ASME SA736 Grade A Class 3 Steel Plate | SA736 Gr.A Cl.3 Age-Hardening Vessel Plate

ASME SA736 Grade A Class 3, also written ASME SA736 GR.A CL.3, is low-carbon age-hardening alloy plate under ASME SA-736/SA-736M. The alloy family is nickel-copper-chromium-molybdenum-columbium (niobium). Current ASTM A736/A736M-17 and A736/A736M-25 state the product is available in Grade A, Class 3 only. Older books and mill catalogs still list Grade A Class 1, Grade A Class 2 and Grade C. This page is the combination that matches the current product specification. As Direct Mill Supply by SHH STEEL, the plate is produced to ASME SA-736/SA-736M.

Buyers write ASME SA736 Grade A Class 3, ASME SA736 GR.A CL.3, SA736 Grade A Class 3, SA736 Gr.A Cl.3, SA736GRA CL3, SA-736 Grade A Class 3 and SA 736 Gr A Cl 3. ASTM A736 Grade A Class 3 is the companion product spec. A purchase order that only says “SA736 Grade A” is incomplete. Class 3 is quenched and precipitation heat treated. Class 1 and Class 2, when they appeared in older editions, were different heat-treatment routes and different tensile lines.

This page is not SA537 Cl.2. SA537 is heat-treated C-Mn-Si. SA736 Grade A Class 3 is an age-hardening Ni-Cu-Cr-Mo-Nb alloy. It is not SA517 Gr.A QT alloy in the A517 family. It is not SA841 TMCP. It is not ASME SA516 carbon plate and not ASME SA387 Cr-Mo plate. Copper at about 1.00–1.30% and niobium are part of the precipitation system. That is why the heat-treatment sentence is “quenched and precipitation heat treated,” not “normalized only.”

Thickness is limited by the ability of the chemistry and the precipitation treatment to hold the Class 3 tensile table. Thin plate uses the higher tensile line. Thicker plate steps down. Dual marking SA736 / A736 Grade A Class 3 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 and it does not sit with structural steel plates or ASTM A36/A36M. If a buyer sends an HSLA cutting list from ASTM A572 and an age-hardening vessel drawing on the same email, those are two different books.

SA-20 still governs marking, testing location, retests and repair rules. Precipitation heat treatment does not cancel SA-20.

ASME SA736 Grade A Class 3 / ASME SA736 GR.A CL.3 uses Grade A chemistry. Class only changes heat treatment and tensile. Grade C, when it appeared in older tables, used higher manganese and dropped the chromium band.

Heat Analysis and Product Analysis — ASME SA736 Grade A

Carbon at 0.07% heat maximum is the low-carbon marker. Copper at 1.00–1.30% and niobium are not residuals. They drive precipitation hardening after quench. Chromium 0.60–0.90% and molybdenum 0.15–0.25% belong to Grade A. If chromium is missing and manganese jumps to the old Grade C band, the ladle is not Grade A.

If the drawing wants Cr-Mo without copper-niobium aging, look at SA387 Gr.11 Cl.2 or SA387 Gr.22 Cl.2. If it wants QT Mn-Mo-Ni, look at SA533 Type B Class 1. SHH STEEL reports heat analysis on every certificate, including Cu, Ni, Cr, Mo and Nb.

Class 3 tensile depends on thickness. Thin plate holds the high line. Thick plate steps down.

Tensile Requirements — ASME SA736 Grade A Class 3 (typical table by thickness)

Current ASTM wording: quenched and precipitation heat treated, with a minimum specified tensile strength of 85 ksi for thinner plates and 75 ksi and 70 ksi for thicker plates. Always read the thickness line on the order. Do not quote the ≤20 mm numbers on a 60 mm plate.

Density is 7.85 g/cm³. Hardness is not a substitute for the precipitation-treated tensile test. Notch toughness is part of this specification family. Write the impact temperature when the vessel specification names one.

Do not treat 515 MPa yield as permission to substitute ASTM A36 steel plate, high strength low alloy plates or SA516 Gr.70.

SA299 Gr.A, SA225 Gr.C, SA455 and SA285 Gr.C are also vessel plates. None of them is ASME SA736 GR.A CL.3.

ASME SA736 Grade A Class 3 / ASME SA736 GR.A CL.3 is selected when the vessel or piping component wants low-carbon age-hardening Ni-Cu-Cr-Mo-Nb plate, quenched and precipitation heat treated. Allowable stress comes from ASME Section II Part D after the Code lists this Grade and Class.

Typical use is welded pressure vessels and piping components written specifically to SA-736 Grade A Class 3. It is not nickel low-temp plate like SA203 Gr.A or SA203 Gr.D. It is not layered QT carbon like SA724. Stainless inquiries belong on ASME SA240/SA240M, ASTM A240/A240M or stainless steel sheets and plates.

