ASME SA-542/SA-542M
SA542 Type B Class 2 Pressure Vessel Steel Plate Product-Performance
Technical Datasheet
Chromium-molybdenum-vanadium (Cr-Mo-V) quenched and tempered pressure vessel steel plate, with very high strength and good toughness. Suitable for the most demanding high-temperature pressure vessel service in petrochemical and power generation applications.
1. SA542 Type B Class 2 Material Identification & ASTM ASME Standards
Standards
- ASTM A542 / ASME SA542
- ASTM A20/A20M (General Requirements)
- ASME BPVC Section II Part A
Alloy Type
2.25Cr-1Mo-V
Grade Classification
- SA542 Type B Class 3 (2.25Cr-1Mo-V, high strength)
- SA542 Type B Class 4 (2.25Cr-1Mo-V, lower strength)
- SA542 Type B Class 4a (2.25Cr-1Mo-V, intermediate strength)
- SA542 Type B Class 2 (2.25Cr-1Mo-V, very high strength) ← This Spec
- SA542 Type D Class 1 (2.25Cr-1Mo-V)
- SA542 Type E (2.75Cr-1Mo-V)
2. SA542 Type B Class 2 Chemical Composition & Ladle Analysis Requirements
2.1 SA542 Type B Class 2 Chemical Composition Limits
| Element | Smelting Analysis | Finished Product Analysis |
|---|---|---|
| C | 0.11-0.15 | 0.09-0.18 |
| Mn | 0.30-0.60 | 0.25-0.66 |
| Si, ≤ | 0.50 | 0.50 |
| S, ≤ | 0.015 | 0.015 |
| P, ≤ | 0.015 | 0.015 |
| Cr | 2.00-2.50 | 1.88-2.62 |
| Mo | 0.90-1.10 | 0.85-1.15 |
| Ni, ≤ | 0.25 | 0.28 |
| V, ≤ | 0.02 | 0.03 |
| B | ... | |
| Ti | ... | |
| Cu, ≤ | 0.25 | 0.28 |
| Nb | ... | |
| Zr | ... | |
| Others | ... | |
Carbon Equivalent (CE)
CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15
Typical value: 0.65-0.85 (depending on actual composition)
Note: Cr-Mo-V steel requires controlled welding procedures due to high hardenability; low hydrogen practice is mandatory. Vanadium is restricted to <=0.02% (ladle) to control hardenability.
3. SA542 Type B Class 2 Mechanical Properties & Tensile Strength Specification
3.1 SA542 Type B Class 2 Tensile Properties
| Property | Standard Value | Test Method | Remarks |
|---|---|---|---|
| Tensile Strength Rm | 795-930 MPa | ASTM A370 | Transverse specimen |
| Yield Strength ReH | >=690 MPa | ASTM A370 | Upper yield strength |
| Elongation A (2in./50mm) | >=13% | ASTM A370 | Per A20/A20M |
| Charpy Impact KV₂ | ... | — | By agreement |
3.2 Charpy Impact Test Requirements for SA542 Type B Class 2
Standard Grade
Impact testing not required by standard
Very High Strength ServiceLow Temperature Service
- Impact testing by agreement
- Cr-Mo-V provides good toughness
- Typical test temperature: 0°C to -20°C
3.3 SA542 Type B Class 2 Hardness & Brinell Hardness Limits
- As-supplied condition (quenched + tempered): Typically ≤280 HBW
- NACE service environment: Weld & HAZ ≤250 HV10
4. SA542 Type B Class 2 Quenched + Tempered: Heat Treatment Guide
1
As-Rolled (AR)
Not applicable for SA542
High hardenability requires Q+T
→
2
Quenched + Tempered (Q+T)
Austenitizing: 900-960°C
Quench: Water or Oil
Tempering: 620-700°C
→
3
Simulated PWHT (SPWHT)
620-700°C × 2-4h
For property verification
Critical Control Points:
- SA542 must be supplied in quenched + tempered condition
- Austenitizing temperature: 900-960°C, quench in water or oil
- Tempering temperature: 620-700°C, air cool
- Tempering temperature must be carefully controlled to achieve required strength and toughness balance
5. SA542 Type B Class 2 Welding Procedure Specification (WPS/PQR)
