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I Forge Iron

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the decision to cast vs forge will be entirely dependent on the end product, you cant blanket state one is easier or better than the other without the context of the item in question.

 

sorry i cant be more specific =/

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After you read up on it, answer this question, would you rather be landing in a jumbo jet that has cast landing gear or forged landing gear?

 

I know what my answer is going to be.

 

Phil

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 Having Visited several manufacturers in the last 6 months that produce said landing gear parts as well as other various aerospace products, Forgemaster you really dont wanna know the real answers.....

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As a very, very short and oversimplified answer - 

 

Cast is easier to get the shape you want in a hurry, and produce a consistent crystal size throughout the metal. It also allows you to work in some metals that aren't normally forgable, such as cast iron which is hard, but ordinarily too brittle to forge due to high carbon content.

 

Forging allows you to compact that crystalline structure, in order to create or manipulate a grain, which depending how it's done, gives it strength or flexibility.

 

Besides that, it varies wildly from metal to metal and within differing alloys due to a number of physical and chemical differences. Look at the simple difference a tiny percentage of carbon, manganase, vanadium (or as a contaminant, potassium) makes in iron.

 

Metals behave differently, because they are vastly different elements joined by a single common factor, sharing a "sea" of electrons, kinda similar, but not the same as covalent bonding. It's that bond that gives them defining properties as a metal, ductility, reflectiveness, etc. Heating adds energy that speeds up the movement of the electrons, which allows the atoms to move more easily when forged.

 

For more specific answers, ask a real pro, or pick up a book on metallurgy. And try both if ya get the chance and someone to guide you. They're both useful and a lot of fun.

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There are many applications that make casting  more viable than forging  from an artistic and economic point of view. They are very different tools and both have their place in the scheme of things.

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And to quibble with the short over simplified answer:  *it depends*: lets take a low carbon steel strap that you want to make a simple right angle bend in.  Starting with cold metal and using an induction forge your piece should be completely done and cold in under a minute.  Hard to match that casting!

 

Some fast prototyping tasks---I had a woodworker that wanted to make some custom tools for doing bowl work.  I heated the piece up, stuck it in the vise and told him to bend it to the angle *he* wanted.  By next weekend he had bought his own anvil...

 

Of course for some tasks casting is pretty much mandatory; however many of them are tasks that take very expensive set ups---vacuum casting of aerospace alloys,  lost wax casting of intricate parts, etc.

 

I cast parts for handles but forge the blades!

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Well, I did say over-simplified. Can't write an entire 20 pg thesis on a single forum post.

 

I like lost foam method for a lot of things. Take insulating foam to make a form, bury in green sand in a cope, add gas vents, etc. And pour in the gate directly onto the foam. Burns out the foam as it takes its place. Heard that suzuki developed it while looking at different ways to make intake manifold parts.

 

Also I have a cast aluminum hammer head I made as a kind of joke. It was from a melted down piston, and was just looking to make an ingot mold in a hurry. Pressed a hammer directly into wet sand.....and voila.  Liked the look enough to finish it. It works fine on nails, but I don't really use it for fear of chipping it and having aluminum shrapnel flying off.

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I have always been under the influence that forging is superior to casting. Being a blacksmith I am bias to forging anyways. But with metallurgy as advanced as it is today could one argue, given particular circumstances, that casting is as good as forging?

 

I mean just look at anvils. I know of one maybe two anvil manufacturer that forges them. A majority of the others are all cast. I would like to have a forged anvil one day (just to say I have one), but my current anvil is cast steel and it holds up fine. 

 

The argument leads into grain refinement, but it is possible to get finer grain size through different methods of heat treatment depending on the material you are working with. 

 

I have often wondered if this debate is residual "old world" knowledge from a time when forging was the superior manufacturing method. I may be wrong but are'nt the Hofi hammers cast?

 

http://www.iforgeiron.com/topic/23397-bp1000b-the-real-story-about-the-hofi-hammer/

 

Scroll to the bottom of the page for information on this topic. 

 

But then we are presented with information such as this http://www.peddinghausanvils.com/forging_benefits.htm

 

How much of either of these claims are backed up with scientific studies I do not know. They may be true, or they could be a marketing scheme. The conclusion I have come to is that the difference in quality is so minute anymore that I really do not notice. Instead of questioning the actual manufacturing process I question other aspects such as tool geometry and material. 

 

 

 

I cast parts for handles but forge the blades!

 

I have seen blades that are cast, and I for one was appalled. The reviews for the knives said they were not half bad. I reckon it just goes to show that the qualities of today's materials are much higher than they used to be. 

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in the big picture items that are decorative that are cast are brittle. Cast parts do not handle impact. Now if you get into ductile iron Which is cast like anvils and swedge blocks that is a different story. http://www.ductile.org/  With blacksmithing you do not have the porosity that comes with cast iron. In blacksmith you get a much more solid product.  

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Asking blacksmiths if they prefer forging to casting will get predictable results.  Asking foundry folk will likewise get predictable results.  Ruger casts the frames of their guns and Ruger's are justifiably famous for being very strong.  Terrible import tools are infamous for being poor castings.

 

There's a large amount of engineering knowledge that goes into making something a success regardless of the process.

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Each has it's appropriate application in industry. For myself it is like this I don't want to forge a bronze sculpture with the artist's fingerprints in it, for that I would cast it by the lost wax method. I can't cast a patterned welded steel blade, for that I would forge it. See you use what is appropriate for the application. Casting is just wonderful for some items and not so good for others and forging is wonderful for some techniques and not for others. Ruger has been manufacturing guns using the lost wax method for decades using cast steel parts and they make wonderful parts that wear well and function as designed. The same parts could be made by forging and then machining but with casting there is much less work to be done. So which is better casting or forging? It depends on the application.

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