ASTM A517 / ASME SA517

ASTM SA517 Grade B Pressure Vessel Steel Plate Chemical Composition & Mechanical Properties

Chinese-made American Standard Steel Plate Technical Data

High-strength quenched and tempered alloy steel plate for fusion-welded boilers and pressure vessels. Grade B is a Cr-Mo-B grade with good hardenability and toughness, suitable for unfired pressure vessels and tanks.

1. ASTM SA517 Grade B Material Identification & Standards

Standards

  • ASTM A517 / A517M
  • ASME SA517 / SA517M
  • ASTM A20/A20M (General Requirements)
  • ASME BPVC Section II Part A

Alloy Type

Cr-Mo-B

Chromium-Molybdenum-Boron steel

Grade Classification

  • ASTM SA517 Grade B (Cr-Mo-B) ← This Spec
  • SA517 Grade A (C-Mn)
  • SA517 Grade E (Cr-Mo-B)
  • SA517 Grade F (Ni-Cr-Mo-B)
  • SA517 Grade H (Ni-Cr-Mo-B)
  • SA517 Grade P (Ni-Cr-Mo-B)
  • SA517 Grade Q (Ni-Cr-Mo-V)
  • SA517 Grade S (Mn-Mo-Ti-Cb)

Note: ASTM A517 Grade B is a Cr-Mo-B grade with no nickel addition. Maximum thickness for Grade B is 1.25 inches (32 mm) per ASTM A517 specification [citation:6][citation:12]. Grade B is suitable for unfired pressure vessels and tanks requiring high strength in relatively thin sections.

2. ASTM SA517 Grade B Chemical Composition & Ladle Analysis Requirements

2.1 ASTM SA517 Grade B Chemical Composition Limits

Table 2.1: ASTM SA517 Grade B Chemical Composition Requirements (ASTM A517/ASME SA517 Mass Percent)
Element Smelting Analysis Finished Product Analysis
C 0.15-0.21 0.13-0.23
Mn 0.70-1.00 0.64-1.10
Si 0.15-0.35 0.13-0.37
S, ≤ 0.035 0.035
P, ≤ 0.035 0.035
Cr 0.40-0.65 0.36-0.69
Mo 0.15-0.25 0.12-0.28
B 0.0005-0.005
V 0.03-0.08 0.02-0.09
Ti 0.01-0.03 0.01-0.04
Ni ...
Cu ...
Nb ...
Zr ...

Carbon Equivalent (CE)

CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15

Typical value: ~0.51% CEV (Grade B has moderate carbon equivalent) [citation:2]

Note: High-strength quenched and tempered steel requires controlled welding procedures; low hydrogen practice is mandatory. Preheat and interpass temperature control are critical for Grade B [citation:2].

3. ASTM SA517 Grade B Mechanical Properties & Tensile Strength Specification

3.1 ASTM SA517 Grade B Tensile Properties

Property Thickness ≤65mm Thickness 65-150mm Test Method
Tensile Strength Rm 795-930 MPa 725-930 MPa ASTM A370
Yield Strength ReH >=690 MPa >=620 MPa ASTM A370
Elongation A (2in./50mm) >=16% >=14% ASTM A370
Charpy Impact KV₂ Lateral expansion ≥0.38mm By agreement

3.2 Charpy Impact Test Requirements for ASTM SA517 Grade B

Standard Requirement

Transverse Charpy V-notch impact test required

Lateral expansion: ≥0.38 mm

Guaranteed to -40°C [-40°F] [citation:2][citation:4]

Mandatory

Test Temperature

  • By agreement between manufacturer and purchaser
  • Not higher than 0°C (32°F) per ASTM A517
  • -40°C guaranteed by some manufacturers [citation:2][citation:4]
By Agreement

3.3 ASTM SA517 Grade B Hardness & Brinell Hardness Limits

  • As-supplied condition (quenched + tempered): Typically 235-290 HBW
  • NACE service environment: Weld & HAZ hardness control required

4. ASTM SA517 Grade B Quenched + Tempered: Heat Treatment Guide

1

As-Rolled (AR)

Not applicable for SA517

High strength requires Q+T

→
2

Quenched + Tempered (Q+T)

Austenitizing: ≥900°C

Quench: Water or Oil

Tempering: ≥620°C

→
3

Simulated PWHT (SPWHT)

By agreement

For property verification

Critical Control Points:
  • SA517 must be supplied in quenched + tempered condition [citation:2]
  • Austenitizing temperature: not less than 900°C (1650°F)
  • Quench in water or oil
  • Tempering temperature: not less than 620°C (1150°F)
  • Tempering temperature must be carefully controlled to achieve required strength and toughness balance

5. ASTM SA517 Grade B Welding Procedure Specification (WPS/PQR)

5.1 ASTM SA517 Grade B Welding Procedure Specification WPS

SMAW (Shielded Metal Arc) SAW (Submerged Arc) GTAW (Gas Tungsten Arc) FCAW (Flux Cored)

5.2 ASTM SA517 Grade B Preheat & Interpass Temperature Chart

Thickness Range Min Preheat Temp Recommended Preheat Max Interpass Temp
<=32mm 100°C 100-150°C 200-250°C

