Temper Embrittlement (475°C Embrittlement & Reversible Embrittlement)
Engineering definition, metallurgical mechanisms, standard testing specifications, and manufacturing guidelines for closed-die forgings up to 50 kg.
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A loss of Charpy impact toughness occurring in low-alloy steels (Cr-Mo) and duplex stainless steels after prolonged exposure to the 350°C–575°C temperature range.
Technical Explanation & Metallurgical Principles
Temper embrittlement is driven by the segregation of impurity tramp elements (Phosphorus, Antimony, Tin, Arsenic) to prior austenite grain boundaries during slow cooling or prolonged service between 375°C and 575°C. In duplex stainless steels, '475°C embrittlement' occurs via spinodal decomposition of ferrite into chromium-rich alpha-prime phase, drastically embrittling the alloy.
Key Engineering Specifications & Parameters
| Technical Parameter / Metric | Engineering Benchmark / Value |
|---|---|
| Critical Window | 375°C to 575°C (peaking at 475°C) |
| Tramp Element Cap | J-Factor = (Si + Mn) * (P + Sn) * 10⁴ ≤ 100 |
| Detection Method | Shift in DBTT transition temperature in Charpy impact test |
Application at Jayesh Forge (Rajkot Plant)
Jayesh Forge procures ultra-clean vacuum-degassed billets with low J-factor (P + Sn ≤ 0.012%) for high-pressure Cr-Mo boiler forgings up to 50 kg.
Related Materials, Standards & Products
Applicable Material Grades
Related Metallurgical & Testing Terms
Quenching and Tempering (Q&T / Hardening)
A two-stage thermal strengthening process: rapid liquid cooling from austenitizing temperature to form martensite, followed by reheating to restore toughness.
Charpy V-Notch Impact Test (CVN)
A standardized dynamic test that measures the kinetic energy absorbed by a notched 10x10mm specimen when fractured by a swinging pendulum hammer at specified temperatures.
Ductile-to-Brittle Transition Temperature (DBTT)
The critical temperature threshold below which a body-centered cubic (BCC) metal loses its plastic ductility and fractures in a sudden, brittle cleavage manner.
Questions Regarding Temper Embrittlement (475°C Embrittlement & Reversible Embrittlement)
By enforcing stringent limits on tramp elements (Phosphorus, Tin, Antimony, Arsenic) and rapid cooling through the 575°C–375°C range after post-weld heat treatment.
Request a Forging Quote with Temper Embrittlement (475°C Embrittlement & Reversible Embrittlement) Compliance
Our Rajkot metallurgy desk is ready to review your technical drawings, testing protocols, and delivery schedules for custom closed-die forgings strictly up to 50 kg.