Fracture toughness — Charpy ↔ K_IC
Convert Charpy CVN to K_IC fracture toughness
Four published correlations between Charpy energy and plane-strain fracture toughness K_IC. Use when only Charpy data exist (most common), or when the Master-Curve T₀ test is impractical.
Inputs
J
Standard 10×10 mm V-notch absorbed energy
MPa
Used in Barsom-Rolfe and API 579 formulae
Charpy ↔ K_IC correlations are inherently approximate (CVN is dynamic / blunt-notch, K_IC is static / sharp-cracked). Conservative practice is to use the lowest of the methods, or run an actual K_IC test per ASTM E399 for code-of-record.
Results
Barsom-Rolfe upper shelf (1971)113MPa·√m
Barsom transition (1975)40MPa·√m
Sailors-Corten (1972)113MPa·√m
Roberts-Newton (1981)72MPa·√m
API 579-1 Annex 9F (master-curve)90MPa·√m
Median estimate: 90 MPa·√m
Use this K_IC estimate as the input to /console/fracture (LEFM critical crack) or /console/master-curve (T₀ correlation). For FFS Level 3 / RPV embrittlement, perform actual master-curve testing per ASTM E1921.
- Barsom-Rolfe upper shelf (1971): Original Barsom-Rolfe upper-shelf · validated A572 / A516 / 4140
- Barsom transition (1975): Reduced coefficient for transition region · ~35 % of upper-shelf value at same CVN
- Sailors-Corten (1972): K_IC[MPa√m] = 14.6·√CVN[J] · widely cited "rule of thumb"
- Roberts-Newton (1981): K_IC[MPa√m] = 9.35·√CVN[J] · transition region · more conservative than Sailors-Corten
- API 579-1 Annex 9F (master-curve): API 579-1 Annex 9F ferritic-steel correlation · ½ way between Sailors-Corten and Roberts-Newton
Download all inputs + calculations + outputs as a single PDF.