[JaxKat]

Nice Job.

[grebstev]

WOW, well done sir, well done...

[kain101]

i am liking the rear tire... wish i could do something like that.

[Cruisingram]

I'm going to repeat the information I got from the welder, as I am not one. I know alot about metelurgy and steels, in how they react though because of my other hobby (sword collector), so it made sense to me what he said. And yes, I know he's good enough to trust my life on it.

The geometry change combined with using Stainless Steel for the welding process increased the over all strength of the arm more so than the original. It did decrease the flex a little, but there is still some flex that will absorb alot of the stresses instead of forcing a structural failure. The SS welds are also lower temp welds and have very little heat leaching effects on the carbon surrounding it. The welding was also done with heat reducing actions (short travel weld and then draw the heat away) to further ensure as little carbon as possible was leached.

Visibly I could tell that the surounding steel did not exceed 640 degrees after the weld was done (never passed color blue in the heat oxidation lines) so I'm sure he was spot on.

His final statement "What you have now is stronger than what you started with." and I trust that.



The chain adjusters were customized a bit, but I'm still looking at a possible change for the rear plates the acorn nut snugs up too. I was thinking of doing a custom set but the bandits look like a decent option too. Thanks for the tip.

Krey

Uh, I am in the last year of engineering school, specializing in manufacturing, metalurgy and welding.

Stainless steel, depending on series, is no stronger than mild steel. The only difference in choosing this material is for corrosion protection.

When you weld two pieces of stainless together using the GTAW process (tig) if you use to much heat, you get carbide precipitation, where the chromium is boiled out of the steel. This basically turns that weld and the "heat affected zone" into mild steel.

The electrode itself tells you everything you need to know- and you can get the brochure to go with it

for instance, in SMAW welding (stick welding) you have say, 7018. It basically tells you it is a low hydrogen stick (needs to be kept heated until used after the box is opened) and that it has a yield strength of 70ksi.

If the mild steel you are ASTM spec says it yields at 60ksi, then, of course, if the weld is done right- the open root weld should not yield below 70ksi- making the weld stronger than the steel.

Different brands have different numbers on tig rod

Shielding gas (most likely 100% CO2 in this case, or 75-25 CO2-Ar) is as important as the rod in the case of mild steel. the argon lets you use less heat, but co gives you better penetration.

The rod your welder used most likely has an ESTM or some such on it for numbers- I wish you could get me what rod he used, and I could look it up right here in my books and tell you everything you would ever want to know about the rod used on your swing arm LOL

Knowing how "dirty" japanese steel was from that era- it is very low quality steel-

if you do a good fitment, and throw a good weld down, that penetrates, that weld will be lots stronger than the stock steel outside the heat affected zone.

But the "stainless welding rod" is,um, not quite accurate or precise.

http://en.wikipedia.org/wiki/Austenitic_stainless_steel

In metallurgy, stainless steel is defined as a steel alloy with a minimum of 10% chromium content by mass.[1] Stainless steel does not stain, corrode, or rust as easily as ordinary steel (it stains less), but it is not stain-proof.[2] It is also called corrosion-resistant steel or CRES when the alloy type and grade are not detailed, particularly in the aviation industry. There are different grades and surface finishes of stainless steel to suit the environment to which the material will be subjected in its lifetime. Common uses of stainless steel are cutlery and watch straps.
Stainless steel differs from carbon steel by amount of chromium present. Carbon steel rusts when exposed to air and moisture. This iron oxide film is active and accelerates corrosion by forming more iron oxide. Stainless steels have sufficient amount of chromium present so that a passive film of chromium oxide forms which prevents further surface corrosion and blocks corrosion spreading in the metal's internal structure.


Stainless steel’s resistance to corrosion and staining, low maintenance, relatively low cost, and familiar luster make it an ideal base material for a host of commercial applications. There are over 150 grades of stainless steel, of which fifteen are most common.

You also have three different types of stainless steel:

Austenitic
Feritic
Martenistic.

There is a tyhpe of Austenetic is also non-magnetic- just to throw you off more and more.