5.1 SA542 Type B Class 2 Welding Procedure Specification WPS
SMAW (Shielded Metal Arc) SAW (Submerged Arc) GTAW (Gas Tungsten Arc) FCAW (Flux Cored)
5.2 SA542 Type B Class 2 Preheat & Interpass Temperature Chart
| Thickness Range | Min Preheat Temp | Recommended Preheat | Max Interpass Temp |
|---|---|---|---|
| <=13mm | 150°C | 150-200°C | 250-300°C |
| >13-38mm | 150°C | 150-250°C | |
| >38mm | 150°C | 200-250°C |
5.3 Recommended Welding Consumables for SA542 Type B Class 2
| Process | AWS Classification | Strength Match | Hydrogen Control |
|---|---|---|---|
| SMAW | E11018-M, E11018-M-H4 | 110 ksi | Low Hydrogen (H4) |
| GTAW | ER110S-G | 110 ksi | Shielding: Ar |
| FCAW | E110T5-K4 | 110 ksi | Self/ Gas Shielded |
| SAW | F11A4-EG, F11P4-EG | 110 ksi | Flux bake 300°C*2h |
5.4 SA542 Type B Class 2 PWHT Requirements & Post Weld Heat Treatment
Temperature Range 620-700°C
Holding Time 1h/25mm thickness (min 30min)
Heating Rate <=150°C/h
Cooling Rate <=150°C/h (to 300°C)
PWHT Notes:
- PWHT is mandatory for SA542 steel to achieve required mechanical properties
- Tempering temperature must be carefully controlled to avoid over-tempering
- Cooling rate should be controlled to prevent residual stresses
6. SA542 Type B Class 2 High Temperature Service & Creep Resistance
6.1 SA542 Type B Class 2 High Temperature Properties
High Temperature Capability
- Very high strength at elevated temperatures
- Good hydrogen resistance at elevated temperatures
- Good oxidation resistance (2.25% Cr)
- High thermal conductivity
Applications
- Ultra-high-strength hydroprocessing reactors
- Hydrocracking equipment
- High-temperature heat exchangers
- Petrochemical pressure vessels
6.2 SA542 Type B Class 2 Creep Rupture Properties
Grade SA542 Type B Class 2 provides excellent creep rupture strength at elevated temperatures:
- At 450°C: 100,000 hour creep rupture strength ~200 MPa
- At 500°C: 100,000 hour creep rupture strength ~150 MPa
- At 550°C: 100,000 hour creep rupture strength ~90 MPa
- At 580°C: 100,000 hour creep rupture strength ~60 MPa
7. SA542 Type B Class 2 Inspection & NDT Testing Methods
7.1 Non-Destructive Testing
UT ASTM A578/A578M Level C (Most Strict)
MT ASTM A275/A275M Surface Crack Detection
PT ASTM A165 Surface Open Defects
RT ASME V Article 2 Weld Internal Quality
7.2 Specimen Orientation & Location
Transverse (T)
Preferred for tensile & impact
Reflects transverse properties
Longitudinal (L)
Only when width insufficient
Higher strength, lower toughness
Thickness Position
1/4T or 1/2T
Represents worst location
7.3 Retest Procedures
- Tensile failure: Double retest from same plate; plate acceptable if both pass
- Impact failure: Additional 3 sets (9 specimens) from same plate; average must meet requirement with individual values >=70% of specified
- UT failure: Defect removal and re-inspection or rejection
8. SA542 Type B Class 2 Physical Properties & Thermal Conductivity
Density
7.80
g/cm3 (20°C)
Melting Point
~1510
°C
Thermal Conductivity
35-40
W/(m*K) (20-100°C)
Linear Expansion
11.5
*10-6/°C (20-300°C)
Specific Heat
460-500
J/(kg*K) (20°C)
Elastic Modulus
200-210
GPa (20°C)
9. SA542 Type B Class 2 Dimensions & Thickness Tolerance ASTM A20
9.1 Available Dimensions
Thickness 6-200 mm (Standard 6-100mm)
Width 1500-4350 mm
