Joe Miranda
Titanium
- Joined
- Oct 19, 2004
- Location
- Elyria Ohio
Can anyone tell me if it is easier to weld gray cast iron or ductile cast iron. Thanks.
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welding cast iron
- Thread starter Joe Miranda
- Start date
- Replies 16
- Views 1,563
Forrest Addy
Diamond
- Joined
- Dec 20, 2000
- Location
- Bremerton WA USA
No cast iron is "easy" to weld.
Before you select a welding process you need to define the end use. If you're just sticking two parts of a non-essential item together, a pre-heat and stick weld with a high nickel stainless (30818) will work pretty well.
If you require stenght without machinability then the more expensive all nickel rods is the stuff to use - on preheated work.
If you require machinability and strength I suggest you acetylene braze or gas weld with cast iron rod and flux.
There's more to it than that but I note few people want to cope with the tedious requirements of producing a strong homegenous weld in cast iron. Some jobs are easier than other without a doubt.
Before you select a welding process you need to define the end use. If you're just sticking two parts of a non-essential item together, a pre-heat and stick weld with a high nickel stainless (30818) will work pretty well.
If you require stenght without machinability then the more expensive all nickel rods is the stuff to use - on preheated work.
If you require machinability and strength I suggest you acetylene braze or gas weld with cast iron rod and flux.
There's more to it than that but I note few people want to cope with the tedious requirements of producing a strong homegenous weld in cast iron. Some jobs are easier than other without a doubt.
Mike W
Stainless
- Joined
- Jan 12, 2003
- Location
- Central Kali.
This is a good read on cast iron welding:
http://www.locknstitch.com/CastIronWelding.htm
http://www.locknstitch.com/CastIronWelding.htm
precisionworks
Diamond
- Joined
- Apr 20, 2005
- Location
- Benton, IL USA
Ductile cast iron (aka nodular iron or spheroidal-graphite cast iron)is easier to weld than gray iron (partly because of lower levels of sulfur & phosphorus).
Good info from the Ductile Iron Society http://www.ductile.org/didata/Section8/8intro.htm
And from the Ductile Iron Pipe Research Assn (DIPRA) http://www.dipra.org/pdf/fieldCutBrochure.pdf
Good info from the Ductile Iron Society http://www.ductile.org/didata/Section8/8intro.htm
And from the Ductile Iron Pipe Research Assn (DIPRA) http://www.dipra.org/pdf/fieldCutBrochure.pdf
loggerhogger
Stainless
- Joined
- Aug 12, 2005
- Location
- Tacoma Washington
Somebody correct me if I'm wrong, but I was told that welding ductile iron is a bad idea because the heat of welding changes the molecular structure of the ductile iron, and causes it to become regular old grey iron. I know that parts on backhoes that are ductile have "DO NOT WELD" stamped on them.
HuFlungDung
Diamond
- Joined
- Jan 19, 2005
- Location
- Canada
Logger,
I think you are correct. Ductile is quite 'steel-like' until you start welding on it.
I think you are correct. Ductile is quite 'steel-like' until you start welding on it.
Mike Henry
Titanium
- Joined
- Aug 18, 2001
- Location
- Batavia, IL USA
I recently had a broken arbor support casting for an old printer's saw that was repaired by a local blacksmith shop. I've no clue on teh actual process but here are the before and after results:
The cost was around $30 and they retained alignment of the holes on the broken end pretty well - the threaded shafts were just slightly tight fits.
I've used the saw a few times since the repair and it seems to be working fine so far.
Any comments on the weld?
Mike
The cost was around $30 and they retained alignment of the holes on the broken end pretty well - the threaded shafts were just slightly tight fits.
I've used the saw a few times since the repair and it seems to be working fine so far.
Any comments on the weld?
Mike
HuFlungDung
Diamond
- Joined
- Jan 19, 2005
- Location
- Canada
Mike,
Only the welder knows what he did. A good weld depends on a good prep and you cannot see that nor his preheat/postheat methods. However, if they got the holes lined up, that is a good indication of expert skills
If it is rugged enough to work in service, then its a job well done.
Only the welder knows what he did. A good weld depends on a good prep and you cannot see that nor his preheat/postheat methods. However, if they got the holes lined up, that is a good indication of expert skills
If it is rugged enough to work in service, then its a job well done.
Thermo1
Stainless
- Joined
- Dec 18, 2004
- Location
- Falls Church, VA
As I understand it, ductile iron uses allloying elements to keep the carbon in solution, whereas malleable iron is cast iron that has been heat treated. Probably in both cases, welding will cause the iron to become brittle, like white cast iron, but since malleable iron is based on heat treatment, the effects may be worse than with ductile iron.
Thermo1
Thermo1
stephen thomas
Diamond
- Joined
- Jun 3, 2001
haven't compared welding them, but cant say that ductile will get *plenty* hard just silver soldering it, unless temp is kept as low as possible, and torch played off very gradually to let the iron cool very slowly. I have used ductile iron to make parts where the component had areas that might be a bearing bore for rotational or hinging, and the other end or feature needed hardened. A latch pawl for an index is one that comes to mind. Just heat the "feature" area up to dull red heat and let it cool quickly in still air.
smt
smt
Mike Henry
Titanium
- Joined
- Aug 18, 2001
- Location
- Batavia, IL USA
HuFlung,
The shop is in a small rural town that's been in the family for something like 80+ years and was recommended to me by a friend that seems to know his stuff and does nice tool refurbishing work. Asking about technique didn't seem appropriate as I wouldn't know good from bad. The gaps in the weld seemed a little odd to me, but the repaired works well enough so I wondered if it was typical of that sort of work. It seems to work well enough so the interest is entirely educational.
