How can I measure the friction coefficient of the aluminum alloy when welding this alloy with another metal using the friction welding technique. Note that variable-temperature welding between 25-400C or more. All literature imposes a fixed parameter. But the coefficient of friction as is well known, it changes with the temperature rise. Is there any practical information or Standard experience illustrates the measurement process.
Moment of friction can be measured using let's say piezoelectric transducer or strain gauge attached to the piecework during the FSW pin plunging into it. Since friction-induced heating is achieved for a short time within the subsurface layer it will not strongly change the COF. Another more important factor for the COF growing is aluminum alloy sticking to the FSW tool.
yep just simulate the process in the FEM software and increase the friction from zero until you get the acceptable results.
My question clearly is how can be measured by the coefficient of friction in practice method and not in a way of simulation. The simulation is an imagine to get the perception of process, but does not represent the reality and the practical situation experienced by the materials ... there are a lot of articles that describe the simulation of the coefficient of friction, but not the way of experiment. Thanks
μ = F/ N where F is the rotational force at constant velocity and N is the load assuming that your machine is instrumented with sensors for these forces. Take measurements at different constant speeds up to speeds that produce plasticity. This is just an approximation and in reality it may be difficult to capture this information.
For calculating the coefficient, You seriously require a high temperature tribometer updated with load capacity of at least 30 N. I am recently continuing with this test.
I think, the fist of all, you must measure the forces during the operation, via math equations you can measure the friction coefficient. Another method of measure fiction coefficient is using modelling methods by the help of software programmes.
good lucks for you studies
Assist. Prof. Dr. Zülküf DEMİR
I strongly believe that it could be more accurate to measure the friction coefficient and its variation with process parameters regardless the process (i.e. FSW). In other words, avoid choosing the friction coefficient in that way the forces of the numerical simulation fits that measured experimentally.
Probably this paper could help you: "Finite element modeling of the linear friction welding of GH4169 superalloy "
If the friction welding machine is a sophisticated machine and can record torque during welding, the following formula can be used for calculating COF.
COF- T/FR
T-Torque, F-Axial Force, R-Radius of the rod
Hi
there are two ways.
first you can do Disk Rotating test which is a standard test to calculate the friction between materials using rotating torque needed.
secondly is to calculate during the welding process which need to equip your machine with torque meter, speedometer and force sensors.
for more info, google for Friction testing methods.
i hope it helps
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