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How to solve the adhesion problem in aluminum extrusion

25-July-2024

Application case:
In aluminum extrusion production, aluminum bars need to be preheated to 450-500 ℃ and then extruded into shape through steel molds. Aluminum tends to adhere to steel materials above 450 ° C, causing the ingot to stick to the extrusion pad and potentially seal the extrusion cylinder.
In order to prevent the ingot from sticking, the extrusion pad must be quickly separated from the ingot at the end of each extrusion cycle. Usually, a release film oil is applied to the extrusion pad to achieve easy separation.
Customer's concerns:
The customer mainly produces aluminum profiles and uses talcum powder as a release agent, but the effect is average.
Common types of release agents:
Industrial salt: Low price but not environmentally friendly, with unsatisfactory demolding effect.
Talc powder: It needs to be coated while the ingot is cooled, and cannot adapt to the hot cutting method, resulting in average demolding effect.
Acetylene: The generated carbon black is a good release agent, but it is carcinogenic, flammable, and can produce black marks on the aluminum profile.
Petroleum/grease graphite suspension: can produce dirt, is flammable at high temperatures, may cause bubbles and holes to form in the aluminum profile, and may cause electrical equipment short circuits.
Boron nitride: has better demolding properties than graphite and acetylene, but is expensive.
Extrusion process:
The extrusion of aluminum and aluminum alloy rod profiles usually adopts "non lubricated extrusion", which means that lubricants are not allowed to be applied to the extrusion cylinder wall, and only release agents are applied to the extrusion pad.
Squeezing equipment and tools:
Including extruders, ingots, extrusion molds, outlet cooling devices, etc.
Related parameters:
Extruder: 4000 ton horizontal extruder
Ingot material: Aluminum alloy
Ingot diameter: 27.5cm
Ingot length: 86cm
Heating furnace: gas furnace, electric furnace
Heating temperature: aluminum rod 460-500 ℃, extrusion tube 400-430 ℃, extrusion die 430-460 ℃
Squeezing ratio: approximately 230
Squeezing method: forward squeezing
Squeezing speed: 1.8mm/s
Export speed: 0.8mm/s
Existing issues:
When using talcum powder for demolding, cold sawing is required, resulting in high metal loss and low production efficiency.
The demolding effect is average, with occasional aluminum sticking phenomenon.
Solution:
Use boron nitride release agents to improve the demolding effect.
On site application situation:
Boron nitride release agent can not only meet the requirements of non stick demolding, but also improve product quality and extend the service life of extrusion pads.
Product page:https://www.ceramic-solutions.com/Boron-Nitride.html
Contact page:https://www.ceramic-solutions.com/Contact.html
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