It uses nickel to stabilize the iron in the steel.


So you see- the idea behind stainless steel is not strength at all- but for corrosion.


If you are talking martenistic stainless steel, you are talking a rare breed, mostly used in industrial machining and needing a special heat treatment that needs alot of resources to accomplish.

The most common additive to make steel stronger is chromium AND molybendumum- the chromium in a stainless rod, and if it is for martenistic stainless steel- MAY contain molybendunum- which will make steel stronger.


I love chrome moly the most

Wanna talk about chrome moly? I could talk about that all day!

[Kreylyn]

Stainless steel, depending on series, is no stronger than mild steel. The only difference in choosing this material is for corrosion protection.

Not completely accurate for the application. There are many descriptors for steel, and they can be confusing when used for alot of people. It's not that stainless is not stronger than mild steel per say. It's that chromium has a direct effect on the steel in how the carbon and iron bond, causing it to be more brittle than high carbon steel alone. Strenth in this situation refers to long expansions of steel and their ability to prevent breakage from occuring when forces are applied to the side (stainless will snap, mild will retain the deformation, high carbon will "spring" back if heat treated correctly). This is not nearly as much of a concern in much shorter applications. A simple comparison... Stainless knives work great, stainless swords are dangerous pieces of junk. It's the stresses applied on lengths that would be the primary concern.

Using the choosen stainless for the weld was in part so that the matieral of the weld it's self did not become brittle, and would allow flex without having to do a full heat treatment on the arm. The weld it's self is not of any significant length, and the base material would give before it would.

When you weld two pieces of stainless together using the GTAW process (tig) if you use to much heat, you get carbide precipitation, where the chromium is boiled out of the steel. This basically turns that weld and the "heat affected zone" into mild steel.

Carbibe precipitation when refereced to the effect of high heat on the carbon content, yes heat will take (or burn) it out. This is of a major concern when dealing with primarily high carbon steels because it will do just that... make it mild steel.

Chromium is affected almost the opposite at a certain temperature range (around 1100 to 1650f I believe). The heat draws chromium, and promotes the precipitation or gathering of chromium carbides at grain boundaries and the loss of chromium from the base pieces, but only in the temperature range of the heat affected zone. It does not occur in the primary weld zone because the temperature is much higher and cools very quickly.

This happens in the sensitization process. The final effect is the heat affected zone will now have parrallel lines where the amount of chromium has been reduced on either side of the weld. This means those lines are alot less corosive resistant (it will rust). Since the weld was stainless (and keeps it's chromium) and the main pieces were not stainless (no chromium to leach) it's not real relevant to this situation. I already knew the rest of the steel would rust.

Knowing how "dirty" japanese steel was from that era- it is very low quality steel-

I feel a need for clarification on this topic. True "japanese" steel was sourced from an area that was primarily iron enriched sand so it wasn't the best source based upon how much ore you got from the qty of material you had to deal with. On the other hand, the process of making steel regardless of the source, is removing the impurities from the iron ore, and keeping the right amount of carbon for the situation.

this contains iron, carbon, silicon and many various trace elements. Approx. 0.6-0.7% carbon. One modern smelter in Japan that was used during World War II provides steel of the following composition: 0.04% molybdenum, 0.05% tungsten, 0.02% titanium, 1.54% copper, 0.11% manganese, and a few other traces, a varying amount of silicon (due to the sand - amount depends on sand/ore ratio in a particular load), between 0.1% and 3% carbon and the balance being iron. The presence of silicon increases structural strength as well as improving flexibility characteristics.

Going back prior to that, and I would ANY steel source would have been considered "dirty" to todays processes, but not that much. There are many examples of extreamly high craftsmanship in the use of carbon steel for hundreds of years before the bessemer smelting process became commonly used. In referece to swords for example, the actual process of forging the steel helped to purify it. If you folded and forge welded an ingot 10 times, your looking at 2048 "layers" (of course, no real layers as it's been welded back together to form a homogenous piece of steel, but for basic explanation...). This process works very well in removing a great majority of impurities. How thick is 1.5 or even 2" divided by 2048?....

