ASME SA841 Grade D Class 3 Steel Plate | SA841 Gr.D Cl.3 TMCP Vessel Plate

ASME SA841 Grade D Class 3 is the first high-strength step after Grades A, B and C in ASME SA-841/SA-841M. Grades A, B and C share Class 1 and Class 2. Grade D does not. The specification assigns Grade D to Class 3 only. Class 3 is not a small upgrade. Yield is 690 MPa. Tensile is 1000–1170 MPa. Elongation in 50 mm drops to 13%. Maximum nominal thickness is 40 mm. As Direct Mill Supply by SHH STEEL, the plate is produced to ASME SA-841/SA-841M by thermo-mechanical control process.

Buyers write the same product as SA841 Grade D Class 3, SA841 Gr.D Cl.3, SA841GRD CL3, SA-841 Grade D Class 3, SA841 D3 and SA 841 Gr D Cl 3. ASTM A841 Grade D Class 3 is the companion mill specification. A purchase order that only says “SA841 Grade D” is still incomplete if the Class is missing, but in current SA-841 the Grade D tensile line is Class 3. Do not invent Grade D Class 1 or Grade D Class 2. Those combinations are not in the tensile table.

This page is not SA841 Grade A Class 1 chemistry with a higher stamp. Grade D carbon is 0.09% maximum. Phosphorus is 0.010% maximum. Sulfur is 0.005% maximum. Nickel is 1.0–5.0%. Molybdenum may sit up to 0.40%. That ladle is a different steel from Grade A or Grade C. It is also not SA517 Gr.Q. SA517 is quenched and tempered. SA841 Grade D Class 3 is TMCP. It is not SA533 Type C Class 3, which is QT Mn-Mo-Ni with a 65 mm Class 3 cap and a different tensile band. It is not ASME SA516 and not ASME SA387.

Thickness is the second filter after chemistry. Grade D stops at 40 mm. An 80 mm Class 3 inquiry cannot be rolled as SA841 Grade D. Move that conversation to another specification after the drawing is revised. Dual marking SA841 / A841 Grade D Class 3 is available. Certificates can be EN 10204 3.1 or 3.2. Company scope: China steel Mill Agent-SHH STEEL.

This plate still sits in the pressure vessel steel plates family. It does not sit with carbon steel plates that have no TMCP Class 3 table, 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 a vessel drawing on the same email, those are two different books.

SA-20 still governs marking, testing location, retests and repair rules. TMCP does not cancel SA-20. Class 3 strength does not cancel SA-20 either. Two tension tests from each plate-as-rolled remain the specification habit unless the order tightens the plan.

ASME SA841 Grade D Class 3 uses Grade D chemistry. Class 3 is the only Class on this Grade, so there is no second chemistry table hiding behind the tensile line.

Heat Analysis — ASME SA841 Grade D

Product analysis follows SA-20 / A20 tolerances on those heat limits. Read the nickel band slowly. 1.0–5.0% is not a residual. Grade A nickel max is 0.25%. Grade B nickel max is 0.60%. Grade C nickel max is 0.25%. A ladle at 0.40% Ni is not Grade D. A ladle at 0.20% C is not Grade D. Phosphorus at 0.025% is not Grade D. Sulfur at 0.015% is not Grade D.

Manganese on Grade D is 1.00–2.00% through the 40 mm cap. There is no “over 40 mm” manganese line because Grade D is not permitted over 40 mm. Silicon is lower than Grades A–C. That combination, plus restricted residuals, is how the mill reaches 690 MPa yield by TMCP instead of by quench and temper.

If the ladle is Cr-Mo in a SA387 Gr.22 Cl.2 window, the plate belongs on the Cr-Mo page. If the ladle is QT Mn-Mo-Ni, look at SA533 Type B Class 3 or SA533 Type C Class 3. If the ladle is carbon only, look at SA516 Gr.70 or SA515 Gr.70. SHH STEEL reports heat analysis on every certificate, including nickel, molybdenum, phosphorus and sulfur.

Class 3 is the reason this page exists. Grade D only identifies the chemistry family.

Tensile Requirements — ASME SA841 Grade D Class 3

There is no “over 40 mm” column. The specification marks thicker Class 3 on Grade D as not applicable. Do not quote 65 mm Class 3 numbers from Grades A–C onto this page. Grades A–C never use Class 3. Class 3 is Grade D.

Elongation at 13% in 50 mm is the Class 3 line. That is not a defect. It is the trade for 690 MPa yield. Designers who need 22% elongation are on Class 1 or Class 2, not on this page.

