AutoPIPE uses fatigue curves to evaluate fatigue damage as per ASME BPVC Section III. A fatigue curve defines the relationship between stress range and the number of allowable cycles, which is used to calculate the fatigue usage factor.

Detailed information for all fatigue curves, including their sources and ASME code references, is available in AutoPIPE at:
Help > Reference Information > Code Compliance Calculations > ASME BPVC‑III‑1‑NA (1972–2023)

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Commonly Used Fatigue Curves in AutoPIPE

1. ASME III – ADLPIPE (Default):

• • This is the default fatigue curve used in AutoPIPE.
  • Although labeled as ASME III – ADLPIPE (Default), it is internally generated, not user‑defined.
  • AutoPIPE uses fitted curves based on:
    • Carbon Steel
    • Austenitic Stainless Steel
  • The curve is limited to a maximum of 1,000,000 cycles.

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2. ASME III I‑9.1 – 80 ksi Carbon Steel:

• • Used for:
    • Carbon Steel
    • Low Alloy Steel
    • Martensitic Stainless Steel
  • Based on Table I‑9.1 of ASME Section III.
  • In the 2009 Addenda, the fatigue data range was expanded to cover 10 to 10¹¹ cycles.

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3. ASME III I‑9.2 – Austenitic Stainless Steel:

• • Used for:
    • Austenitic Stainless Steel
    • High Nickel and Nickel‑Copper alloys
  • Based on Table I‑9.2 of ASME Section III.
  • In the 2009 Addenda, older curves (A, B, C) were removed, and the fatigue range was extended from 10 to 10¹¹ cycles.

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