The vast body of titanium alloy in precision machining of
2015-12-24 hits: 1160

As everyone knows, the precision machining aerospace industry for material requirements are very high, of course, one is to meet the particularity of aviation equipment, and more importantly because the panorama space effect. Because of the special environmental impact, so the general material on the market certainly can not meet the needs of the environment, will need some special materials for replacement. Today to introduce a common material that is titanium alloy, especially in aerospace applications, it is common, why use this material more? There is a certain relationship between the and its characteristics.

Titanium alloy, the proportion of small, decide the quality, strength and high thermal strength, determines the hardness and high temperature, and the salt water and acid corrosion and a series of excellent physical and mechanical properties, the decision in whatever environment can be used, in addition, the deformation coefficient is very small, so widely used in aerospace, aviation, shipbuilding, petroleum and chemical industries.

Because the titanium alloy has more than ordinary materials and not the same place, it also decided to have great difficulty in precision machining, many mechanical processing plants are not willing to go to the processing of this material, also do not know how to process this material. Therefore, with the grace of lubricating oil through long-term understanding and some titanium alloy processing customers, finishing some small skills to share with you!

Because the titanium alloy deformation coefficient, high cutting temperature, tip stress, work hardening is serious, resulting in a cutting tool, easy to wear, chipping, cutting quality is difficult to guarantee. How do the cutting?

Titanium alloy cutting, the cutting force is small, the work hardening is not serious, easy to obtain good surface finish, but the thermal conductivity of titanium alloy, high cutting temperature, tool wear, tool life, tool should be used with titanium chemical affinity, high thermal conductivity, high strength, tungsten cobalt the type of hard alloy cutting tools, small grains such as YG8, YG3 and other tools. Titanium alloy in the turning process, chip breaking is a difficult problem in processing, especially the processing of pure titanium, in order to achieve the purpose of breaking chip, the chip curling groove cutting part into full arc edge, shallow deep, narrow wide, making chip easily discharged out, so as not to let the chip winding on the workpiece surface, caused by scratches on the surface of workpiece.

The cutting of titanium alloy deformation coefficient is small, and the small cutter chip contact area, high cutting temperature, in order to reduce the cutting heat, the tool rake angle is not too large, hard alloy tool rake angle and generally 5-8 degrees, due to the high hardness of titanium alloy, in order to increase the impact strength of the tool, the tool after the angle should not be too large, generally 5 degrees, in order to strengthen the strength of the tip part, improve heat dissipation, improve the shock resistance of the cutting tools, negative tilt angle larger with absolute value.

Reasonable control of cutting speed, not too fast, and the use of titanium alloy special cutting fluid cooling in the machining process, which can effectively improve the tool life, and select the feed.

Drilling is also commonly used, titanium alloy drilling difficult, often appear in the process of burning knife and broken drill phenomenon. The main reason is the grinding bad chip is not timely, resulting in poor cooling and process system of poor rigidity and other reasons. As the diameter of the drill and grinding, narrow chisel edge, width is generally 0.5 mm, in order to reduce the axial force, reduce the vibration caused by the resistance. At the same time in the distance of the drill tip of 5-8 mm, the drill blade grinding narrow, leaving 0.5 mm or so, is conducive to the drill bit in the chip. The geometry must be grinding right, two cutting edges must be symmetrical, so it can prevent the drill only one side cutting edge, cutting forces are concentrated in the side of the drill wear prematurely, even cause chipping phenomenon due to slippage. Always keep the blade sharp, when the blade blunt, should immediately stop drilling, grinding and cutting bit. If you use blunt drill to drill cutting force, and soon due to friction and high temperature annealing, resulting in scrap drill burn. At the same time thickening hardened layer of the workpiece, to increase the difficulty and the number of re drilling grinding drill. According to the requirements of the drilling depth, should try to shorten the length of the drill, increase web thickness to increase rigidity, prevent the drilling chipping caused by jitter. Practice has proved that Phi 15 bit long 150 longer than 195 life. So the choice of the length is very important.

After the above two kinds of processing, processing of titanium alloy is relatively difficult, but after processing good or can produce good precision parts, titanium alloy parts for aerospace equipment.

(source: titanium wire)