Effect of Rare Earth on 30CrMnSi Steel Investment Castings Cracking
Through adding different amounts of rare earth into the crack sensitive 30CrMnSi steel samples used in investment casting, the cracking tendency of the steel was evaluated and the optimum amount of rare earth addition was obtained. The results show that the cracking susceptibility decreases with the increase of the amount of rare earth added. The cracking susceptibility was lowest at the addition amount of rare earth ferrosilicon alloy being 450g per 50kg of 30CrMnSi steel, while increasing again thereafter with the addition amount up to 600g. It was revealed that the addition of rare earth with an appropriate amount can refine grains, reduce sulfur content, change the volume fraction and size of inclusions as well as improve their distribution, reduce or eliminate ferrite network in castings, and improve the hardness of the matrix, thus finally reduce the cracking susceptibility of the steel.
Guojun Zhang and Jessica Xu
Z. L. Tang and X. P. Zhang, "Effect of Rare Earth on 30CrMnSi Steel Investment Castings Cracking", Advanced Materials Research, Vols. 160-162, pp. 692-697, 2011