Design, processing and cost considerations in materials substitution

Materials substitution should be performed as part of an integrated activity where redesign, processing and cost are analysed simultaneously. The paper illustrates this approach by analysing the substitution of the material of a steam control valve gate. The selection is narrowed to two candidate materials, each with its alternative design and sequence of manufacturing processes. A simpler design requiring a less complex manufacturing sequence is associated with the Haynes Alloy R-41, thus making it economically more attractive than type S42200 stainless steel, which requires a more complex design and manufacturing sequence. However, there has been no experience of using the Haynes Alloy as valve gate material.