Trimming process requirements and methods for titanium alloy forging

In the application of various titanium alloy products, forgings are mostly used in occasions requiring high strength, high toughness, and high reliability, such as gas turbine compressor discs and medical artificial bones. Therefore, not only high dimensional accuracy is required for forgings, but also materials with excellent characteristics and high stability are required. For this reason, in the manufacturing process of forge titanium ring, the characteristics of titanium alloys should be fully utilized to obtain high-quality forgings. Titanium alloy metal is difficult to forge and is prone to cracks. Therefore, it is very important to properly control the forging temperature and plastic deformation in the production of titanium alloy forgings.

Trimming of titanium alloy forgings must meet the following requirements:

1. The incision is smooth, and the metal on the blank must not collapse.

2. There must be no cracks in the part adjacent to the incision surface of the blank, and there must be no uneven grain size caused by uneven trimming deformation.

3. No indentation of the punch shall be left on the trimmed blank, and the shape of the punch and the part shall be exactly the same.

The edge can be trimmed with a milling machine or cut with a band saw and a specially designed friction plate. For large forgings and thick burrs, regardless of the size or batch size of the parts, it is inconvenient to thermally trim the edges, and flame cutting is an effective method. Oxygen gas, plasma, and other techniques can be used to successfully and economically cut burrs of 50 mm or thicker. After flame cutting, heat treatment should be carried out so that the heat-affected zone can be machined. For larger batches of medium and small titanium alloy forgings, the edge is usually trimmed with a die on a crank press, and the edge trimming is carried out at 600-800°C. If straightening must be carried out immediately after trimming, the trimming temperature should be close to the upper limit. Titanium alloys are rarely trimmed with a mold in a cold state because the burrs are very hard and brittle, which may easily cause uneven incisions, and even cause the risk of metal cracking and rapid debris splashing; for some alloys with a high degree of alloying, cold trimming It will cause cracks on the shear surface, and the cracks will extend into the metal from time to time.