What Type Of Steel Are Maico Frames

[Ji Gantor]

GMC I still feel you were right.
I think you said that it may be CrMo but not the same strength as 4130 which is correct.

Ji

[Ji Gantor]

High carbon steel means high strength for sure.
High carbon steel can also be tempered.
What tempering are we interested in.
The heat from welding may be.

So if our tube metal has low carbon content does that mean we should perform pre and post welding heat treatments.

Ji

[vmx42]

So why is carbon added to steel?
What benifits does having more or less carbon bring?Ji

…and why was chromium added, and why was molybdenum added and why was manganese added and why…

Alloy composition (by weight)
SAE grade    % Cr    % Mo    % C *    % Mn    % P (max)    % S (max)    % Si
4118   0.40–0.60   0.08–0.15   0.18–0.23   0.70–0.90   0.035   0.040   0.15–0.35
4120   0.40–0.60   0.13–0.20   0.18–0.23   0.90–1.20   0.035   0.040   0.15–0.35
4121   0.45–0.65   0.20–0.30   0.18–0.23   0.75–1.00   0.035   0.040   0.15–0.35
4130   0.80–1.10   0.15–0.25   0.28–0.33   0.40–0.60   0.035   0.040   0.15–0.35
4135   0.80–1.10   0.15–0.25   0.33–0.38   0.70–0.90   0.035   0.040   0.15–0.35
4137   0.80–1.10   0.15–0.25   0.35–0.40   0.70–0.90   0.035   0.040   0.15–0.35
4140   0.80–1.10   0.15–0.25   0.38–0.43   0.75–1.00   0.035   0.040   0.15–0.35
4142   0.80–1.10   0.15–0.25   0.40–0.45   0.75–1.00   0.035   0.040   0.15–0.35
4145   0.80–1.10   0.15–0.25   0.43–0.48   0.75–1.00   0.035   0.040   0.15–0.35
4147   0.80–1.10   0.15–0.25   0.45–0.50   0.75–1.00   0.035   0.040   0.15–0.35
4150   0.80–1.10   0.15–0.25   0.48–0.53   0.75–1.00   0.035   0.040   0.15–0.35
4161   0.70–0.90   0.25–0.35   0.56–0.64   0.75–1.00   0.035   0.040   0.15–0.35

* The carbon composition of the alloy is denoted by the last two digits of the SAE specification number, in hundredths of a percent


[/quote]

…I think Maico was pretty smart in their tube metal selection.Ji

Now I will preface this by saying that I am really not trying to be rude here [a bit frustrated, but not rude] - But if you don't understand the basic composition of steel alloys and how they affect the final material properties then how on earth can you make this judgement?

Were they [Maico] 'smart' or did they just use what was available locally in the right price range… none of this makes a single jot of difference as it is all supposition. The premise that manufacturers in the 70's spend copious time trawling the world looking for superior materials is just nonsense. Most were struggling to keep their heads above water with the coming Japanese onslaught.

I agree it is always good to expand your knowledge but this thread tries to fill in pieces of a jigsaw that is constantly redefined at will. It is bogged down with small pieces of information that alone make no real contribution to the answering of the original question.

If we are going to stress out [and make unsubstantiated claims] about a variation of 2% in the carbon content of our frames and how/why it varied then we need to get out more. Take a look at the above chart and you can see that the standard spec for 4130 allows for a 5% variation in carbon content - so the 2 or 3% variation found in the samples means absolutely nothing. Not significant - normal production variations - end of story. Not enough evidence to make these extrapolations.

So to summarise - if your frame breaks, send it to GMC [or the like] who will fix it using good old fashioned Aussie commonsense and hard earned practical experience. Listen to his advice [if he chooses to give it] and go and ride the thing.

If you want to fix it yourself then use the previously recommended welding rods and processes and see what happens. If it works then all is good, if not then try again. It is what GMC has done for years - it is why he is so good at what he does.

Round and round and round we go… where this stops nobody knows.

Ah, that feels better… [and far cheaper than therapy]
VMX42

[vmx42]

High carbon steel means high strength for sure.
High carbon steel can also be tempered.
What tempering are we interested in.
The heat from welding may be.

So if our tube metal has low carbon content does that mean we should perform pre and post welding heat treatments.

Ji

So now we want to temper our frames - give me strength. One day we are heat treating to normalise the material post-welding and the next we are tempering…

This is getting ridiculous. Next we will be discussing benefits of tempering in oil vs. tempering in water. Or does the moon influence welding flow, should I stand on one foot.

Do aquarians make better frames…


UGGGGGGGGGGGGGGGG!!!!!!!!!!!!!

[firko]

Were they [Maico] 'smart' or did they just use what was available locally in the right price range… none of this makes a single jot of difference as it is all supposition. The premise that manufacturers in the 70's spend copious time trawling the world looking for superior materials is just nonsense. Most were struggling to keep their heads above water with the coming Japanese onslaught.

So true. Maico was a small, boutique manufacturer with little scope for designer steel. I think you'll find that they used common old over the counter chro-mo that happens to contain the 'recipe' from the particular manufacturer they bought from. You can bet your goolies that if another manufacturer offered their chro-mo at a cheaper price, Maico (or any other small manufacturer) would most probably have used it and you would have got a slightly different result of your test material . If they had varied their source you'd notice small variations in carbon, moly or whatever content.
It's all the same stuff at the end of the day.