5.3 Recommended Welding Consumables for ASTM SA517 Grade B

Process AWS Classification Strength Match Hydrogen Control
SMAW E11018-M, E11018M-H4R 110 ksi Low Hydrogen (H4)
GTAW ER110S-G 110 ksi Shielding: Ar
FCAW E110T1-G 110 ksi Self/ Gas Shielded
SAW F11A2-EM12K, F11P2-EM12K 110 ksi Flux bake 300°C*2h
Welding Notes:
  • A517 Grade B requires controlled welding procedures with preheat and interpass temperature control [citation:2]
  • Use only low hydrogen type electrodes; E11018 is commonly specified for matching strength
  • Control heat input to avoid HAZ softening
  • Post-weld heat treatment may degrade HAZ strength and toughness; pretesting is recommended

6. ASTM SA517 Grade B High Strength Service & Applications

6.1 ASTM SA517 Grade B Service Capability

Service Characteristics

  • High strength-to-weight ratio
  • Good toughness at low temperatures (-40°C guaranteed) [citation:2]
  • Cr-Mo-B composition provides good hardenability
  • Suitable for pressure vessel applications [citation:2]

Typical Applications

  • Unfired pressure vessels [citation:2]
  • Storage tanks [citation:2]
  • Fusion-welded boilers
  • Heavy-duty pressure equipment

6.2 ASTM SA517 Grade B Thickness Capability

Maximum thickness for Grade B: 1.25 in. [32 mm] [citation:6][citation:12]

Grade B has the most limited thickness capability among A517 grades. Other grades have higher limits: Grade S (50mm), Grade F (65mm), Grade P (100mm), Grade E/Q (150mm).

7. ASTM SA517 Grade B Inspection & NDT Testing Methods

7.1 Non-Destructive Testing

UT ASTM A435/A435M, A577/A577M, A578/A578M Per Supplementary Requirements
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)

Required for tensile & impact

Per ASTM A517 requirements [citation:2]

Test Specimen

40mm rectangular for ≤20mm

12.5mm round for >20mm

Charpy V-Notch

Transverse orientation

Lateral expansion measurement [citation:2]

8. ASTM SA517 Grade B Physical Properties

Density

7.7-8.03

g/cm3 (25°C) [citation:5]

Elastic Modulus

190-210

GPa (25°C) [citation:5]

Poisson's Ratio

0.27-0.30

[citation:5]

9. ASTM SA517 Grade B Dimensions & Thickness Tolerance

9.1 Available Dimensions

Thickness (Grade B) 4.78-31.75 mm 0.188-1.25 in. per ASTM A517 [citation:4]
Width 1800-3050 mm
Length 6100-14900 mm
Unit Weight Max 30 MT

9.2 Thickness Tolerances (ASTM A20)

Nominal Thickness Class A (Unrestricted) Class B (Restricted)
5-25mm +1.20mm, -0.30mm +/-0.60mm
>25-32mm +1.50mm, -0.30mm +/-0.80mm

10. ASTM SA517 Grade B 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. ASTM SA517 Grade B Equivalent Grades: A517 Steel Comparison

Grade Yield MPa Tensile MPa Elong % Max Thk Key Characteristics
SA517 Grade B ≥690 (65mm) 795-930 ≥16 32 mm Cr-Mo-B, no Ni, most limited thickness [citation:6]
SA517 Grade E ≥690 795-930 ≥16 150 mm Cr-Mo-B, highest thickness capability
SA517 Grade F ≥690 795-930 ≥16 65 mm Ni-Cr-Mo-B, good low-temp toughness
SA517 Grade P ≥690 795-930 ≥16 100 mm Ni-Cr-Mo-B, high Ni for low-temp toughness
SA517 Grade Q ≥690 795-930 ≥16 150 mm Ni-Cr-Mo-V, highest thickness capability
SA517 Grade S ≥690 795-930 ≥16 50 mm Mn-Mo-Ti-Cb, optimized weldability
Grade Selection Notes:
  • Grade B: Cr-Mo-B, no Ni, most limited thickness (32mm) [citation:6]
  • Grade E: Cr-Mo-B, highest thickness capability (150mm)
  • Grade F: Ni-Cr-Mo-B, good low-temp toughness, 65mm max
  • Grade P: Ni-Cr-Mo-B, high Ni for excellent low-temp toughness, 100mm max
  • Grade Q: Ni-Cr-Mo-V, highest thickness capability (150mm)
  • Grade S: Mn-Mo-Ti-Cb, optimized weldability, 50mm max

Warning: Equivalent grades are approximate. Project-specific Gap Analysis and PQR qualification required. High-strength quenched and tempered steels require controlled welding procedures and qualified personnel.

12. ASTM SA517 Grade B Design Considerations & Fabrication Guidelines

Design Considerations

  • High strength: Grade B provides yield strength of 690 MPa for thickness up to 65mm
  • Thickness capability: Maximum thickness for Grade B is 32mm (1.25 in.) [citation:6][citation:12]
  • Cr-Mo-B composition: Provides good hardenability
  • Impact requirements: Transverse Charpy V-notch with lateral expansion ≥0.38mm [citation:2]

Fabrication Considerations

  • Cold forming: May require stress relief after forming depending on strain level
  • Hot forming: Forming temperature 900-960°C, re-quenching and tempering required after forming
  • Welding: Low hydrogen practice mandatory; preheat 100-150°C; interpass temperature control [citation:2]
  • Machining: High strength requires proper tooling and cutting parameters

Common Failure Mode Prevention

  • Hydrogen-induced cold cracking: Strict low-hydrogen practice, preheat, control diffusible hydrogen <=5 mL/100g
  • HAZ softening: Control heat input during welding to avoid excessive softening
  • Lamellar tearing: Consider through-thickness properties for critical joints
  • Stress corrosion cracking: Consider environment and use appropriate protective measures

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