Wire Drawing

Much more important than people realize, your tyres are riding on this wire…

From my presentation to the Wire Association International in 2004. Still the most wonderful, talented group of engineers I know.

Lubrication in steel wire drawing operations generally brings soap powders to mind. For larger wires this is uniformly the case. The soap powder melts in the wire/die interface and provides a viscous film that supports the drawing force. The fillers and additives in the drawing soap impart polishing, extreme pressure, and many other properties to the lubricants. As wire sizes get smaller, the soap powders become unsuitable for high performance drawing. The viscosity of the molten film is too high, and the film occludes the hole, reducing the wire diameter and eventually breaking the wire. Additives may corrode the wires causing breaks. The polishing aids and other particulate materials may be drawn into the wire, weakening it and resulting in failures. Wet drawing lubricants are required to overcome this problem.

Wet drawing lubricants are based on water and/or oil and have considerably lower viscosities than the molten soaps they replace. This reduces the film thickness and the chances that the film will occlude or block the die orifice. Wet lubricants do not contain particulate materials, so foreign inclusions are not drawn into the surface from the lubricant. The additive level is much lower in a wet lubricant and can be controlled by dilution. The wet lubricants also provide cooling to the operation, a feature absent from dry drawing operations. The wet lubricant requires different maintenance techniques than those required for dry soaps. A comparison of the two types of wet lubricants and their individual requirements for usage will be presented.

I’m Katherine, and I’m a chemical tribologist in the metalworking industry. What’s that? A chemical tribologist is a chemist who studies friction and wear. I became interested in this field when I was a co-op student at Drexel University. I co-oped for Apex Alkali Products (now RichardsApex Company), where I learned the fundamentals of lubrication as it applies to wire drawing processes. The work was so interesting that I stayed with Apex for long after my co-op cycle was over! I began to work on lubricant development projects and use bench testing machinery. It was very exciting to see the chemistry I had learned in school in action.

The funny thing is, this all started long before college, or even high school. As a little girl, I had the opportunity to visit the new foundry of the New York Air Brake company (now Knorr Brake). My father is a mechanical engineer (everything in life is a force balance!), and was part of the product design team at the Air Brake. The children on the tour got to do some of the things that the foundry workers did every day. I got to make a sand cast of a complex pnuematic valve assembly. This involved pouring the sand and pressurising the mould. I then inserted little styrofoam blocks into the sand cast to support it under the weight of the molten metal. I put the sand cast onto a conveyor, and followed it to a platform where I was directed to pull a large handle- it was as long as I was tall! The parts came out of the other end of a large machine, and we follwed them around the factory as they were machined and fitted out. Many years later, I realised that I had pulled the ladle and made an iron casting. It was a long time before I figured out what each step of the process was for and what I had actually done, but from the day of the visit on, I was completely fascinated by manufacturing and big metal. The foundry experience shaped my life in ways I wouldn’t appreciate for over 15 years.

After 2 and a half years at Apex, I decided to finish my coursework full time. I left Apex for a year of intense study and graduated from Drexel University in 1994 with my BS in Chemistry.

After graduation, I joined Houghton International, a leading independent manufacturer of metalworking fluids. This is where the fun really got going! I started in the Fluid Power group, learning about hydraulic systems and their lubrication requirements. That didn’t last long, as an opening turned up in the Metal Forming group. Metal forming is the chipless deformation of metals- and wire drawing is one of the many processes that fall under its umbrella. I was right at home!

While working at Houghon, I had many opportunities- I completed my MS in Organometallic Chemistry at Drexel in 1998, and passed my candidacy exams for PhD in January of 2000. I hope to complete my PhD one day. I have also published several research and technology papers (see list below). I have become very involved in the development of new lubricant testing methods which provide more representative pictures of the lubrication system at work in a given process.

I worked with several processes at Houghton- non-ferrous (aluminum and copper) wire drawing, steel wire drawing, hot and cold forging, cold heading, deep drawing, stamping, fine blanking, rolling, extrusion and many other low metal loss processes. I occasionally worked with sintered metals and die casting. I was asked to design lubricants for each of these processes. This required a complete understanding of the process and its lubrication requirements. My mechanics background came in very handy with this part of the job! I then mapped the process by determining the simplest configuration of testing pieces which will give an accurate representation of the conditions of the metal/die contact I was studying. I also developed test methods for the bench tester I planned to use. Some of the testers I used are the Falex pin and vee block rig, the 4-ball EP and 4-ball wear, the ball on three disc, and the Reichert device.

My favourite project is the development of specialised lubricants for the wet drawing of steel filaments. I hope to obtain a patent on this work.

After 7 great years at Houghton, I was approached by Arizona Chemical Company, the chemicals division of International Paper to take over their metalworking program. Arizona takes waste streams from the kraft paper pulping process called black liquor and refines these wastes into pure fatty acids and fatty acid blends. Nearly 30% of the material is made of rosins and rosin acids These important materials play a big role in metalworking by forming strong films which support heavy loads.

I was doing research to study how Arizona’s products can be used in metalworking. It was a lot of fun, and was the opportunity I was looking for to do molecular level development work. Arizona is in Savannah, GA, a beautiful southern city with a lot to offer!

Now I’m at Henkel Corporation outside of Detroit. Back at home, if you ask me!

To learn more about tribology, check out the Society of Tribologists and Lubrication Engineers and the American Society of Mechnical Engineers.