Deformation and corrosion of SS316 welded plate at 300 oC

[KRYM2006]

Hi!
We need to develop a heating plate for the food industry.
Conditions and Requirements:
- Humidity is close to 100%, condensation is visible;
- Temperature is 300 oC (actually cycling between 250 and 300 oC);
- The plate is suspended on nine rods (corners, center, and the middle of each side);
- Size – 40”x24”;
- Maximum weight is about 70 kg;
- The plate should preserve its flatness as much as possible (desirable non-flatness not more than 1/8” per 40”). Bulges are not welcome too;

We are choosing between aluminum and SS316. If we can use stainless steel it will be much easier for us.

Thus, our initial approach looks like following. Two SS316 plates, 0.20” thick at the bottom and 0.375” thick at the top, are stacked. Heating element of about 0.125” thick is placed between the plates. Plates are welded together along the perimeter (from the butt). Weld-in rivets are established each 8”. The resulting structure is mounted in nine points as was mentioned earlier.

Now, two questions:
1) How much this structure will deform if cycled between 250 and 300 oC 24/7?
2) How quickly it is going to corrode?

Does anybody have an experience with similar application?

Thank you in advance!

 

[desertfox]

Hi KRYM2006

Not sure whether you intend to put food directly on your product but aluminium is a definite no no in connection with food.
From the information given we cannot predict what will happen in terms of deflection, stress etc.

desertfox