Baoji Baoze Overcomes The Technical Problems Of Titanium Alloy Precision Machining

Titanium alloy, its small specific gravity determines its small mass, high strength and thermal strength, determines its hardness and high temperature resistance, and has a series of excellent physical and mechanical properties such as resistance to seawater and acid and alkali corrosion. In addition, the coefficient of deformation is very small, so it has been widely used in aerospace, aviation, shipbuilding, petroleum, chemical and other industries.

Just because titanium alloy has the above differences from ordinary materials, it also determines that it is very difficult in precision machining. Many machining factories are unwilling to process this material, and do not know how to process this material. . For this reason, after long-term understanding and communication with some titanium alloy processing customers, Suien Lubricant has sorted out some small skills to share with you!

Due to the small deformation coefficient of titanium alloy, high cutting temperature, large tool tip stress, and severe work hardening, the tool is easy to wear and chip during cutting, and the cutting quality is difficult to guarantee. So how to do cutting?

When cutting titanium alloy, the cutting force is not large, the work hardening is not serious, and it is easy to obtain a better surface finish, but the thermal conductivity of titanium alloy is small, the cutting temperature is high, the tool wear is large, and the tool durability is low. Small chemical affinity, high thermal conductivity, high strength, small grain size tungsten-cobalt cemented carbide tools, such as YG8, YG3 and other tools. In the turning process of titanium alloy, chip breaking is a difficult problem in processing, especially in the processing of pure titanium. In order to achieve the purpose of chip breaking, the cutting part can be sharpened into a full-arc chip flute, shallow at the front and deep at the back, narrow at the front The wide back makes the chips easy to discharge outwards, so that the chips will not wrap around the surface of the workpiece and cause scratches on the surface of the workpiece.

The cutting deformation coefficient of titanium alloy is small, the contact area between the tool and chips is small, and the cutting temperature is high. In order to reduce the generation of cutting heat, ① the rake angle of the turning tool should not be too large, and the rake angle of the carbide turning tool is generally 5-8 degrees , due to the high hardness of titanium alloy, in order to increase the impact strength of the turning tool, the back angle of the turning tool should not be too large, generally 5°, in order to strengthen the strength of the tip part, improve the heat dissipation conditions, and improve the impact resistance of the tool Ability, using a negative blade inclination angle with a large absolute value.

Control reasonable cutting speed, not too fast, and use titanium alloy special cutting fluid for cooling during processing, which can effectively improve tool durability and select reasonable feed rate.

Drilling is also commonly used. Titanium alloy drilling is more difficult, and burning and broken drills often occur during processing. The main reason is poor sharpening of the drill bit, untimely chip removal, poor cooling and poor rigidity of the process system. Depending on the diameter of the drill bit, the chisel edge is narrowed and the width is generally 0.5mm in order to reduce the axial force and reduce the vibration caused by resistance. At the same time, at a distance of 5-8 mm from the tip of the drill bit, the edge of the drill bit is narrowed, leaving about 0.5 mm, which is conducive to the chip removal of the drill bit. The geometric shape must be sharpened correctly, and the two cutting edges must be kept symmetrical, which can prevent the drill from cutting on only one edge, and the cutting force is all concentrated on one side, causing premature wear of the drill, and even chipping due to slipping. Always keep the cutting edge sharp, and when the cutting edge becomes dull, stop drilling immediately and resharpen the drill bit.

If you continue to forcibly cut with a blunt drill bit, the drill bit will soon be burned due to friction and high temperature, and the drill bit will be scrapped due to annealing. At the same time, the hardened layer of the workpiece is thickened, which increases the difficulty of re-drilling and the number of times for grinding the drill bit. According to the drilling depth requirements, the length of the drill bit should be shortened as much as possible, and the thickness of the drill core should be increased to increase rigidity and prevent chipping due to vibration during drilling. It has been proved by practice that the φ15 drill bit has a longer life of 150 than that of 195. So the choice of length is also very important.

According to the above two commonly used processing, the processing of titanium alloy is relatively difficult, but after good processing, good precision parts can be processed, such as titanium alloy parts for aerospace equipment.