ASME SA533 Type C Class 1 Steel Plate | SA533 Gr.C Cl.1 Mn-Mo-Ni Vessel Plate

ASME SA533 Type C Class 1 is the highest-nickel manganese-molybdenum-nickel combination in ASME SA-533/SA-533M at the Class 1 strength window. The current specification lists five Types (A, B, C, D, E) and three Classes (1, 2, 3). Type C heat nickel is about 0.70–1.00%. Type B is about 0.40–0.70%. Type D is about 0.20–0.40%. Type A has no nickel requirement. Class 1 is 550–690 MPa tensile and 345 MPa yield. As Direct Mill Supply by SHH STEEL, the plate is produced to ASME SA-533/SA-533M.

The same plate is written SA533 Type C Class 1, SA533 Gr.C Cl.1, SA533 Grade C Class 1, SA533GRCCL1, SA-533 Type C Cl.1, ASTM A533 Type C Class 1 and A533 Gr.C Cl.1. The standard text says Type. Buyers still search Grade C Class 1. They mean the same plate.

Do not ship Type B and call it Type C. Do not ship Class 2 and call it Class 1. Do not treat this page as normalized SA302 Gr.C. SA302 Grade C is Mn-Mo-Ni in the normalized condition. SA533 Type C Class 1 is quenched and tempered. Company scope: China steel Mill Agent-SHH STEEL.

This plate is a vessel product under ASME Section VIII when dual marked. It is not structural ASTM A36 steel plate. It is not fine-grain carbon like SA516 Gr.70 or A516 Gr.70. It is not silicon-killed high-temp carbon like SA515 Gr.70. It is not low-tensile carbon like SA285 Gr.C or A285 Gr.C. Current practice normally limits Type C Class 1 to about 300 mm. Class 3 on Types A–D is capped at 65 mm. Minimum nominal thickness is 6.5 mm.

Chemistry for ASME SA533 Type C is the Type table. Class 1, Class 2 and Class 3 share Type C chemistry unless Supplementary Requirement S3 is used to raise manganese on Class 2 or Class 3. Nickel is the reason Type C exists.

Heat Analysis — ASME SA533 Type C

Product Analysis — SA533 Gr.C / A533 Type C

A ladle at 0.55% Ni sits in Type B, not Type C. A ladle with no nickel sits in Type A, not Type C. Type D heat nickel is only about 0.20–0.40%. Type E uses a tighter residual practice and a different thickness cap. SHH STEEL reports heat analysis on every certificate, including nickel and molybdenum, and adds product analysis when SA-20 requires it.

Compare that ladle with SA302 Gr.C (normalized Mn-Mo-Ni), SA302 Gr.B (normalized Mn-Mo), SA387 Gr.11 Cl.2 (Cr-Mo) and SA516 Gr.60 (fine-grain carbon). None of those tables is SA533 Type C. If the drawing says ASME SA533 Type C Class 1 or SA533 Gr.C Cl.1, the ladle must sit in the Type C nickel window and the tensile test must sit in the Class 1 window.

Class 1 is the strength line. Type C only tells the alloy.

Tensile Requirements — ASME SA533 Class 1

Class 2 is 620–795 MPa and 485 MPa yield, with 16% elongation. Class 3 is 690–860 MPa and 570 MPa yield, with 16% elongation and a 65 mm cap on Type C. A Class 1 heat cannot be stamped Class 2 because someone wants the higher name. Density is 7.85 g/cm³. Hardness is not a default line. Charpy is not a hidden default in SA-533. Thick-wall Type C Class 1 work almost always writes impact temperature, location and orientation as extras.

Compare SA537 Cl.1 and SA517 Gr.Q. Overlap on a number is not a substitute. SA537 Class 1 is heat-treated carbon-manganese-silicon. SA517 Grade Q is a different QT alloy family with a different thickness rule.

Order ASME SA533 Type C Class 1 when the drawing names Type C and Class 1. SHH STEEL does not swap this plate for A516 Gr.70 or A517 Gr.Q.

ASME SA533 Type C Class 1 is selected when the vessel needs QT Mn-Mo-Ni at the Class 1 window and the higher nickel band. Nickel at 0.70–1.00% is the toughness and hardenability argument versus Type B. Allowable stress comes from ASME Section II Part D for SA-533 Type C Class 1 after dual marking.

Typical use is heavy-wall process vessels, high-restraint shells and dual-certified export plate specified to SA-533 Type C Class 1. Nuclear beltline work more often names Type B Class 1. If the drawing says Type B, nickel is lower. If the drawing says Type D, nickel is lower still. If the drawing says Class 2, tensile and yield both rise.

It is not a replacement for SA387 Gr.22 Cl.2 creep-related Cr-Mo service or SA203 Gr.D 3.5Ni low-temperature service. Those drawings name different alloys and different design temperatures. It is not a replacement for SA537 Cl.2 heat-treated carbon.

SA533 Gr.C Cl.1 is QT Mn-Mo-Ni with the highest nickel band in Types A–D. Welding is Code welding, not structural fillet practice from ASTM A36 steel plate.

Procedures are qualified to ASME Section IX. Low-hydrogen practice is mandatory. Consumables must match the required joint strength and toughness after any PWHT. Carbon can sit at 0.25%. Molybdenum is in the 0.45–0.60% heat band. Nickel is in the 0.70–1.00% heat band. Calculate carbon equivalent from the actual ladle, not from a memory of Type B.

