Titanium Alloy Workpieces Too Hard? Tool Wear Issues? BJCJTi Experts Advise: Incorrect Machining Methods Are the Problem!
Titanium alloys are inherently hard and high in strength, often leading to tool wear during machining. What techniques can ensure smooth and successful processing? Titanium and titanium alloys are new materials that have emerged only in recent decades, classified as non-ferrous metals. Due to their unique properties and cutting characteristics, their machinability is relatively poor. However, by fully understanding their performance and selecting appropriate cutting conditions, successful machining can be achieved.
First, What is the Composition of Titanium Alloy?
Titanium alloys possess a range of excellent mechanical and physical properties, including low density (approximately 4.5 g/cm3), high strength, and corrosion resistance to various media such as acids, alkalis, seawater, and the atmosphere. Consequently, they are increasingly utilized across industries like aviation, aerospace, nuclear energy, chemical processing, petroleum, metallurgy, and medical equipment.
Classification of Titanium Alloys. Titanium is an allotropic isomer with a melting point of 1720℃ and an allotropic transformation temperature of 882℃.
Performance Characteristics of Titanium Alloy.
- • High specific strength.
- • High thermal strength.
- • Good corrosion resistance.
- • High chemical activity.
- • Low thermal conductivity and low modulus of elasticity.
- • Good low-temperature performance.
Cutting Characteristics of Titanium Alloy
When the hardness is less than 300HBW, titanium alloys are prone to tool adhesion and are difficult to cut. The optimal cutting hardness for titanium alloy is 300～350HBW. The difficulty in cutting titanium alloys is not solely due to hardness but also influenced by their inherent mechanical, physical, and chemical properties. Their cutting characteristics are as follows:
- • Small deformation coefficient.
- • Poor cutting thermal conductivity.
- • High cutting force per unit area.
- • Tools are prone to wear. After forging, hot rolling, and other processing methods, titanium alloy blanks form a hard, brittle, and uneven outer skin, making intermittent cutting highly prone to tool wear.
- • Prone to forming a surface degradation and contamination layer.
Conclusion
Although titanium alloy is considered a difficult-to-machine material, by thoroughly understanding its properties and cutting characteristics, and by making appropriate selections for tool materials, tool geometric parameters, cutting parameters, and cutting fluids, along with addressing common machining challenges, various cutting operations can be successfully completed.