ASME SA533 Type B Class 3 Steel Plate | SA533 Gr.B Cl.3 Mn-Mo-Ni Vessel Plate

ASME SA533 Type B Class 3 is the manganese-molybdenum-nickel, quenched-and-tempered vessel combination in ASME SA-533/SA-533M that uses Type B chemistry and the Class 3 strength table. The current specification lists five Types (A, B, C, D, E) and three Classes (1, 2, 3). Type tells the alloy. Class tells the tensile window.

Type A is Mn-Mo with no nickel requirement. Type B adds nickel at about 0.40–0.70% heat analysis. Type C is higher nickel. Type D is lower nickel. Type E has tighter residuals. Class 3 is the 690–860 MPa tensile window with 570 MPa minimum yield. Class 1 is 550–690 MPa and 345 MPa yield. Class 2 is 620–795 MPa and 485 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 B Class 3, SA533 Gr.B Cl.3, SA533 Grade B Class 3, SA533GRBCL3, SA533 B Cl.3, SA-533 Type B Cl.3, ASTM A533 Type B Class 3, A533 Gr.B Cl.3 and A/SA533 Type B Class 3. The standard text says Type. Buyers still search Grade B Class 3. They mean the same plate.

Class 3 has a hard thickness cap that Class 1 and Class 2 do not share. Maximum thickness of Class 3 plates is 65 mm (2.5 in.) for Types A through D and 50 mm for Type E. If the inquiry is 80 mm or 120 mm at Class 3 strength, this specification cannot be used at Class 3. Move the conversation to Class 1 or Class 2, or to another QT specification such as SA517 Gr.Q, after the drawing is revised.

Do not ship Type A Class 3 and call it Type B Class 3. Type A has no nickel line. Do not ship Class 2 and call it Class 3. Class 2 is a different tensile table and a different thickness practice. Do not treat this page as SA302 Gr.B or A302 Gr.B. SA302 Grade B is normalized Mn-Mo. SA533 Type B Class 3 is quenched and tempered Mn-Mo-Ni.

This is not SA516 Gr.70 or A516 Gr.70. Those pages are fine-grain carbon. It is not SA515 Gr.70. It is not SA285 Gr.C or A285 Gr.C. It is not SA537 Cl.2. SA537 is heat-treated C-Mn-Si. It is not SA517 Gr.B. SA517 Grade B is a different QT alloy with a 32 mm cap. It is not nickel cryogenic plate like SA203 Gr.A or SA203 Gr.D. It is not Cr-Mo like SA387 Gr.22 Cl.2.

The steel shall be killed and shall meet fine austenitic grain practice under ASME SA-20. Plates are quenched and then tempered at not less than 595 °C (1100 °F), with a minimum hold of 0.5 h/in. (1.2 min/mm) and not less than 0.5 h. As-rolled SA533 is crack-sensitive in transit, especially above about 25 mm, and may ship as-rolled only by written agreement.

Minimum nominal thickness is 6.5 mm. For Class 2 and Class 3, the specification allows a higher manganese maximum when Supplementary Requirement S3 is invoked. That option is not automatic.

For Code work the plate is used under ASME Section VIII. Dual marking ASME SA533 Type B Class 3 / ASTM A533 Type B Class 3 is available. Certificates can be EN 10204 3.1 or EN 10204 3.2.

When a project is still choosing QT vessel plate, a China mill Agent path through SHH STEEL puts SA533 Type B Cl.3 next to SA302 Gr.C, SA537 Cl.1 and A36 steel plate. Company scope: China steel Mill Agent-SHH STEEL.

This plate is a vessel product. It is not structural ASTM A36 steel plate. It is not SA516 Gr.60. It is not SA285 Gr.A.

Chemistry for ASME SA533 Type B is the Type table. Class 3 shares Type B chemistry unless S3 raises manganese.

Heat Analysis — ASME SA533 Type B

Product Analysis — SA533 Gr.B / A533 Type B

Nickel is the Type B marker. Type A has no nickel requirement. Type C heat nickel is about 0.70–1.00%. Type D heat nickel is about 0.20–0.40%. A Type A ladle cannot be stamped Type B.

For Class 3, the specification allows manganese maximum to 1.60% heat and 1.65% product when S3 is specified. SHH STEEL applies that increase only when the purchase order says S3.

Compare that ladle with SA302 Gr.C, SA387 Gr.11 Cl.2 and SA516 Gr.70. None of those tables is SA533 Type B.

If the drawing says ASME SA533 Type B Class 3 or SA533 Gr.B Cl.3, the ladle must sit in the Type B table and the tensile test must sit in the Class 3 window. SHH STEEL reports heat analysis on every certificate, including nickel and molybdenum, and adds product analysis when SA-20 requires it.

Class 3 is the highest strength line in SA-533.

Tensile Requirements — ASME SA533 Class 3

Class 1 is 550–690 MPa and 345 MPa yield. Class 2 is 620–795 MPa and 485 MPa yield. A Class 2 heat cannot be stamped Class 3 because someone wants the higher name.

