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- Dear Dr Popela,
Since you are dealing with a very hard alloy of platinum , which suggests that the platinum has been alloyed with gold or silver, there is certainly the opportunity for segregation in the casting, sometimes called coring, if not properly done. This is due to the large difference in the melting points of these alloys.
The picture of your wire break does not seem to exhibit the typical cup-cone failure associated with a ductile alloy. Instead it appears that there is evidence of segregation because of the cracking and the different degree of elongation at different points in the wire.
I would therefore conclude that the alloy is non-uniform and therefore was cast improperly.
This approximates my total understanding of platinum and platinum alloy wire drawing technology so I cannot help you more. Perhaps others will but it may take a long time, if ever, to obtain an appropriate response. You therefore may wish to investigate this with the metallurgy department or metallurgical engineering department at a good and nearby university..
- Dear all colleagues,
we are currently dealing with trials of drawing a wire from very hard platinum alloy. Unfortunately our wire breaks during drawing.
In this link you can see the picture of the such obtained fracture: www.dropbox.com/s/3ntlk1ear9reh4d/prumer%208%20lom.jpg?dl=0
Could you please tell me whether this kind of fracture (you see less deformed core and more deformed outer ring while they are cracks between them) is caused by inproper / insufficient hot forming of the material before (so it is not that dense and therefore the deformation in the material is not shared everywhere) or is it cause by too high degree of deformation between dies? We currently use 9% of deformation between the drawing dies.
I'd appreciate your opinion on this!
Thanks a lot! Tomas
[File Attachment: prumer8lom.jpg]
- Dear all
I'm looking for supplier for music wire. Our application is for vibrating wire-strain measurement)
(I.E. measuring stress within steel beam). anyone familiar with this kind of application?
Tech.Division- Geotech Science Co.
- Hello Mr. Martin Gerardp Escobar Angel,
Your issues are the insulation faults at the primary insulation line or between the primary insulation process and the multi-passes under the electron beam head. Moreover, I would be quite surprised if the wire storage temperature of 40C (104F) was creating faults although I am unaware of the polyolefin you are actually using.
The increase in faults during irradiation is normal and due to the insulation failures and the energy imparted by the electron beam head.
I always have concerns about a spinning spooling take up at 900 meters/ minute (About 2950 F.P.M.) and flying off at 850 meters per minute (About 2800 F.P.M.). I would look very carefully at the equipment at the take up with focus on the guides and pulleys where damage could occur. Likewise the same careful inspection must occur at the cone packs including the tension control device which prevents kinking and the inside surface of the cones.
If the extrusion faults are proven to occur at the insulation line, you must review your extrusion practices including extrusion temperatures, the time between shut down and clean out, plus the effectiveness of the clean out. Likewise you should know when and where these faults occur. Perhaps it is near the end of the run before the extrusion line clean out is due or just after the extrusion line had been poorly cleaned out. Finally, there had better no damage to the screw, cross head throat or tooling.
- Hello Dear Forum,
Hoping everybody are doing great!!
I have been getting spark leaks at my Irradiation unit working with Polyolefin compound with a 1.42 density, let me put some key parameters at extrusion and irradiation unit
extruder size 80mm
line speed 900 mts/min
x-head average pressure 500 Bars
RPM's average 30
sparker settings 2 Kv
cooling water first stage at 60 C after that water at 27 C
Ebeam size 800 KeV
line speed 850 mts/min
Dosage 7.5 MRad
Sparker settings 5 Kv ( the cable spec ask for this voltage)
My main issue is that at extrusion side I have sometimes 1-2 spark leaks but when this cable pass it thru the Irradiation unit these 1-2 sparks became 6-10 spark faults, I checked the outcoming cable temperature (inside the cone pack where cable is coiled) and is around 40 C, so one of my theory is that this high temp are producing in someway those sparks
I know some units has cooling wire system but they're not very recommended due corrosion and rust of internal chamber of components , has anybody any idea in how to cool down the cable just coming out of E beam and before get into the reel?? I'm very limited with space between devices ( 2 meters) , just thinking on install some high speed air wipes.
some actions that I did were:
Adjust spark detector sensibility
replace some spark detector pieces to fit my process and line speed
I can't go down in energy on irradiation unit because I can have "non cured " cable
align all measurement devices
verify that spark detectors are measuring the right resistance, impedances, etc ( just calibrated)
Running out of ideas now......90 % of my product needs to be rewinded to segregate the spark faults
I'd really appreciate the Forum's support for their tips, advices and time to read this Topic
- Dear Mr. Ajalloueian,
From now on please do not add questions or other statements to old and archived threads. Instead, start up a new thread. Your action caused confusion and delay. Thank you.
As far as your question goes, I did contact Mr. Burke but for some reason, he is unavailable. Thus you will just have to be patient.
I also suggest you talk with a very qualified metallurgical engineer or metallurgist at your local university in order to generate some thought on this issue.