Modified T-200 Maraging Steel

[mighoser]

I'm looking for a source for this type of maraging steel in resonable quantities 1000 lbs or less. This is standard T-200 Maraging Steel MIL-S-46850, Type III, Condition A1 except; chemical composition is modified as follows.

Cobalt .75% max
Titanium .6%-.8%

Charpy V-notch impact strength in the maraged condition needs to be 65 Foot-Pounds min. in the long. direction. at room temperature IAW with ASTM E23-82, Notched Bar Impact Testing of Metallic Materials.

We used to buy this from Allvac (teledyn/vasco) but they no longer can supply it. Any thoughts??? I'm also considering alternatives: 13-8 SUPER-TOUGH, AERMET 100,...??? Aermet doesn't really meet the impact strength and 13-8 Super-Tough might equally hard to procure as modified T-200. Any help would be appreciated.

Thank you.

 

[EdStainless]

You might be able to make properties with other PH grades, Custom 465 comes to mind.
Either way, try tech assist at Cartech.

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[mighoser]

Edstainless,

Can you think of an alloy which would have the following properties (equal or better) and is readily available (no large min. buys):

Ultimate Tensile Stress KSI: 210
Yield Stress KSI:205
Elongation %:14
Reduction in Area %:62-70
Charpy V-Notch LT (FT-LBS):81-95
Fatigue Endurance Limit (KSI):110
Fracture Toughness KSI-IN1/2:112-129
Hardness (HRC):43/47

Thanks

 

[CoryPad]

Why do you need such huge Charpy values? AerMet 100 can meet the strength and fracture toughness values, which makes me question if the Charpy values are actually necessary.

The other alloy system with both high strength and toughness is the Multiphase alloys from SPS (MP35N, MP159, MP98). They are like AerMet 100 (will meet the strength and toughness, probably not the Charpy). They won't be easy to obtain.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[mighoser]

I believe we started with T-200 which has similar properties as posted above but much lower charpy values. Parts were made and tested. From this we decided that we needed to increase charpy values. Switching the composition to, Cobalt .75% max & Titanium .6%-.8%, accomplished this. Decades pass and we finally ran out of the material (we had to buy 20,000 lbs). The mill is "willing" to run the material again but the cost is extremely prohibitive(the quote was equivalent to a no bid).

Any other ideas?

 

[EdStainless]

Don't fool yourself about the price. Todays prices are at least 4 times what you would have seen a decade ago. And that is without any special permiums.
We are doing specialty tubing work for people and paying over $30/lb for strip.

I also am doubtful of you rimpact values. I can find a numbe rof alloys that meet the properties (custom 465 aged at 1000F), except for the impact. If you have the endurance limit and K1c what does the impact matter?

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[mighoser]

Edstainless,

If we needed the min buy then we could probably live with the price. We will probably use 1000lbs for the next ten or twenty years. Point taken about redundany of charpy versus fracture toughness and sigma e. Had to dust of the fracture mechanics brain cells. I'm going to read up on custom 465. I just printed the alloy data sheet. Any other information to consider (warnings, when not to use this alloy, etc.). Do you know the availablity and min. buys for this alloy? I'll have to call carpenter for the final word but I thought perhaps you would know off hand.

Thanks.

 

[EdStainless]

What product form are you after?
Can it be slit from sheet?

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[mighoser]

Bar. 2" square. Possibly smaller.