So you see- the idea behind stainless steel is not strength at all- but for corrosion.

For most applications yes, but based upon the information I discussed, our intention was not soley for it's anti corrosion properties, it's just a small perk.

I love chrome moly the most

Wanna talk about chrome moly? I could talk about that all day!

I believe we will be looking at attempting a tubular chrome moly swingarm from scratch this summer.... it's good stuff!

Krey

[robleen69]

i want that done how much to get it done for me

[Kreylyn]

i want that done how much to get it done for me

I'm exploring that right now for someone else. Keep an ear out (or eye in this case... )

Krey

[Cruisingram]

When I say "dirty"- it was almost out of spec with silicates. To much sand in the steel basically.

I tested this using mass spectrometer, did V-notch charpy, rockwell hardness, tensile strength, ductility and yield strenght- also- we did it using several heat treatments, just to be sure we had it right- from outright normalization (most call it stress relieving or heat treated) to -60f to 500f

I used samples from Z1, Katana and honda shadow and V65 Sabre frames.

Quality of metals vs todays quality from Japan didn't really start to rise until the mid-90s.

In testing, stainless was no more or less brittle than mild steel of basicallly same yield strenght etc

in other words, there was no real difference in hardness or ductility in stainless and mild steel of the same spec

It is only when you go further with more alloying compounds that you either get into high carbon steel or chrome moly steel- both of which require heat treatments and what not to maintian ductility and hardness

[Kreylyn]

When I say "dirty"- it was almost out of spec with silicates. To much sand in the steel basically.

I tested this using mass spectrometer, did V-notch charpy, rockwell hardness, tensile strength, ductility and yield strenght- also- we did it using several heat treatments, just to be sure we had it right- from outright normalization (most call it stress relieving or heat treated) to -60f to 500f

I used samples from Z1, Katana and honda shadow and V65 Sabre frames.

Quality of metals vs todays quality from Japan didn't really start to rise until the mid-90s.

I can see a decrease in silica coming from Japan's steel market now, as they have restricted ore deposits from the island it's self, and now import alot of the ore they process.

In testing, stainless was no more or less brittle than mild steel of basicallly same yield strenght etc

in other words, there was no real difference in hardness or ductility in stainless and mild steel of the same spec

It is only when you go further with more alloying compounds that you either get into high carbon steel or chrome moly steel- both of which require heat treatments and what not to maintian ductility and hardness

Hardness, ductility, and Strength are not measurements one in the same between any of them. That was the point I was trying to make.

Hardness - Some stainless can be heat treated to have a much higher Rockwell than mild steel. Many knife blades are made with this. Some stainless steel will not... it's about the amount of carbon in the stainless series that makes that different primarily, but other trace amounts can also affect it. "Stainless" refers to primarily % chromium alloyed with the steel, and carbon can vary quite a bit.

Ductility - If you tested mild and stainless with near matching carbon content, again... you would see results that says not much different.

Strength - Again, this is a measure of how well the material will resist deformation when pressure is applied to the side of a long expanse.... If you take a rod of mild vs high carbon steel and provide duplicate heat treatments, then lay them on their side between to points at the tips. Apply increasing weight, the point at which they take and keep deformation will reference steel "strength".

Brittleness is in reference to that same test, and how much it takes before the piece of steel breaks, not just deforms.

Stainless steel swords are made at least twice as thick than just high carbon steel swords because they will snap/break with light use (swinging them around, but no contact) if they do not. Even at 2X+ thickness, they will still break and are very unsafe with basic contact.

See example A...

[ame="http://www.youtube.com/watch?v=v2EQWCpnIR8"]YouTube - Shop at Home Guy Vs. Ninja Sword[/ame]


Mild steel = low carbon content
High carbon steel = higher carbon content, ussually .3 - 3.0% carbon
Pot steel = really high carbon content, ussually 3.1 + %..
Stainless = chromium content... carbon content can vary the full range, and as such vary in hardness, but still is not as strong due to chromium interfering with the carbon bond. Also, that is what greatly increases the brittleness of stainless as you increase the carbon content. Some 300 series are low carbon, 440 series are high carbon... but still both stainless.

