Stress Relieving Heat Treatment
Engineering definition, metallurgical mechanisms, standard testing specifications, and manufacturing guidelines for closed-die forgings up to 50 kg.
Quick AnswerFeatured
Sub-critical heating of a metal component to 550°C–650°C followed by slow cooling to relieve internal residual stresses from forging, welding, or heavy machining.
Technical Explanation & Metallurgical Principles
Unlike full annealing or normalizing, stress relieving is performed below the lower critical transformation temperature (Ac1). It does not alter the fundamental microstructure or reduce tensile strength, but allows residual elastic stresses to relax via microscopic creep, ensuring permanent dimensional stability during subsequent precision CNC finish turning.
Key Engineering Specifications & Parameters
| Technical Parameter / Metric | Engineering Benchmark / Value |
|---|---|
| Temperature | 550°C – 650°C for carbon/alloy steels |
| Holding Time | 1 hour per 25mm of section thickness |
| Cooling Mode | Slow furnace cooling down to 400°C to prevent re-stressing |
Application at Jayesh Forge (Rajkot Plant)
Executed on heavy forged rings, couplings, and complex valve bodies up to 50 kg prior to final CNC finish-boring.
Related Materials, Standards & Products
Engineered Product Lines
Related Metallurgical & Testing Terms
Annealing (Full Annealing)
A heat treatment process involving heating metal above its upper critical transformation temperature, soaking, and slowly furnace-cooling to produce maximum softness and ductility.
Normalizing Heat Treatment
A heat treatment process where steel is heated 40°C to 60°C above its upper critical transformation temperature (Ac3), soaked, and cooled in still air.
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.
Questions Regarding Stress Relieving Heat Treatment
Only if the stress relief temperature exceeds the original tempering temperature; it must always be kept 30°C below the tempering temperature.
Request a Forging Quote with Stress Relieving Heat Treatment 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.