ASME SA724 Grade A Steel Plate | SA724 Gr.A QT Layered Vessel Plate

ASME SA724 Grade A is carbon-manganese-silicon steel plate, quenched and tempered, under ASME SA-724/SA-724M. The specification exists for welded layered pressure vessels. That sentence in the scope is not decoration. Layered vessels use relatively thin high-strength plate wrapped or stacked as layers. Grade A is one of three grades in the book. Grade B is stronger. Grade C shares the Grade A tensile table and may carry boron. As Direct Mill Supply by SHH STEEL, the plate is produced to ASME SA-724/SA-724M.

The same plate is written SA724 Grade A, SA724 Gr.A, SA724GRA, SA-724 Grade A, SA724 A and SA 724 Gr A. ASTM A724 Grade A is the companion product spec. There is no Class and no Type. A purchase order that invents “SA724 Grade A Class 1” 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. SA724 Grade A is QT plate written for layered construction. It is not SA517 Gr.A alloy QT. It is not [SA841 Grade A Class 1] 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. If the inquiry is 40 mm SA724 Grade A, stop and read the practice limit before booking a slab. Dual marking SA724 / A724 Grade A is available. Certificates can be EN 10204 3.1 or 3.2. Company scope: China steel Mill Agent-SHH STEEL.

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.

ASME SA724 Grade A has its own heat and product columns. Grade B carbon is higher. Grade C carbon is higher still and may include boron. Do not print one table for all three grades.

Heat Analysis and Product Analysis — ASME SA724 Grade A

Grade A is C-Mn-Si. Nickel, chromium and molybdenum are residuals with tight maxima, not alloy additions. If the ladle sits in a Cr-Mo window, the plate belongs under SA387 Gr.11 Cl.1 or SA387 Gr.22 Cl.1. If boron is required, that is Grade C language, not Grade A.

SHH STEEL reports heat analysis on every certificate and product analysis when SA-20 requires it

Grade A shares the tensile table with Grade C. Grade B is the higher line.

Tensile Requirements — ASME SA724 Grade A

Grade B is 515 MPa yield and 655–795 MPa tensile, with 17% elongation. Do not stamp Grade A as Grade B because a coupon came in high. Density is 7.85 g/cm³. Typical QT hardness is higher than 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 485 MPa yield as permission to substitute ASTM A36 steel plate, ASTM A572 or high strength low alloy plates.

SA299 Gr.A, SA225 Gr.C, SA455 and SA285 Gr.C are also vessel plates. None of them is SA724 Grade A.

ASME SA724 Grade A is selected when the vessel is a welded layered design and the layer plate must be quenched and tempered C-Mn-Si at 485 MPa yield. Allowable stress comes from ASME Section II Part D after the Code lists SA-724 Grade A.

Typical use is layer shells, wrapper courses and related thin QT plate in multilayer construction. It is not nickel low-temp plate like SA203 Gr.A. 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.

SA724 Gr.A 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 0.18%. 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 A 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.1 procedure or a SA533 Type B Class 1 procedure onto Grade A without review. The fabricator owns the WPS.

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 A shall then be tempered at not less than 595 °C (1100 °F). Tempering soak shall be not less than ½ hour.

That is the specification route. It is not TMCP. It is not a normalize-only route used for SA516 Gr.60. Grade C temper is higher (not less than 620 °C). Do not apply the Grade C temper sentence to Grade A 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.

Usual delivery is quenched-and-tempered Grade A plate.

The certificate lists ASME SA724 Grade A and, when dual certified, ASTM A724 Grade A; heat number; heat analysis; product analysis when ordered; tensile results to the Grade A table; QT statement; Charpy results when ordered; and supplementary tests. Certificates may be EN 10204 3.1 or EN 10204 3.2.

Usual supply range from SHH STEEL for SA724 Gr.A QT layered vessel plate:

• Thickness: 6 mm – 22 mm as current practice for Grade A. 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 A 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.

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.

Most export ASME SA724 Grade A 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.

DIN 17100, ASTM A516, ASME SA515 and ASTM A285 are not SA724 Grade A.

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.

SHH STEEL works as a China Mill Direct Exporter for plates to ASME SA-724/SA-724M. On ASME SA724 Grade A that means mill pricing, dual SA724/A724 marking, Grade A chemistry, recorded quench and temper, tensile results at 485 MPa yield and 620–760 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 A is not Grade B and is not Grade C. SA724 is not SA516 Gr.55. SA724 is not SA387 Gr.91 Cl.2. SA724 Gr.A 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.