But to be honest, we are talking about some pretty detailed stuff without actually have all the details. I can't tell you exactly the steel rod he used to weld it off hand. I'll see if I can find out...

Oh, I do need to ask... in your testing, were the frames primarily mild or high carbon steel frames?

Krey

[Cruisingram]

Dude- mild carbon steel, all the way across the board- and I don't know if most folks know this- but they didn't even use DOM tubing/pipe. They used welded tubing/pipe- Amazing that those frames didn't flex more than they did!

I also noted they had a patern on steel frames of where the welds on the welded tubing faced- for instance, in all swing arms- the welds are facing each other on the main tubes.

Even Duati's older chrome moly frames won't meet todays spec on chrome moly!

BTW- on my frames, I use chrome moly from an aircraft source , 90ksi yield strength

Costs 50 bucks for the spec sheet for the material, BTW

edted to add: that vid is funny!

[Kreylyn]

Dude- mild carbon steel, all the way across the board- and I don't know if most folks know this- but they didn't even use DOM tubing/pipe. They used welded tubing/pipe- Amazing that those frames didn't flex more than they did!

I also noted they had a patern on steel frames of where the welds on the welded tubing faced- for instance, in all swing arms- the welds are facing each other on the main tubes.

Even Duati's older chrome moly frames won't meet todays spec on chrome moly!

BTW- on my frames, I use chrome moly from an aircraft source , 90ksi yield strength

Costs 50 bucks for the spec sheet for the material, BTW

edted to add: that vid is funny!

Thats what I was thinking as well from what little testing I did with the scraps from my mods. Even the swingarm on the kat seems to be simply mild steel. I would have thought it had a higher carbon content and heat treated, but I don't think so. I'm going to try to further verify that, but if that is the case, we went way overboard with our concerns about welding it.

I'll see if I can do some quench tests and see if the scrap pieces show any difference.

Krey

[Cruisingram]

My speciality is in manfuacturing and industry- which most folks don't realize is the REAL area for innovations to make it to market. You can do all kinds of one of a kind mods to a bike- but to make a high-performance bike come to market- the real area is that has to make strides is in the manufacturing area

for instance, the triple forged welded aluminum frames we see out of japan today is very cheap- as long as you are making more than about 100k units, otherwise, under 100k units, it is cheaper to use tubular CM like with Ducati, which can make less units- niche' bikes- that are competitive in price with the japanese and thier large production bikes.

So really, we had most of the tech we see today on bikes over 40 years ago- but we didn't catch up to make it economically feasible to do until much more recently.

[Catcha23]

looks sweet and excellent write up with cool pics!

[JokerZwild]

Quote:
Originally Posted by katana_ron
What a great write up.

Awesome job!!!

Now for us mechanically dumb riders (or lazy ones, you chose) when are you going to be selling those.......

LOL... If people want them, the welder and machinist are all set on making more.

Krey
A 5.5 rim would look Kick ARSE on that!....

Krey


Ok your absolutly right now I really want one!!! How much will the fab work cost? Or at the very least ...Id like to fab up that brake arm and go with the 170.
All that grip is gonna wreak havoc on those adjusters. So im gonna add in a few pics of my corrections for this problem. perhaps It will help ya b4 things get ugly from a hard 2nd gear.


Joker

[Kreylyn]

Ok your absolutly right now I really want one!!! How much will the fab work cost? Or at the very least ...Id like to fab up that brake arm and go with the 170.

All that grip is gonna wreak havoc on those adjusters. So im gonna add in a few pics of my corrections for this problem. perhaps It will help ya b4 things get ugly from a hard 2nd gear.

Joker

I'm actually planning on picking up some bandit caps real soon. It's one of many items still on the wish list....

I'm mocking up another arm now (should be back from the welder anytime) and I'll probably do a few brake arms with this one as well. I'm doing this with the approach of getting a price for others. I traded alot of work for favors the first time around, so I didn't really spend any cash myself.

Krey

Krey