The processing of titanium alloys is mainly divided into three categories: “material reduction manufacturing” (such as turning, milling, drilling, and grinding) that removes materials, “plastic processing” (such as forging and rolling) that is based on molding, and “additive manufacturing” (that is, 3D printing) that accumulates layer by layer.Among them, material reduction manufacturing is common, but it is also challenging.
Material reduction manufacturing
This is the titanium
Turning and boring: used for machining rotary bodies.The core difficulty is the high cutting temperature and fast tool wear.It is recommended to use YG cemented carbide tools (such as YG8) to keep the blade sharp, use a lower cutting speed (about 40m/min for rough turning, about 60m/min for fine turning), and must be fully cooled.
Milling: Used to process planes, grooves, etc.The difficulty is that intermittent cutting can easily lead to chipping.In terms of technology, it is recommended to use the forward milling method and use high-speed steel or cemented carbide tools.In order to reduce vibration, the rigidity of the entire process system should be improved.
Drilling and tapping: This is one of the difficult processes, prone to knife burning and broken drilling.In operation, it is necessary to return the knife frequently, force feed, and use special cutting fluids such as soybean oil to fully lubricate.When tapping, you can choose a “jumping tap” and appropriately increase the size of the bottom hole to reduce the risk of the tap getting stuck.
Grinding: Used to obtain high surface quality.The main problems are clogging of the grinding wheel and burns on the surface of the workpiece.Green silicon carbide (TL) grinding wheels should be selected, with softer hardness and thicker particle size, and with sufficient cooling, otherwise the high temperature will cause the fatigue strength of the parts to decrease significantly.
Key common points：
Tools: Tungsten-cobalt (YG) cemented carbide is preferred, and titanium-coated tools are avoided to prevent affinity reactions with titanium alloys.
Cooling: High-pressure, high-flow coolant must be used, which can not only improve cutting speed and tool life, but also improve the quality of the machining surface.
Plastic processing
This kind of process is mainly used to produce raw materials or blanks of titanium alloys, such as plates, bars, forgings, etc., which are key links in the upstream manufacturing industry.
Forging: Deformation of titanium alloy by applying pressure is the core process of manufacturing bearing parts such as aircraft structural parts and engine discs.Depending on the temperature, it is divided into high-strength (α+β) forging and β forging that can improve fracture toughness.
Rolling: Used in the production of titanium plates, titanium tubes, titanium rods, etc.It is formed by letting the metal pass through a rotating roll.For example, the production of thin titanium plates requires multiple processes such as hot-rolled billet opening and cold-rolled finishing.
Extrusion and drawing: Extrusion is used to manufacture profiles and pipes with complex cross-sections; drawing is used to produce wires and thin pipes.For titanium alloys that are difficult to deform, “package extrusion” technology is sometimes used for processing.
Additive manufacturing
This is a “scratch-from-scratch” technology, especially suitable for manufacturing parts with complex internal structures and difficult to process by traditional techniques, or for repairing expensive parts.
Principle and process: Through computer control, the metal powder is melted layer by layer to build the entity.The main processes include laser selective melting (SLM, suitable for small and medium-sized precision parts), laser cladding deposition (LMD, suitable for large parts or repair) and so on.
Typical applications: In the aerospace field, the material utilization rate of titanium alloy propellers manufactured with it can be greatly improved from the traditional method; in the medical field, bone implants can be customized based on patient data.In addition, this technology can also repair the overall blades of the high-value aero-engine, so that the performance of the damaged parts can be restored.
Different processing environments and requirements have different processing techniques, so choose the method that suits you.
