Full Transcript:

This week our video starts a new series about aircraft alloy steels. For our previous introduction to aircraft alloys … click here ( Videos 18 – 21)

Video 18 – Premium Quality Aircraft Steels – 4330 – 300M – 135 – 9310 – 8620 -52100

Video 19 – Aircraft Quality Metal Specifications – AQ Steel Specs – 4130 – AMS 2304 – 2301 – 2300

Video 20 – Bearing Quality Alloy Steel – 8620 – 9310 – 52100 – 4130

Video 21 – Alloy H Steels and End Quench Hardenability – 8620H – 4140H – 4340H

Aircraft Quality (aka AQ)  alloy steels differ from Commercial Quality (CQ ) in steps taken in manufacture to minimize inclusions and elements that would be harmful to highly stressed components.  Stringent testing requirements assure reliable performance and resistance to fatigue failure. All very important in aerospace applications.

For the most critical applications; Premium Aircraft Quality requirements include multiple melting steps to further reduce any inclusions or contaminants.

We will be taking a deeper dive into the individual alloys and common specs in the weeks to come, so we thought it would be useful to do a quick review of some of the abbreviations that we will be using along the way….

Here goes ….


CEM – Consumable Electrode Melted

CEVM – Consumable Electrode Vacuum Melted

ESR – Electro Slag Remelted

VAR – Vacuum Induction Melted

VIM – Vacuum Induction Melted

VD – Vacuum Degassed


2300 – AMS 2300 Premium Aircraft Quality Cleanliness

2301 – AMS 2301 Aircraft Quality Cleanliness

2304 – AMS 2304 Special Aircraft Quality Cleanliness


A – Annealed

N – Normalized

N & T – Normalized and Tempered

SR – Stress Relieved


BHN – Brinnell Hardness Number

Rb – Rockwell B scale

Rc –  Rockwell C scale


EQH – End Quench Hardenability

DI – Ideal Diameter


Rc – Hardness

MP – Mechanical Properties


YS – Yield Strength

TS – Tensile Strength

Elong – Elongation

RA – Reduction of Area

PSI – Pounds per square inch

KSI – 1 KSI = 1,000 pounds per square inch

Stay tuned for that deeper dive into the most popular alloys and specifications and above all don’t forget to CHECK THE SPECS. This is Michael with Michael Talks Metal. Thanks for watching, Michlin is a distributor of stainless steel and nickel products, check the website for more info! Made it this far and haven’t subscribed, click here. Missed last week, click here. Thanks for tuning in, see you next Thursday 10am. I’m out!