In reference to Mossbergs question:

The origional thread was deleted so I will start a new one.


The 30 in 4130 represents a value of 0.30 percent carbon content. 4130 works better for castings and is preferred. 4140 is used were higher levels of heat treating are needed, such as smaller high stress parts. It's also easier to weld to 4130 this is helpful when attaching brake line brackets or adding rod end spacers to the arms.

Sorry no D70 arms.

Watch out for the formation of martinsite when welding those higher carbon alloys kids.

Originally posted by Pig Penn
Watch out for the formation of martinsite when welding those higher carbon alloys kids.

Proper preheat , post-heat, watching your interpass temps and the use of a low hydrogen process will keep that damn matinsite out of the HAZ. Low hydogen, low residual stress= no brittle martinsite.:D :rasta: If your lucky and if it is on Thursday also!:D

thanks for the info Chris! each arm will be machined
out of a solid piece of 1 1/2" x 6" 4140. including the king pin, wich will be
machined sepretly, then a hole drilled in the arm were the
king pin will be inserted and tig welded with high strenth rod.
another hole drilled at the end of the rod, wich will be able to accept either chevy 1 ton or fj80 ends, because of removable 4140 tapered sleeves. pics in a coulple of days...

after asking you if you had 4140 arms on the last post i
went to your websight and saw that you do not do Dana stuff i
deleted the post. :beer:

I don't understand. Why is the 4140 on like say speedymetals.com dirt cheap compared to the 4130 on Mcmaster, chassisshop, aircraftspruce? On speedy it says its hot rolled and their claiming 140,000 tensile and 90,000yield as rolled(hot rolled) which is way higher then then 4140 claims for cold roll on aircraft spruce. Why don't they make 4340/4150 in a sheet? Yep, i'm a newb