Study On The Weldability Of Austempered Ductile Iron

The paper discusses chiefly several questions below based on the production of low-alloy austempered ductile iron by accessible in our country: First, this paper studies the effects of some inoculants on quantitiveness, size and properties of spheroid graphite. It comes to the scheme about the use of these inoculants that it can enlarge the limit of Mn content in raw materials used for the production of low-alloy austempered ductile iron. This scheme accedes complexly a quantity of Si-Ca, the inoculants of ferrite, Bi. Then there are a lot of spheroid graphite with small size, full circle, uniform distribution in low-alloy austempered ductile iron, which is beneficial to gain the nature of well mechanicality .Second, this paper discusses the effects of initial organization and heat-treat technical measures on microstructure and mechanical properties of austenitic-bainitic ductile iron. The heat-treat technical measures are annealing, autenitizing and bainitizing. The annealing parameters are "(910+10)+stove cooling to 600+natural air cooling" . The autenitizing and bainitizing parameters are " (900+ 10) X 1.5h+(370+5) X2h" . It draws the best project that can be directly applied to the mechanized and automatic production line. And the properties of these products should be settled and fine.This paper studies mainly the welding behaviors of austenitic-bainitic ductile iron and the remedy for it's defects. And I have gotten a measure of success. The graphitizing welding rod Z258 have been used in both aspects noted above. And low-alloy system of Mo, Ni, Cu is used to gain austenite and bainite in the braze seam of the latter. Finally, this paper founds a mimic program of the welding temperature field that it should be point of reference for the study on the organism of brazing seam.