Full Transcript:

What’s up guys?!?! Michael with Michael talks metal back with a little 420 today. No, that was last week. Today, our video is about another of the stainless steels found in specifications for aerospace applications. Several variants of type 420 exist, but we will confine our video to the alloy that appears in AMS standards.

The basic type 420 alloy has the UNS designation S42000. It is a martensitic alloy that can be heat treated to higher hardness and strength levels than type 410 due mainly to its higher carbon content. 420 has a minimum carbon content of 0.15%. In the variant in the AMS standards the minimum is higher at  0.30 %

Typical applications require its increased strength and hardness but where the limited corrosion resistance of this 13% chromium alloy is adequate.  Elevated temperature applications are generally limited to a maximum of 800 deg F.

Typical annealing temperature  is from  1550 to 1650 deg F followed by slow cooling.

Typical hardening range is 1750 to 1850 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 420 stainless steel magnetic? Yes, 420 stainless steel is magnetic

420       SAE 51420    UNS S42000

Density:      point 28 lbs per cubic inch

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

5.7 microinch per inch per deg F

Machinability rating: 45 %   (of 1212)

420 Chemistry 
Carbon           0.30 – 0.40 %
Manganese     1.00 % Max
Silicon             1.00 % Max
Phosphorus     0.040 % Max
Sulfur               0.030 % Max
Chromium       12.00 – 14.00 %
Nickel               0.50 % Max
Molybdenum     0.50 % Max
Copper             0.50 % Max
Tin                     0.05 % Max

Typical maximum hardness in the annealed condition:  241 BHN

Response to heat treatment in standard sample: 50 RC Minimum

420 Specifications for annealed condition 
AMS 5621Bars, Forgings,  Mechanical Tubing, and Rings
AMS 5506Sheet, Strip and Plate
AMS-QQ-S-763 Bars, Shapes, and Forgings

ASTM and ASME 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

Don’t forget to check out our 420 info page here.