Abstract: A magnesium-treated, decarburizingly-annealed cast iron material includes 4% or less carbon by weight, 2% or less silicon by weight, at least 0.010% magnesium by weight, and at least 0.001% sulphur by weight, the remainder being iron. The cast iron material is subjected to a first annealing phase in which graphitic carbon portions are formed. Thereafter, the cast iron material undergoes a second annealing phase during which certain of the graphitic carbon portions are burned out. The resultant structure includes cavities in place of certain of the graphitic carbon portions in a substantially ferritic matrix. The resultant cast iron material exhibits good welding and cutting properties with little susceptibility to hard cracking.