Blade development helps high-temperature alloy turning

Challenge: Poor machinability

High temperature alloys (HRSA) are very demanding on machine tools because they have high strength at high temperatures. These properties make it an advantage as a part material, but due to its high mechanical load, there is a large amount of cutting heat on the cutting edge, which means that its machinability is poor. The specific cutting force of a typical superalloy material (a standard that directly measures the degree of difficulty in machining a cutting material) is almost twice the cutting force of a typical steel. Nickel-based, iron-based or cobalt-based alloys have unique properties that can be used in the aerospace, energy, and medical industries, with performance that varies only near their melting point. But in terms of processability, this also means:

- higher power required;
- need ultra-stable processing conditions;
- high requirements for cutting edges;
- optimized coolant application;
- Select the most suitable tool in the application.

Choosing the right cutting edge is a very important factor in the turning of superalloy materials. Round inserts are the basic choice for many processes.
Unlike other blade shapes, the Xcel insert offers a solution with a reachability of 93° tool and a 45° entry angle. The depth of cut is suitable for semi-roughing operations.

When the cutting edge is affected by a combination of high stress, high strain and high heat, it is easy to generate many harmful wear. Large compressive and shear forces act on the cutting edge, making it susceptible to damaging effects. To make matters worse, the surface of the superalloy material is easily hardened, which may cause other types of wear, which may cause excessive burrs on the part and make subsequent processes more difficult.

When machining superalloy materials, the cutting speed is naturally limited, so the machining must be kept at a much lower cutting speed than most workpiece materials. When processing high-temperature alloy materials, the cutting parameters should be comprehensively considered: speed, feed rate and depth of cut. These cutting parameters directly determine whether a process can be successfully completed.

Care must be taken to plan the processing of superalloy materials before processing, as this is a critical determinant. First of all, we must consider the state of the workpiece material, whether it is a casting, a forging or a bar, whether it is a heat-treated part, a solution heat-treated part, or a material has been aged, etc., which will affect the choice of tools and processing methods. The surface of the workpiece is changed, the hardness is mainly affected by the processing, and the hardness varies from HRC30-50. The processing strategy for superalloy turning must also meet the following requirements: composition form, different stages of processing (roughing, semi-finishing or finishing).