Hello there,
I need help and suggestion from you experts out here.. I am doing my master thesis regarding copper capillary tubes. At the moment I am doing a drawing process for tubes with internal plug for tube with dimension 2mm outer diameter x 0.6 mm wall thickness, with weight 150 kg.. With this weight, the tube length is so long , about 7 km..
The capillary tube should later be annealed to get that annealed/ soft state.. Before going into the annealing furnace, the tube has to be purged with Nitrogen (to remove the oxygen to prevent oxidation).. With 5.5 bar nitrogen pressure (pressure of the gas from the gas pipeline of the oven) I would need about 10 hours to blow the whole length of tube with nitrogen.. But i thought, hmm, i could get a nitrogen gas tank which can go up to 100 bar - my problem is solved..
But in the annealing furnace, the oil/lubricant residue from the drawing process will be evaporated due to high temperature in the annealing furnace.. But because the length of the tube is tooooooooooo long and the pressure drop inside the capillary tube is too high, it is unlikely that the "evaporated" oil/ lubricant can be fully removed from inside the tube..
I need suggestions, what kind of lubricant that is suitable for drawing this capillary tube?
What is high viscosity and low viscosity oil? Does high viscosity oil means oil with high carbon contain?
I have tried using thin oil (Rhenus 6040), but the capillary tube immediately broke during the start of the process - gliding properties is very bad??
Then I tried using medium-viscosity oil (medium thickness) - Kubitrac 4068 - the process worked fine sometimes but sometimes the tube broke..
I think, for my the capillary tube drawing, i would need to use medium viscosity oil to achieve that hydrodynamic lubrication... but the question is is there medium viscosity oil for drawing tube process that has low carbon contain? (because the internal cleanliness that should be achieved for this tube us quite high 0,2mg/dm2) ..
Thanks so much!
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