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Calculators › 150LB Butterfly Valve › Stem Torsional Strength
Butterfly Valve / Valve Design Manual

150LB Butterfly Valve Stem Strength

Torsional stress verification at stem sections II-II and III-III with keyway correction. Formula: τN2 = MD/W2, τN3 = MD/ωs3

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Standard: Valve Design Manual | Formula: τN2 = MD/W2, τN3 = MD/ωs3
150LB Butterfly Valve Stem Strength

Why This Calculator

Dual-Section Check

Torsional stress at both section II-II and III-III.

Keyway Correction

Section III-III accounts for keyway reduction in polar modulus.

Polar Modulus

W2 = π*dF^3/16 for solid section, ωs3 for keyway section.

Torque Input

Accepts total torque MD from stem torque calculator.

Auto Pass/Fail

Instant judgment: τN vs. allowable [τN].

Instant Verification

Real-time calculation with no page reload required.

How It Works

Enter Torque

Input total stem torque MD from torque calculator.

Set Stem Diameter

Input stem section diameters dF and d2.

Define Keyway

Input keyway width b2 and depth t2 for section III-III.

Verify Stress

Compare τN2 and τN3 to allowable [τN].

Who Is It For

Valve Design EngineersStress AnalystsQuality InspectorsCompliance Teams

Key Highlights

Dual SectionKeyway CorrectionTorsional StressAuto Judgment

Ready to Calculate?

Enter your design parameters and get instant verification results.

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