ASME SA542 Type C Class 4a Steel Plate | SA542 Type C Cl.4a QT Cr-Mo-V Vessel Plate
What is ASME SA542 Type C Class 4a Steel?
ASME SA542 Type C Class 4a, also written ASME SA542 TYPE C CL.4A, is quenched-and-tempered chromium-molybdenum-vanadium alloy plate under ASME SA-542/SA-542M. Type C is the 3Cr-1Mo-V line. Chromium heat is 2.75–3.25%. Molybdenum heat is 0.90–1.10%. Vanadium heat is 0.20–0.30%. Class 4a shares the 585–760 MPa tensile band with Class 4, but yield is 415 MPa and elongation is 18%. Temper floor for Class 4a is 675 °C on Type A, B, C, D and E. That is the Class buyers most often mix with SA832 21V / 23V and with SA387 Gr.21 Cl.2. 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 C Class 4a, ASME SA542 TYPE C CL.4A, SA542 Type C Class 4a, SA542 Type C Cl.4a, SA542C CL4A, SA-542 Type C Class 4a and SA 542 Type C Cl 4a. ASTM A542 Type C Class 4a is the companion product spec. A purchase order that only says “SA542 Type C” 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 Type A or Type B. Those are 2.25Cr-1Mo without the Type C vanadium band. It is not Type D, which is 2.25Cr-1Mo-V. It is not Type E Class 4a, which is also 3Cr-1Mo-V but uses Type E residuals and a higher austenitizing floor. It is not SA832 21V or 23V; those are normalized-and-tempered. It is not SA517 Gr.B. It is not SA516 Gr.70. Minimum thickness in the specification is about 5 mm. Maximum thickness is limited by the ability of the heat to meet Class 4a after quench and temper.
Dual marking SA542 / A542 Type C Class 4a 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 C Class 4a | Confirmed |
| Product Specification | ASME SA-542/SA-542M | Applied |
| Companion Spec | ASTM A542 Type C Class 4a | Dual cert available |
| General Requirements | ASME SA-20 / ASTM A20 | Applied |
| Process | Quenched and tempered | Confirmed |
| Class 4a temper floor | 675 °C min | Applied |
| Alloy idea | 3Cr-1Mo-V | 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 pressure vessel steel plates and next to the ASME SA387 family, not as a substitute. It does not sit with carbon steel plates or ASTM A36 steel plate.
SA-20 still governs marking, testing location, retests and repair rules.
Chemical Composition
ASME SA542 Type C Class 4a / ASME SA542 TYPE C CL.4A uses Type C chemistry. Class only changes strength and temper floor.
Heat Analysis and Product Analysis — ASME SA542 Type C (typical Table 1 limits)
| Element | Heat Analysis (%) | Product Analysis (%) |
|---|---|---|
| Carbon (C) | 0.10 – 0.15 | 0.08 – 0.18 |
| Manganese (Mn) | 0.30 – 0.60 | 0.25 – 0.66 |
| Phosphorus (P), max | 0.025 | 0.025 |
| Sulfur (S), max | 0.025 | 0.025 |
| Silicon (Si), max | 0.10 | 0.13 |
| Chromium (Cr) | 2.75 – 3.25 | 2.63 – 3.37 |
| Molybdenum (Mo) | 0.90 – 1.10 | 0.85 – 1.15 |
| Vanadium (V) | 0.20 – 0.30 | 0.18 – 0.33 |
| Titanium, boron, copper, nickel, niobium, calcium | As Table 1 of the named edition | As Table 1 of the named edition |
Vanadium is not optional decoration. If V is missing, the plate is closer to SA387 Gr.21 Cl.2 than to SA542 Type C. Chromium at 2.00–2.50% is Type A, B or D, not Type C.
SHH STEEL reports heat analysis on every certificate, including Cr, Mo and V.
Mechanical Properties
Class 4a is the higher-yield partner of Class 4.
Tensile Requirements — ASME SA542 Type C Class 4a
| Property | Requirement |
|---|---|
| Yield strength, min | 415 MPa (60 ksi) |
| Tensile strength | 585 – 760 MPa (85 – 110 ksi) |
| Elongation in 50 mm, min | 18% |
| Density | 7.85 g/cm³ |
| Hardness | Not a default substitute for tensile |
Class 4 is 380 MPa yield, same tensile band, 20% 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 on hydroprocessing work.
Do not treat 415 MPa yield as a free swap with A516 Grade 70, SA533 Type A Cl.1 or high strength low alloy plates.
