Some alloys are either forged or cast. What are the differences?


[Modified by YipMan_Style, 5:13 PM 2/20/2002]

 

In other words.

Cast = needs less material to make since it is roughly as dense as you start
Forged = need a lot more material since you are smashing it into it's self to make it smaller and the shape you want it.

 

sorry to butt in here but you have some basic fundamentals mixed up - you do not make the materials any denser by the actual forging operation, the water based solution you speak of is probably part of a quench and temper or a "solution treatment" for long term hardness / tensile - chemical hardening, material produced for forging is usually order "dead soft for cutting" it is supersoft on order for it to be formed into detailed shapes, forged material needs to have all that forging stress - releived in a heat treatment process or abnormalities in physical properties will surface. Mg, Ti are much lighter than what you speak of above and are tens of times more expensive, they are used as alloying agents, small additions of these materials can improve certain aspects of the steel in question.

it is simple plastic deformation of steel that basically affects its mechanical props, not compression.


[Modified by rtype11, 3:47 PM 2/20/2002]

 

hmm you know what guys.....
ive always heard cast was being cast as in its poured into a mold and then set to dry/harden

and then forged was it was carved out of a shape/form ... much like a person whittles wood to make shapes/figurines

anyone else ever heard of this??

 

Carving out of a block of material is billet. Expensive as hell to make just one item. I don't know about the tensile or torsional durability of a billet item, but the grain uniformity is supposedly pretty high. At least that's the way they market it.

 

Teken, what does it mean when the wheel is stamped? Is that like stamping a design into it? Or is that the actual process of making the wheel?

 

Yeah, i wanna get into our engineering dept. CNC mill and make me some rods Theyll never know, hehehe.

 

well, we all agree on casting, so let me take a stab at forging.

orginally, and the way most eng schools still teach it, is that forging is taking a piece of metal, heating it to its plastic state (this is when its bendable, but hasnt completely weakened the material), then hammering, rolling or bending it until you reach the desired state. the water process is done to reinforce the bonds of the material, strethening them as you move along. hot, cold, hot, cold, etc. this coldness, quenching, gives it its strength. you are stretching the bonds, then hammering them tite together, then freezing them there, then repeating..

i believe what teken described, and how most auto companies forge, is called closed die forging. similar to casting, in that you are using a form, but since you are starting with a solid piece of metal, the end result is a stronger product. the scraps are then cut away from the end result. note - this is liking using forms to bake cookies. lol. you are closed die forging the cookies.

next, billet was nothing to do with a process. you dont 'billet' cams. all billet is, is starting out with a solid piece of metal, a billet, then rolling, forging, etc. one example of rolling - the chick from the movie ghost. she was rolling her pottery from billets. lol.

hth

 

Thanks Teken

::keeps post in archives::