Stainless Castings 3

[4RRS]

I have a complex semiconductor chamber I'd like to make from casting. The chamber has atomic hydrogen and HCl exposed to it's internal surfaces at 1100 C. Hydrogen embrittlement is not a problem for a chamber made from forged material, will it be a problem for a casting? Second question, in the casting process is there a mechanism for providing internal channels for water cooling, or must those features be gun drilled after casting?

 

[cloa]

Which castable stainless steel?

 

[TVP]

Q1. Check out this reference:

http://www.sandia.gov/matlsTechRef/

Q2. Yes, it is possible to use cores in the casting process to produce internal channels/passages. Google "investment casting core" or "sand casting core" for more information.

 

[btrueblood]

- or "lost foam casting".

 

[metengr]

The chamber has atomic hydrogen and HCl exposed to its internal surfaces at 1100 C. Hydrogen embrittlement is not a problem for a chamber made from forged material, will it be a problem for a casting?

Dealing with monatomic hydrogen and HCl at 1000 deg C are alloy specific issues and unrelated to end product forms. If a casting is pressure tight it will act no differently in comparison to a forging for this type of application.

Alloy selection will be more difficult because of the metal temperature and environment. What is the internal pressure?

The reason for my question is that if this is some type of high pressure autoclave you will have other concerns related to alloy selection and design.

 

[4RRS]

Holy crap, you guys rock! Typically we use 316L for these chambers. There are advantages to Inconel and Hastelloys from a corrosion standpoint, but the material availability and machining difficulty has prevented use in large chambers. From the information provided confirming casting feasibility, I can revisit that. Thanks!

 

[arunmrao]

You will need to consider the issue of thin walls of the chamber,cracking during solidification of casting and pressure tightness.

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