QUESTION: I have an interest in anvil repair . The anvils I will focus on are wrought iron body with a tool steel top surface. I am aware of a process using tig with a s-7 filler rod . S-7 is air hardening in this situation. Will the outcome be affected by numerous passes and what would you suggest as a heating cooling cycle.
ANSWER: I don't know if you have seen my article on making anvils from scratch, but it also applies to anvil repairs.
My choice of process was dual-shield hardfacing.
TIG has problems with hardfacing because it is a slow process.
It heats the metal slowly and it cools slowly.
Stick and dual-shield work much faster and can cover a larger area with a more consistent surface.
TIG might work for small spot repair, but it is a poor choice for build up of a anvil face.
S-7 is a great tool steel for blacksmithing tools, but it very difficult to weld without it cracking. It must preheated to above 600F and must cool very slowly.
It also has shrinkage cracking issues.
I would recommend against TIG for this and TIG is what I am best at with 33 years experience, and 16 years of that teaching.
You may get it to work, but run some experiments on scrap first before risking an anvil face.
Multi-pass welds with TIG on tool steel are even trickier and very crack prone.
If you don't have access to a big MIG machine then use your TIG machine to weld Stick.
There are many good hardfacing Stick rods that work very well with only moderate preheat and slow cooling.
Just be aware of how hard the surface will be.
I always used a build-up filler that gave a surface of around 45 on the Rockwell C scale, and a final surface filler of around 56 Rockwell C.
This combination has made my anvil surfaces last for decades.
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QUESTION: Thanks for your reply,
It's not that I really need an anvil from this process. I have a few and use them all. This question was more or less for an expieriment after seeing an article on this subject on the Blacksmiths Anvil site. A fellow named Amos Tucker gave his take on this repair process and it appeared he had good results. I guess most smiths want a pristine anvil to work with. This is because of the state of mind we are all in in this day and age. The edges cave off the old Peter wrights because they were hard. Same with most with a tool steel top. I suppose I will just forget this idea now after your response. All it really did was help me to realize that the only space on the anvil I am concerned with is the surface directly in the path of my hammer face. If you smith with this in mind, most anvils have a wide and varied surface to work with. Thanks ,I like this forum and will continue to monitor it. I do have stick ,mig and tig in my shop so your site hits all the questions I may come up with.m
As an experiment it is interesting.
A lot would depend on how much diffusion you get of the S-7 into the high-carbon steel top plate.
I would run tests on something less valuable than an anvil.
Something like a chunk of cutter bar from a bulldozer blade.
The difference between a "used" anvil and an "abused" anvil is distinct.
A used anvil has a worn area in the middle of the face and the edges are rounded.
This is caused by decades of use.
An abused anvil has the edges broken off, dents in the horn and chisel shelf, and cracks in the face.
This is caused by striking cold metal on it.
When doing large surfaces of hardface, I would spot fill small bubbles by using the dual-shield hardface wire as TIG filler. It kind of works.
I have repaired a lot of anvils with stick rod.
You can also bust the flux off of stick electrodes and use it as TIG filler.