Interchangeable grades of materials

Experience has proven that the so-called interchangeable grades of materials have to be evaluated carefully as to their affect on the quality of a product. Another important consideration as far as equivalent grade of material is concerned is its processing characteristics. There can be large differences in properties of a product and test data if the... 

The presence of hafnium in zirconium does not significantly influence mechanical properties other than the thermal neutron cross-section. Moreover, hafniiun is a valuable metal for many applications. The source of hafnium comes as the byproduct in the production of zirconium. The nonnudear grades of zirconium alloys are also low in hafnium content. Consequently, the coimterparts of nuclear and normuclear grades of zirconium alloys are interchangeable in mechanical properties. However, specification requirements for nuclear materials are more extensive than those for nonnuclear materials. Only requirements for nonnuclear materials are given in Table 22.3 and Table 22.4. It can be seen that Zr 705 is the... 

Tables H.2, H.3, H.4 and H.5 may be used for guidance regarding materials specifications. If these tables are used, it should not be assumed that the material specifications are acceptable without taking full account of the service in which they will be applied. Table H.2 lists corresponding international materials which may be acceptable. These materials represent family/type and grade only. The final required condition or hardness level (where appropriate) is not specified. These materials might not be interchangeable for all applications.

Poly(ethylene Terephthalate) (PET). There are tremendous commercial apphcations for PET as an injection-molding-grade material, for blow-molded bottles, and for oriented films. In 1998, the U.S. consumption of PET was 4,330 million lb, while domestic consumphon of PBT was 346 million lb. PET, also known as poly(oxyethylene oxy-terephthaloyl), can be synthesized from dimethyl terephthalate and ethylene glycol by a two-step ester interchange process, as shown in Fig. 2.18. The first stage involves a so-... 

---