Deep Hardening of Large Steel Parts

[rmb3]

Hello,

I need a method and/or supplier who can harden at least a portion of a large steel part. The part is a hollow cylinder, approximately 68 in. O.D., 37 in. I.D., and 56 in. long. The finished weight is around 13 tons. The portion needing hardening forms a 12 in. band around the circumference of the outside diameter.

My hardness requirements are 335 Bhn to a depth of 0.4 in.

I have some flexibility with material selection. However, I know that through hardening of 4340 is too expensive of a solution. Many lower cost alloys (ex. 1045) that are consistent with the (currently unknown) hardening method can be selected.

Eliminating the need to harden the part is also not an option.

So... does anyone know of a method and/or supplier to harden large steel parts to at least 335 Bhn to a depth of 0.4 inches?

Thanks in advance.

 

[metengr]

How about using 4140 alloy steel, and induction hardening? AISI Type 4140 exhibits the necessary hardenability to achieve the hardness range you desire to a depth of 0.4".

Induction hardening can provide a rapid and effective method to locally harden the circumference of this part.

 

[unclesyd]

That is nice chunk of metal.
Induction hardening would be the best method to achieve your required results but I think it will be extremely hard to find anyone that can handle the part and have the coils and power needed to harden the part. It would take someone well versed in the art to even attempt a procedure such as you have.
I would go with a through hardening material and it’s going to be bear to get it made.

Have you selected your material yet?
Have you decided how you would like it made?

 

[rmb3]

I've looked into induction and flame hardening. The size of this piece quickly limits the number of potential heat treaters. Of the very few that remain, all claim depths of hardness reaching only 0.25 in. They will not promise any more, regardless of material selection. This is too bad, because induction and flame hardening are very attractive from both cost and simplicity perspectives. Are any other selective hardening processes that can go deeper?

As for materials, I've found 4340 to be too expensive for the application. I don't know about 4140 costing. Utlimately, material selection will be driven somewhat by the hardening process.

To answer your other quesion, the parts will be made as forgings.

I do have a technically feasible solution in hardface welding. However, I need something simpler and lower cost. If you consider hardfacing the baseline, induction hardening is less expensive, and through hardening 4340 is substaintally more.

 

[unclesyd]

My goodbuddy that does ring rolling said it was out of range.

You are going to have to make the component with a process such as the one at this site. They can work from the forging temperature. I would give them a call and discuss your problem with them. They have all the alloys. Any way you look at it, it’s not going to be inexpensive.
Look at the photo gallery.

http://www.scotforge.com/sf_hollows.asp

Comeback and let us know how things are going. I think everyone will be interested. I'll keep thinking, but its hard to think that big on routine basis.

 

[arunmrao]

I have a similar issue on heat treating large castings. The application is rollers for rubber making machinery. Conventionally chill cast rolls are used. As the units manufacturing these are closed, now the user wants to use a low alloy steel through hardened to RC 55. My question is whether this is advisable to replace with a steel casting and what will be the effect of temperature on the rolls as they are exposed to 250 Celsius in operation.

Thanks in advance

 

[GRoberts]

If welding is too expensive, as another option, could you shrink fit, or otherwise attach a band of hardened material to the outside of the tube instead of the weld overlay?

 

[Maui]

Rmb3, what exactly is the application?

Would you consider using a clad material? This would allow you the flexibility to specify the material properties that you need from the outer diameter to your depth of 0.4 inches, while at the same time permit you to select a different material to use as the inner liner. You might want to discuss this with the experts at

http://www.cruciblecompaction.com/products/clad.cfm

Maui

 

[rorschach]

10XX alloys do not exhibit good hardenability, the 41xx series are much more amenable to that.

I don't know where you are, but Lone Star Heat Treating here in Houston might be able to help, or at least advise you in alternatives. they are used to doing large oilfield parts so they might be able to handle it.