150LB Plug Valve Plug Head Strength

Plug head torsional shear stress verification at normal and 2× torque per Valve Design Manual. Formula: τN = MF/Ws, Ws = β·a³, MF_MAX = [τN]·Ws

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Standard: Valve Design Manual | Formula: τN = MF/Ws, Ws = β·a³, MF_MAX = [τN]·Ws

Why This Calculator

Section Modulus

Ws = β·a³ with coefficient β from b/a ratio.

Normal Torque Check

τN = MF/Ws compared to 0.8·Sm allowable.

2× Torque Check

τN1 = 2·MF/Ws compared to stricter 0.6·Sm allowable.

Max Allowable Torque

MF_MAX computed from section modulus and allowable stress.

CF8 Material Default

Stainless steel CF8 plug with Sm=137 MPa preset.

Dual Pass Verdict

Independent PASS/FAIL for both normal and 2× torque cases.

How It Works

Input Torque

Enter driving torque MF (N·mm) from Module 2.

Set Section

Input section dimensions a, b and coefficient β.

Material Stress

Specify design stress intensity Sm (MPa).

Verify Strength

Check τN and τN1 against allowables.

Set Material

Input allowable tensile stress [σL] for body material.

Add Corrosion

Specify corrosion allowance C based on service conditions.

Verify Thickness

Compare actual body thickness SB to calculated S'B.