Will the friction under screw head increase in a screw joint when hardness of clamped part increase?

In a screw joint screws are used to fix a Flange to a Pump housing. Assembly torque is 13Nm. Below screw head there is no washer. Screw head directly rests on Flange surface. Flange is made of...

03 March 2016 9,848 3 View