Steel Metalurgy -- 4140

[ras]

What does 4140 mean in steel terminology? I think the xx40 is the carbon as in .40% carbon; but what does the 41xx represent? How would 4140 compare to 4130 in terms of strength, all else being equal? TIA

 

[Ed Caffrey]

Your correct on the "40" being .40% carbon. The "41" represents a series of steels designated as Chrome/Moly steels. I have a list of the number series on my site at http://www.caffreyknives.com/steelid.htm
4140 is used widely in gun barrels. It has extremely good characteristics for handling the pressures involved in a firearms application. It also makes great impact tools such as power hammer dies and the likes. Compared to 4130, only the carbon content differs. Industry considers the minimum amount of carbon to attain any hardness at .35% (Which is what most wood type srews have) Like all the steels, it has it's intended purposes.

 

[ras]

Thanks much. Very useful info on your site.