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TECH INNOVATION

Super effectiveness is Required for

MACHINING SUPERALLOYS

uperalloys - metal alloys, which Exceptional high-temperature the ISO S group application. Depending on
reflect their complex alloyed struc- strength and corrosion resistance are the the prevailing element, superalloys are di-
Sture, have become one of the main undeniable advantages of superalloys. vided into three types: iron (Fe), nickel (Ni)
engineering materials for a long time. They However, there are two sides to the coin: and cobalt (Co) based alloys. Machinability
feature extremely high elevated tem- superalloys are not only highly priced, drops in the specified order; from the iron-
perature strength, and therefore often are but their machinability is poor, which can based alloys, which can be compared with
referred to as high-temperature superal- pose challenges to manufacturing. The austenitic stainless steel, to cobalt-based
loys (HTSA) or heat-resistant superalloys specific cutting force that characterizes alloys that represent the most hard-to-cut
(HRSA). The history of superalloys started the resistance of the material to chip materials in the group.
with the development of gas-turbine removal and defines the mechanical Increasing efficiency of machining
engines that required reliable materials for load on a cutting tool is high for superalloys has become the focus
high operating temperature ranges. As a superalloys. Although the main difficulty of various scientific research and
result of intensive research and progress is heat, superalloys have poor thermal technological improvements. Their result
in metallurgy, modern superalloys (SA) conductivity. Elemental and loose chips, was a significant advance in producing SA
provide a long service life for working which are generally generated when components. Manufacturing has effectively
temperatures more than 1000°C. machining superalloys, do not provide embraced new machining strategies and
Understandably, the largest superalloy adequate heat dissipation from the cutting innovative methods of cutting coolant
consumers today are aero- and marine zone. A tendency to work hardening supply, such as high-pressure cooling
engine producers (Fig. 1). Superalloys are makes the situation worse. (HPC), minimum quantity lubrication
also very common in the medical industry, The manufacturer deals with various (MQL) and even cryogenic cooling has
which effectively use them for prosthetic SA workpieces: cast, wrought, sintered, successfully been introduced. This has
implants in orthopedic surgery. In addition, etc. The workpiece fabrication methods taken the productivity of machining
superalloys have become widespread also have an impact on machinability. superalloys to a new level. However, like
in power generation and the oil and gas For example, abrasiveness of forged in the case of titanium alloys, the key
industries as crucial materials for essential workpieces higher that cast ones element for improving the productivity of
parts of various devices. substantially lower in comparison with SA machining is a cutting tool that directly
sintered workpieces. removes material layers from a workpiece
Consequently, a cutting tool is under that produces chips. A cutting tool features
significant thermal and mechanical load, the tool material and its geometry, which
which dramatically reduces tool life. determines the tool’s triumph or its failure.
Therefore, in machining superalloys, the Today, coated cemented carbides
cutting speed directly connected with are the most common materials for
the heat generation during chip removal cutting tools for machining superalloys.
is considerably lower when compared The development of a carbide grade, in
to other common engineering materials which strength and wear resistance will
such as steel or cast iron. The direct be mutually complemented is a tricky
result of the cutting speed limitation is process that requires an appropriate
poor productivity. Hence, overcoming carbide substrate, coating composition,
machining difficulties and increasing and coating method. To the amazement of
Fig. 1 – Superalloys are the key productivity are the main challenges for those who believe that the breakthrough
materials for turbojet and turboprop
engines of modern aircrafts. Jet engine the manufacturer of SA parts. possibilities in this direction are almost
blisk machined with ISCAR’s CUT- According to ISO 513 standard, superal- exhausted, cutting tool producers continue
GRIP systems. loys together with titanium alloys relate to to create new effective carbide grades.

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