What Type Of Steel Are Maico Frames

[Ji Gantor]

I actually thought this was pretty standard stuff, but okay lets not let the cat out of the bag.

When I TIG weld CrMo bike frames this is what I use,

Tungsten      Lanthanated 1.6mm
Gas flow        7 litres/minute
Amps            65amps
Pulse             Off

Pre heat treatment direct a heat gun at frame untill above 25 degs C
Post heat treatment including temp and time raise the HAZ tubes to 600 degs C for 30 minutes and allow to cool to room temp, if cold day or wind blowing wrap with muffler bandage.
Oven or oxy heater? heat gun then butane
Filler is ER70s-2 or ER80

Ji
 

[GMC]

Hi Ji
As I’ve said in the past, ER90 is the better rod for the strongest weld but using ER 80 is good too and even ER70 will weld fine. As the welds often end up thicker than the base material then your not really losing much strength with the ER70 rod. (ER70 is also a very common MIG wire)
Most of what you ask is common knowledge for a TIG welder and was covered in your TIG welding thread. They also vary with different circumstances so there aren’t any base settings they can be used all the time.
I don’t believe in trying to perform post weld treatment myself, I prefer to leave this to the professionals that can heat the whole frame to the correct temperature and let it cool properly, this has the added advantage of normalizing the whole frame, thus reducing any work hardened areas that may have occurred over the years.
Again there is no rule to this as it depends on what work has been done to the frame. Repairs to minor brackets and the sub frame behind the shock mounts aren’t really worth worrying about. It’s not like the steel turns to glass but it can become the weak link in the chain. Other simple work like repairing engine mounts can also be fine without any major concerns however if I have to replace any frame tubes I do so with 4130 therefore the frame needs to be normalized properly. It may last for years before a problem shows itself but any such problem becomes a reflection of my work therefore I don’t take shortcuts.
Your test results will be interesting to see if my gut feelings are right but it won’t change my work practices for the above reasons.
If anyone wants to have a go at repairing their own frame then I would encourage them to do so, don’t be scared of the so-called high tech Cro-mo, it welds fine.
What I would encourage anyone to do though is to get some tubes of similar size to practice their welds on.
Practicing on a flat piece of thick steel means nothing when trying to weld around the circumference of thin tubes.
Heat treating isn’t all that costly compared to blasting and powder coating / 2 pack, so I would encourage them to do this before fresh paint is added.
If it’s a running repair then just keep an eye on it, if it starts to crack it may be because the material has gone brittle, not because of their poor workmanship.

[firko]

If anyone wants to have a go at repairing their own frame then I would encourage them to do so, don’t be scared of the so-called high tech Cro-mo, it welds fine.

Hallelujah Geoff. Chrome-Moly isn't anything special, it's just another type of steel and if you can weld mild steel, Chro-Mo won't be a problem. Knowing the makeup of Maico frame material will be of some interest but won't change my, or your technique for welding it.

After well over 20 years of welding my Chro-Mo with 316 stainless filler rods I now find that I've been using the wrong material all along.  However, seeing that none of my or my aircraft licences mates frame repairs have ever broken again, I'll stick to my stash of staino rods until they run out in about 2020.

[GMC]

You can buy rods for welding cast iron or dissimilar materials.
The magic ingredient in these rods is Nickel.
It’s the Nickel in stainless rods that make them suitable for a lot of different applications.
While they may not be text book stuff they are a suitable alternative for a lot of things.

[GMC]

Carnt wait for the (ive got a new glue gun for xmas thread )   .i.ll put me kimmbies on for that one so i dont have to leave the room, and while were at it , weres maico girls how to make pickled onions or eggs  thread going to happen

Personally I can’t wait for The Flux Capasitor’s spelling and punctuation thread.

[firko]

I think the spelling, grammar and punctuation might point to his identity. 

[Ji Gantor]

Hi GMC,
I did not think the things I asked were any real big trade secret or requiring you to tell us your pin or leave your keys but there you go.
I agree CrMo is no big deal to weld, after all it is just steel, set the welder and have a practice until the settings are correct. I agree and have said before if your just putting a bracket back on I don't heat treat, but if replacing a tube or the HAZ reaches a CrMo tube than heat treatment is required.
From my experience as a Dummy welder and research I have discovered there are two types of HAZ.
The first is what Geoff hit on and that being a section that is only a few millimeters away from the toe of the bead. Actually there is a formula that can be calculated to find what measurement away from the bead this will occur. From my calcs on 2mm thick tube the HAZ is only 0.8mm. This HAZ talks about embrittlement, or for us Dummies the tube via the welding heat has become tempered to a very strong state and thus brittle. There is a test one can do to determine this tempering effect and that is to drill a 3mm diameter hole as close to the bead as possible. an easier test that is not so destructive is to run a file near the toe.