Material Comparison
| Grade | Route | Alloy / strength idea | Swap? |
|---|---|---|---|
| SA542 Type C Class 1 | QT 3Cr-1Mo-V | 585 / 725–860 | No |
| SA542 Type C Class 2 | QT 3Cr-1Mo-V | 690 / 795–930 | No |
| SA542 Type C Class 3 | QT 3Cr-1Mo-V | 515 / 655–795 | No |
| SA542 Type C Class 4 | QT 3Cr-1Mo-V | 380 / 585–760, temper 650 °C | No |
| SA542 Type C Cl.4a | QT 3Cr-1Mo-V | 415 / 585–760, temper 675 °C | This page |
| SA542 Type A / B Class 4a | QT 2.25Cr-1Mo | No Type C vanadium band | No |
| SA542 Type D Class 4a | QT 2.25Cr-1Mo-V | Lower chromium | No |
| SA542 Type E Class 4a | QT 3Cr-1Mo-V | Type E practice | No |
| SA387 Gr.21 Cl.2 | Cr-Mo family | 3Cr-1Mo, not QT Type C | No |
| SA832 21V / 23V | N+T Cr-Mo-V | Not QT Type C | No |
SA299 Gr.B, SA225 Gr.D, SA455 steel plate and SA285 Gr.C are also vessel plates. None of them is ASME SA542 TYPE C CL.4A.
QT Cr-Mo-V Vessel Service
ASME SA542 Type C Class 4a / ASME SA542 TYPE C CL.4A is selected when the vessel wants quenched-and-tempered 3Cr-1Mo-V at the Class 4a line. Typical equipment is high-temperature welded pressure vessels and components written to SA-542 Type C Class 4a. 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 or SA203 Gr.E. It is not layered QT carbon like SA724. It is not SA302 Gr.C. Stainless inquiries belong on ASME SA240 or ASTM A240.
Do not form this plate as if it were as-rolled SA285 Gr.A. Quench-and-temper properties are the product. A later PWHT cycle has to be planned and, when required, simulated on coupons.
Weldability
SA542 Type C Cl.4a is killed, fine-grain 3Cr-1Mo-V at Class 4a strength. Welding is Code welding.
Qualify procedures to ASME Section IX. Use consumables written for 3Cr-1Mo-V QT at 585–760 MPa tensile, not a Class 1 procedure copied down and not an unreviewed SA387 Gr.12 Cl.2 procedure. Vanadium belongs in the WPS review. Hydrogen control, preheat, interpass and PWHT follow the qualified procedure and the vessel specification.
The fabricator owns the WPS. SHH STEEL as supplier can share mill heat data for review.
Heat Treatment
Plates shall be austenitized, quenched in a suitable liquid medium, then tempered. For Class 4a on Type A, B, C, D and E, the minimum tempering temperature is 675 °C (1250 °F). Soak is not less than 1.2 min/mm of thickness and not less than ½ hour. Class 4 uses 650 °C. Class 1, 2 and 3 use 565 °C. Type E uses a higher austenitizing floor. Do not temper Class 4a at the Class 4 floor and stamp Class 4a.
If the vessel will see a long PWHT, test coupons shall follow a simulated cycle. This is not the SA832 N+T route and not the SA537 Cl.1 heat-treated carbon route. SHH STEEL as mill exporter prints QT, Type C, Class 4a, 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 C Class 4a / ASME SA542 TYPE C CL.4A plate.
The certificate lists ASME SA542 Type C Class 4a and, when dual certified, ASTM A542 Type C Class 4a; heat number; heat analysis including Cr, Mo and V; product analysis when ordered; tensile results to the Class 4a table; QT statement with the 675 °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 C Cl.4a QT Cr-Mo-V vessel plate:
- Thickness: commonly 8 mm – 150 mm, minimum about 5 mm, limited by the ability of the heat to meet Class 4a 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 C Class 4a / ASME SA542 TYPE C CL.4A 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 Grades
hese names are project-comparison grades. They are not automatic substitutes. Heat treatment, vanadium band, Class 4a tensile and the 675 °C temper floor still have to match the purchase order.
| Designation | Standard / region | Notes |
|---|---|---|
| ASME SA542 Type C Class 4a / ASME SA542 TYPE C CL.4A | ASME SA-542/SA-542M | Code name on this page |
| ASTM A542 Type C Class 4a | ASTM A542/A542M | Companion US product spec |
| SA542 Type C Class 4 | ASME SA-542 | Same Type, lower yield |
| SA542 Type E Class 4a | ASME SA-542 | Related 3Cr-1Mo-V, Type E practice |
| SA387 Gr.21 Cl.2 | ASME SA-387 | 3Cr-1Mo, no Type C V band / QT Class |
| ASTM A387 Grade 21 Class 2 | ASTM A387 | Same caution as SA387 Gr.21 |
| SA832 Grade 21V | ASME SA-832 | N+T 3Cr-1Mo-V, not QT |
| SA832 Grade 23V | ASME SA-832 | N+T 3Cr-1Mo-V, 1010 °C normalize |
| 13CrMoV42 / 13CrMoV4-4 related | DIN / older German | 3Cr-Mo-V family comparison |
| 12CrMo9-10 / 10CrMo9-10 | EN 10028-2 / DIN | 2.25Cr-1Mo family, not Type C |
| 13CrMo4-5 | EN 10028-2 | 1.25Cr-0.5Mo, not this grade |
| X12CrMo5 related | EN | 5Cr family, not 3Cr-1Mo-V |
| SCMV4 | JIS G4109 | 2.25Cr-1Mo vessel, not Type C |
| SCMV5 / SCMV6 related | JIS G4109 | Higher-Cr Mo vessel comparison |
| 12Cr2Mo1R | GB/T 713 | 2.25Cr-1Mo Chinese vessel plate |
| 12Cr2Mo1VR / 12Cr3MoV related | GB/T 713 / GB project specs | 2.25–3Cr Mo-V comparison |
| 15CrMoR | GB/T 713 | 1.25Cr-0.5Mo, not Type C |
| 2.25Cr-1Mo-0.25V / 3Cr-1Mo-0.25V | API / hydroprocessing practice | Process names, confirm Code stamp |
| ASME SA387 | SA-387 family | Related Cr-Mo, not this QT Class |
DIN 17100, ASTM A516, ASME SA515 and ASTM A285 are not SA542 Type C Class 4a
Applications
| Industry | Typical components |
|---|---|
| High-temperature vessels | ASME SA542 Type C Class 4a shells and ASME SA542 TYPE C CL.4A heads |
| QT 3Cr-1Mo-V equipment | SA542 Type C Cl.4a courses |
| Dual-certified export | SA542 / A542 Type C Class 4a plate from SHH STEEL |
| Fabrication | SA542 Type C Cl.4a 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.A, A516 Grade 70, SA533 Type C Cl.2, SA517 Gr.P, SA387 Gr.11 Cl.2.
