Factory frame metal -- ALS450, cromoly, etc

[ducatiz]

I am still trying to figure out what ALS450 is --  I found my owner's manual for my 600SS which states the frame is "chrome-molybdenum" .. this manual is not for the USA market, so I wonder if there is some difference in the info they put out depending on market.

[Porsche Monkey]

I am still trying to figure out what ALS450 is --  I found my owner's manual for my 600SS which states the frame is "chrome-molybdenum" .. this manual is not for the USA market, so I wonder if there is some difference in the info they put out depending on market.

Whatever it is Ducati can't seem to make a pretty weld with it.  Ive seen some ugly ones 

[ducatiz]

...which is funny because I have a welding book and it shows a closeup of a Ducati frame as an example for TIG.   

[Drjones]

FWIW

From:  http://www.motorcyclistonline.com/howto/answers/122_0907_ask_the_pro/index.html

EN 10296-1
E420M

http://books.google.com/books?id=SpcF9IrYKRoC&pg=PA230&lpg=PA230&dq=e420m+steel&source=bl&ots=CdyBMf50Li&sig=hSjoee_zOWQS_OOANdrpRmNevzM&hl=en&ei=XSaxSsWiLcac8Qb4ybDCDg&sa=X&oi=book_result&ct=result&resnum=4#v=onepage&q=e420m%20steel&f=false

[MotoCreations]

ALS = "alloy steel"

450 is a composition of carbon, chromium, molybdenum, copper, manganese and nickel.

Perk is better corrosion resistance than 4130 and easier to weld.  But you lose a few benefits of 4130 as well for that tradeoff.

Some of what I have seen on Ducati's frames are rolled / welded and equivalent to mild steel tubing. Others have the internal characteristic of the raised line per DOM tubing.

I used 4130 chromoly for all my frames.  Higher carbon content and less moly/chromium.  But more involved to TIG weld / heat normalize and most people wouldn't know the difference accept the higher cost itself. (I know the difference and thus require its use even with the additional costs involved of the tubing itself)

Ducati HAS built some high quality frames with good tubing in them -- but only for racing use mostly or some of the rare 851's.

As for the welds themselves on Ducati frames?  Hideous is a good word to describe most of them.

[Travman]

ALS = "alloy steel"
Perk is better corrosion resistance than 4130 and easier to weld.  But you lose a few benefits of 4130 as well for that tradeoff.

What are the benefits of 4130 over ALS450?  Lighter weight?  Why is a higher carbon content with less moly/chromium a good thing?

When I was a little kid in the 70's a neighbor had a BMX style bike that was supposedly chromoly.  His bike was lighter than everyone else's bikes.  That always stuck with me b/c we never really know what chromoly was.  To us it was some sort of exotic metal.

[ducatiz]

What are the benefits of 4130 over ALS450?  Lighter weight?  Why is a higher carbon content with less moly/chromium a good thing?

When I was a little kid in the 70's a neighbor had a BMW style bike that was supposedly chromoly.  His bike was lighter than everyone else's bikes.  That always stuck with me b/c we never really know what chromoly was.  To us it was some sort of exotic metal.

probably PRICE

[Norm]

Ducati frames are made from a mild steel. I've researched that # both in the US and in Europe and while some of the metal guys have heard of it thru Ducati useage, no one can actually find it as a commercial variation of steel.
Chro-mo steel is a high strength steel that is used for about a zillion applications and is today's standard for fabrication tubing for custom motorcycles, self built airplanes, race car roll cages, etc. The # commonly associated is 4130, although I've heard arguments that 4130 doesn't technically meet chro-mo specs.
If you want to know more (and really get confused), google steel alloys and different heat treatments and you will find enough info to keep you busy for a while.
Each one has different stretch characteristics, weldability, machineability, stiffness, etc.,......................................................

[Travman]

Norm,  Is 4130 lighter than the mild steel used in Ducati frames?  Or is it just stronger.  Or maybe it is stronger and therefore you can use less of it for building a frame and the frame is lighter because of less material being necessary?  Is 4130 what you used for your custom built bikes?

[Travman]

The 4130 is a code of the American Iron & Steel Institute and defines the approximate chemical composition of the steel.
Here is some information I found on the web which may be relevant:

The "41" denotes a low alloy steel containing nominally 1 percent chromium and 0.2 percent molybdenum (hence the nickname "chromoly"). The "30" denotes a carbon content of 0.30 percent. In addition, as normal constituents of plain carbon and low alloy steels, there will be around 0.2-0.5 percent silicon, 0.5-1.0 percent manganese, and well under 0.1 percent of each of a dozen or so other elements whose presence is unavoidable, in a few cases deliberate, and generally not harmful. The remaining 97-98 percent is iron (Fe).

There are many tens, perhaps hundreds, of different steels defined by that AISI 4-digit code system. The code does not specify any particular mechanical properties, only approximate chemical composition. For any particular grade (composition) (AISI number) of steel, the mechanical properties depend on what heat treatment has been applied, and what (if any) cold work has subsequently been done.

[dbran1949]

This sounds like a good topic for Kevin Cameron to cover in his TDC column in Cycle World

[ducatiz]

Ducati frames are made from a mild steel. I've researched that # both in the US and in Europe and while some of the metal guys have heard of it thru Ducati useage, no one can actually find it as a commercial variation of steel.
Chro-mo steel is a high strength steel that is used for about a zillion applications and is today's standard for fabrication tubing for custom motorcycles, self built airplanes, race car roll cages, etc. The # commonly associated is 4130, although I've heard arguments that 4130 doesn't technically meet chro-mo specs.
If you want to know more (and really get confused), google steel alloys and different heat treatments and you will find enough info to keep you busy for a while.
Each one has different stretch characteristics, weldability, machineability, stiffness, etc.,......................................................

Any thoughts?  From the 1998 600SS owner's manual.

Ducati claims it is chrome-moly

[Langanobob]

Or maybe it is stronger and therefore you can use less of it for building a frame and the frame is lighter because of less material being necessary?

Yes, that's it.  All types of alloy steels weigh about the same, for all practical purposes.  With stronger material you can use thinner wall tubing for the same strength.

The downside is that although physically stronger, it can be more susceptible to cracking from vibration or impact, especially around welds.  At one time I was close to building an experimental aircraft and the online discussions about welding 4130 tubing were kind of like our oil threads here.

[Langanobob]

Ducati claims it is chrome-moly

If anyone has a scrap frame laying around, alloy and carbon steels give off distinct spark patterns compared to low carbon steel when ground with an abrasive grinder.  That'd be one first and simple test.

Or maybe one of the members here works in a metallurgical lab - would be an interesting job.

[ducatiz]

If anyone has a scrap frame laying around, alloy and carbon steels give off distinct spark patterns compared to low carbon steel when ground with an abrasive grinder.  That'd be one first and simple test.

Or maybe one of the members here works in a metallurgical lab - would be an interesting job.

plenty of tail chops....

but my manual is from 1998, so it isn't current... and you're not cutting my little bike frame!