Coefficient of expansion linear

Thermal Stresses. When the wak of a cylindrical pressure vessel is subjected to a temperature gradient, every part expands in accordance with the thermal coefficient of linear expansion of the steel. Those parts of the cylinder at a lower temperature resist the expansion of those parts at a higher temperature, so setting up thermal stresses. To estimate the transient thermal stresses which arise during start-up or shutdown of continuous processes or as a result of process intermptions, it is necessary to know the temperature across the wak thickness as a function of radius and time. Techniques for evaluating transient thermal stresses are available (59) but here only steady-state thermal stresses are considered. The steady-state thermal stresses in the radial, tangential, and axial directions at a point sufficiently far away from the ends of the cylinder for there to be no end effects are as fokows ... 

The coefficient of linear expansion of these alloys in the temperature range of 21 to 100°C (70 to 212°F) is 12.2 X lO C (6.8 X 10"V°F), which is slightly above that of cast iron (National Bureau of Standards). Since these loys have practically no elasticity, it is necessary to use expansion joints in relatively short pipe hnes. Connections for flanged pipe, fittings, valves, and pumps are made to 125-lb American Standarci drilling. 

Any bi-niclal combination, having large differences in their coefficients of linear expansion, such as a bimetal of brass and steel is used for sueh applications. One end of a strip is fixed and the other is left free for natural movement. When heated, brass expands more than the steel and bends towards the steel as shown, giving the desired movement to actuate a tripping lever. 

Deflection temperature under load (1.8 MPa) Coefficient of linear expansion (-30°C to +30°C Specific heat 20-300°C >300°C... 

Metal A lomic number Atomic weight Lattice structure Density at 20°C (g/em ) Melting point (°C) Thermal conductivity at 0-l00°C (W/m°C) Specific heat at 0°C (J/kg C) Coefficient of linear expansion at 20-iOO°C X 70 Thermal neutron cross-section (barns) (10-- m ) Resistivity at 0°C (fiil em) Temperature coefficient of resistance o-ioo°c X 10 ... 

Coefficient of linear expansion Unimportant Differences between substrate and coating layer lead to craze and peel... 

---