Mike
The shop is in a small rural town that's been in the family for something like 80+ years and was recommended to me by a friend that seems to know his stuff and does nice tool refurbishing work. Asking about technique didn't seem appropriate as I wouldn't know good from bad. The gaps in the weld seemed a little odd to me, but the repaired works well enough so I wondered if it was typical of that sort of work. It seems to work well enough so the interest is entirely educational.
Mike
Mike C.
Diamond
- Joined
- Nov 25, 2004
- Location
- Birmingham, AL
Looks like a wad of nickel rod to me. Don't drop it or it'll shatter like glass. Tyr to drill a hole in it and you'll see what I mean.
Best way to repair broken iron is to make a combination mechanical/braze repair. Plates and screws capable of mechanical strength enough to stand as a repair can be inletted and mounted in place flush with the surface. Part is then preheated and brazed, then post-heated and cooled as slowly as possible. No brittle breaks at the weld joint, no glass hard white iron. Usually stronger than the original part. The brazing fills all gaps, preventing fretting or movement as well as tying the broken parts together. Plates and screws make a far stronger joint than brazing alone. Brazed area can be filed and ground down to be invisible after paint.
Best way to repair broken iron is to make a combination mechanical/braze repair. Plates and screws capable of mechanical strength enough to stand as a repair can be inletted and mounted in place flush with the surface. Part is then preheated and brazed, then post-heated and cooled as slowly as possible. No brittle breaks at the weld joint, no glass hard white iron. Usually stronger than the original part. The brazing fills all gaps, preventing fretting or movement as well as tying the broken parts together. Plates and screws make a far stronger joint than brazing alone. Brazed area can be filed and ground down to be invisible after paint.
HuFlungDung
Diamond
- Joined
- Jan 19, 2005
- Location
- Canada
Mike Henry,
Depending on the nickel rod that was used, there can sometimes be a bit of arc flare that tends to deflect the arc slightly, and the base may not be uniformly wetted by the nickel. So this creates some slight undercut along the edge of the weld. That, combined with the possible impurities present near the surface of the cast iron itself can lead to small blowholes, etc.
The appearance at the top looks like the remnants of a properly veed joint, that was not fused completely through. This is typical on parts that are ground and fit together with a narrow zone butting for proper location. There is no need to apply so much heat so as to burn through, as this causes entirely too much metal mixing. The nickel deposit is lots strong enough, and if a preheat, hot-peening and slow cooldown was used, it should not be super brittle in the weld zone.
Depending on the nickel rod that was used, there can sometimes be a bit of arc flare that tends to deflect the arc slightly, and the base may not be uniformly wetted by the nickel. So this creates some slight undercut along the edge of the weld. That, combined with the possible impurities present near the surface of the cast iron itself can lead to small blowholes, etc.
The appearance at the top looks like the remnants of a properly veed joint, that was not fused completely through. This is typical on parts that are ground and fit together with a narrow zone butting for proper location. There is no need to apply so much heat so as to burn through, as this causes entirely too much metal mixing. The nickel deposit is lots strong enough, and if a preheat, hot-peening and slow cooldown was used, it should not be super brittle in the weld zone.
precisionworks
Diamond
- Joined
- Apr 20, 2005
- Location
- Benton, IL USA
HFD - I agree completely with your statements (which is unusual 
)
I've done more CI repairs than I can remember, mostly with Nickel 99 TIG filler. A Nickel 99 weldment is harder than mild steel - it grinds and works much like a soft stainless steel.
No coincidence that SS has a high nickel content also, anywhere from 8% to 14%. Most Ni99 weldments machine fairly easily.
)I've done more CI repairs than I can remember, mostly with Nickel 99 TIG filler. A Nickel 99 weldment is harder than mild steel - it grinds and works much like a soft stainless steel.
No coincidence that SS has a high nickel content also, anywhere from 8% to 14%. Most Ni99 weldments machine fairly easily.
P J
Aluminum
- Joined
- Aug 5, 2005
- Location
- Central coast of CA
Northof54, Peening? Yes we did a lot of hot peening in the old days (1960s), especially when using 'Eutetic Quench-Trode" (sp?) on cast iron.
Peening on steel can be quite useful when making numerous TIG low heat stringers preventing a lot of heat build-up. Slow process, after each pass, parts had to go to X-ray, so we worked on several throughout the day. Thought about "Repetitive Motion Injury", told to get back to work.
Peening on steel can be quite useful when making numerous TIG low heat stringers preventing a lot of heat build-up. Slow process, after each pass, parts had to go to X-ray, so we worked on several throughout the day. Thought about "Repetitive Motion Injury", told to get back to work.
Rick Rowlands
Titanium
- Joined
- Jan 8, 2005
- Location
- Youngstown, Ohio
Absolute best way to repair a broken iron part is to have me make you an entirely new casting out of ductile. It won't break again and it will be far stronger than the original piece.
Ductile iron retains its properties up to quite a high temperature. It is magnesium in the molten metal that causes the carbon to form little nodules instead of flakes as the metal is solidifying. So until you bring the metal's temp up to the point where you're melting the iron the carbon is going to stay in the nodular form. Now when you weld ductile the metal melts and resolidifies with graphite flakes in the heat affected zone.
Ductile iron retains its properties up to quite a high temperature. It is magnesium in the molten metal that causes the carbon to form little nodules instead of flakes as the metal is solidifying. So until you bring the metal's temp up to the point where you're melting the iron the carbon is going to stay in the nodular form. Now when you weld ductile the metal melts and resolidifies with graphite flakes in the heat affected zone.
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