Density is 7.85 g/cm³ for weight take-off. Hardness is not a mandatory SA-841 Table 3 value. Typical TMCP Class 3 plate is hard compared with Grade A Class 1. Mill values often sit in a high-HB range. If a drawing writes a hardness cap, put that number on the order. SHH STEEL will then test and print it. Do not read Brinell as a substitute for the 690 MPa yield test.

Charpy is not a hidden default in the same way on every Grade D order, but a 690 MPa TMCP vessel plate without an impact temperature is unusual in export work. Write the test temperature, energy, location and orientation. Simulated PWHT coupons are common because shops that buy Class 3 strength still want a vessel PWHT cycle.

Do not treat 690 MPa yield as permission to substitute high strength low alloy plates, EN 10025-6 structural QT plate, or SA517 Gr.F. Those books have their own chemistry, thickness caps and Code listings.

SA299 Gr.B, SA225 Gr.D, SA455 and SA285 Gr.C are also vessel plates. None of them is Grade D Class 3.

The practical question is usually whether Class 3 TMCP can replace QT vessel plate. Only if the drawing and the allowable-stress line name SA-841 Grade D Class 3. 690 MPa on a coupon is not a substitution rule.

ASME SA841 Grade D Class 3 is used when the vessel needs a large jump in yield and the wall stays inside 40 mm. The nickel band and the restricted residuals exist so the mill can reach that yield by TMCP, with weldable carbon still at 0.09% maximum.

Allowable stress comes from ASME Section II Part D after the Code lists this Grade and Class. Do not copy a SA537 Cl.2 allowable and apply it here. Do not copy a SA517 Gr.Q allowable either.

Typical components are thin-to-medium high-strength shells, heads and courses written specifically to SA-841 Grade D Class 3. It is not cryogenic 3.5Ni plate like SA203 Gr.D or SA203 Gr.E. Grade D nickel is a hardenability and toughness tool for TMCP Class 3, not a -101 °C nickel-steel designation. Stainless work belongs on ASME SA240/SA240M, ASTM A240/A240M or stainless steel sheets and plates.

The TMCP temperature cap still applies. Except for Grade G, forming and PWHT stay at or below 650 °C, and only when clause 6.1 and any simulated coupons are satisfied. Class 3 yield disappears faster than Class 1 yield if the plate is overheated. Do not run a 900 °C normalize on Grade D and expect 690 MPa to remain.

SA841 Gr.D Cl.3 is killed, fine-grain TMCP plate at 690 MPa yield. Welding is Code welding for high-strength vessel plate, not structural fillet practice from ASTM A36 steel plate.

Qualify procedures to ASME Section IX. Use low-hydrogen consumables matched to the required joint strength after any PWHT. Carbon is low, which helps. Nickel at 1.0–5.0% and molybdenum up to 0.40% do not. Calculate carbon equivalent from the actual ladle, not from a Grade A worksheet.

Preheat depends on thickness, restraint, hydrogen and the qualified WPS. At 40 mm and 690 MPa, restraint cracks are a real shop risk if hydrogen control is sloppy. After welding, many shops want PWHT. That cycle must stay inside the TMCP window and must be proven on mill coupons when the vessel specification already knows the hold.

Do not copy a SA387 Gr.12 Cl.2 Cr-Mo procedure or a SA533 Type B Class 2 QT procedure onto Grade D Class 3 without review. Consumable strength for 1000 MPa tensile plate is not the same as consumable strength for SA516 Gr.70. The fabricator owns the WPS. SHH STEEL supplies the plate and the test data.

The steel shall be killed and shall meet fine austenitic grain practice under ASME SA-20. Plates shall be produced by TMCP. Slab reheating, heavy reduction, finish temperature and accelerated cooling are the mill tools. There is no mandatory furnace normalize and no mandatory quench and temper in the specified condition.

If the vessel will be warm formed or post-weld heat-treated, the test coupons must follow that cycle. A coupon tested as-rolled does not prove a 620 °C shell hold on 690 MPa TMCP plate. Ask for simulated PWHT when the vessel specification already knows the temperature and time.

This is not the normalize route used for SA516 Gr.60. It is not the QT route used for SA537 Cl.2 or SA517 Gr.E. SHH STEEL prints TMCP and Class 3 on the certificate so the inspector does not treat the plate as ordinary as-rolled carbon.

Usual delivery is TMCP Grade D Class 3 plate, 8 mm to 40 mm.

The mill test certificate lists ASME SA841 Grade D Class 3 and, when dual certified, ASTM A841 Grade D Class 3; heat number; heat analysis including Ni, Mo, P and S; product analysis when ordered; tensile results to the Class 3 table; TMCP statement; impact results when ordered; simulated PWHT results when ordered; and UT when ordered. Surface is vessel-plate quality. Shot blast and shop primer are available.

