Wrought production

Porcelain enameling requires the use of frits and melting temperatures of 550 °C or below. Enamels are appHed over chemical conversion coatings that are compatible with the frit. AHoy selection is important to obtain good spall resistance. Alloys 1100, 3003, and 6061 are employed most extensively among wrought products and alloy 356 for castings. 

The two corrosion-resistant alloys presented ia Table 5 rely on chromium and molybdenum for their corrosion resistance. The corrosion properties of IJ1 timet are also enhanced by tungsten. Both alloys are available ia a variety of wrought product forms plates, sheets, bars, tubes, etc. They are also available ia the form of welding (qv) consumables for joining purposes. 

The output from brass mills in the United States is spHt nearly equally between copper and the alloys of copper. Copper and dilute copper alloy wrought products are melted and processed from electrically refined copper so as to maintain low impurity content. Copper alloys are commonly made from either refined copper plus elemental additions or from recycled alloy scrap. Copper alloys can be readily manufactured from remelted scrap while maintaining low levels of nonalloy impurities. A greater proportion of the copper alloys used as engineering materials are recycled than are other commercial materials. 

The process requires considerable equipment, and skills ia castiag must be acquired. Coatiauous castiag is useflil where souadness and high volume of parts are needed. The process is also used to produce shapes, such as billets, bars, and cakes, as starting materials for the wrought-product iadustry. 

It will be noted that the materials covered by the BS specifications fall into several distinct groups, sometimes with apparently small differences within the group. Characteristics which could influence the selection of the most appropriate material for a specific application are tabulated in Table 4.1 for wrought products, but some elaboration is desirable since the successful utilisation of aluminium begins with the selection of alloy. Additionally, mention should be made of materials not covered by the BS General Engineering series. 

A wide range of cast and wrought alloys is available. For detailed expositions of properties and uses the reader is referred to publications on many specialised aspects obtainable from the Copper Development Association offices in various countries. Relevant publications of the British Standards Institution include BS 1400, Copper Alloy Ingots and Castings and BS 2870-5, Copper and Copper Alloy Wrought Products. All standards of the American Society for Testing and Materials relating to copper and copper alloys are included in a volume published annually ... 

Applications of beryllium within the reoent past have included structures that arc loaded in compression. Wrought products with yield strengths approaching 690 MPa (1,000,000 psi) and 20% elongation at loom temperature have been achieved. 

Principal applications for radiography include the inspection of castings, electrical assemblies, weldments, small, thin, and complex wrought products, some nonmetallics. solid propellant rocket motors, cans or containers, composites, and nuclear reactor fuel rods, amoug many others. 

Based on the chemical composition, corrosion-resistant nickel-based alloys consist of commercially pure nickel. Ni-Cu alloys, Ni-Mo alloys, Ni-Cr-Mo alloys, and Ni-Cr-Fe alloys.63 The cast versions of the nickel-based alloys do not have the same corrosion resistance as the corresponding wrought products, mainly due to the higher carbon and silicon contents and the anisotropic microstructure of the cast products. (Rebak)5... 

Tbngsten (piue W, doped W, W-Re) is commercially available as wrought products (sintered bars, billets, forgings, rods, pins, disks, cylinders, tubes, sheet, strips, ribbons, wires) as well as in the form of a broad variety of shaped parts (crucibles, springs, heating elements, rivets, etc.). 

Appearance. Verify parts by understanding their marking system and develop a trained eye. See Chapter 6, Identification Markings. The mechanic or planner learns how a material should look. If a nut, for example, is made by powder metallurgy (P/M) it may be porous and lack the corrosion resistance of an equivalent wrought product. Close examination of a P/M nut shows a surface full of tiny pores, whereas a wrought nut will have an unbroken surface. Basic problems such as imperfections on flange faces must be identified and the cause of rejection documented. 

Figure 6-11. Stencil markings are used on wrought products and are usually applied during the manufacturing process.

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