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)
|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 5621||Bars, Forgings, Mechanical Tubing, and Rings|
|AMS 5506||Sheet, 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