What Are The Characteristics Of Titanium Alloy Processing?

What are the characteristics of titanium alloy processing?

When processing titanium alloys, it is extremely difficult and costly. Many experienced masters have encountered setbacks in this situation. Now, we will discuss in detail and in-depth the key matters that must be paid attention to during the processing of titanium alloy. They are all practical and important content and can help you avoid making mistakes.

Small deformation coefficient and large friction

When cutting titanium alloys, there is a significant feature, that is, the deformation coefficient is less than or equal to 1. This situation is completely different from ordinary steel. When the chips flow out, the contact area with the rake face is extremely small, but the pressure per unit area is quite large.

As a result, the friction between the tool and the chips becomes extremely intense. The rake surface of the tool will be quickly ground into a crater, and its wear rate is much faster than that of processing ordinary steel. In actual processing conditions, you will find that the same tool may be used for a long time when processing steel parts. If it is used to process titanium alloy, it must be replaced in just a few hours.

High cutting temperature makes heat dissipation difficult

When titanium alloy is being processed, the temperature of titanium alloy processing is so high that it is extremely scary. The most important reason is that its thermal conductivity is pitifully small. The heat generated during the machining process is basically concentrated in the cutting area and the tool edge, and it is difficult to dissipate quickly through chips or workpieces.

According to data obtained from actual tests, during the process of processing titanium alloys, the temperature in the tool edge area is almost twice as high as when processing stainless steel. There are factories that have conducted comparisons. Using the same parameters for processing, titanium alloy can cause the tool to reach a high temperature of more than 800 degrees in an instant. This is a huge test for the material of the tool.

The cold hardening phenomenon is very serious

Titanium alloys are extremely chemically active at high temperatures and can easily absorb oxygen and nitrogen in the air, forming a hard and brittle outer skin. Moreover, plastic deformation during the cutting process will further increase the surface hardness.

This phenomenon of cold hardening will lead to two direct consequences. One is that the surface of the part will form a hardened layer, which will greatly reduce the fatigue strength. What are the characteristics of titanium alloy processing? The second situation is that the hard-skinned part of this layer will repeatedly wear the tool like sandpaper, thereby greatly shortening the life of the tool. Many parts are scrapped because the surface hardened layer is not properly processed.

Be particular about tool selection

For titanium alloy processing, the tool quality must be excellent. Tools specially used for titanium alloy processing are an ideal choice. If there is no such special tool, you can choose a carbide tool with a hardness of 55 degrees upwards, which is the world's leading level in titanium alloy processing , because the higher the hardness, the better the heat transfer effect.

Here is a special reminder: try not to use coated tools. In view of the fact that titanium alloy will have an affinity reaction with the titanium in the coating, causing serious knife sticking. In the actual machining process, many novices choose ordinary coated knives to save trouble, and in the end the tools are quickly scrapped.

Cutting parameters should be lowered

When processing titanium alloys, the cutting linear speed must be reduced, and a low-speed, low-feed strategy must be adopted. Why is this so? Because the heat transfer rate of titanium alloy is slow, once it is cut at high speed, the heat will accumulate locally, and the tool tip will soon be burned out.

During rough machining, special attention must be paid to the issue of tool yield. Titanium alloy is a relatively soft material, so it is very easy for the cutting to fail to reach the position, but it is basically unlikely that overcutting will occur. Therefore, the margin should be kept as small as possible to avoid repeated processing, so as to ensure dimensional accuracy.

Cooling measures must be in place

Never perform dry cutting when machining titanium alloys, and be sure to fully cool it, especially in the finishing stage of small and micro-cutting. The small chips generated may burn at more than 200 degrees, which will seriously affect the quality of the product.

Many factories use high-pressure and large-flow cooling methods to directly take away the heat generated in the cutting area. An experienced master craftsman concluded that if the cooling does not reach the corresponding level, then the processing of titanium alloy is basically a waste of effort. Either the processed size does not meet the requirements, or the surface is burnt.