A metallurgical change in the microstructure of joints in carbon and certain low-alloy steels subjected to long term service in the temperature range of 450 to 600°C (850 to 1100°F).Graphitization is a breakdown of carbides in the steel to small patches of graphite and iron, caused by the thermal cycle of arc welds. This microstructural change seriously reduces strength. A practical remedy for this problem is to use steels alloyed with chromium or molybdenum, or both. Reference: American Welding Society. G. E. Linnert, Welding Metallurgy, p. 329-3 1 ;Vol. 2, Third Edition. Miami, Florida: American Welding Society, 1994.