Preheat depends on thickness, restraint, hydrogen and the qualified WPS. Thick Class 1 plate is not a 12 mm carbon fillet. After welding, many shops want to PWHT. Simulated PWHT of mill coupons should be on the purchase order when the vessel cycle is known.

Do not copy a SA387 Gr.22 Cl.1 Cr-Mo procedure or a SA517 Gr.A QT procedure onto Type C Class 1 without review. The fabricator owns the WPS.

Plates shall be quenched and tempered. The steel shall be killed and shall meet fine austenitic grain practice under ASME SA-20.

Tempering shall be at a suitable temperature to produce the specified Class 1 properties, but not less than 595 °C (1100 °F), with a minimum holding time of ½ h/in. (1.2 min/mm) and not less than ½ h.

As-rolled delivery is not the specified condition. As-rolled shipping is crack-sensitive above about 25 mm and requires written agreement between mill and buyer. SHH STEEL reports quench and temper temperatures and holds on the MTC for every SA533 Type C Class 1 plate.

Do not apply the normalize-only route used for SA302 Gr.C and call the plate SA533 Type C Class 1.

Usual delivery is quenched and tempered Type C Class 1 plate.

The certificate lists ASME SA533 Type C Class 1 and, when dual certified, ASTM A533 Type C Class 1; heat number; heat analysis including Ni and Mo; product analysis when ordered; tensile results to the Class 1 table; QT temperatures; Charpy results when ordered; and supplementary tests. Surface is vessel-plate quality. Shot blasting and shop primer are available.

Certificates may be EN 10204 3.1 or EN 10204 3.2. BV, LR, DNV, TUV, SGS or the buyer’s agency can witness rolling, quenching, tempering and testing when the order says so.

Usual supply range from SHH STEEL for SA533 Gr.C Cl.1 Mn-Mo-Ni vessel plate:

• Thickness: 6.5 mm – about 300 mm for Class 1 (current practice on Type C)
• Width: up to about 4000 mm
• Length: up to about 12000 mm

Class 3 is not this page. Class 3 on Type C stops at 65 mm. If the inquiry is Class 3, both the tensile table and the thickness cap change. Cut-to-length shells and nest sizes are available inside the ordered thickness.

Dimensional limits follow ASME SA-20. Thickness, width, length, flatness and camber are vessel-plate tolerances, not structural-plate habits from ASTM A36 steel plate.

Ultrasonic testing to A435, A577 or A578 is commonly added on thick QT plate. Extra-flatness is a negotiated item. Coil-origin rules in A20 / SA-20 apply only when the plate is produced from coil; most Type C Class 1 heavy plate is discrete plate.

Most export ASME SA533 Type C Class 1 orders add extras. SHH STEEL does not assume them because Type C Class 1 already carries nickel.

Charpy and drop-weight. Temperature, energy, location and orientation. Thick-wall Type C work almost always writes this.

Simulated PWHT. Same-heat coupons follow the vessel cycle. Tensile and Charpy are then run on those coupons.

NDE. UT to A435 / A577 / A578; edge MT/PT after cutting.

Restricted residuals. When high-restraint or nuclear-adjacent work specifies them.

Restricted P, S. Tighter than 0.025% when specified.

S3 manganese increase. Applies to Class 2 and Class 3, not to a silent Class 1 upgrade.

Third-party. Witness of QT and testing. Output can be EN 10204 3.2.

If an item is not on the purchase order, it is not assumed, not tested and not printed as if it were.

For stamping, write ASME SA533 Type C Class 1 or dual SA533 / A533 Type C Class 1.

Do not use this grade as a silent stand-in for SA203 Gr.B or SA517 Gr.S. Those drawings name different alloys and different heat treatments.

SHH STEEL works as a China Mill Direct Exporter for plates to ASME SA-533/SA-533M. On ASME SA533 Type C Class 1 that means mill pricing, dual SA533/A533 marking, Type C chemistry with nickel in the 0.70–1.00% heat band, recorded quench and temper, Class 1 tensile results at 550–690 MPa and 345 MPa yield, 3.1 as standard and 3.2 when specified.

We keep the order on the right Type and Class. Type C is not Type B and is not Type A. Class 1 is not Class 2. SA533 is not SA516 Gr.55. SA533 is not SA285 Gr.A. SA533 Type C Cl.1 is not SA517 Gr.Q. If the drawing names Type B, we will not ship Type C and call extra nickel an upgrade. If it names normalized Mn-Mo-Ni, we point the inquiry to SA302.

Company scope: China steel Mill Agent-SHH STEEL.

ASME SA533 Type C Class 1 Steel Plate is quenched-and-tempered manganese-molybdenum-nickel vessel plate under ASME SA-533/SA-533M, using the highest nickel band among Types A–D at the Class 1 strength window. Whether the inquiry says SA533 Type C Class 1, SA533 Gr.C Cl.1, SA533 Grade C Class 1 or A533 Type C Class 1, SHH STEEL supplies plate with Type C chemistry, recorded QT, Class 1 tensile results, and EN 10204 3.1 or 3.2 certification.

As a China mill Distributor, SHH STEEL provides ASME SA533 Type C Class 1 / SA533 Gr.C Cl.1 Mn-Mo-Ni Vessel Plate for ASME Section VIII work.

Contact SHH STEEL for mill rolling, dual SA533/A533 marking, 3.2 inspection or a quotation.

ASME SA533 Type C Class 1 Steel Plate, SA533 Gr.C Cl.1, SA533 Grade C Class 1, ASTM A533 Type C Class 1, Mn-Mo-Ni QT vessel plate, Direct Mill Supply by SHH STEEL