Hardmetal Qualities and Applications

As mentioned earlier in the introduction to this chapter, tfie properties of WC-Co based hardmetals can be varied widely and consequently their applicability is extremely widespread. The properties are intimately connected with their microstructure (including micro- and macroporosity) and surface conditions (grinding cracks and excessive roughness). These can be influenced by several raw material properties and processing conditions  

It is important to bear in mind that many of these items are interlinked. 

TABLE 9.2. Basic Data for Different WC-Co and WC-(W,Ti,Ta,Nb)C-Co HardMetal Grades [9.1] 

Grade (wt%) Hardness HV30 Compressive strength (N mm ) Transverse rupture strength (N mm ) Young s modulus (kN mm ) Fracture toughness (MPa m- /2) Mean thermal expansion coefficient (10- K- ) 

Applications can be divided into two main fields nonmachining and machining. 

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This chapter will follow the different stages of powder metallurgical manufacture. More emphasis will be put on the description of WC powder production methods and qualities, and the preparation of graded powders. Less emphasis will be put on sintering, hardmetal qualities, and applications. In this context, we refer to several excellent books and review articles dealing particularly with hardmetal technology, properties, and applications [9.1, 9.2, 9.4, 9.7-9.9]. 

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