1. Turning and boring of titanium alloys
The main problems of turning titanium alloys are: high cutting temperature; severe tool wear; large cutting rebound. under suitable processing conditions. And neither turning nor boring are particularly difficult operations. For continuous cutting, mass production or high volume metal removal, carbide tools are often used. When forming cutting, turning or cutting, it is suitable to adjust steel tools, also use cermet tools. Like other machining operations, constant force feed is always used to avoid interruptions in cutting. Do not stop or slow down during cutting. Generally, do not cut it, and it should be fully cooled; the coolant can be 5% sodium nitrate aqueous solution or 1/20 soluble oil emulsion aqueous solution. Before forging, the oxygen-enriched layer on the surface of the raw bar should be turned with a cemented carbide tool. The cutting depth should be greater than the thickness of the oxygen-enriched layer. The cutting speed is 20 ~ 30m/min, the feed rate is 0.1 ~ 0.2mm/r, The holes are finely machined, especially for thin-walled titanium products. Burning and clamping deformation of parts should be prevented when drilling.
2. Drilling of titanium alloys
Titanium alloys are prone to slender and curled chips when drilling, and at the same time, the high drilling heat causes the chips to accumulate excessively or stick to the edge of the hole, which is the main reason for the difficulty of drilling titanium alloys. Drilling should be done with a short, sharp drill bit and a low-speed forced feed, and the support frame should be tightened repeatedly and cooled sufficiently, especially for deep hole drilling. During the drilling process, the drill bit should be kept in the drilling state in the hole, idling in the hole is not allowed, and the drilling speed should be kept low and constant. Drill holes carefully. When drilling is about to be drilled, it is best to retract the drill in order to clean the drill, drill holes and remove chips. When the hole is finally broken, forced feeding can be used to obtain a smooth hole.
3. Tap Titanium
Tapping of titanium alloys is probably the most difficult process. When tapping, the removal of titanium shavings is limited, and a severe tendency to bite can lead to poor thread fit, which can lead to tap seizure or breakage. Titanium alloys tend to dry tighten on the tap after tapping. Therefore, blind holes or overly long through holes should be avoided as much as possible to prevent the surface roughness of the internal thread from becoming larger or the phenomenon of taper breaking. At the same time, tapping methods should also be continuously improved, such as grinding the trailing edge of the tap. Axial chip flutes are ground at the tooth tip along the length of the tooth flank. On the other hand, taps with an oxidized, oxidized or chromed surface are used to reduce seizure and wear.
4. Sawing of titanium alloys
When sawing titanium alloys, a low surface speed and continuous forced feed should be used. Experiments have shown that the coarse-toothed high-speed steel saw blades with a pitch of 4.2 mm to 8.5 mm are suitable for sawing titanium alloys. If a band saw titanium alloy is used, the saw blade pitch is determined by the thickness of the workpiece, generally 2.5 mm ~ 25.4 mm, the thicker the material, the larger the pitch. At the same time, the forced supply capacity and the required coolant must be maintained.
5. EDM of titanium
EDM of titanium alloys requires an operating clearance between the tool and the workpiece. The range of the gap is preferably 0.005mm±0.4mm. Smaller gaps are typically used for finishing operations that require smooth surfaces, while larger gaps are used for roughing operations that require rapid metal removal. Copper and zinc are the best electrode materials.