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A537 Cl.2

ASTM A537

Pressure VesselASTM Fine Grain

A537 Cl.2 is a pressure-vessel steel (Fine Grain family) to ASTM A537. It has a specified 0.2 % proof stress of 415 MPa and a typical tensile strength of about 550 MPa, with a uniform elongation of 20 %. Nominal carbon content is around 0.24 %. For nonlinear FEA, a bilinear model uses E = 210 GPa up to yield and a tangent modulus of 689 MPa above it. Fine-grain processing delivers good low-temperature toughness alongside the quoted strength.

0.2% proof Rp0.2
415MPa
UTS Rm (typ)
550MPa
Uniform elong. εu
20.0%
Condition / basis
t≤65mm, Q&T

Bilinear material model — nonlinear FEA

Elastic modulus E
210GPa
0.2% proof Rp0.2
415MPa
UTS Rm (typ)
550MPa
Tangent modulus Et
689MPa

Uniform elongation εu = 20.0% · conservative analysis limit ½εu = 10.0%

Bilinear (BISO) approximation. Elastic modulus E up to the 0.2% proof stress R_p0.2, then a single tangent slope Eₜ to the ultimate tensile strength: Eₜ = (Rₘ − R_p0.2) / (εu − R_p0.2/E − 0.002), where εu is the uniform elongation and Rₘ is a typical (nominal) UTS within the specified band. The half-εu figure is a conservative strain limit for the analysis. Treat these as guidance for first-pass models; for critical work use a measured true stress–strain curve for the actual product and condition.

Ratings — engineering judgement

Weldabilitymoderate

Medium carbon (~0.24%) — preheat and hydrogen-controlled consumables advisable, especially in thicker sections.

Machinabilitymoderate

Soft and gummy at low carbon — sharp tooling helps surface finish.

Corrosion resistancepoor

No inherent corrosion resistance — protect by paint, galvanising or plating in exposed use.

Hardenabilitylow

Limited hardenability at low carbon — surface hardening is possible but through-hardening is not.

Toughnessgood

Fine-grain / alloy processing gives good low-temperature toughness for its strength.

Indicative ratings derived from composition and family — engineering guidance, not specification values.

Physical properties

Density7850kg/m³
Elastic modulus210GPa
Shear modulus80.8GPa
Poisson's ratio0.30
Thermal expansion12.0×10⁻⁶/°C
Thermal conductivity48W/(m·K)
Specific heat470J/(kg·K)
MagneticYes

Typical values for astm fine grain steel — use the mill certificate for the specific product.

Chemical composition (wt %)

C
≤ 0.24
Mn
0.70–1.35
Si
0.15–0.50
P
≤ 0.035
S
≤ 0.035

Typical composition per ASTM A537 (normalised / Q&T C-Mn).

Available forms

plateexcellent
boiler & vessel plate
Primary form, certified to the vessel code.
forginggood
flanges, heads
For nozzles and heavy sections.

Common applications

  • Boilers and pressure vessels
  • Storage tanks and process drums
  • Heat exchanger shells
  • Piping components (to code)

History

The ASTM pressure-vessel plates (A516 carbon, A537 fine-grain) are the North-American counterparts to the EN P-grades, specified throughout the ASME Boiler & Pressure Vessel Code. Class 2 is quenched & tempered for higher strength; Class 1 is normalised.

  1. 1915
    ASME Boiler & Pressure Vessel Code first issued
  2. 1960
    ASTM A516 becomes the standard carbon vessel plate

This profile is generated from the grade's core data and family. Composition is decoded from the designation where its naming system defines it; physical properties are family-typical and ratings are indicative. Confirm critical values against the governing standard or the mill certificate. Equivalents, historical designations and hand-written expert notes are added per grade over time.