ASME SA542 Type B Class 4 Steel Plate | SA542 Type B Cl.4 QT Cr-Mo Vessel Plate
What is ASME SA542 Type B Class 4 Steel?
ASME SA542 Type B Class 4, also written ASME SA542 TYPE B CL.4, is quenched-and-tempered 2.25Cr-1Mo alloy plate under ASME SA-542/SA-542M. The specification covers Type A, B, C, D and E, and Class 1, 2, 3, 4 and 4a. Type B is the same 2.25Cr-1Mo idea as Type A, with tighter limits on carbon, phosphorus, sulfur, copper, nickel and vanadium. Class 4 shares the 585–760 MPa tensile band with Class 4a, but yield is 380 MPa, not 415 MPa. Elongation is 20%. Temper floor for Type A, B and C Class 4 is 650 °C, not the 565 °C floor used on Class 1, 2 and 3, and not the 675 °C floor used on Class 4a. SHH STEEL is the supplier, exporter and distributor of this Type and Class. Plate is produced to ASME SA-542/SA-542M.
Buyers write ASME SA542 Type B Class 4, ASME SA542 TYPE B CL.4, SA542 Type B Class 4, SA542 Type B Cl.4, SA542B CL4, SA-542 Type B Class 4 and SA 542 Type B Cl 4. ASTM A542 Type B Class 4 is the companion product spec. A purchase order that only says “SA542 Type B” is incomplete. A purchase order that writes Class 4 when the drawing says Class 4a is the wrong yield and the wrong temper floor.
This page is not SA832 22V. SA832 is normalized-and-tempered Cr-Mo-V. SA542 Type B Class 4 is QT 2.25Cr-1Mo without the 22V vanadium band. It is not SA517 Gr.A. It is not SA841 TMCP. It is not ASME SA516 carbon plate. Minimum thickness in the specification is about 5 mm. Maximum thickness is limited by the ability of the heat to meet Class 4 after quench and temper.
Dual marking SA542 / A542 Type B Class 4 is available from SHH STEEL as mill supplier. Certificates can be EN 10204 3.1 or 3.2. Company scope: China steel Mill Agent-SHH STEEL.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Type / Class | ASME SA542 Type B Class 4 | Confirmed |
| Product Specification | ASME SA-542/SA-542M | Applied |
| Companion Spec | ASTM A542 Type B Class 4 | Dual cert available |
| General Requirements | ASME SA-20 / ASTM A20 | Applied |
| Process | Quenched and tempered | Confirmed |
| Class 4 temper floor | 650 °C min | Applied |
| Alloy idea | 2.25Cr-1Mo, Type B residuals | Confirmed |
| Sister N+T spec | SA-832 / A832 | Not this page |
| Supply role | Supplier / exporter / distributor | SHH STEEL |
| Certification | EN 10204 3.1 or 3.2 / third-party | As ordered |
This plate sits in the pressure vessel steel plates family and with ASME SA387 as a related Cr-Mo family, not as a substitute. It does not sit with carbon steel plates or ASTM A36/A36M.
SA-20 still governs marking, testing location, retests and repair rules.
Chemical Composition
ASME SA542 Type B Class 4 / ASME SA542 TYPE B CL.4 uses Type B chemistry. Class only changes strength and temper floor.
