Rolled vs Forged Bar
Rolled vs Forged Bar
(OP)
Hello,
A customer is asking for "forged bar" as the starting material for a certain finished part. We have in stock what the mill refers to as "rolled bar", which the customer will not accept. I can't seem to find a definitive difference between "forged" and "rolled" bar. Depending on where you look in ASTM specifications, rolled is sometimes listed as a type of forging process, elsewhere as a separate process.
If anyone can please explain the difference, especially within the context of an ASTM spec, I would greatly appreciate it.
A customer is asking for "forged bar" as the starting material for a certain finished part. We have in stock what the mill refers to as "rolled bar", which the customer will not accept. I can't seem to find a definitive difference between "forged" and "rolled" bar. Depending on where you look in ASTM specifications, rolled is sometimes listed as a type of forging process, elsewhere as a separate process.
If anyone can please explain the difference, especially within the context of an ASTM spec, I would greatly appreciate it.





RE: Rolled vs Forged Bar
RE: Rolled vs Forged Bar
Depending on the size of the bar, there are some rolled bars produced by continuous casting mills that may have very little rolling/forging reduction, which can have a negative effect on the mechanical properties. Generally, this is controlled by specifying the amount of reduction required, but perhaps your customer has other concerns as well.
The important thing is that your customer will not accept the rolled bar and wants a forged bar. Why is really not the issue. Most steel mills will be specific that their product is a "rolled bar". You will probably need to find an open die forging operation to obtain a forged bar. You can google Scot Forge for a start.
RE: Rolled vs Forged Bar
RE: Rolled vs Forged Bar
In some mills, the forging of the original castings into intermediate products known as blooms is then followed by rolling to the final size and geometry. I would check to see if this is the case here. If it is, then your customer should be happy. If not, then you need to address their quality concerns.
Maui
www.EngineeringMetallurgy.com
RE: Rolled vs Forged Bar
Conventional open die forging at Akmetal in Turkey
http://www.akmetal.com/images/p1b.JPG
State-of-the-art open die forging at Timken Faircrest
http://www.france-metallurgie.com/wp-content/Timke...
Radial forging at ATI Allvac
http://businessclimate.com/sites/default/files/ima...
another example of radial forging
http://www.samkimc.co.kr/bbs/data/file/01/35475925...
State-of-the-art bar hot rolling mill (Daniel Morgårdshammar)
http://www.danieli.com/var/danieli/storage/images/...
close-up of roll
http://www.danieli.com/var/danieli/storage/images/...
RE: Rolled vs Forged Bar
Thanks for your input, it means a lot...
dbooker, metengr - the "rolled" bar that we planned on using has a 7:1 reduction ratio, 5.5" OD round bar.
We spoke to the mill who provided the bar. They said that they only make forged bar down to about a 6.5" OD. They said that as you reduce bar size, they roll their bar, as it is a much easier method. Forging may damage the bar and make it difficult to hold the bar size tolerances ASTM specs demand.
Maui - It is 316/L bar, so I don't think there is too much to worry about in terms of carbides, but that is some insightful input. Yeah it seems the providing mill (along with many others I understand) forges the ingots/billets and rolls them to final size.
We joke that if we heated the bar up to temperature and whacked it on an open die hammer a couple times, it qualifies as "forged" bar, even though it would be probably be making the bar worse.
RE: Rolled vs Forged Bar
Maui
www.EngineeringMetallurgy.com
RE: Rolled vs Forged Bar
Does anyone know of any good research that has been done to support rolled bar over forged bar, or that they are at least both similar and acceptable practices for quality product?
RE: Rolled vs Forged Bar
You should discuss this with your client.
RE: Rolled vs Forged Bar
Thomas J. Walz
Carbide Processors, Inc.
www.carbideprocessors.com
Good engineering starts with a Grainger Catalog.