Full Transcript:

What’s up guys?!?!?! This is Michael with Michael Talks Metal, back for more metals why? Well because it’s THURSDAY! Next up in this series on aircraft quality alloy steels is a modification of 4340 aka 300M. Like all 43xx series alloys, Chromium, Nickel, and Molybdenum are key to its performance. With the addition of Silicon and Vanadium as alloying elements it is capable of higher strength and hardness than 4340. Carbon content is determined by specification. It  can be heat treated to a hardness up to 52 Rc in sections 3-1/2 inches or less and higher hardness in thinner material. Applications for this high strength alloy also require premium CEM Quality.

Chemical Composition4340M / 300M
ElementMin %Max %
Carbon (AMS 6417).38.43
Carbon (AMS 6419).40.45

Small variations in these chemistry requirements exist in some specifications.

Response to Heat Treatment in this alloy is determined by the mechanical properties developed in a standard sample and procedure.

Typical Heat Treatment Temperatures:

Normalize   1700  deg F

Austenitize   1600  deg F

Temper         500 – 600 deg F

We have just two specs today so here goes:

SpecificationProduct FormQualityMeltCondition
AMS 6417Bars, Forgings,Tubing2300CEMSee Spec – Various
AMS 6419Bars, Forgings,Tubing2300CEMSee Spec – Various

As always, details in specifications and part requirements can alter what we have shown you here today. So for time 97!!!! Check the Specs! Twice. This is Michael with Michael Talks Metal. Michlin Metals is a supplier and distributor of 4340, check the website for more info www.michlinmetals.com. Thanks for tuning in, still here and haven’t subscribed, click here. If you missed last weeks video, click here. This is Michael with Michael Talks Metal, see you next Thursday, 10am, I’m out!