ASME SA841 Grade G Class 9 Steel Plate | SA841 Gr.G Cl.9 TMCP Vessel Plate

ASME SA841 Grade G Class 9 is the middle Class line on Grade G in ASME SA-841/SA-841M. Grade G does not share Class 1 or Class 2 with Grades A, B and C. It does not use Class 3 through Class 7. Grade G uses Class 8, Class 9 and Class 10. Class 9 is the middle Grade G line: 585 MPa yield and 690–825 MPa tensile. Unlike Class 8, Class 9 is written for both the 40 mm band and the 40–50 mm band. 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 G Class 9, SA841 Gr.G Cl.9, SA841GRG CL9, SA-841 Grade G Class 9, SA841 G9 and SA 841 Gr G Cl 9. ASTM A841 Grade G Class 9 is the companion mill specification. A purchase order that only says “SA841 Grade G” is incomplete. Class 8 is 550 MPa yield through 40 mm only. Class 10 is 620 MPa yield. Those plates do not interchange with Class 9.

Grade G is not a small chemistry tweak on Grade F. Nickel is 6.0–7.5%. Chromium is 0.30–1.00%. The specification warns that Grade G is susceptible to magnetization. Handling with magnets after processing can leave residual magnetism that later hurts fabrication or service. Forming is tighter than on Grades A through F. Grade G plates may be formed at temperatures not exceeding 530 °C (985 °F) when clause 6.1 is met. The 650 °C window used on the other Grades does not apply here.

Transverse Charpy V-notch testing is required for Grade G. Unless the purchase order names another temperature, the default test temperature is −195 °C (−320 °F), with lateral-expansion limits by thickness. That is a cryogenic toughness rule, not a room-temperature afterthought.

This page is not SA203 Gr.E 3.5Ni plate and it is not 9% nickel A353 / A553. It is not SA537 Cl.2. It is not SA517 Gr.Q. It is not SA533 Type C Class 3. It is not ASME SA516 and not ASME SA387.

Grade G as a Grade may be supplied up to 50 mm. Class 9 uses that cap. Dual marking SA841 / A841 Grade G Class 9 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 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 cryogenic 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. The Grade G impact rule is extra, not a replacement for SA-20.

ASME SA841 Grade G Class 9 uses Grade G chemistry. Class 8, Class 9 and Class 10 share that table. The Class only changes the tensile line.

Heat Analysis — ASME SA841 Grade G

Product analysis follows SA-20 / A20 tolerances on those heat limits. Read the nickel band slowly. 6.0–7.5% is the Grade G marker. Grade D nickel is 1.0–5.0%. Grade E and Grade F nickel maxima are 0.60% and 0.85%. A ladle at 0.80% Ni is not Grade G. A ladle at 8.5–9.5% Ni is in 9% nickel territory, not SA841 Grade G.

Silicon is low. Manganese is lower than Grade F. Chromium is a specified range, not only a maximum. That package exists to hold toughness at the Grade G impact temperature while TMCP produces Class 9 yield.

If the drawing wants 3.5Ni low-temperature plate, look at SA203 Gr.D or SA203 Gr.E. If it wants QT Mn-Mo-Ni, look at SA533 Type C Class 2. If it wants Cr-Mo, look at SA387 Gr.22 Cl.2. SHH STEEL reports heat analysis on every certificate, including nickel and chromium.

Class 9 is the strength line on this page. Grade G only identifies the chemistry family.

Tensile Requirements — ASME SA841 Grade G Class 9

Class 8 is 550 MPa yield and is not listed for 40–50 mm. Class 10 is 620 MPa yield through 40 mm and 620 MPa through 50 mm. A Class 8 heat cannot be stamped Class 9 because the thickness is 45 mm. A Class 9 heat cannot be stamped Class 10 because someone wants the higher name.

Density is 7.85 g/cm³ for weight take-off. Hardness is not a mandatory SA-841 Table 3 value. Typical high-nickel TMCP Class 9 plate is harder than Grade A Class 1. If a drawing writes a hardness cap, put that number on the order.

Impact is not optional in the same way as Grade A. Transverse Charpy V-notch tests shall be made. Unless the order names a temperature, tests are conducted at −195 °C. Lateral expansion opposite the notch shall be not less than 0.38 mm up to 31.75 mm thick, and 0.48 mm at 50 mm. Write a project temperature when the vessel specification already has one. Do not assume the default is −20 °C.

Do not treat 585 MPa yield as permission to substitute high strength low alloy plates, EN 10025-6 structural QT plate, or SA517 Gr.Q.

SA299 Gr.B, SA225 Gr.D, SA455 and SA285 Gr.C are also vessel plates. None of them is Grade G Class 9.

ASME SA841 Grade G Class 9 is selected when the vessel wants TMCP high-nickel plate at the Class 9 window, including walls between 40 mm and 50 mm. Allowable stress comes from ASME Section II Part D after the Code lists this Grade and Class.

Typical use is welded low-temperature or high-restraint equipment written specifically to SA-841 Grade G Class 9. It is not a silent stand-in for 9% nickel and it is not a stand-in for SA203 Gr.D. Stainless work belongs on ASME SA240/SA240M, ASTM A240/A240M or stainless steel sheets and plates.

Forming and PWHT are tighter than on Grade A through F. Stay at or below 530 °C unless the order and clause 6.1 say otherwise. Simulated coupons are not optional when the shop already knows a hold. Magnet handling after processing should be avoided if residual magnetism will hurt later welding, NDE or service.