[vmx42]

Hey Walter,
What gets me frustrated is that this thread is such as disjointed way of finding a path through some relatively simple information.

I don't mind disjointed threads heaven knows they are some of the most entertaining, but when pronouncements and extrapolations are made using small and usually incomplete bits of information it drives me nuts. This thread is like a bad meeting at the bike club where the arguments go round and around until everybody forgets the original question.

For example: [and again I am not trying to pick on Ji I have always enjoyed his threads] back in reply #120 the question is asked 'why is carbon added to steel'. Now that is a good question, but based on a one line response from GMC, Ji is now telling us that:

'High carbon steel means high strength for sure'

So a few minutes ago, he doesn't know what effect introducing carbon into steel has and the next he is telling us that it 'means high strength for sure'. What the hell does that mean? So if 0.18% carbon is good, then 0.56% must always be better? Sorry but that is naive in the extreme.

Thats what drives me nuts!

Let's go one step at a time and not leap about like mad men and then maybe we can all learn something valuable.

And lastly when I said I was frustrated, I was being 'tongue in cheek'. I had a smile on my face the entire time I was responding but it really isn't a very effective way to learn something.

VMX42

Whoops, sorry I forgot my smiley faces:           Thats better!!

[EML]

NO ONE CARES ANYMORE-GIVE IT UP

[vmx42]

NO ONE CARES ANYMORE-GIVE IT UP

Sound advice EML. And probably the most logical thing to do.

But I have always maintained that LOGIC has no place in VMX [or my shed] and I am not going to change my mind now [even if I could].

Sorry,
VMX42   

[maico girl]

i thenk silicone crap. many woman pump stuff into titties but still cannot get seductive maico girl 'quadruple D cup' figure...

[AjayVMX]

Gee,  I just found this thread.  It sure seems long. 

So, what type of steel IS used in Maico frames? 

[GMC]

the standard spec for 4130 allows for a 5% variation in carbon content - so the 2 or 3% variation found in the samples means absolutely nothing.

Actually it’s more like 0.05 %  and it does mean a lot

The actual variation in the Carbon content of the Maico frame test to 4130 is around 0.04 to 0.08 %
2% is a huge change when talking of percentage of carbon in steel.
Mild steels have under 0.2 % carbon and tool steels have 1.5 – 2 % so a small amount can make a big difference.

There are many different attributes of steels…
Tensile strength
Compressive strength
Ductility
Malleability
Elasticity
Creep strength
Hardness
Toughness
Fatigue strength

Several of these are traded at the expense of others ( a bit like expansion chamber design ) and all must be considered.
You wouldn’t want to temper a frame as it would increase hardness at the expense of ductility.
This would only be an advantage to those that keep throwing their bikes down the road and would need a frame that would be hard wearing against bitumen




Although Maico wouldn’t have designed their own steel they probably would have chosen to use 4130. As this material was mainly used in the aircraft industry (much more commonplace these days) which is made to certified specs and therefore expensive.
You can get a Mill run of almost any steel you want if you order enough. Maico would have been building enough frames to justify a mill run and so probably ordered the spec from a local Mill. As it didn’t need to be certified it would have been cheaper for them. The lower spec Carbon was probably something the Mill did and the variation between the years would have been different Mill runs.

Not a fact, just a commonsense presumption.



Pondering the make up of steels can be interesting for techno nerds but if you think about it too much then nothing gets done.
Try not to think about how the universe works

[evo550]

Gee,  I just found this thread.  It sure seems long. 

So, what type of steel IS used in Maico frames? 

It's round, sometimes flat and can be bent
It makes a tink, tink sound when you tap it with a hammer.
It can be painted, usually silver, black or red.
But best of all, especially Maico steel, they make great boat anchors.
For more specific details see the thread "What steel is used to make steel "

[AjayVMX]

Gee,  I just found this thread.  It sure seems long. 

So, what type of steel IS used in Maico frames? 

It's round, sometimes flat and can be bent
It makes a tink, tink sound when you tap it with a hammer.
It can be painted, usually silver, black or red.
But best of all, especially Maico steel, they make great boat anchors.
For more specific details see the thread "What steel is used to make steel "

Thanks Evo.  That helps immensely. 

[Ji Gantor]

It is always good to read your words GMC.

Ji

[Ji Gantor]

Increasing carbon to a point will increase the tensile strength of steel, it will also make it more brittle.
High carbon steel can be tempered to increase its tensile strength and again this also makes it more brittle.
If we weld a normalised CrMo 4130 tube and cool it quickly this is tempering and this will increase the tensile strength and make the joint more brittle. This is what we want to avoid and that is why GMC and others oven normalise their frames after welding. Why would we want to temper our frames well of course we wouldn't, and that is why we may choose to use a lower carbon steel for our frames if we were not going to post weld heat treat. So did Maico use a designer metal, I don't know and I never said they did, the point I was trying to make was they used a low carbon CrMo so they did not have to normalise their frames after welding just by selecting a common CrMo material.

Ji