Precipitation hardening is the product. A later high-temperature cycle can over-age or under-age the copper-niobium strengthening. Simulated coupons are required when the vessel specification already knows a PWHT hold.

SA736 Gr.A Cl.3 is killed, low-carbon, age-hardening alloy plate. Welding is Code welding.

Qualify procedures to ASME Section IX. Use low-hydrogen consumables chosen for the Ni-Cu-Cr-Mo-Nb system and the required strength after any permitted precipitation or PWHT cycle. Carbon is low, which helps. Copper at 1.00–1.30% and niobium do not weld like SA516 Gr.70.

Preheat, interpass and any post-weld aging follow the qualified WPS. Do not copy a SA387 Gr.12 Cl.2 Cr-Mo procedure or a SA533 Type B Class 2 QT procedure onto Grade A Class 3 without review. The fabricator owns the WPS.

Class 3 plates are quenched and precipitation heat treated. That is the current ASTM sentence for Grade A Class 3. It is not TMCP. It is not normalize-only. It is not the SA517 quench-and-temper recipe copied onto this alloy.

If the vessel will see warm forming or PWHT, test coupons shall follow a simulated cycle so the precipitation response is measured after that hold. This is not the normalize route used for SA516 Gr.60 and not the QT route used for SA537 Cl.1. SHH STEEL prints quenched and precipitation heat treated, Grade A and Class 3 on the certificate.

Usual delivery is quenched and precipitation heat treated Grade A Class 3 plate.

The certificate lists ASME SA736 Grade A Class 3 and, when dual certified, ASTM A736 Grade A Class 3; heat number; heat analysis including Cu, Ni, Cr, Mo and Nb; product analysis when ordered; tensile results by thickness; precipitation-treatment statement; impact 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 SA736 Gr.A Cl.3 age-hardening vessel plate:

• Thickness: commonly 8 mm – 100 mm, with the tensile line changing by thickness. Thicker plate is possible only if chemistry and precipitation treatment still meet Class 3
• Width: 1500 mm – 4000 mm
• Length: 3000 mm – 12000 mm
• Cut-to-length shells, piping components and nest sizes inside those limits

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. UT to A435 / A577 / A578 is commonly added on thicker age-hardening plate.

Most export ASME SA736 Grade A Class 3 / ASME SA736 GR.A CL.3 orders add extras. SHH STEEL does not assume them.

Charpy / notch toughness details. Temperature, energy, location and orientation.

Simulated PWHT / aging cycle. Same-heat coupons follow the vessel hold.

NDE. UT to A435 / A577 / A578.

Restricted residuals. When specified.

Third-party. EN 10204 3.2.

DIN 17100, ASTM A516, ASME SA515 and ASTM A285 are not SA736 Grade A Class 3.

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.C, A516 Gr.70, SA533 Type C Class 2, SA517 Gr.P.

SHH STEEL works as a China Mill Direct Exporter for plates to ASME SA-736/SA-736M. On ASME SA736 Grade A Class 3 / ASME SA736 GR.A CL.3 that means mill pricing, dual SA736/A736 marking, Grade A chemistry with copper and niobium reported, quenched and precipitation heat treated delivery, Class 3 tensile results by thickness, 3.1 as standard and 3.2 when specified.

We keep Grade and Class on the order. Current ASTM lists Grade A Class 3 only. We will not invent Grade C on a current-spec order. SA736 is not SA516 Gr.55. SA736 is not SA387 Gr.91 Cl.2. SA736 Gr.A Cl.3 is not SA533 Type C Class 1. If the drawing names heat-treated carbon, we point the inquiry to SA537. If it names Class 1 from an old catalog, we will say current A736 is Class 3.

Company scope: China steel Mill Agent-SHH STEEL.

ASME SA736 Grade A Class 3 Steel Plate, also searched as ASME SA736 GR.A CL.3, is low-carbon age-hardening Ni-Cu-Cr-Mo-Nb plate under ASME SA-736/SA-736M, quenched and precipitation heat treated. Whether the inquiry says ASME SA736 Grade A Class 3, ASME SA736 GR.A CL.3, SA736 Gr.A Cl.3 or SA736GRA CL3, SHH STEEL supplies plate with Grade A chemistry, recorded precipitation heat treatment, Class 3 tensile results by thickness, and EN 10204 3.1 or 3.2 certification.

As a China mill Distributor, SHH STEEL provides ASME SA736 Grade A Class 3 / ASME SA736 GR.A CL.3 Age-Hardening Vessel Plate for ASME Section VIII work that actually names this Grade and Class.

Contact SHH STEEL for mill rolling, dual SA736/A736 marking, 3.2 inspection or a quotation.

ASME SA736 Grade A Class 3 Steel Plate, ASME SA736 GR.A CL.3, SA736 Gr.A Cl.3, SA736GRA CL3, SA-736 Grade A Class 3, age-hardening vessel plate, Direct Mill Supply by SHH STEEL