SA841 Gr.G Cl.9 is killed, fine-grain, high-nickel TMCP plate at the middle Grade G Class. Welding is Code welding for nickel-bearing vessel plate, not structural fillet practice from ASTM A36 steel plate.

Qualify procedures to ASME Section IX. Use low-hydrogen consumables chosen for the nickel level and the required toughness after any permitted thermal cycle. Carbon is 0.13% maximum. Nickel is 6.0–7.5%. That combination does not weld like Grade C. Calculate carbon equivalent from the actual ladle and review nickel effects on the WPS, not only CEV.

Preheat, interpass and PWHT follow the qualified procedure and the 530 °C Grade G ceiling. Do not copy a SA387 Gr.12 Cl.2 Cr-Mo procedure or a SA533 Type B Class 2 QT procedure onto Grade G Class 9 without review. Do not copy a 9% nickel procedure blindly either. The fabricator owns the WPS.

The steel shall be killed and shall meet fine austenitic grain practice under ASME SA-20. Plates shall be produced by TMCP. 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, and the temperature must respect the Grade G limit. A coupon tested as-rolled does not prove a 500 °C shell hold. Ask for simulated PWHT when the vessel specification already knows the temperature and time.

This is not the normalize route used for SA516 Gr.70. It is not the QT route used for SA537 Cl.1 or SA517 Gr.F. SHH STEEL prints TMCP, Grade G and Class 9 on the certificate.

Usual delivery is TMCP Grade G Class 9 plate, 8 mm to 50 mm.

The mill test certificate lists ASME SA841 Grade G Class 9 and, when dual certified, ASTM A841 Grade G Class 9; heat number; heat analysis including Ni and Cr; product analysis when ordered; tensile results to the Class 9 table; TMCP statement; transverse Charpy / lateral expansion; simulated PWHT results when ordered; and UT when ordered. Surface is vessel-plate quality. Magnet lifting after final processing is avoided when residual magnetism is a concern.

Certificates may be EN 10204 3.1 or EN 10204 3.2.

Usual supply range from SHH STEEL for SA841 Gr.G Cl.9 TMCP vessel plate:

• Thickness: 8 mm – 50 mm. Class 9 uses the full Grade G cap. Class 8 does not
• Width: 1500 mm – 4000 mm, subject to the high-nickel TMCP schedule
• Length: 3000 mm – 12000 mm
• Cut-to-length shells, dish-head blanks and nest sizes inside those limits

A 55 mm inquiry is outside Grade G. 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, width, length, flatness and camber are vessel-plate rules.

High-nickel TMCP plate can move during cooling. Flatness should be written if the head shop is tight. Ultrasonic testing to A435, A577 or A578 is common. Extra-flatness and edge-camber limits are negotiated items.

Most export ASME SA841 Grade G Class 9 orders add extras. Grade G already carries a default impact rule. Other extras are still not assumed.

Impact temperature other than −195 °C. Written when the vessel specification names a different temperature.

Simulated PWHT and warm forming. Same-heat coupons follow the vessel cycle inside the Grade G temperature cap.

NDE. UT to A435 / A577 / A578.

Restricted residuals. When specified.

Magnetism control. Written when residual magnetism will affect later fabrication.

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

If an item is not written, it is not tested beyond what Grade G already requires.

There is no one-to-one dual stamp outside ASTM A841. The names below are project comparisons only.

DIN 17100, ASTM A516, ASME SA515 and ASTM A285 are not Grade G Class 9. 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 G Class 9 that means mill pricing, dual SA841/A841 marking, Grade G chemistry with nickel in the 6.0–7.5% band, recorded TMCP delivery, Class 9 tensile results at 585 MPa yield through 50 mm, transverse impact to the Grade G rule, forming advice inside 530 °C, magnetism handling noted, 3.1 as standard and 3.2 when specified.

We keep Grade and Class on the order. Grade G Class 9 is not Class 8 and is not Class 10. Grade G is not Grade D and is not Grade F. SA841 is not SA516 Gr.55. SA841 is not SA387 Gr.91 Cl.2. SA841 Gr.G Cl.9 is not SA533 Type C Class 1. If the drawing names 45 mm Class 8, we will move it to Class 9 or Class 10. If the shop plans a 650 °C form as if this were Grade B, we will say Grade G does not allow that habit.

Company scope: China steel Mill Agent-SHH STEEL.

ASME SA841 Grade G Class 9 Steel Plate is high-nickel TMCP pressure-vessel plate under ASME SA-841/SA-841M, with 585 MPa yield through 50 mm and the Grade G impact and forming rules. Whether the inquiry says SA841 Grade G Class 9, SA841 Gr.G Cl.9, SA841GRG CL9 or SA-841 Grade G Class 9, SHH STEEL supplies plate with Grade G chemistry, recorded TMCP delivery, Class 9 tensile results, and EN 10204 3.1 or 3.2 certification.

As a China mill Distributor, SHH STEEL provides ASME SA841 Grade G Class 9 / SA841 Gr.G Cl.9 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, −195 °C impact testing, 3.2 inspection or a quotation.

ASME SA841 Grade G Class 9 Steel Plate, SA841 Gr.G Cl.9, SA841GRG CL9, SA-841 Grade G Class 9, TMCP high nickel vessel plate, Direct Mill Supply by SHH STEEL