Why Choose SHH STEEL
SHH STEEL is the supplier, exporter, distributor and stockist of ASME SA-542/SA-542M plate. On ASME SA542 Type C Class 4a / ASME SA542 TYPE C CL.4A that means mill pricing, dual SA542/A542 marking, Type C chemistry with Cr-Mo-V reported, recorded quench and temper at the Class 4a floor of 675 °C, tensile results at 415 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 C is not Type A, Type B, Type D or Type E. Class 4a is not Class 4. SA542 Type C is not SA387 Gr.21 Cl.2. SA542 is not SA516 Gr.55. SA542 Type C Cl.4a is not SA533 Type C Cl.1. If the drawing names Class 4, we will not ship Class 4a and call it close. 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 C Class 4a / ASME SA542 TYPE C CL.4A?Buyers write ASME SA542 Type C Class 4a, ASME SA542 TYPE C CL.4A, SA542 Type C Class 4a, SA542 Type C Cl.4a, SA542C CL4A, SA-542 Type C Class 4a and SA 542 Type C Cl 4a. SHH STEEL as supplier prints the wording on the purchase order.
- Is ASME SA542 Type C Class 4a the same as ASTM A542 Type C Class 4a?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 C Cl.4a?415 MPa minimum. Tensile is 585–760 MPa. Elongation is 18% in 50 mm.
- How is ASME SA542 TYPE C CL.4A different from Class 4?Same tensile band. Class 4a yield is 415 MPa and temper floor is 675 °C. Class 4 yield is 380 MPa and temper floor is 650 °C.
- What EN, JIS or GB grades compare with SA542 Type C Class 4a?uyers compare it with SA387 Gr.21 / A387 Gr.21, SA832 21V / 23V, GB 12Cr2Mo1VR or 12Cr3MoV related plates, JIS SCMV5/SCMV6 related vessel grades, and older DIN 13CrMoV42 names. Those are family comparisons. They do not replace QT Type C Class 4a unless the order names that dual mark.
- Is SA542 Type C Class 4a the same as SA832 21V or SA387 Grade 21?No. SA832 21V is N+T Cr-Mo-V. SA387 Grade 21 is 3Cr-1Mo in the SA387 family. SA542 Type C Class 4a is QT 3Cr-1Mo-V at Class 4a strength.
- Who supplies ASME SA542 Type C Class 4a?SHH STEEL is the supplier, exporter, distributor and stockist.
- Can welding of SA542 Type C Cl.4a be qualified to ASME Section IX?Yes. Use a WPS written for QT 3Cr-1Mo-V at Class 4a strength. The fabricator owns the procedure.
- Can SHH STEEL issue EN 10204 3.2 for ASME SA542 Type C Class 4a?Yes. EN 10204 3.1 is standard. EN 10204 3.2 is arranged when written on the order.
- What is the density of ASME SA542 TYPE C CL.4A?7.85 g/cm³.
Conclusion
ASME SA542 Type C Class 4a Steel Plate, also searched as ASME SA542 TYPE C CL.4A, is quenched-and-tempered 3Cr-1Mo-V plate under ASME SA-542/SA-542M, with 415 MPa yield and a 675 °C temper floor. Whether the inquiry says ASME SA542 Type C Class 4a, ASME SA542 TYPE C CL.4A, SA542 Type C Cl.4a or SA542C CL4A, SHH STEEL as supplier, exporter, distributor and stockist supplies plate with Type C chemistry, recorded QT delivery, and EN 10204 3.1 or 3.2 certification.
SHH STEEL is the China mill vendor of ASME SA542 Type C Class 4a / ASME SA542 TYPE C CL.4A QT Cr-Mo-V 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 C Class 4a Steel Plate, ASME SA542 TYPE C CL.4A, SA542 Type C Cl.4a, SA542C CL4A, SA-542 Type C Class 4a, QT Cr-Mo-V vessel plate, SHH STEEL supplier exporter distributor stockist
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