Insider tips on how to machine and fabricate using TZM (Titanium-Zirconium-Molybdenum)
Acroturn specializes in the machining of Titanium-Zirconium-Molybdenum (TZM), a notoriously difficult material to manufacture, yet revered for its superior strength and wearability properties. As leaders in tough metals machining, here are some insights on best practices for working with TZM for machining and fabrication.
Working with TZM
TZM is machinable by all common machining processes. TZM retains its strength at high temperatures. But at ambient temperatures, it is not particularly strong. TZM’s ductility is not as high as either carbon steel or brass. It is also susceptible to stress and other pressures that may cause cracking. When working with TZM, you can attain excellent surface finishes and exacting tolerations through a close attention to detail.
When working with TZM, machines should be rigid and free from backlash. As well, you should make sure that work is securely clamped.
Tools should be kept sharp. Instead of cutting TZM cleanly, dull tools can tear the material and create micro cracks that diminish a component’s lifespan.
Carbide tools and carbide grades
For most applications, carbide tools may work best because of their hardness and wear resistance. High-speed tools can also be used, so long as their sharpness is intact. Carbide grades work well where longer, uninterrupted cuts are required, while avoiding problems arising from abrasion from chips and dust. See your tool material supplier for more information about the relative performance of different tool material grades.
When machining TZM, heavy machining can be done without lubrication. But for the most part, emulsion lubricants are required to keep dust away from the tool and work piece and keep it cool. Talk to sales rep from a lubricant manufacturer to determine the best lubricant system for your job.
Below are some basic machining recommendations for TZM. They are a good starting for machining this tough metal, to optimize your procedures and minimize costs.
Electrical discharge machining (EDM)
EDM techniques can be used to machine TZM, including both wire EDM and plunge EDM. When machining TZM with EDM equipment, you should minimize the formation of a recast layer on the work piece surface. A recast layer usually has micro cracks and should be removed by mechanical or chemical polishing before placing the part in service
Silicon carbide and aluminum oxide wheels can be used to grind TZM. Consult the manufacturer of grind wheels for identifying the best wheel composition and grinding practices. Proper grinding coolants should also be used to prevent overheating and generate good results.
*Source: The information provided is modified with permission from the International Molybdenum Association. For further details, see the publication Applications of Molybdenum Metal and its Alloys.