What effect does heat have on deflection of valve blade

[BlueBull]

We are manufacturing a valve from a rectangular stainless steel plate 1700 mm x 2150 mm. The deflection of the 20 mm thick plate at normal temp. is 1,9 mm. if the air flow temp is 900 deg C what iffect will this have on the deflection. Is there a way of calculating this effect.

 

[Barry1961]

900 degrees C, (1652F),is above the higher critical temperature for most steels. You may be exceeding yeild at that temperature.
What type of SS are you using?

Barry1961

 

[BlueBull]

We are using stainless steel grade 310

 

[Barry1961]

You are beyond the maximum operating temperature for SS310. Here is a link with some information but not really what you need. Sounds like whatever you are doing will be fun!!

http://www.azom.com/details.asp?ArticleID=1175#_Structural_Stability

Barry1961

 

[arunmrao]

Barry

310 is a well accepted and time tested material for operating temperatures of 900-950C. There is no scaling or creep failure. Ofcourse continuous exposure at this high temperature makes it brittle. Furnace parts, cement kilns,which have a continuous and long campaign use 310 parts.

 

[Barry1961]

Sorry about that, was reading C and thinking F.

Barry1961

 

[EnglishMuffin]

From your post,the geometry and temperature distribution (possibly non-uniform)is not clear. If these are known, and assuming this is not a creep problem, you could almost certainly compute the effects using FEA. For these relatively high temperatures, you will also need to know the relation between the coefficient of expansion and temperature, so a non-linear analysis may be required. If the temperature distribution and geometry are simple enough, you may be able to get close enough with traditional methods. If necessary, you may even be able to calculate the temperature distribution using FEA.

 

[BlueBull]

I managed to find a site

http://www.sandmeyersteel.com/310-310S.html

which gives the following info.
Density lbm/in3 g/cm3
at 68°F (20°C) 0.29
8.03
Coefficient of Thermal Expansion (min/in)•°F (mm/m)•°K
at 68 - 212°F
(20 - 100°C) 8.8 15.9
at 68 - 932°F
(20 - 500°C) 9.5 17.1
at 68 - 1832°F
(20 - 1000°C) 10.5 18.9
Electrical Resistivity mW•in mW•cm
at 68°F (20°C) 30.7 78.0
at 1200°F (648°C) -- --
Thermal Conductivity Btu/hr•ft•°F W/m•K
at 68 - 212°F
(20 - 100°C) 8.0 13.8
at 68 - 932°F
(20 - 500°C) 10.8 18.7
Specific Heat Btu/lbm•°F J/kg•K
at 32 - 212°F
(0 - 100°C) 0.12 502
Magnetic Permeability (annealed)1
at 200H 1.02
Modulus of Elasticity (annealed)2 psi GPa
in tension (E) 29 x 106
200
in shear (G) 11.2 x 106 77

 

[BlueBull]

I have used formulae from R.J.Roark & W.C. Young
I have assumed simply supported edges. These are the results
Plate size = 2,15 x 1700 x 16 (5/8") thick
Working pressure = 50 mm WG = 0,0710476 lb/sq. inch
Deflection = .01246" = 0,3 mm
Max stress = 307 lb/sq. inch
Creep/Expansion in 2,15 meter directio = 35 mm
used 2,15 M x(900-20)x 18,9 is this result possible

 

[prex]

So by deflection you mean the in plane expansion of the blade?
Your result is correct concerning the expansion.
For the out of plane deflection under pressure, suppose you used the Young's modulus provided by that link, that is valid at ambient temperature. Also suppose that when the valve is shut off, the temperature of the plate won't be that of the fluid, as there is no flow. However in this case there is a temperature difference across the plate, with possibly a much higher bow (deflection).


prex

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