with symmetrical patterns only.
Tubular blanks can be formed over a grooved mandrel, which permits internal corrugation of the blank white external shape is rolled. Material and Solid Blank Preparation. Because the Grob Rolling process displaces material instead of removing it, proper material selection is important. With this process, almost any ductile material may be used. Generally, material with a hardness of less than Rockwell "C" 20 works well. If
carbon steel or alloy steel is to be used, it must...
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