Wood insert modified and improved .... in every respect

[bidouille23]

Re,

and the final touch in addition to the two enormous advantages mentioned by Alain is that the pollution due to the poor combustion at the start is approximately halved;).

Life is not beautiful

;)

otherwise Alain saw that I have you on hand, I think back to the tube that could be bent, and yes I do not let go so easily (for the moment the few heating sessions have no effect), suddenly I tell myself that maybe there would be a reason why there could be no noticeable movement (there will undoubtedly be micro cracks everywhere, of course but they shouldn't be annoying because of the absence of 'mechanical effort if it is not carried its own weight is to say not much, I think that within ten years I imagine that the tube will be puffed by rust;)).

In short, I was saying that maybe the fact of having covered the tubes with holes, the material can expand in a certain way by closing the holes slightly, basically I imagine that it is possible that the holes give a certain "elasticity" or "degree of freedom" of expansion without causing excessive internal stresses, thus avoiding deformation?

What do you think ?

Or quite simply that the temperature is not yet critical for stainless steel? What about the working temperatures of stainless steel, for example to bend a tube in what color do you have to mount it to work it? I read 1200 ° c is rather realistic true or not at all?

And another question, the last, for tonight :
Is the color range corresponding roughly to the temperature for steel the same as for stainless steel (although I look for the moment I can't find anything)?

Thank you in advance

[Ahmed]

Your holes being small and asymmetrical, they cannot play any favorable role to avoid deformation ...
The internal stresses are zero at operating temperature since at this time, all of the metal is malleable.
The stresses can be expressed during the rise in temperature or during the cooling phase.

1200 ° for hot bending of ordinary steel is too much; from dark red (700 °) to cherry red (800 °), steel is quite malleable.

[bidouille23]

Bonjour,


Ahmed you say:
"Your holes being small and asymmetrical, they cannot play any favorable role to avoid the deformation ..."

There are certainly small but very numerous the total piercing surface per kill is of the order of 4 cm² on each 2.8mm outer diameter tube, so proportionally to the size of the tube I do not think it is that small the holes .
asymmetrically, it's a remark that certainly leaves me to think about it, this said I have a feeling that it is asymmetrical does not change anything .
I imagine the stainless steel which expands and which closes the holes by expanding, thus avoiding mechanical stress due to the expansion.
where the truth is elsewhere;) (completely or partially) ...


I also said
"roughly I imagine that it is possible that the holes give a certain" elasticity "or" degree of freedom "of expansion without causing too much internal stresses, thus avoiding deformation?"

Ahmed you answer me:


"The internal stresses are zero at operating temperature since at this time, all of the metal is malleable.
The stresses can be expressed during the rise in temperature or during the cooling phase.
"
It is these constraints that I'm talking about , during the rise and fall in temperature.


"1200 ° for hot bending of ordinary steel is too much; from dark red (700 °) to cherry red (800 °), steel is quite malleable.
"

I said "Or quite simply that the temperature is not yet critical for stainless steel? What about working temperatures for stainless steel, for example to bend a tube in what color you owe it? mounted to work it? I read 1200 ° c is rather realistic or not at all?
"

1200 ° c for stainless steel not ordinary steel.
I ask if the temperature (1200 ° c) for working with stainless steel is real or not (if not at what temperature does stainless steel work?)?

What if the color / temperature ratio with stainless steel is the same as with ordinary steel?

Otherwise thank you for what is common steel I know the app, my workshop colleague forges from time to time and I read the subject, there is a lot more information on common steel forging than on stainless steel;). Personally I would say more around 900 ° c to 1000 ° c for work and between 750 ° c and 850 ° c for annealing according to the carbon rate but this is another story.

So thank you for this answer but I would say that I am not convinced and that I am left on my hunger;).

who would have a valid link on the work of stainless steel and its temperature? thank you in advance

rain

[Alain G]

Hello Bidouille!

In short, I was saying that maybe the fact of having covered the tubes with holes, the material can expand in a certain way by closing the holes slightly, basically I imagine that it is possible that the holes give a certain "elasticity" or "degree of freedom" of expansion without causing excessive internal stresses, thus avoiding deformation?

Here are some interesting links on the properties of stainless steel:

http://fr.wikipedia.org/wiki/Acier_inoxydable
http://fr.wikibooks.org/wiki/Mat%C3%A9r ... noxydables

I had a good site for the properties of stainless steel but I can no longer find the link, but you can find very good information on these 2 links which helps to understand the qualities of certain alloys, we also understand why it changes color under the effect of intense heat such as soldering and why the weld must be cooled quickly to avoid surface corrosion.

Depending on what can be seen here;

intergranular corrosion, traveling between the microcrystals of the metal, eventually disintegrates the metal. It is linked to the precipitation of chromium carbide along the joints. For it to occur, three conditions must be met: at least 0,035% carbon, sensitization by maintaining a temperature of 400 to 800 ° C, an acidic external environment with an oxidizing power between two well-defined limits;
pitting corrosion is generally not due to the heterogeneity of the material but to the accidental presence of a metallic dust which, in a humid environment, forms an electric battery. The surface of the steel then forms the cathode and corrodes. We can thus see sheets 2 mm thick drilled in a few hours. A very acidic and very oxidizing environment can produce similar effects

304 stainless steel will not withstand long in a stove subjected to the heat and acidity of damp wood fumes so not good news for you, that's probably why no one uses the air ducts under the strong flame.


