Qualifying WPS for tensile strength only

[waqasmalik]

Hi all, i have a question that why only tensile strength is qualified while qualifying any WPS? Some parts may also be under shear stress so why not shear stress at times?

 

[weldstan]

Codes wish to make sure that the welding procedure produces mechanical properties equal to the minimum tensile properties of the base metal and provide minimum ductility (bend tests) approximately equal to that of the base metal.
It is also somewhat more difficult to make shear tests and shear properties are a function of tensile/yield properties anyway. Engineers need to design the item with regard to shear, fatigue, stress corrosion cracking service, etc.

 

[metengr]

I agree with weldstan. The main purpose for weld procedure qualification is to demonstrate the weld and surrounding base material meet or exceed the base material mechanical properties. Tensile properties are most common to measure with shear being related to measured tensile properties.

 

[BUGGAR]

The engineer designs the connection configuration to be strong enough using appropriate materials (steel grades). If the welds in the connection meet the strengths of the joined materials, the connection works. This way, the welder doesn't have to worry about anything other than laying good bead. Let the engineer worry about the shear and tension and the stuff he's supposed to know about.

 

[tbuelna]

A WPS is usually validated by inspecting/testing specimens taken from a qualification test weld sample. However, the WPS itself is usually created by engineers, and the WPS qual test requirements are defined by engineers/analysts. So if the engineers/analysts sign-off on a WPS that only requires qual testing of tensile specimens, then it is likely they have allowed for the difference between shear and tensile properties in the weld joint.