Posts material for Press

[WillPowerAutomation]

Hello all, a question, I am building a 150 Ton press, it is going to be a 4 post design, I had selected 1084 3" Round Bar for the posts. My machinist wants to use 4140 or 4340 instead of 1084. The posts will be in tension to 150 Tons over a span of 44" threaded on both ends with 2 3/4" UNF thread and nuts. There is no shock loading, force is applied using an air over fluid pump.

Any thoughts or suggestions?

Thanks

WillPower Automation.

 

[EdStainless]

What strength do you need?
With 3" bar 4140 will be fine, but you need to look at the required strength to select a tempering temperature.
You will want it Q&T, don't use normalized. Q&T has better toughness.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[metengr]

The 4340 will provide greater hardening capability for through thickness tensile properties in quenched and tempered condition. You need to establish the minimum strength level with appropriate safety factors to prevent local yielding of the round bars in service. Get this done first using outside help and material selection and heat treatment follows.

 

[gruntguru]

Not sure why you prefer 1084? Price?

4140 or 4340 do just about everything better in your application.

je suis charlie

 

[Tmoose]

I think most commercial presses use flat plates and bars of lower strength steel.

http://media.machines4u.com.au/machinery/92/67492/Metalmaster-150-ton-Hyd-Press-HP-150T_299000.l.jpg

That permits some details that allow Easily adjustable work length, strategic reinforcement around holes, etc..

Are you working with requirements for limited adjustability, portability or other restraints?

 

[tbuelna]

The difference in raw material cost between 1084 and 4340 for 18ft of 3" dia bar would not seem to be a major concern compared to other costs for producing your custom press. The benefits of using 4340 are well worth the added cost for a component that your personal safety will rely on.

You'll also want to use the same material for the mating nuts at each end of these posts.