luring machining. The trade-off to this combination of properties, however, is the loss of transverse properties, including th, ductility, and tough ess Fig. 14 Significant volume fraction of manganese sulfide inclusions in wedge-shaped tapered ring microstructure. 73x Analysis of the forces present in the tapered-ring locking device revealed that when the fastening screws were torqued, a significant hoop stress was placed on the middle rings due to the wedging action between the inner and outer rings as well as the relatively small cross section of the middle rings at the fastener holes(see Fig. 11). Since the large inclusion was present at the minimum section thickness zone of the middle ring, the stresses applied to the middle rings during norma torquing caused failure at the inclusion. Since the material contained a high volume fraction of these inclusions, this material choice was not appropriate for this application. The material was weak in an orientation of relatively high stress ailure prevention recommendations involved specification of a nonresulfurized grade of a low-alloy steel Example 2 illustrates some of the complexity and subtlety of RCA. The material was no doubt chosen for its ease of machining. The designer may not have been heavily involved in the material specification or may not have realized the sensitivity of this particular design to material anisotropy. The material itself was not defective or bad, and the part design was reasonable too, except for the material selection, which turned out to be the critical factor in this case Material Defects Unacceptable imperfections or discontinuities in materials are defects, and some types of imperfections may be generally detrimental to the performance or appearance of a product or system. Some of the classical types of material discontinuities that have been identified as causal factor(s)in failures include Metal product form Types of discontinuities Forgin Bursts Flakes Thefileisdownloadedfromwww.bzfxw.comduring machining. The trade-off to this combination of properties, however, is the loss of transverse properties, including strength, ductility, and toughness. Fig. 14 Significant volume fraction of manganese sulfide inclusions in wedge-shaped tapered ring microstructure. 73× Analysis of the forces present in the tapered-ring locking device revealed that when the fastening screws were torqued, a significant hoop stress was placed on the middle rings due to the wedging action between the inner and outer rings as well as the relatively small cross section of the middle rings at the fastener holes (see Fig. 11). Since the large inclusion was present at the minimum section thickness zone of the middle ring, the stresses applied to the middle rings during normal torquing caused failure at the inclusion. Since the material contained a high volume fraction of these inclusions, this material choice was not appropriate for this application. The material was weak in an orientation of relatively high stress. Failure prevention recommendations involved specification of a nonresulfurized grade of a low-alloy steel. Example 2 illustrates some of the complexity and subtlety of RCA. The material was no doubt chosen for its ease of machining. The designer may not have been heavily involved in the material specification or may not have realized the sensitivity of this particular design to material anisotropy. The material itself was not defective or bad, and the part design was reasonable too, except for the material selection, which turned out to be the critical factor in this case. Material Defects Unacceptable imperfections or discontinuities in materials are defects, and some types of imperfections may be generally detrimental to the performance or appearance of a product or system. Some of the classical types of material discontinuities that have been identified as causal factor(s) in failures include: Metal product form Types of discontinuities Forgings Laps Bursts Flakes Segregation The file is downloaded from www.bzfxw.com