In the production of engineering grades of flake graphite irons, manganese contents in excess of 1.7 times the sulfur content are used to tie up sulfur as manganese sulfide to overcome the effects of ''free'' sulfur in promoting carbides, chill, and abnormal graphite forms. The present work demonstrates that the amounts by which man ganese contents exceed the stoichiometric balance have significant effects upon the tensile properties and structure. With the widely used excess of 0.3%, tensile strengths, modulus of elasticity, hard ness and chilling tendencies are at minimum levels. However, with a smaller excess of manganese, tensile strengths may be increased by up to 60Nlmm' (8.7 ksi) with only a small change in chilling tendency. Brinell hardness is increased by up to 60 HB. An excess of manganese of 0.3% provides a generous margin which could be safely reduced to 0.1% if the higher strengths are sought, provided that the increase in hardness does not lead to difficulties in machining. The small changes in chilling tendency should not be significant in the production of castings from irons inoculated prior to pouring.
Mendeley saves you time finding and organizing research
There are no full text links
Choose a citation style from the tabs below