Because of the amount of handling that occurs during material production, within warehouses, and during manufacturing operations, along with the handling of loading, unloading, and shipping, material mix-ups and mixed materials are not an un-common occurrence. Mixed materials also occur when industrial scrap is collected, or when discarded products are used as new raw materials through recycling.
Assume that you have equipment to perform each of the tests described in this chapter (as well as access to the full spectrum of household and department store items and a small machine shop). For each of the following material combinations, determine a procedure that could permit separation of mixed materials. Use standard data-source references to help you identify distinguishable properties.
a. Hot-rolled bars of AISI 1020 and 1040 steel.
b. Stainless steel sheets of Type 430 ferritic stainless and Type 316 austenitic stainless.
c. 6061-T6 aluminum and AZ91 magnesium that have become mixed in a batch of machine shop scrap.
d. Transparent bottles of polyethylene and polypropylene (both thermoplastic polymers) that have been collected for recycling.