High Impact Strength Steel 2

[FullMetalBracket]

I'm looking for a material recommendation for what we think is a rather extreme design. We are firing a steel piston into a steel anvil with an impact speed of 50m/s. Current attempts have resulted in material failure. We need a steel that can withstand this impact over a low cycle range. Right now we are running at room temperature however our real interest lies in properties at around 400C.

Some recommendations I've received are VascoMax C-250 (maraging steel) and DIEVAR hot-work tool steel.

Any thoughts on these alloys or other recommendations would be greatly appreciated.

 

[metengr]

FullMetalBracket;
Several questions to better your material selection;

1. What strength level is required for the steel?

2. How do classify failure? If steel piston tears the steel anvil or penetrates completely through the anvil?

3. What thickness is the anvil?

 

[Burdan]

S7 is a high quality shock steel, i think they use it for Jackhammer bits.

an inexpensive alternative may be 5160 steel, which is common in leaf springs.

 

[unclesyd]

While waiting for the OP to respond here is one of the hot work tool, H13, steels that could possibly do the job.

One additional question, does the projectile have to be reused ?

http://www.diehlsteel.com/h13.aspx

 

[FullMetalBracket]

Sorry for the delay, and thanks for the suggestions thus far.

The anvil and piston that this will tested on are both 4" dia and 4" long. We will however be using this data to validate approaches at a larger 12" dia x 12" long version. Any significant cracking is considered a failure, and yes the idea is to fire many times (low cycle).

A recent attempt at this speed (only one shot, on the larger version) with S7 resulted in severe cracking which is why were are now looking for something new. I should note however that this was tested at room temperature.

Any and all recommendations will be considered and highly appreciated!

 

[Metalguy]

If you cracked properly heat treated S7 with one shot, you are going to have to give up some strength to get more toughness.

Because the vast majority of the property known as toughness is from a material's ability to absorb energy as it's plastically deformed, it means your piston/whatever will have some permanent size changes after every shot.

"You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein

 

[israelkk]

How about Hadfield steel?

 

[Metalguy]

Don't think so. Hadfield steels start out with a pretty low yield strength, 50-60ksi. They require plastic deformation to resist wear, so it all depends on how much deformation the OP can stand.

"You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein

 

[Wrenchbender]

A Projectile vs Armor problem! The two approaches are experimentation, or computer simulations ('hydrocodes'). The latter are commonly used in the DOD and by the national labs. Assumption is you are going the first route - experimentation.

At zero degrees incidence, your projectile will obviously either shatter, deform or penetrate to some degree. If you don't want shattering or penetration, you must accept deformation. Based on past results, higher toughness (area under the stress-strain curve) is necessary. (400deg C is a step in the right direction. Can you make it 500C?)

This book may be helpful in selecting a toughness-strength compromise.

http://books.google.com/books?id=up...&resnum=1&ved=0CBYQ6AEwAA#v=onepage&q&f=false

Also Zukas is a good source for material behavior at 'high strain rates':

http://books.google.com/books?id=qE...Q6AEwAg#v=onepage&q=zukas strain rate&f=false

 

[JAWright]

Considering that you require 400C operating temperature, you probably want an alloy that is tempered above this temperature. If you want the best combination of strength and toughness you might consider an alloy like Ferrium M54:

http://www.questek.com/ferrium-m54.html

Jim

 

[unclesyd]

Have you looked at the Aermet Alloys like 100,310,340? The Aermet 100 might be a good candidate.

Here is a brochure that gives some comparison date for several alloys including the Aermet Alloys.

http://carpentersteel.com/uploadedFiles/Products/tialternatives11-07final.pdf

Off the wall:

You might want to talk to the Astralloy folks, Birmingham, about their Astralloy V bar as well as other V alloys

http://www.astralloy.com/pdf/astralloy_v_plate.p

 

[TemperedMartensite]

Take a look at 13-8 SuperTough - it does not have the strength of C250 or Aermet 100, but it does offer fantastic tougness with Room Temp K1C of greater than 120

http://www.alleghenytechnologies.com/allvac/pages/PDF/tech/SS-238 13-8SuperTough.pdf

 

[mighoser]

I've use Vasco T-200 in aircraft cannon applications. It has survived where 13-8 supertough and H-11 failed.