Metallurgists are concerned with the physical and chemical behaviour of metals and alloys. Metallurgists may specialise in chemical, physical or process metallurgy and this determines the type of job they do. Chemical metallurgists are involved in the extraction of metals from ores and they study metal corrosion and fatigue. Physical metallurgists monitor the behaviour of metals under stress and study changes in temperature. Process metallurgists shape and join metals and select the best metal for the job. Work may be in research and development, design and manufacture, production management and quality assurance.