Autoclave temperature effects on existing composite tube/pipe

[JT at Sequent]

We’re looking at purchasing some 6” carbon fiber tube for some materials testing in an upcoming project.  Our needs would be to add additional material onto an existing carbon fiber tube, and send it through another autoclave process to cure the added material layers.  Our main point of interest is in the temperature handling ability of the manufactured tube section.  Our normal processes may go up to around 300° F to cure the new layers of fiber.  Would this exceed the tube’s limits?  What might those temperature limits be?

 

Specific options we are considering from Rock West are…

45568 in 25” length

46326 in a 25” length

35055-U in a 24” length

 

I can see a max operating limit of 238° F on the 45568 and  46326 material specs.  We would naturally minimize the stress to the materials in the autoclave process.  What temperature limits could the materials handle respectively without degrading their original properties. We would naturally put the vaccum pressure on the inner and outer surfaces of the tube to avoid stressing the materials.  We just wonder mainly about the rigidity of the pipe structure in the process.  

Any insight/experience in these matters would be most appreciated. 

Thanks!

[lo_0l]

On 3/27/2024 at 11:30 AM, JT at Sequent said:

We’re looking at purchasing some 6” carbon fiber tube for some materials testing in an upcoming project.  Our needs would be to add additional material onto an existing carbon fiber tube, and send it through another autoclave process to cure the added material layers.  Our main point of interest is in the temperature handling ability of the manufactured tube section.  Our normal processes may go up to around 300° F to cure the new layers of fiber.  Would this exceed the tube’s limits?  What might those temperature limits be?

 

Specific options we are considering from Rock West are…

45568 in 25” length

46326 in a 25” length

35055-U in a 24” length

 

I can see a max operating limit of 238° F on the 45568 and  46326 material specs.  We would naturally minimize the stress to the materials in the autoclave process.  What temperature limits could the materials handle respectively without degrading their original properties. We would naturally put the vaccum pressure on the inner and outer surfaces of the tube to avoid stressing the materials.  We just wonder mainly about the rigidity of the pipe structure in the process.  

Any insight/experience in these matters would be most appreciated. 

Thanks!

Hey @JT at Sequent, welcome to Composites Community!

The spec you're referring to is the glass transition temperature - the point at which the resin begins to change from a solid to a liquid.

Is there a reason you don't want to start with a thicker tube to begin with? Additionally, if you need high-heat capabilities there are other resin systems that can be utilized.

[JT at Sequent]

Thinner is better in this case, it is just serving as a base structure.  The sensor tech being used in this experiment is to be laid into several layers within the build.  Having one layer as close to the inner surface of the tube as we can get is desirable.   We just want to make sure the tube will hold it's shape in the new curing process in the autoclave.  The question is mainly whether the base tube structure can do that since it has already been cured. 

Thanks in advance for the great info!

 

[lo_0l]

5 minutes ago, JT at Sequent said:

Thinner is better in this case, it is just serving as a base structure.  The sensor tech being used in this experiment is to be laid into several layers within the build.  Having one layer as close to the inner surface of the tube as we can get is desirable.   We just want to make sure the tube will hold it's shape in the new curing process in the autoclave.  The question is mainly whether the base tube structure can do that since it has already been cured. 

Thanks in advance for the great info!

 

So long as you don't exceed Tg, you should be good. Do be aware of the exothermic reaction temp. Not just the autoclave temp. And definitely add some margin to ensure you don't exceed your limits.

One thing you could do is insert a mandrel to hold the shape.

[JT at Sequent]

All good points. I'll include that in the material selection process for sure.   I hope to give it all a try soon as the project gets underway. 

Thanks!

[lo_0l]

21 minutes ago, JT at Sequent said:

All good points. I'll include that in the material selection process for sure.   I hope to give it all a try soon as the project gets underway. 

Thanks!

You're welcome! Definitely keep us posted!

We'd love to get some updates and pictures if/when you're able 🙂