA724 GR.B, SA724 Grade B, SA724 Gr.B, SA724GRB, SA-724 Grade B, SA724 B and SA 724 Gr B. SHH STEEL prints the wording on the purchase order.
- Is ASME SA724 Grade B the same as ASTM A724 Grade B?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.B / SA724 Gr.B?515 MPa minimum. Tensile is 655–795 MPa. Elongation is 17% in 50 mm.
- How is ASME SA724 Grade B different from SA724 Grade A and Grade C?Grade A is 485 MPa yield and 620–760 MPa tensile. Grade B is 515 MPa yield and 655–795 MPa tensile. Grade C shares the Grade A tensile table, may include boron, and is the thicker practice grade.
- Is ASME SA724 GR.B the same as SA537 Class 2?No. Both can be heat-treated C-Mn-Si. ASME SA724 Grade B is written for welded layered vessels. SA537 is a different specification.
- What thickness of ASME SA724 Grade B can SHH STEEL supply?Current practice for Grade B is about 22 mm. Grade C is the usual choice toward 50 mm.
- What is the heat treatment for ASME SA724 GR.B?Quench from 870–925 °C, then temper at not less than 595 °C for at least half an hour.
- Can welding of SA724 Gr.B be qualified to ASME Section IX?Yes. Use a low-hydrogen WPS written for QT layered vessel plate at Grade B strength. The fabricator owns the procedure.
- Can SHH STEEL issue EN 10204 3.2 for ASME SA724 Grade B?Yes. EN 10204 3.1 is standard. EN 10204 3.2 is arranged when written on the order.
- What is the density of ASME SA724 GR.B?7.85 g/cm³.
Conclusion
ASME SA724 Grade B Steel Plate, also searched as ASME SA724 GR.B, 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 B, ASME SA724 GR.B, SA724 Gr.B or SA724GRB, SHH STEEL supplies plate with Grade B chemistry, recorded QT delivery, 515 MPa yield, and EN 10204 3.1 or 3.2 certification.
As a China mill Distributor, SHH STEEL provides ASME SA724 Grade B / ASME SA724 GR.B 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 B Steel Plate, ASME SA724 GR.B, SA724 Gr.B, SA724GRB, SA-724 Grade B, QT layered vessel plate, Direct Mill Supply by SHH STEEL
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