Full Transcript:

What’s up guys?!?!?! This is Michael with Michael Talks Metal. Back for more metal musings. Today, our video will introduce you to another  stainless steel found in specifications for aerospace applications.   Type 418, also known as Greek Ascoloy, has the UNS designation  S41800.

It is a martensitic alloy that can be heat treated to moderate hardness and strength levels. Typical applications require  strength and hardness but where the limited corrosion resistance of this 12% chromium alloy is adequate.  Elevated temperature applications are generally limited to a maximum of 1000 deg F. This alloy is capable of retaining more strength at the higher end of the temperature range than other of the 12% chromium alloys.

Typical annealing temperature  is from 1250 to 1350 deg F followed by slow cooling.

Typical hardening range is 1700 to 1900 deg F followed by an air or oil quench depending on section size. Temper as required for desired hardness

Maximum corrosion resistance is in the fully hardened condition.

Is 418 Greek Ascoloy Magnetic? Yes, 418 is magnetic

418       SAE 51418    UNS S41800

Density: point 29 lbs per cubic inch

Mean Coefficient of Thermal Expansion from 32 -212 deg F:

5.8 microinch per inch per deg F

Machinability rating: 45 %   (of 1212)

418 Greek Ascoloy Chemical Composition:  
Carbon           0.15 – 0.20 %
Manganese     0.50 % Max
Silicon             0.50 % Max
Phosphorus     0.040 % Max
Sulfur               0.030 % Max
Chromium       12.00 – 14.00 %
Nickel               1.80 – 2.20 %
Tungsten           2.50 – 3.50 %
Molybdenum     0.50 % Max
Aluminum         0.15 % Max
Copper             0.50 % Max
Tin                     0.05 % Max
Nitrogen           0.08 % Max

Typical maximum hardness in the annealed condition:  311 BHN

Response to heat treatment in standard sample: 45 RC Minimum

418 Specifications for annealed condition: 
AMS 5616 Bars, Forgings,  Mechanical Tubing, and Rings

Standards for commercial applications are too numerous to detail here.

Refer to our website for more information and videos on stainless steels.  Additional specifications and part requirements can alter what we have shown you here today. SO CHECK THE SPECS !!!!!!!!!!!  Check out the earlier videos on stainless steels….   and visit us at our website

www.michlinmetals.com. Thanks for watching, and if you made it this far and haven’t subscribed, how about it? Click here, missed last weeks’ video? Click here. See you next Thursday, 10am, this is Michael with Michael Talks Metal. I’m out!