The second HAZ is to do with strength loss due to the welding heat.
This is classified as being within 25 to 50mm of the toe of the bead.
This affects tensile strength on members that reached a higher strength due to manufactured heat treatments like aluminium T6.

Ji

[Ji Gantor]

Hi GMC,
There is a few trains of thought about filler rod when welding CrMo.
Yes I agree that ER90 is the ticket but only if you are heat treating post weld.
ER70 is recommended if no heat treatment is to be performed post weld.

I use ER80 when heat treating post weld and ER70 when not, usually when replacing a bracket that does not get to close to a structural tube. The less strength in the weld is compensated due to a larger bead as you have said and also it is better to tear off the bracket again rather than distorting the tube.

S/S is not recommended but I know Mark uses it with a truck load of aerospace welders that have had no problems.

Ji

[firko]

you are so right firko   its me steve 

Oh well, I was wrong.   Mmmm, which Steve, that's the question.

S/S is not recommended but I know Mark uses it with a truck load of aerospace welders that have had no problems

I'm not saying that SS is the only filler rod to use. I fully acknowledge that ER90/80 is the correct, by the book rod to use. I'm merely saying that it's worked for me and most of the aerospace welders I know without any problems whatsoever.
Back in the seventies I worked for a bloke named Ace Nofsinger who built midget race car chassis'. (I was filling in operating a profile cutter for 6 weeks for a guy hurt in a race accident). Aces Mexican chassis guy was the first bloke I saw using staino filler rod on Chro-Mo and he actually taught me to TIG weld Chrome Moly. My previous experience was with brazing mild steel dragster chassis so it was extremely interesting to me.
A little while later I visited Ron Butlers chassis shop in LA. Ron, a Kiwi, had gone to America to build midget race car chassis but had graduated to building pro stock frames for some of the bigger teams (The infamous Sox and Martin Hemi powered Dodge Colt (Galant here) was on the jig during my visit). I watched Ron welding the Galant's chassis and lo and behold, he also used staino filler too. Ron was originally an Air New Zealand sheety so perhaps the aerospace industry knows somethying the 'book' doesn't. I wonder why the Qantas guys almost to a man use SS? I share a few beers with some very good Pommy welders who work for Quantas but are subcontracted to the RAAF at Richmond and this subject has been a topic amongst us since it first came up last year.

Robert, you probably think I'm being disruptive here but that's not my intention. I'm merely offering another slant into the subject. If I wanted to be disruptive, my knee would come back into the thread

[Ji Gantor]

I said S/S was used without problems Mark. I have seen it done many times and I understand the reasons why it works, it is just not recommended by any car or bike racing association. This does not make it wrong. The NHRA (National Hot Rod Ass) only recommends TIG welding CrMo farmes. I love TIG but there are other great ways to weld CrMo.

I have read a library on the matter and the only thing against S/S filler is it makes a weaker joint but not by much.
Most joints are not designed to their capacity anyway so the filler only becomes a problem due to brittleness if that is a word.
s/s does not suffer from that fate like ER90 or ER80 for that matter if no post weld heat treatments are done and that is why ER70 is a better mouse trap.
All race car roll cages and chassises are built into the car and can not be removed for heat treatment post welding. This is the reason ER70 is recommended in this case. 

I have aways enjoyed your additions to my posts when they are constructive.

Ji

[Ji Gantor]

Okay the test results are back and the findings are very interesting.
This is the first time ever that this information has been made public.
So exciting.
The info may not change anything but we all move forward happier and smarter knowing what is behind us.

First I have to thank Les Richters of Mainly Maico.
Les allowed fragments to be removed from two Maico frames for this tests to be performed.
Thank you Les you are a friend to all Maico owners around the world.

I also want to thank forum member  ".............."
Member "..........." on this forum made the most generous offer to test the fragments free of charge.

Ji

[Ji Gantor]

This is a world wide exclusive

Drum roll please

I can hardly type the results into a graph

And the results are

Hang on I have to go and pick up my wife
I will be back soon.

Ji
 

[All Things 414]

Okay the test results are back and the findings are very interesting. 

So exciting.

I also want to thank forum member  ".............."
Member "..........." on this forum made the most generous offer to test the fragments free of charge.

Ji

Good on ya' Paul. You're a good egg!

[T250K]

World wide exclusive test results        Wife     

Crikey Ji, I wish you'd get your priorities in order 

[dkupf]

So with out reading through all this thread because I don't understand anything at all about welding . Did we sort out what a Maico frame was made out of. I have a cracked frame and the bloke at work won't weld because we not to sure what sort of metal it is  Darcy