Protecting steel sections from high temperatures

[morkeldupreez]

Hi there

How can steel structures be protected from 650 to 800 degree celsius temperatures? Can ceramic material be used to coat the steel sections? Will the ceramic material not keep the heat in and weaken the steel?

Any help will be much appreciated

 

[Astronuc]

Hi there

How can steel structures be protected from 650 to 800 degree celsius temperatures? Can ceramic material be used to coat the steel sections? Will the ceramic material not keep the heat in and weaken the steel?

Any help will be much appreciated

What is the application of the steel - building structure or furnace housing? The application is key.

An insulating ceramic will have a low thermal conductivity (insulator) and therefore low heat transfer, which will maintain a high temperature differential across the ceramic. With the heat flux (transfer rate) sufficiently low, with steel can conduct away the heat or the heat is convectively transferred to the surrounding air.

If the heat load is high, then an air or water cooling system could be installed between the ceramic and steel.

 

[Studiot]

You really need to give more details of the application (This is not a homework question I hope)

As Astronuc has indicated it depends upon time and heat flux.

 

[morkeldupreez]

Its something I've seen at a mine a while back and it got me thinking.

Its a structure (a mobile trailer) that they put solidified material on that is around the temperature specified earlier.

They usually dump the material directly onto the steel structure, but due to the heat, the steel beams fail quite regularly.

I thought ceramic material could be a solution but wasn't sure, because I do not know that much about it.

The heat flux and stuf like that is unknown.

I know they use the trailer to transport the material about 1000m.

 

[Studiot]

Its a structure (a mobile trailer) that they put solidified material on that is around the temperature specified earlier.

They usually dump the material directly onto the steel structure, but due to the heat, the steel beams fail quite regularly.

I thought ceramic material could be a solution but wasn't sure, because I do not know that much about it.

The heat flux and stuf like that is unknown.

I know they use the trailer to transport the material about 1000m.

Unknown exactly, but can be estimated sufficiently for our purposes.

From your description, the material placed on the trailer is cooling anyway and does not have a continuous new supply of heat.

I would hazard a guess that refractory linings for the trailer are not used because they are too fragile to survice the dumping process and the jolting from the journey.

I further guess that the beam supports for the trailer are under-designed if they fail often. Simply making them of more massive section should take care of this.

As to the trailer bed you haven't indicated if the hot material is placed directly onto the beams or onto some sort of sheet flooring.

Either way some possibilities suggest themselves.

Firstly any flooring could be double skinned, allowing airflow between the skins. this would prevent excess heat reaching the beam sections.
Alternatively if there is no flooring then flat sacrificial tubing placed (fixed) on top of the beams would serve the same job.

Alternatively the works may simply be in too much of a hurry and allowing the hot material to cool for another couple of minutes may do the trick.

 

[morkeldupreez]

From what I've seen is the current trailer designed in such a way that the hot material is placed directly on top of the steel beams.

They put the hot material on the trailer and it is then transported to an area where it is dumped to be cooled.

The sacrificial tubing is something I did not think of.

Thanks guys