×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

What effect does heat have on deflection of valve blade

What effect does heat have on deflection of valve blade

What effect does heat have on deflection of valve blade

(OP)
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.

RE: What effect does heat have on deflection of valve blade

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

RE: What effect does heat have on deflection of valve blade

(OP)
We are using stainless steel grade 310

RE: What effect does heat have on deflection of valve blade

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.

RE: What effect does heat have on deflection of valve blade

Sorry about that, was reading C and thinking F.

Barry1961

RE: What effect does heat have on deflection of valve blade

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.

RE: What effect does heat have on deflection of valve blade

(OP)
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

RE: What effect does heat have on deflection of valve blade

(OP)
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

RE: What effect does heat have on deflection of valve blade

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

http://www.xcalcs.com
Online tools for structural design

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources