Steel: What kind?

[Cat Whisperer]

Good reference, thanks George, I wasn't hitting those in my searches the other day.

Note the DIFFERENCES in elongation.  Very diferent.
From: http://metals.about.com/library/bldef-Elongation.htm -- Definition:  A test to measure the ductility of steel. When a material is tested for tensile strength it elongates a certain amount before fracture takes place. The two pieces are placed together and the amount of extension is measured against marks made before starting the test and is expressed as a percentage of the original gauge length.

Please read in this one ( http://www.keytometals.com/Article53.htm ) the paragraph on DUCTILITY.
Ductility
The ductility of a metal is the property that allows it to be stretched or otherwise changed in shape without breaking and to retain the changed shape after the load has been removed. The ductility of a metal can be determined from the tensile test. This is done by determining the percent of elongation. Gauge marks are made two inches apart across the point where fracture will occur. The increase in gauge length related to the original length times 100 is the percentage of elongation. This is done by making center punch marks two inches apart at the reduced section of the test coupon, testing the coupon, tightly holding the two pieces together and re-measuring the distance between the center punch marks. The original two inches is subtracted from the measured length and the difference is divided by two and multiplied by 100 to obtain percentage of elongation

[Cat Whisperer]

I am not a mechanical engineer nor a metalurgist, but I have worked as a tooling engineer.  (That says there are better educated folks on this subject than me.)  But when I see the ductitlity of 316 being much greater than of 1020, I would pick 316.  Yield strength AND ductiltiy are BOTH important.  Yield strengths of cast iron and bronze are roughly comparable - but one of them is much more ductile and one of them works much better in cannons.  Draw your own conclusions - use the best tools to make your decisions.  For me, that is to use what has worked for lots of others in lots of applications (note rules put down by AAA and N-SSA for their cannons allowed in competition).

[dan610324]

now my english isnt good enough for this discussion but I hope that you will explain for me what yield means , I dont understand when you compare cast iron with bronze .
 
cast iron expands very little before it crack as its a hard and brittle metal , while the bronze can take expansion (plastic deformation) much better .

back in the old days they said that a good quality cannon of bronze should have the same thickness of the walls surrounding the chamber as the bore diameter
but cast iron should be 1,25 to 1,5 times the bore diameter to achive the same strength

so I dont understand when you say that cast iron and bronze is the same , but thats probably because that I dont understand the word yield .

[Cat Whisperer]

You hit it spot on!

Compairng the two but just looking at strength (the numbers) they are similar - until you look at the effects of FIRING them.  Cast iron cracks - because it is brittle, not ductile.  Bronze flexes - because it is ductile not brittle.

So to compare two steels, just looking at the tensile strength numbers will not give you a fair evaluation of how it will perform in the application of being a cannon.  One MUST look at ductility.

[Cannoneer]

after swveral hot  glögg snd an small rum azd prpsi there if no iodfg topcontinu yhis anym mkore




  god natt kära vännrt nu ptttsonm sketa full    nö möre writng hrer youniht

after swveral hot  glögg snd an small rum azd prpsi there if no iodfg topcontinu yhis anym mkore
Translation:  After several hot glöggs and a small rum and Pepsi, there is no ??point?? to continue this any more.

I would concur with this assessment.   

First of all, never let it be said that GGaskill doesn't possess a dry sense of humor, and evidently also a gift for deciphering certain types of encrypted messages.

I've been working on Dan's second line for days now, and while I hate to admit defeat I am definitely at an impasse.

"god natt kära vännrt nu ptttsonm sketa full    nö möre writng hrer youniht"
Good night ?? - kära vännrt nu - Pettersson ? as in Dan  - sketa full - no more writing here tonight.

[Double D]

Funny when Dan wrote that I don't know what he said but aggreed with what he meant.  

I will have to check, but I am pretty sure I will have put sketa on the banned work list.  

[Cannoneer]

So is 316 good? Or not good?

Oreo,
I'll echo what Cat W said in that I'm neither a metallurgist nor a mechanical engineer, so I don't know if 316 is good for the purpose of making BP artillery, but I personally feel safer when I know that a cannon that I have is made from the same type of steel that the firearms industry is using to manufacture guns, and they are currently using a lot of 416 stainless.

[Cannoneer]

Funny when Dan wrote that I don't know what he said but agreed with what he meant.  

I will have to check, but I am pretty sure I will have put sketa on the banned word list.  

I honest to goodness tried not to make a post on this, but I'm weak, I couldn't pass it up.

[dan610324]

ok    I will translate it for you  

but this time I at least understand it myself , the time before I couldnt understand what I wrote

its always complications when I got to use a foreign language  
of course its because I dont use my native language , or what do you think ??  

but here it is :

after several hot glögg and an "small" rum and pepsi there is no idea to continue this any more ( I cant agree more   )
good night dear friends now is Pettersson poop drunk   no more writing here tonight

so the mystery is solved , but please dont ask me to translate the first one , I tried it back when it happened and I couldnt understand a word of it .
I guess it got to be some problem with my translation program  

BACK TO STEEL QUALITIES NOW   

[Cannoneer]

Dan, you're the man!

[Double D]

In the name of science...

Last week was a week of below zero temperatures.  George came up with an idea to test the brittle temperature of 1018 and sent up a foot long piece of 1 inch 1018.   

The bar has been left outside since it arrived last Thursday to cold soak for 2 days.   The test was was delayed shortly before smashdown in order to consultant an engineer about notching.   Temperature has not been above 14 degrees until yesterday. while waiting for a response from the engineer the outside temperature went up 45 degrees., (insert your favorite engineer joke here) The bar was pulled in and put in freezer between the frozen pot roast and the  ice cream.   This morning when I got up it was -1 degree F.  I put the rod back out side for an hour.

1/2 inch of each end of the 1 inch 1018 bar supported by 1 1/2 inch thick ingot of zinc.  A 40 lb, foot long section of rail road rail was slammed down on center of supported rod. Rail was slammed down so the length of the rail head impacted the 1018 at 90 degrees.

The 1018 Bar bent and did not break or bounce. The bend, when the bar is placed back on the supports  does not touch the ground.  Impact point of the rail on the bar has a dent-plastic deformation.