Certificates may be EN 10204 3.1 or EN 10204 3.2. Third-party surveyors can witness rolling, cooling and testing when the order names the agency.

Usual supply range from SHH STEEL for SA841 Gr.D Cl.3 TMCP vessel plate:

• Thickness: 8 mm – 40 mm. That 40 mm ceiling is the Grade D rule in SA-841, not a mill preference
• Width: 1500 mm – 4000 mm, subject to the thin high-strength rolling schedule
• Length: 3000 mm – 12000 mm
• Cut-to-length shells, dish-head blanks and nest sizes inside those limits

A 45 mm inquiry is outside Grade D. Do not “see if the mill can roll it” and still stamp SA841 Grade D Class 3. Grades A, B and C go to 100 mm, but they do not carry Class 3.

Structural lengths 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 tolerance, width, length, flatness and camber are vessel-plate rules.

High-strength TMCP plate can move during cooling. Flatness on 690 MPa plate should be written if the head shop is tight. Ultrasonic testing to A435, A577 or A578 is common on Class 3 plate. Extra-flatness and edge-camber limits are negotiated items, not assumed extras.

Most export ASME SA841 Grade D Class 3 orders add extras. The specification does not assume them.

Charpy V-notch. Temperature, absorbed energy, specimen location and orientation. High-strength thin vessel plate almost always carries this.

Simulated PWHT and warm forming. Same-heat coupons follow the vessel cycle. Tensile and impact are then run on those coupons. This is the item shops forget and then fight at inspection.

NDE. UT to A435 / A577 / A578. Edge MT or PT after cutting when the shop wants it.

Restricted P, S and CEV. Table 1 is already tight. Some projects go tighter still.

Through-thickness / Z testing. When lamellar tearing is a design concern.

Third-party inspection. EN 10204 3.2, with the agency named on the order.

If an item is not written, it is not tested and it is not printed as if it were.

There is no one-to-one dual stamp outside ASTM A841. The names below are project comparisons. Chemistry, TMCP route, 40 mm cap and impact temperature still have to match the purchase order.

DIN 17100, ASTM A516, ASME SA515 and ASTM A285 are not Grade D Class 3. SHH STEEL will dual-certify SA841 / A841. EN, JIS or GB dual marking is only when the mill heat meets both books and the order says so.

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.F, SA302 Gr.C, A516 Gr.70, SA533 Type D Class 3, SA517 Gr.P.

SHH STEEL works as a China Mill Direct Exporter for plates to ASME SA-841/SA-841M. On ASME SA841 Grade D Class 3 that means mill pricing, dual SA841/A841 marking, Grade D chemistry with nickel in the 1.0–5.0% band, restricted phosphorus and sulfur, recorded TMCP delivery, Class 3 tensile results at 690 MPa yield and 1000–1170 MPa tensile, the 40 mm ceiling respected, 3.1 as standard and 3.2 when specified.

We keep Grade and Class on the order. Grade D is not Grade A, not Grade B and not Grade C. Class 3 is not Class 1 and is not Class 2. SA841 is not SA516 Gr.55. SA841 is not SA387 Gr.91 Cl.2. SA841 Gr.D Cl.3 is not SA533 Type C Class 1. If the drawing names 80 mm at this strength, we will say Grade D cannot be used. If it names QT alloy, we point the inquiry to SA517 or SA533. If the shop plans a 900 °C form, we will say TMCP Class 3 is the wrong process before the slab is booked.

Company scope: China steel Mill Agent-SHH STEEL.

ASME SA841 Grade D Class 3 Steel Plate is high-strength TMCP pressure-vessel plate under ASME SA-841/SA-841M, limited to 40 mm, with 690 MPa yield and 1000–1170 MPa tensile. Whether the inquiry says SA841 Grade D Class 3, SA841 Gr.D Cl.3, SA841GRD CL3 or SA-841 Grade D Class 3, SHH STEEL supplies plate with Grade D chemistry, recorded TMCP delivery, Class 3 tensile results, and EN 10204 3.1 or 3.2 certification.

As a China mill Distributor, SHH STEEL provides ASME SA841 Grade D Class 3 / SA841 Gr.D Cl.3 TMCP Vessel Plate for ASME Section VIII work that actually names this Grade and Class.

Contact SHH STEEL for mill rolling, dual SA841/A841 marking, simulated PWHT testing, 3.2 inspection or a quotation.

ASME SA841 Grade D Class 3 Steel Plate, SA841 Gr.D Cl.3, SA841GRD CL3, SA-841 Grade D Class 3, TMCP high strength vessel plate, Direct Mill Supply by SHH STEEL