ASTM A216 Grade WCC Valves Pressure Temperature Ratings

Overview

Engineering reference data for ASTM A216 Grade WCC Valves Pressure Temperature Ratings in material science and properties.

Key Formulas

Stress

$\sigma = \frac{F}{A}$

Force per unit area.

Strain

$\varepsilon = \frac{\Delta L}{L_0}$

Change in length per original length.

Hooke's Law

$\sigma = E \varepsilon$

Stress proportional to strain in elastic region.

Thermal Expansion

$\Delta L = \alpha L_0 \Delta T$

Length change due to temperature.

Variables

References

• Original Source

Material Properties

ASTM A216 Grade WCC is a cast carbon steel grade widely used for valve bodies in pressure-containing applications. The material specifications include:

• Minimum Yield Strength: 275 MPa (40 ksi)
• Minimum Tensile Strength: 485 MPa (70 ksi)
• Temperature Range: -29°C to 425°C (-20°F to 800°F)
• Applicable Standard: ASME B16.34

Pressure-Temperature Rating Formula

The maximum allowable working pressure for valves per ASME B16.34 is calculated using:

$P = \frac{2 \times S \times E \times t}{D - 1.2t}$

Where:

• $P$ = Maximum allowable working pressure (MPa)
• $S$ = Allowable stress at design temperature (MPa)
• $E$ = Joint efficiency factor (typically 1.0 for castings)
• $t$ = Minimum wall thickness (mm)
• $D$ = Outside diameter (mm)

Pressure-Temperature Ratings Table

Key Design Considerations

Pressure Class Selection: Choose the appropriate pressure class based on the maximum operating temperature and pressure conditions. Always verify that the selected rating exceeds the maximum system pressure at operating temperature.

Derating Factors: Allowable stress values decrease as temperature increases due to reduced material strength at elevated temperatures. This is reflected in the progressively lower pressure ratings at higher temperatures.

Application Notes:

• Grade WCC is suitable for moderate temperature service
• Impact testing may be required for services below -29°C
• NACE MR0175 compliance should be verified for sour service applications
• Hydrostatic test pressure is typically 1.5× the rated working pressure at 38°C