ABSTRACT
In engineering practice, the selection of materials of construction depends on the equipment being designed and the service requirements imposed on them. Selection of materials involves the thorough understanding of their availability, source, lead time, product forms, and size. In simple terms, the following factors are to be considered while selecting the materials for heat exchanger and pressure vessel components:
1. Compatibility of the materials with the process uids 2. Compatibility of the materials with the other component materials 3. Ease of manufacture and fabrication by using standard methods like machining, rolling,
forging, forming, and metal-joining methods such as welding, brazing, and soldering 4. Material strength and ability to withstand operating temperature and pressure 5. Cost 6. Availability
While selecting materials, one has to balance many requirements; these requirements include the following [1]:
Expected total life of plant or process Expected service life of the material Reliability (safety, hazard, and economic consequences of failure) Material costs Fabrication costs Maintenance and inspection costs Availability in required size, shape, thickness, and so on, and delivery time Return on investment
Materials are selected based on past experience, corrosion tests, the literature, and the recommendations of material suppliers. The direct measure of success in material selection and fabrication is reected in the behavior of the equipment in service. In order to assure safe, reliable, and uninterrupted service with monetary benets, proper attention must be given to material selection commencing from the design stage and must continue through fabrication, installation, and maintenance. Once on stream, the equipment should be monitored for specied performance. With this background information, the logical sequence of material selection for the construction of pressure vessels and heat exchangers is discussed next.
