Materials

There's something new under the sun for aerospace composites.

Endmilling stainless steel and aluminum reveals that these two materials are surprisingly similiar.

New alloys improve the performance of HSS cutting tools.

The use of compacted graphite iron is continuing to grow, particularly for automobile castings. The benefits of CG iron vs. gray cast iron are its ability to handle heat better and better machinability. The author gives an overview of the material's characteristics and discusses feed-and-speed considerations when machining CG iron.

An expert on heat treating write about the advantages and disadvantages of available approaches and systems: stainless steel foil, atmospherically controlled furnaces, pressure-quench vacuum furnaces and two-zone vacuum furnaces. There's also a sidebar on cryogenic treatment of metals.

Due to the exceptional strength of IN 100, INCO 718 and other nickel-based alloys, they're difficult to machine. The author, who spent 40 years endmilling these aerospace materials, discusses their unique characteristics and methods for successfully machining them.

Author discusses the advantages of CVD-diamond tools compared to other types of diamond tools. He also explains how CVD-diamond tools are manufactured and gives case histories involving their usage.

The trend toward developing finer and finer carbide grains continues. The author looks at recent developments in the production of nanosized tungsten-carbide grains, which are smaller than 0.2 microns in diameter. Though not used widely at present for the production of cutting tools, some predict that will change as the technology evolves.

High-silicon aluminum--aluminum that consists of at least 11.8 percent silicon--has qualities such as lightness and strength that appeal to automakers. The abrasives nature of the material, however, makes it difficult to machine. The author offers suggestions for milling, tapping, drilling, turning and grinding high-silicon aluminum.

When shops crank up the speed, they have to be prepared for the consequences, even if they’re milling "easy-to-machine" aluminum.