On the FX-3000 the preheating ducts are located on the top sides where no direct flame can reach them.


There is something to meditate on!

[bidouille23]

Good evening,


thank you Alain for the links I will look at it closely and carefully.

Why quickly cool the weld or refold the argon tube or anneal, it is to make the stainless steel passive, because after being put under high heat it is disactive and therefore sensitive to corrosion , that I know;).

this is why in my previous post I said that the tubes will undoubtedly corrode before bending.

Fortunately, it is 316 L stainless steel and not 304;), it will resist longer.

This say ALain as you say it leaves something to think about, so I will order things in a different way on my next realization, the one will live the time he will live. Now at least I am warned, it is true that I was not badly started on the principle that stainless steel was one of the materials that resisted heat well, and here is another idea received that I would have done better to control before ...

and say that on the Jotul F3 it is also a stainless steel sheet which acts as a 2nd air heater deflector and with holes for the injection of this air precisely.
that reassured me in my choice for stainless steel grrrrrr.
So here is a good lesson .

This is not a big deal either, it's two working days, that's all, in the meantime I have lime and I only consume a little wood, there or before I was going to make a wheelbarrow of wood every day , well it's a every 2.5 days to see 3 days, and it is downright warmer in the house, so ... This does not affect anything when it comes to operation but on the other hand to make the construction sustainable I have to find a solution is clear.
Now that I know the problem, find the solution will be easier;).

Thanks again see you later

[bidouille23]

Re,

well that's a little precise
According to the wiki link
c%% Cr
"X2CrNiMo18-10 1.4404 Z2CND17-12 316 L 0,02 16 to
% Ni% Mo% Si% Mn% P% S
18 10,5 to 13 2 to 2,5 1 2 0,04 0,03 -

"Intergranular corrosion, traveling between the microcrystals of the metal, eventually disintegrates the metal. It is linked to the precipitation of chromium carbide along the joints. For it to occur, three conditions must be met: at least 0,035 % carbon, sensitization by maintaining a temperature of 400 to 800 ° C, an acidic external environment with an oxidizing power between two well-defined limits "

C = 0.02% so <0.035% a priori therefore no intergranular corrosion or not very likely, a priori I say .


"Pitting corrosion is generally not due to a heterogeneity of the material but to the accidental presence of a metal dust which, in a humid environment, forms an electric battery. The surface of the steel then constitutes the cathode and corrodes . We can thus see sheets 2 mm thick pierce in a few hours. A medium that is both very acidic and very oxidizing can produce similar effects; "

At the beginning there was none so it should go a priori too

"Stress corrosion causes the objects it attacks to go out of service very quickly. Fortunately, it is very rare. For it to occur, the parts must have parts which are under tension, even slightly, under pressure. effect of service constraints or side effects of welding, stamping ... and that they are also exposed to a corrosive environment such as impure water, chloride solutions even very dilute, hot caustic soda. "

On the other hand ... since the tubes are fixed on the deflector box, there must be a slight constraint even if there are reinforcements after reflection and not only those resulting from the heating ... it is the

"it is necessary that the parts include parts put under tension, even slightly, under the effect of the constraints of service or the side effects of the welds, of the stamping"

that make me say that I bet for stress corrosion more than another .
The trick is that it is slow;) ...

I have finished reading wiki ... it suggests it's clear , but it teaches a lot of cool things like electrolytic polishing that I didn't know but which interests me a lot , a simple electrolysis delirium, for small parts it's cool ...

[bidouille23]

Hello,

Following my reading 316L stainless steel is the least worse of stainless steel, it has a very low carbon content and a little molybdenum which normally gives it a slight better resistance to high temperature but a priori the percentage is not enough to call it refractory steel.

So there is only the future that will tell me how it reacts ...

"Try and error" I think that's the correct term;)

[Alain G]

Hi Bidouille!

I finished reading wiki ... it suggests it's clear, but it teaches a lot of cool things like electrolytic polishing that I did not know but which interests me a lot, a simple electrolysis delirium, for small parts is cool ...

I tried electrolysis cleaning equipment 13 years ago and it did not convince me at all except when the solder is perfect without contamination, where the solder is very easy to clean, it works for soldering at TIG but not for that at Mig which does not give such a good result at the inter molecular level because of the thermal shock.

[Philippe Schutt]

As far as I know, Aisi 310L stainless steel is better than 316L in terms of heat resistance.
This is what pellet stove manufacturers use when the 316L does not hold.

[bidouille23]

Good evening,

Alain personally, I thought I would try on small parts that I don't want to polish the welds, in short, I have my little idea I'm going to try and see the result, it could be enough for what I want to do.



Philippe then thank you the name Aisi allowed me to find more things and indeed the aisi 309 and 310 stainless steel are of the refractory class

cf.

www.larobinetique.com/media/pdfaidemem/page38.pdf

But hey for now let's leave the tubes like that and see their lifespan with regular checks to ensure safety of course.

It's crazy every time we put our finger on something and we scratch a little we open a kind of pandora's box, ...