Density is 7.85 g/cm³. Charpy is not a hidden default. Class 3 work almost always writes impact temperature, location and orientation.

Compare SA537 Cl.2 and SA517 Gr.Q. Overlap on a number is not a substitute.

Material Comparison

Order ASME SA533 Type B Class 3 when the drawing names Type B and Class 3 and thickness is 65 mm or less. SHH STEEL does not swap this plate for A516 Gr.70 or A517 Gr.Q.

ASME SA533 Type B Class 3 is selected when the vessel needs the top SA-533 strength window, nickel in the Type B band, and the wall stays inside 65 mm. Allowable stress comes from ASME Section II Part D for SA-533 Type B Class 3.

Typical use is high-strength shells and heads specified to SA-533 Type B Class 3. If the drawing says Type A Class 3, there is no nickel. If the wall is 80 mm, Class 3 is the wrong Class.

It is not a replacement for SA387 Gr.91 Cl.2 or SA203 Gr.E.

SA533 Gr.B Cl.3 is QT Mn-Mo-Ni at the highest Class. 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. Carbon can sit at 0.25%. Molybdenum is in the 0.45–0.60% heat band. Nickel is in the 0.40–0.70% heat band. Calculate carbon equivalent from the actual ladle.

Preheat depends on thickness, restraint, hydrogen and the qualified WPS. After welding, many shops want to PWHT. Simulated PWHT of mill coupons should be on the purchase order.

Do not copy a SA387 Gr.22 Cl.1 or SA517 Gr.A procedure onto Type B Class 3 without review. The fabricator owns the WPS.

Plates shall be quenched and tempered.

Tempering shall be at a suitable temperature to produce the specified Class 3 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. SHH STEEL reports quench and temper data on the MTC.

Do not apply the normalize-only route used for SA302 Gr.B and call the plate SA533 Type B Class 3.

Usual delivery is quenched and tempered Type B Class 3 plate, 6.5–65 mm.

The certificate lists ASME SA533 Type B Class 3 and, when dual certified, ASTM A533 Type B Class 3; heat number; heat analysis including Ni and Mo; product analysis when ordered; tensile results to the Class 3 table; QT temperatures; 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 SA533 Gr.B Cl.3 Mn-Mo-Ni vessel plate:

• Thickness: 6.5 mm – 65 mm (Class 3 maximum on Type B)
• Width: up to about 4000 mm
• Length: up to about 12000 mm

If the inquiry is 70 mm, Class 3 cannot be used. Use Class 1 or Class 2, or revise the specification.

Dimensional limits follow ASME SA-20. UT to A435 / A577 / A578 is commonly added on Class 3 plate.

Most export ASME SA533 Type B Class 3 orders add extras. SHH STEEL does not assume them.

S3 manganese increase. Allowed for Class 2 and Class 3. Written on the order or not applied.

Charpy details. Temperature, energy, location and orientation.

Simulated PWHT. Same-heat coupons follow the vessel cycle.

NDE. UT to A435 / A577 / A578.

Restricted residuals / P / S. When specified.

Third-party. EN 10204 3.2.

Do not use this grade as a silent stand-in for SA203 Gr.B or SA517 Gr.S.

SHH STEEL works as a China Mill Direct Exporter for plates to ASME SA-533/SA-533M. On ASME SA533 Type B Class 3 that means mill pricing, dual SA533/A533 marking, Type B chemistry with nickel in the 0.40–0.70% heat band, recorded quench and temper, Class 3 tensile results at 690–860 MPa and 570 MPa yield, the 65 mm ceiling respected, 3.1 as standard and 3.2 when specified.

We keep the order on the right Type and Class. Type B is not Type A. Class 3 is not Class 1 and is not Class 2. SA533 is not SA516 Gr.55. SA533 is not SA285 Gr.A. SA533 Type B Cl.3 is not SA517 Gr.Q. If the drawing names a wall over 65 mm at this strength, we will say Class 3 cannot be used. If it names Type A, we will not add nickel after the fact.

Company scope: China steel Mill Agent-SHH STEEL.

ASME SA533 Type B Class 3 Steel Plate is quenched-and-tempered manganese-molybdenum-nickel vessel plate under ASME SA-533/SA-533M, limited to 65 mm, with 690–860 MPa tensile and 570 MPa yield. Whether the inquiry says SA533 Type B Class 3, SA533 Gr.B Cl.3, SA533 Grade B Class 3 or A533 Type B Class 3, SHH STEEL supplies plate with Type B chemistry, recorded QT, Class 3 tensile results, and EN 10204 3.1 or 3.2 certification.

As a China mill Distributor, SHH STEEL provides ASME SA533 Type B Class 3 / SA533 Gr.B Cl.3 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 B Class 3 Steel Plate, SA533 Gr.B Cl.3, SA533 Grade B Class 3, ASTM A533 Type B Class 3, Mn-Mo-Ni QT vessel plate, Direct Mill Supply by SHH STEEL