Additive Manufacturing with High Strength Steel
or Tensile Testing the Texas Way
For Additive Manufacturing (AM) to become a mainstream technology finished material properties must match typical nominal values. You should never assume that a metal AM part will be as strong or durable as a cast, forged, or fabricated part. We seldom see hard data on mechanical properties of AM parts which makes me skeptical. This post is another addition to our ongoing reporting of real material properties along with a little fun.
To explore the upper limits of material properties we decided to build high strength low alloy steel parts using a FANUC America Corporation robot a Lincoln Electric pulsed GMA welding system and high strength Midalloy Specialty Materials, LLC. ER140S-G welding wire.
We are learning some tricks to enhance material properties of AM built parts and we used all of them. After welded we tested the part AS-BUILT without post-weld heat treatment or stress relief. The results exceeded our expectations, but you have to watch the video to get the numbers.
Spoiler Alert: we achieved yield and tensile strengths TRIPLE that of mild steel!