Filed under: Forged vs Cast
While castings certainly have their applications, forgings still create a product with true wrought properties that castings cannot. There are even cases where Queen City Forging has been able to produce parts for emergency orders the same day; faster than a casting could be produced. The inherent properties of a forging cannot be imitated by the casting process.
Well the forging process is going to prevent defects that would otherwise exist in a cast structure, because of that deformation energy, because we’re actually stretching and changing the material. It’s almost like we’re kneading bread, I guess you could say. We’re eliminating voids, we’re taking any inclusions that might have been in the original cast structure and making the raw materials and dispersing them so that they aren’t concentrated, they can’t be points of fatigue, starting a crack in the part.
One of the problems also with castings, is many times because of the kinetics of solidification of the materials, you can come up with a very coarse structure. That coarse structure then doesn’t heat treat as readily. It is, you might say, sluggish in its heat treatment. We’ve seen this in our forgings. We’ve made forgings really in direct comparison to castings, and we can go through heat treat processes such as solutionization of aluminum in time periods that are far below what they can do with the casting. We might be able to get full solutionization on an aluminum part in as little as 30 to 40 minutes, where as the standard says that for a casting you might need eight hours. That’s a tremendous difference then in the cost of the heat treating.
Castings and forgings are very different in their ability to produce parts, or even produce parts quickly. One of the things you could say is that for forging, what we always do, is we always have the tooling available. We can always move that tool into a machine and as long as we have the raw material available, we could be making parts within a day or two. Maybe even there are times in our history, we’ve made parts the same day that a customer says, “Help, we’re out.”
In castings, they have to go through a process of making molds so that they have to take their pattern, they have to make a mold, they have to remove the pattern from the mold. They then have to set up the alloy to be melted, they have to make sure it isn’t going to be contaminated with whatever they were melting prior, so generally your lead times are going to be longer with castings than they can be with forgings.
What I’d say about the quality of castings versus forgings, is that with the forging materials, we are starting with what you might call qualified raw material going into the forging process. Most times this is super clean material. This is material that’s been sonic inspected. We have any number of parts where the material is sonic inspected before it goes in to the forging process.
With the casting, every single piece is a new piece. So whatever came out of that crucible and went into that mold, is what you get this time. There are many cases where castings really have to be x-rayed or checked 100% of the time, where as with forgings, yes we do testing ongoing, but we don’t have to check necessarily every single forging