Mag,
My first experience with manganese - Very challenging material to work with to say the least, but who doesn't like a challenge:)
What percent Manganese are you trying to weld? Is there a D15.1 spec you need to follow.
This procedure below I have found works for us after many days of trial and error for 11-14% Manganese plate. Although, we are welding manganese to A36. Currently we are using FCAW 309L wire. We have high production runs. Ok per spec.
Important: Holding at start of weld and back filling at end of weld creating a button prevented a good percent of our cracking issues.
Takes some practice...
Manganese-
Fitup on materials need to be tight as possible.
If it is excessively heated during fabrication or welding, grain growth and carbide precipitation rapidly occur leading to serious embrittlement and cracking.
In general the welding shall proceed from the center to the open edges of the plate, keeping heat to a minimum and the work should never be hotter than can be 400F before the next run is deposited in that area. Consider also that long stages at temperatures higher than 300°C (570°F) induce carbide precipitations which strongly decrease toughness and non-magnetism property.
General Recommendations: Welding is performed with low heat
Welding is performed with low heat input – interpass temperature limited to about 100°C (2 10°F) – with water-cooling between each pass if necessary. Peening by use of a needle gun or similar should be carried out immediately the arc is extinguished.
Heterogeneous welds: (Main practice):
For manual arc welding:
- weld deposit design 18Cr8Ni6Mn per AWS A5.4.E307
- weld deposit design 20Cr10Ni3Mo per AWSA5.4E308Mo
- AWS: E312-16 probably your best choice
GMAW
- solid wire – ER 309 Mo per AWS ER312 (we had no luck using 309 solid wire with many cracks)
- flux cored wire – 309L
Safety - Wear a respirator.
Good luck!!
A bit off topic, but you'll understand.