Heat Analysis and Product Analysis — ASME SA542 Type B (typical Table 1 limits)
| Element | Heat Analysis (%) | Product Analysis (%) |
|---|---|---|
| Carbon (C) | 0.11 – 0.15 | 0.09 – 0.18 |
| Manganese (Mn) | 0.30 – 0.60 | 0.25 – 0.66 |
| Phosphorus (P), max | 0.015 | 0.015 |
| Sulfur (S), max | 0.015 | 0.015 |
| Silicon (Si), max | 0.50 | 0.50 |
| Chromium (Cr) | 2.00 – 2.50 | 1.88 – 2.62 |
| Molybdenum (Mo) | 0.90 – 1.10 | 0.85 – 1.15 |
| Nickel (Ni), max | Restricted vs Type A | Restricted vs Type A |
| Copper (Cu), max | Restricted vs Type A | Restricted vs Type A |
| Vanadium (V), max | Restricted vs Type A | Restricted vs Type A |
Type B is not Type D. Type D adds a vanadium band of about 0.25–0.35% and is 2.25Cr-1Mo-V. Type C and Type E sit on the 3Cr-1Mo-V band. If the ladle is 2.25Cr-1Mo-V, SHH STEEL will not ship it as Type B Class 4.
Mechanical Properties
Class 4 shares tensile with Class 4a. Yield is lower.
Tensile Requirements — ASME SA542 Type B Class 4
| Property | Requirement |
|---|---|
| Yield strength, min | 380 MPa (55 ksi) |
| Tensile strength | 585 – 760 MPa (85 – 110 ksi) |
| Elongation in 50 mm, min | 20% |
| Density | 7.85 g/cm³ |
| Hardness | Not a default substitute for tensile |
Class 4a is 415 MPa yield, 585–760 MPa tensile and 18% elongation. Class 3 is 515 MPa yield and 655–795 MPa tensile. Class 1 is 585 / 725–860. Class 2 is 690 / 795–930. Do not stamp Class 4 as Class 4a because tensile matches.
Density is 7.85 g/cm³. Notch toughness is commonly added. Write the temperature, energy, location and orientation. Simulated PWHT is common.
Do not treat 380 MPa yield as permission to substitute SA516 Gr.70, SA533 Type A Class 1 or high strength low alloy plates.
Material Comparison
| Grade | Route | Alloy / strength idea | Swap? |
|---|---|---|---|
| SA542 Type B Class 1 | QT 2.25Cr-1Mo | 585 / 725–860 | No |
| SA542 Type B Class 2 | QT 2.25Cr-1Mo | 690 / 795–930 | No |
| SA542 Type B Class 3 | QT 2.25Cr-1Mo | 515 / 655–795 | No |
| SA542 Type B Cl.4 | QT 2.25Cr-1Mo | 380 / 585–760, temper 650 °C | This page |
| SA542 Type B Class 4a | QT 2.25Cr-1Mo | 415 / 585–760, temper 675 °C | No |
| SA387 Gr.22 Cl.2 | Cr-Mo family | Not SA542 QT Class 4 | No |
| SA832 22V | N+T Cr-Mo-V | Not QT Type B | No |
SA299 Gr.B, SA225 Gr.D, SA455 and SA285 Gr.C are also vessel plates. None of them is ASME SA542 TYPE B CL.4.
QT Cr-Mo Vessel Service
ASME SA542 Type B Class 4 / ASME SA542 TYPE B CL.4 is selected when the vessel wants quenched-and-tempered 2.25Cr-1Mo at the Class 4 line, with Type B residual control. Typical equipment is high-temperature welded pressure vessels and components written to SA-542 Type B Class 4. Allowable stress comes from ASME Section II Part D after the Code lists this Type and Class.
SHH STEEL supplies this plate as exporter and stockist. It is not nickel low-temp plate like 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.
Do not form this plate as if it were as-rolled carbon. Quench-and-temper properties are the product. A later PWHT cycle has to be planned and, when required, simulated on coupons.
Weldability
SA542 Type B Cl.4 is killed, fine-grain 2.25Cr-1Mo at Class 4 strength. Welding is Code welding.
Qualify procedures to ASME Section IX. Use consumables written for 2.25Cr-1Mo QT at 585–760 MPa tensile, not a Class 1 procedure copied down and not an unreviewed SA387 Grade 22 procedure. Hydrogen control, preheat, interpass and PWHT follow the qualified procedure and the vessel specification.
