Description

Technical Field - Heat treatment cycle to obtain 25-30 HRC hardness on EN24 rods from annealed condition.

The Derived Heat treatment cycle is:
Hardening
Temperature: 820°C
Soaking time: 30 minutes
Quenching media: Oil
Tempering
Temperature: 650°C
Soaking time: 90 minutes
Quenching media: Forced Air (approx. 6000m3/hour)

Background - A Specific nut used in an engine assembly needs to be fabricated from EN 24 material with the hardness range of 25-30 HRC, The general Heat treatment cycles of hardening at 850°C and tempering around 500-650 °C produce high hardness for the EN 24 Material in the range of 30 HRC - 50 HRC . The raw material is in the annealed condition and the aim was to convert the hardness to 25-30HRC.

Test Setup / Facilities used

1) Hardening Furnace of Class 2 (AMS)

2) Tempering Furnace of Class 2 (AMS)

3) Servo quench 707 Quenching oil (Hardening)

4) Forced Air Quenching( Tempering) - Approximate 6000m3/hour air delivery

CLAIMS

We claimed that the -

1. Conceptual design of the heat treatment cycle of EN24 Alloy rods, formulated by Aerospace Division consists of following:

(a) Quenching for hardening in oil media

(b) Quenching for tempering in forced air media

2. Design of claim 1, wherein oil media means servo quench 707 oil by Indian Oil Corporation with quench delay less than 20s.

3. Design of claim 1 wherein said forced air media means a forced air circulation of approximate air flow of 6000m3/hour.