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  #1  
Old 01-24-2009, 07:58 PM
digger2 digger2 is offline
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Default cast steel vs. flat bar stock strength

Hey guys,
Well i guess the title pretty well says it all,well almost.
Without going into alot of detail,i need to know-Is cast steel,size for size,any stronger than flat bar stock?
I guess another way of putting it would be,if i had a peice of cast steel,1/2"x1 1/2"x6" long,would it be stronger than a peice of flat bar stock
of the same dimensions?When i say "stonger",i mean as far as resisting a load as far as bending.This is assuming the steel is the same basic material.
I'm about ready to start building something and i'd like some opinions
on this before i actually start.My life does'nt depend on it bending or not bending,so its not a major big deal,i'd just like to know.I was always under the impression that the main reason things are cast was for ease of shaping the steel into whatever shape you wanted,not for strength.
thanks,Digger2
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Old 01-24-2009, 08:31 PM
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midmosandblasting midmosandblasting is offline
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The main reason things are cast is ease of fabricating that part.Some else will have to say if a cast bar is more or less stronger than a rolled or extruded bar. All steel starts out cast into either a slab or a ingot . From there it will go through a rolling mill to get the thickness needed. Rolling temps and speeds play a lot in what the final quality of the material is on LC or HSLA material..
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Old 01-24-2009, 11:52 PM
Bolt Bolt is offline
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I don't have the answer you are looking for either, but I do believe cast and mild steel both have the same expansion and contraction rates as well.
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Old 01-25-2009, 09:25 AM
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There are different types of cast steel and std. flat bar is about the same all the time. Usually the cast steel will be a little more rigid if that is what you are calling strong. Get two pcs and put them in a vice and bend them and you will see the difference.
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Old 01-25-2009, 09:35 AM
digger2 digger2 is offline
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Thats kinda what i figured,stiffer.Dont know why i thought that,but i just have it in my head,for some reason ,that cast is stiffer.I think that even cast aluminum,given the same dimensions,would be somewhat stiffer.Maybe not.For what i'm doing,i think the flat bar stock will be strong enough,and if not no big deal.I'll just have to go back to the drawing board....wont be the first time.
OK,thanks for the info....................Digger2
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Old 01-25-2009, 12:34 PM
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The modulus of elasticity (stiffness) of steel doesn't vary much, whether cast or cold rolled or alloyed. The yield strength of the cold rolled is higher.

Now when you say bending, do you mean just deflecting, or permanently bending?
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Old 01-25-2009, 12:36 PM
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I would have to know what it will be used for before I comment..
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Old 01-25-2009, 11:42 PM
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I'd want to see the tensile properties for both raw materials. the cast in compression would probably be ok... tension may be another story.

the stress strain curve may be a different shape once you get into plastic deformation. I would think it would be a much shorter curve in this area for cast vs rolled bar. (the distance on the curve from the yield point to the failure point, ie the cast fails catastrophically faster than the rolled plate)

I try to look at castings when the volume is high, and the part geometry has a lot of shape to it that would be very cost prohibitive to machine from a billet. you can add geometry to the cast shape to help overcome the tensile property shortcomings.
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  #9  
Old 01-30-2009, 03:26 PM
digger2 digger2 is offline
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OK,what i'm building is whats called a "toothbar" for my Kubota tractor.
Fits on the bottom of the front end loader bucket.You've seen the teeth on a backhoe bucket...well this is the same idea only on the bottom front edge of the front loader bucket.The idea is to have the teeth engage in the dirt or whatever you are doing before the edge of the bucket thereby putting all the force on the teeth,"cracking" the dirt making it easier for the bucket edge to enter the load.Its supposed to work pretty good.Cost from $350-$500 factory made.Being as cheap as i am,i'll make it myself.
Being that it wont be hardened steel,it wont last as long,but for as much as i use it,it'll be good enough.As they wear,i'll just run some beads on the wear area and resharpen with the grinder.Reason i asked the strength question was because-genuine factory units are what amounts to cast steel shanks attached to the bucket with hardened replacable teeth pinned onto the cast shanks.Total stickout from the bucket edge,about 4".There will be about 7 of these teeth across the bucket,made out of this 1/2" x 1 1/2" black metal bar.
I dont think the actual weight (bulk) of the material i'm going to use is any less than these factory made teeth,its just i'm using mild steel bar instead of cast steel.Yes its going to wear,but it wont cost much to build.
And as i said,i really wont be using it that much.
So.....the question is-with equal stickout (4"),and equal support,will this
black metal bar be as stong as these factory made cast teeth shanks.
thanks....... Digger2
They will be supported on the top and bottom of the bucket edge.Kind of a "fishmouth" setup over and under the bucket edge.
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  #10  
Old 01-30-2009, 04:23 PM
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What about some of the subsoiler shanks ? Hard and relatively cheap ,8-15 each.
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