Do not copy a SA387 Gr.12 Cl.2 procedure onto Type B Class 4 without review. The fabricator owns the WPS.
Heat Treatment
Plates shall be austenitized, quenched in a suitable liquid medium, then tempered. For Type A, B and C Class 4, the minimum tempering temperature is 650 °C (1200 °F). Soak is not less than 1.2 min/mm of thickness and not less than ½ hour. Class 1, 2 and 3 use 565 °C. Class 4a uses 675 °C. Do not temper Class 4 at the Class 1 floor and stamp Class 4.
If the vessel will see a long PWHT, test coupons shall follow a simulated cycle. This is not the SA832 N+T route. SHH STEEL as mill exporter prints QT, Type B, Class 4, austenitizing and tempering temperatures on the certificate when the mill record carries them.
Delivery Condition
Usual delivery from SHH STEEL as supplier and distributor is quenched-and-tempered ASME SA542 Type B Class 4 / ASME SA542 TYPE B CL.4 plate.
The certificate lists ASME SA542 Type B Class 4 and, when dual certified, ASTM A542 Type B Class 4; heat number; heat analysis including Cr, Mo and Type B residuals; product analysis when ordered; tensile results to the Class 4 table; QT statement with the 650 °C floor; impact and simulated PWHT when ordered. Certificates may be EN 10204 3.1 or EN 10204 3.2.
Dimensions
Usual supply range from SHH STEEL for SA542 Type B Cl.4 QT Cr-Mo vessel plate:
- Thickness: commonly 8 mm – 150 mm, minimum about 5 mm, limited by the ability of the heat to meet Class 4 after QT
- Width: 1500 mm – 4000 mm
- Length: 3000 mm – 12000 mm
- Cut-to-length shells, heads 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.
Tolerances
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 reactor plate.
Supplementary Requirements
Most export ASME SA542 Type B Class 4 / ASME SA542 TYPE B CL.4 orders add extras. SHH STEEL as supplier does not assume them.
Charpy details. Temperature, energy, location and orientation.
Simulated PWHT. Same-heat coupons follow the vessel cycle.
NDE. UT to A435 / A577 / A578.
Hydrogen-service extras. When the vessel specification names them.
Third-party. EN 10204 3.2.
Equivalent Material Grade
| Designation | Standard | Notes |
|---|---|---|
| ASME SA542 Type B Class 4 / ASME SA542 TYPE B CL.4 | ASME SA-542/SA-542M | Code name on this page |
| ASTM A542 Type B Class 4 | ASTM A542/A542M | Companion spec |
| SA542 Type A Class 4 | SA-542 | Same Class, looser residuals |
| SA542 Type B Class 4a | SA-542 | Higher yield, higher temper floor |
| SA387 Grade 22 | SA-387 | Related 2.25Cr-1Mo, not this QT Class |
| SA832 22V | SA-832 | N+T Cr-Mo-V |
| EN / JIS / GB 2.25Cr-1Mo QT related | EN / JIS / GB | Project comparison |
| ASME SA387 | SA-387 | Related Cr-Mo family |
DIN 17100, ASTM A516, ASME SA515 and ASTM A285 are not SA542 Type B Class 4.
Applications
| Industry | Typical components |
|---|---|
| High-temperature vessels | ASME SA542 Type B Class 4 shells and ASME SA542 TYPE B CL.4 heads |
| QT 2.25Cr-1Mo equipment | SA542 Type B Cl.4 courses |
| Dual-certified export | SA542 / A542 Type B Class 4 plate from SHH STEEL |
| Fabrication | SA542 Type B Cl.4 cut to nest sizes |
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.
Why Choose SHH STEEL
SHH STEEL is the supplier, exporter, distributor and stockist of ASME SA-542/SA-542M plate. On ASME SA542 Type B Class 4 / ASME SA542 TYPE B CL.4 that means mill pricing, dual SA542/A542 marking, Type B chemistry, recorded quench and temper at the Class 4 floor of 650 °C, tensile results at 380 MPa yield and 585–760 MPa tensile, 3.1 as standard and 3.2 when specified.