Length 3000-27000 mm
Unit Weight Max 60 MT
9.2 Thickness Tolerances (ASTM A20)
| Nominal Thickness | Class A (Unrestricted) | Class B (Restricted) |
|---|---|---|
| 6-25mm | +1.20mm, -0.30mm | +/-0.60mm |
| >25-50mm | +1.50mm, -0.30mm | +/-0.80mm |
| >50-100mm | +2.40mm, -0.30mm | +/-1.20mm |
10. SA542 Type B Class 2 Mill Test Certificate & EN 10204 3.2 Documentation
EN 10204 3.1
Manufacturer Test Certificate
Based on non-specific inspection
EN 10204 3.2
Third Party Inspection Certificate
Witnessed by customer or third party
ASME Data Report
Form CM-1
For ASME stamped equipment
Mill Test Certificate must include:
- ✓Heat number, plate number, batch traceability
- ✓Chemical composition (ladle + product analysis)
- ✓Mechanical properties (tensile, impact)
- ✓Heat treatment records (temperature-time curves)
- ✓NDT reports (UT/MT etc.)
- ✓Dimensional inspection records
11. SA542 Type B Class 2 Equivalent Grades: Cr-Mo-V Steel Comparison
| Grade | Standard | Country | Yield MPa |
Tensile MPa |
Cr Content % |
Key Differences |
|---|---|---|---|---|---|---|
| SA542 Type B Class 2 | ASME | USA | >=690 | 795-930 | 2.00-2.50 | ASME BPVC, very high strength 2.25Cr-1Mo-V steel |
| SA542 Type B Class 3 | ASME | USA | >=515 | 655-795 | 2.00-2.50 | Lower strength, same composition |
| SA542 Type C Class 2 | ASME | USA | >=690 | 795-930 | 2.75-3.25 | Similar strength, higher Cr content |
| SA542 Type E Category 2 | ASME | USA | >=690 | 795-930 | 2.75-3.25 | Similar strength and Cr content |
| SA387 Gr.22 | ASME | USA | >=310 | 515-690 | 2.00-2.50 | Similar Cr content, no V, much lower strength |
High Temperature Service Notes:
- SA542 Type B Class 2: Very high strength, yield ≥690 MPa
- SA542 Type B Class 3: High strength, yield ≥515 MPa
- SA542 Type C Class 2: Similar strength, higher Cr content
- SA542 Type E Category 2: Similar strength and Cr content
- SA387 Gr.22: Similar Cr content, no V, much lower strength
- Cr-Mo-V steel requires controlled heat treatment and welding procedures
Warning: Equivalent grades are approximate. Project-specific Gap Analysis and PQR qualification required. Yield strength and creep rupture strength are critical for high-temperature pressure vessel design.
12. SA542 Type B Class 2 Design Considerations & Fabrication Guidelines
Design Considerations
- Very high strength: SA542 Type B Class 2 suitable for the most demanding pressure vessel applications
- Hydrogen service: Good resistance to hydrogen attack at elevated temperatures
- Thickness effect: As plate thickness increases, strength and toughness decrease; allowable design stress must be interpolated per ASME II-D Table 1A
Fabrication Considerations
- Cold forming: Limited formability due to very high strength; bend radius recommended >=5t (t=plate thickness)
- Hot forming: Forming temperature 900-960°C, re-quenching and tempering required after forming
- Grinding: Defect removal depth not to exceed 7% of plate thickness, PT/MT verification required
Common Failure Mode Prevention
- Type IV cracking: Avoid prolonged PWHT in 750-850°C range
- Hydrogen-induced cold cracking: Strict low-hydrogen practice, control diffusible hydrogen <=5 mL/100g
- Creep damage: Regular inspection for creep damage in high-temperature service
- Temper embrittlement: Avoid prolonged exposure to 350-550°C range