Stainless Steel - A Better Way
A type of centerless grinding that NT wheels handle very well is stainless steel. Stainless has always been a difficult family of steel to grind, especially the austenitic 300 series. It heats up easier and can lose straightness. It is relatively gummy and tends to load wheels. Stainless is more difficult to finish smoothly and tear free.
A traditional wheel for stainless is either vitrified bond having silicon carbide grain or resin bond having 50% silicon carbide/aluminum oxide grain. Vitrified wheels are insensitive to rising work temperature and tend to load more than do resin bond types. A vitrified finish on long bar may be somewhat rough. Typical resin bond wheels are usually better on long bar but have their own problems. The tearing action of stainless on abrasive grains requires a relatively hard resin bond. The high resin/filler content limits the space available for chips to form - possibly causing cutting or loading problems.
Pacer NT wheels having 100% silicon carbide perform well on stainless. The special NT resin and sharper abrasive enable the wheel to be more free cutting - just what is needed for stainless steel. Since NT resin has more tensile strength and grit adhesion, less bond is needed in the wheel. More space is available for chip
formation. Wheel pressure often is less as is the heat generated. Long bar thus tends to remain straighter. The finish from moderate to light passes is excellent - bright and smooth. SiC/AlO (CA) mixed grains are available.
For high thrufeed rates, Ampco 18 or 21 bronze blades are recommended. Carbide can gall at high thrufeed. Bronze often is used flat. A 6" wide C60P7NT wheel can remove .005" from 3/8” dia, 303 ss bars at 40 ft/min while loosing only .0004" per 12' bar. Call for details
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610-383-4200 Fax: 610-383-4239
200 Red Road, Coatesville, PA 19320