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Titanium and Hastalloy service in high temperature

Titanium and Hastalloy service in high temperature

Titanium and Hastalloy service in high temperature

(OP)
I would like to use titanium to serve in a furnace-500C.
Not sure what properties (for example, titanium) I need to know whether it is suitable to use?
For example, the thermal coefficient...

I found out that Titanium is cheaper than Hastalloy at some point.
Need help...

RE: Titanium and Hastalloy service in high temperature

Ti have very low strength at elevated temps, and 500C is very hot for Ti.
There are Ti alloys that can be used at higher temps, but they get very expensive.

What characteristics are you interested in?
Why Ti vs Alloy C?

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Plymouth Tube

RE: Titanium and Hastalloy service in high temperature

One property to consider would be the rate of oxidation of the metal (for instance, titanium will react rapidly with oxygen in air above 1200 C, and with nitrogen at 900 C, etc.)

RE: Titanium and Hastalloy service in high temperature

(OP)
Yes, titanium will be cross out from the list.
Now I choose SS316 base on "Recommended Material for furnace parts and fixtures" and I am "familiar" with it.
I refer to this book: Heat-resistant Materials edited by Joseph R. Davis
But if you guys have more inputs/recommendation, please let me know.

Thanks guys!

RE: Titanium and Hastalloy service in high temperature

Without knowing the specific component(s) for the furnace, the new material choice is reasonable. The other is 309 stainless steel, as well.

RE: Titanium and Hastalloy service in high temperature

310 maybe

RE: Titanium and Hastalloy service in high temperature

in order of strength at temp and general resistance to oxidation damage
316, 309, 310, 330, 800, 600, and then other special Ni alloys.
It all depends on how much stress is involved, will the temperature cycle (and how quickly), and what impurities are involved.

And don't build the structure too rigid. With temperature cycling parts will either distort or fail. It is better to have distortion.

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Plymouth Tube

RE: Titanium and Hastalloy service in high temperature

Ed, to be clear, your list reads in increasing strength/oxidation resistance from 316 (low) and improving (better) as the list goes on?

RE: Titanium and Hastalloy service in high temperature

(OP)
Where can I find this information regarding the relation of strength/oxidation resistance?

RE: Titanium and Hastalloy service in high temperature

Yes, in increasing order.
The doc linked by Metengr is the real deal.
You need to balance fig 6 (strength) and table 5 (oxidation damage).

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Plymouth Tube

RE: Titanium and Hastalloy service in high temperature

(OP)
Thanks!!

RE: Titanium and Hastalloy service in high temperature

(OP)
If I request to fabricate a part that made out of 309 or 316, for instance, are these material annealed or not annealed by default?
Meaning that is it all the material had performed annealing before selling it to customer?

RE: Titanium and Hastalloy service in high temperature

In terms of cost, you will find it cheaper to buy those alloys "as wrought" or "as rolled" or "as drawn". You can get annealed material by specifying it, but it will not likely be a default condition, nor is there any such thing as a default condition. You can guarantee that if you want something and don't specify it on the drawing, you will likely get something else - Murphy's law.

RE: Titanium and Hastalloy service in high temperature

(OP)
Based on the reading, it seems that the fig. is stated as "annealed".
How about cold rolled and hot rolled? Or it doesn't matter of the raw process since annealing will do the job (stress relief)?

RE: Titanium and Hastalloy service in high temperature

For elevated temp service you really want to use annealed material. Because in service parts of the material may be stress relieved resulting in significant variations in strength. This can lead to severe distortion and accelerated thermal fatigue.

Each ASTM product spec has a required condition. For sheet and plate annealed is by far the most common. Long products (bar and structurals) can be ordered both ways. (sheet can also, but that is very special)

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Plymouth Tube

RE: Titanium and Hastalloy service in high temperature

(OP)
I am not familiar with the heat treatment process.
Let say if I have a part and machine it to size. Material is 304SS (don't know it is annealed or not, how it is made from raw, etc, because not specify in the drawing).
It had about overall of .300" thick, width is about .500" and 12" outside diameter with some complex shape.
I want to hold the flatness and some other tolerance, if I annealed this part, will it change the form (in terms of tolerance, not about the phase)?
And call it for Full Annealing, Process Annealing or Stress Relief Annealing ...?

RE: Titanium and Hastalloy service in high temperature

There is no stress relief of stainless steel, unless you don't care about corrosion resistance.
All you can do is full solution anneal.
What is critical is the uniformity of the cooling.
If dimensions are critical after some thermal cycles,
the piece should be annealed before machining, maybe again after rough machining.
And then maybe even again after it is done.
Yes you will get distortion. Variations in section thickness almost guarantee that you will.

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Plymouth Tube

RE: Titanium and Hastalloy service in high temperature

304 is a better choice for high temperature oxidizing services than 316, as well as usually being cheaper. The Mo content does you no good and can do some harm. H grade for creep resistance above 1000 F.

The issue with Ti isn't reduced strength per se- it's reduced ductility due to oxygen and nitrogen pick-up at elevated temperatures over the longer term. Piping code uses are limited to 600 F (315 C) for this reason.

RE: Titanium and Hastalloy service in high temperature

Based on the description of the machined part size and shape, you might prefer to use a hot rolled ring since this would minimize scrap and provide better mechanical properties. Austenitic stainless materials like 304 or 316 will tend to work harden during machining operations, so if you require precise dimensional stability in your finished part you might consider annealing the part prior to final machining.

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