4140 or better

[SupraQuinn]

Hello! I have been tasked with sourcing material for a new order. It will be tested to 15000psi and 25000psi I believe. Currently the material is 4140, however the customer would like the product to be lighter. Outside of machining extra material away is there any material out there that would make the part lighter but not compromise any strength or ever better? The "leeway" on material is a 10-20% greater cost.

thank you

 

[redpicker]

You haven't given enough information to allow us to give you a meaningful response.

What are you making? What properties do you require from the 4140 material?

You obviously have to change the design of the part to make it lighter. I think you are asking how can you change the design to make it lighter. We can't tell you anything if we don't know what the design is.

rp

 

[SupraQuinn]

It is for a valve body. We have identified a lot of "extra" material on it which can be machined away to help lighten the product. However, we can not get to our target weight which is why we must change the material. Looking for a lighter material which has the same strength as 4140. The properties I require though from the 4140 is that it is able to hold up to the high pressures it will be subject to. Currently the body of the valve weights 100lbs. By removing the extra material we have lightened it to 85lbs. However, our target goal is 65lbs. Sorry. this is not my field of expertise, so what other information would you need?

 

[1gibson]

It would be much more realistic to select a stronger material, then make the part thinner.

 

[ricklts]

Is the valve BW ends or Flanged?
If Flanged, have you thought about making it Dbl. Studded, with spool adapters where needed?
Is the valve body cast or forged?
If forged, is it block or shaped?

Many more questions could follow.

 

[MPEngineer]

Try 4340 or 8740. Don't know about the cost, but the Metallic Materials Properties
Development and Standardization (MMPDS) manual says these can substitute for 4140. You can get a free download here:

http://www.everyspec.com/FAA/FAA-General/DOT-FAA-AR-MMPDS-01-JAN2003_24102/

 

[SupraQuinn]

The valve is female thread for 2" pipe. It is cast, and rounded shape.

 

[jbeckhou]

2" LP is only rated for 5000 psi working pressure. I would not recommend changing any material unless you have an engineer review the design. If the company making the casting could cut 20 lbs from the body, they would have done so already.

Petrotrim Services

http://www.petrotrim.com

 

[mfgenggear]

two ways I know of getting more strength "yield" properties.
Heat treat it.
make it thicker.

OK there's another, make from it from higher strength steel then have it heat treated & make it thinner.
but like the other senior members said, be sure to have it calculated & tested carefully.
be sure to have the correct safety factor.



Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

 

[steelsteel]

Going from 100 lbs to 65 lbs is a pretty radical reduction. Unless the rough casting is way overdesigned there will be no easy way to do this.

Just about any "solution" will likely need to be equally radical and potentially economically unfeasible unless the valve is being used in some exotic application.

 

[redpicker]

Have you considered moving from a casting to a forging?

rp

 

[lkrzyzan]

Using a boron steel should yield similiar physicals at a lower weight

lk

 

[ricklts]

SupraQuinn,

I don't know of a standard threaded connection suitable for 15K or 20K pressures. Maybe one of the premium tubing threads from VAM or someone like that. What code are you working to? I would think that API 6A might be applicable? If so, that limits your material choices dramatically.

 

[dvd]

Strength at what temperature?