The invention provides an austempered 
ductile iron adjusting chemical component. The chemical component uses Mn and Si as a base to substitute Mo and Ni, and contains a plurality of elements comprising Cu, B, Nb and Cr to realize low and micro alloying, so the respective effects of all elements are fully performed, the interactive effect promotion is realized, the 
hardenability is increased, the 
alloy consumption is reduced, and the cost is reduced. The invention also provides a new austempered 
ductile iron quenching technology matched with the austempered 
ductile iron. The technology is a step 
austempering technology using step 
quenching oil and an air isothermal furnace. The heat treatment of a workpiece through the technology realizes 
crystal grain refinement, good 
hardenability, high strength and 
toughness, low 
hardness (HB190-240) before the step 
austempering treatment, and good 
processing performances; and the obtained processed austempered ductile iron has a high 
hardness (HRC35-56) and extremely less oxidation and deformation, so the precision is guaranteed, and finishing treatments comprising 
grinding and the like are not needed. Compared with traditional 
nitrate bath 
austempering technologies, the austempered ductile iron 
quenching technology has the advantages of low cost, no generation of large amounts of harmful substances comprising 
nitrite or the like, low 
pollution and safety.