Weld Repair On A High Mn Part

[tc7]

We need to repair a large pillow block on a press which may date back to 1950's era so we don't have any vendor support to identify what the material may be.
Our simple spark test indicates the following:
C = .24
Mn = 1.42
Si = .34
Ni = .091
Cr = .12
Mo = .047
W = .083
V = .065
Al = .012

These ingredients seem to match fairly well to ASTM A516 Gr70 chemistry except for the higher Mn (1.42 v. 1.3 max). I have been told that older machines used high boron levels but my tester cannot detect Boron.

Anyway, my questions are threefold-
1. is there a better guess at what this alloy might be?
2. I am inclined to weld repair with SMAW 9018 rod, minimum preheat (say 150 deg F), no interpass temp restriction ?? (please comment on this) and no PWHT. Welds will be ~3/4" groove w 1/4" fillet reinforcement. Codes do not apply to this repair.
3. not sure how the higher manganese may cause the weldment to behave - should an extended stress relief be considered?

Comments/advice pls and thankyou.

 

[metengr]

tc7;
Well, welcome back to the forum.

The Mn content is not that significant in this application because it probably is a cast steel. The cast steel is is similar to a 1025 carbon steel with some combination of tramp and other alloy elements added.

I would check the hardness of this pillow block to verify heat treatment, if any.

I would use a straight E7018 H4 filler metal for the weld repair using the SMAW process. The preheat looks right, but I would use 200 deg F. The maximum interpass temperature should be 700 deg F.

Regarding PWHT, I would elevate the preheat as I described to avoid PWHT if you are limiting the welds to 3/4". Perform wet fluorescent MT of all of the repair welds and surrounding base material when you are completed.

 

[tc7]

Thanks Met & happy New Year to you.

I should have mentioned the hardness checked out at Rockwell B83 which converts to ~80ksi tensile and that is why I favored the 9018 rod. With this in mind would you still recommend the 7018?

The part in question really does not appear to be a casting. After doing some additional research I found that the alloy could possibly be an 1100 series alloy, such as AISI 1116. IF this happened to be the case, it may have a fairly high sulfur content which I can't detect with our spark tester. Now I know sulfer is evil - can you recommend precautions to be taken for welding high sulfer steel?

Thankyou again.

 

[metengr]

tc7;
I would nip a piece off of this block and have a full chemical analysis performed in the lab, just to be sure. Also, E7018 would work fine for this repair from a strength standpoint.