I started this post a while back and wanted to re-examine the question. One poster suggested thinking about an anvil made of sand and how making it less “sand-like” would limit the distortion experienced by the workpiece when struck with a hammer. I want to know if the difference between “sand-like” behavior in mild steel vs medium carbon steel, like 4140 vs a hardened anvil surface with higher elasticity would make a meaningful difference compared to anvil mass.
Another poster asked me to consider the effect of placing a 1" thick plate vs a 36" thick plate on a flexible surface like an unsupported plank of wood and noting that striking the 1" thick plate would cause more distortion in the plank when struck with the same force. However, this was in reference to my question about mass under the hammer and whether or not it affected inertia. If the 36" thick piece were placed on its side would there be more deflection that if it were placed on end?
Thanks
(Would have been easier just to reply to your earlier thread - you might like to ask a mod to join this one to the end of that one.)
Rather than worry about all the surrogate anvils, it shouldn’t be all that difficult.
Hardened steel is just that - harder. It doesn’t undergo plastic deformation as quickly as unhardened steel. So it may retain an unblemished surface better when someone is beating the heck out of it. However, it isn’t stiffer than ordinary steel. This is something of a myth. It is more brittle.
An anvil is just a big lump of inertia. The stiffness of the steel it is made of, and its mass, mean that it usefully approximates an unmoving work surface. The more mass, the less the entire anvil moves. The stiffer the material, the less the surface moves when struck. The stiffness of an object increases by the cube of its thickness. So a 36 inch thick by inch wide piece of steel is 1296 times as stiff as a one inch thick by 36 inches wide piece. Just consider how bendy a steel ruler is in the flat direction versus trying to bend it in the edge on direction. Same deal with an anvil.
You just want a large lump steel. It needs to be heavy, and it needs to be thick, both avoid the surface moving when you hit it with hammer. Thickness increases the stiffness of the unit, and increases the mass. You need both. Hence the shape of anvils. The density of different steels is essentially identical.
I would suspect that a hardened surface on an anvil would be a bad idea as you risk it fracturing rather than deforming. The surface will likely work harden no matter what. Maybe a slight hardening would be OK, and there might be an optimal alloy or hardness. But the risk of fracturing the surface needs to be balanced against this. Surface cracks will reduce the ability of the anvil’s surface to provide an approximation to an immovable object. I suspect they are why the ball bearing drop is a guide to the need to resurface an anvil, and their removal returns the ball drop to a nice rebound - but I don’t know enough about anvils to kknow.
The material of an anvil is quite important to it’s usefulness. Steel anvils are superior to cast iron anvils. Steel topped anvils are next best. Steel anvils deform less and the hammer rebounds higher resulting in less work for the blacksmith. Cheap cast iron anvils are known within the trade as ASO, Anvil shaped Objects.
I generally counsel people to avoid cast iron anvils. I was wondering about the performance of a hunk of mild steel compared to a hunk of hardened steel (around 55RC). Testing rebound by dropping a ball bearing on it and seeing how high it returns is often recommended for quality. There are also those who say that rebound means nothing since you’re hitting a piece of hot metal which is pretty plastic. I want to know who’s right. While I can see that an anvil which is more elastic could have some effect on performance, I suspect it would be minor, but I will let the physicists weigh in. Hopefully I haven’t asked how to suck spaghetti.
While a higher carbon anvil will last longer and won’t deform much from misses, I tend to think that these advantages are likely minor as well.
I thought we weren’t supposed to do that.