We keep Type and Class on the order. Type B is not Type A and is not Type D. Class 4 is not Class 4a. SA542 is not SA387 Grade 22. SA542 is not SA516 Gr.55. SA542 Type B Cl.4 is not SA533 Type C Class 1. If the drawing names Class 4a, we will not ship Class 4. If the drawing names N+T Cr-Mo-V, we point the inquiry to SA832.
Company scope: China steel Mill Agent-SHH STEEL.
FAQ
- What names are used for ASME SA542 Type B Class 4 / ASME SA542 TYPE B CL.4?Buyers write ASME SA542 Type B Class 4, ASME SA542 TYPE B CL.4, SA542 Type B Class 4, SA542 Type B Cl.4, SA542B CL4, SA-542 Type B Class 4 and SA 542 Type B Cl 4. SHH STEEL as supplier prints the wording on the purchase order.
- : Is ASME SA542 Type B Class 4 the same as ASTM A542 Type B Class 4?Chemistry and tensile limits match. ASME SA-542 is the Code version. ASTM A542 is the product spec. As exporter and mill distributor, SHH STEEL dual-certifies both names when the vessel must be stamped.
- What is the yield strength of SA542 Type B Cl.4?380 MPa minimum. Tensile is 585–760 MPa. Elongation is 20% in 50 mm.
- How is ASME SA542 TYPE B CL.4 different from Class 4a?Same tensile band. Class 4 yield is 380 MPa and temper floor is 650 °C. Class 4a yield is 415 MPa and temper floor is 675 °C.
- How is ASME SA542 Type B Class 4 different from Class 1, 2 and 3?Class 4 is 380 / 585–760. Class 3 is 515 / 655–795. Class 1 is 585 / 725–860. Class 2 is 690 / 795–930. Temper floors also change.
- Is SA542 Type B Class 4 the same as SA832 22V or SA387 Grade 22?No. SA832 22V is N+T Cr-Mo-V. SA387 Grade 22 is 2.25Cr-1Mo in the SA387 family. SA542 Type B Class 4 is QT 2.25Cr-1Mo at Class 4 strength.
- Who supplies ASME SA542 Type B Class 4?SHH STEEL is the supplier, exporter, distributor and stockist.
- Can welding of SA542 Type B Cl.4 be qualified to ASME Section IX?Yes. Use a WPS written for QT 2.25Cr-1Mo at Class 4 strength. The fabricator owns the procedure.
Conclusion
ASME SA542 Type B Class 4 Steel Plate, also searched as ASME SA542 TYPE B CL.4, is quenched-and-tempered 2.25Cr-1Mo plate under ASME SA-542/SA-542M, with Type B residual control, 380 MPa yield and a 650 °C temper floor. Whether the inquiry says ASME SA542 Type B Class 4, ASME SA542 TYPE B CL.4, SA542 Type B Cl.4 or SA542B CL4, SHH STEEL as supplier, exporter, distributor and stockist supplies plate with Type B chemistry, recorded QT delivery, and EN 10204 3.1 or 3.2 certification.
SHH STEEL is the China mill vendor of ASME SA542 Type B Class 4 / ASME SA542 TYPE B CL.4 QT Cr-Mo Vessel Plate for ASME Section VIII work that actually names this Type and Class.
Contact SHH STEEL for mill rolling, stock inquiry, dual SA542/A542 marking, simulated PWHT testing, 3.2 inspection or a quotation.
ASME SA542 Type B Class 4 Steel Plate, ASME SA542 TYPE B CL.4, SA542 Type B Cl.4, SA542B CL4, SA-542 Type B Class 4, QT Cr-Mo vessel plate, SHH STEEL supplier exporter distributor stockist
Quality Steel Needed? Inquire for Offers
Related Products
