Valve Stem made of Cast Bronze

[WAJDI]

Can we use cast Bronze as a stem material or is the Forged type is the mostly preferred ?
The valve is an angle Globe valve used as a fire hydrant. The service is Sea or Raw water at normal conditions. The valve Body is made of ASTM B150 C63200 Cast Bronze.

 

[cranekiran]

Hi,

Have you considered the axial forces & bending forces on the stem? Depending on the total pressure acting on the disc,your stem should be able to withstand the load safely.
calculate the stem dia. wrt the ultimate tensile or compressive value for the material you intend to use as the stem material.I suggest you to consider giving all the details to a good valve design engineer before deciding on anything drastic.
Bye!

 

[keyardee]

Hi,wajdi,Normally for all valve stem applications it is customary and logical to use 'wrought' products like forged, or rolled or extruded rods.These products have better grain structure and capable of withstanding repeated compressive stresses and operating torque(in case of rotating spindle designs).For these reasons Cast rods are not preferred.In your service (Fire fighting) reliability is more important, and as such go for forged/rolled/extruded valve stems only.