Larson-Miller Parameter Calculator
An alloy lasting 1000 h at 650 °C would rupture after about 65.8068 h at 700 °C under the same stress.
65.8067684628808 h
Full answer, then cut to fewer decimals (not rounded):
- 65.8067684628808 h
- 65.806768462880 h
- 65.80676846288 h
- 65.8067684628 h
- 65.806768462 h
- 65.80676846 h
- 65.8067684 h
- 65.806768 h
- 65.80676 h
- 65.8067 h
- 65.806 h
- 65.80 h
- 65.8 h
- Larson–Miller parameter
- 21232.45
- In years
- 0.007507046368 years
Step-by-step solution
- LMP = 923.15 × (20 + log₁₀ 1000) = 21232.45 (T in K, t in h)
- log₁₀ t₂ = LMP/T₂ − C = 1.818270565 → t₂ = 65.80676846 h
Larson-Miller Parameter Formula
LMP = T (C + log₁₀ t_r)
T in kelvin, t_r in hours, C ≈ 20 for many alloys
Worked Example
An alloy that ruptures in 1000 h at 650 °C, raised to 700 °C at the same stress:
- LMP = 923.15 × (20 + log₁₀ 1000) = 21232.45 (T in K, t in h)
- log₁₀ t₂ = LMP/T₂ − C = 1.818270565 → t₂ = 65.80676846 h
In years: 0.007507046368 years
GATE tip
A 50 °C rise typically cuts creep life by more than an order of magnitude, as here (1000 h → about 66 h). Convert °C to K before using the formula.
More Mechanical Behaviour Calculators
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Paris Law Calculator
da/dN = C (ΔK)^m, ΔK = YΔσ√(πa)
N = [a_f^(1−m/2) − a₀^(1−m/2)] / [C(YΔσ√π)^m (1 − m/2)] for m ≠ 2
Example: A crack growing from 1 mm to 10 mm under a 150 MPa stress range, C = 10⁻¹¹, m = 3, Y = 1.12: Cycles to grow the crack N_f = 163791.
-
Fracture Toughness Calculator
K_I = Y σ √(πa)
fracture when K_I ≥ K_Ic; a edge crack length or half an internal crack
Example: A 2 mm edge crack (Y = 1.12) under 300 MPa: Stress intensity K_I = 26.6336 MPa·√m.
-
True Stress-Strain Calculator
σ_T = σ_e(1 + ε_e), ε_T = ln(1 + ε_e)
Hollomon σ_T = Kε_Tⁿ; necking begins at ε_T = n
Example: A tensile test reading 400 MPa at 20 % engineering strain: True stress σ_T = 480 MPa.
Frequently asked questions
Why use the Larson–Miller parameter?
It collapses rupture data at different temperatures and times onto one master curve against stress, letting short high-temperature tests predict long service lives.
What is the stress exponent in creep?
In power-law creep ε̇ = Aσⁿe^(−Q/RT); n ≈ 3–8 for dislocation creep and about 1 for diffusional creep.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
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APA
Scientific Converters. (2026, October 15). Larson-Miller Parameter Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/larson-miller-calculator/
IEEE
Scientific Converters, "Larson-Miller Parameter Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/larson-miller-calculator/