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Austempered ductile iron (ADI) has several advantages of replacing cast steel and forged steel in many engineering fields. A new Mn-Cu alloyed ADI with excellent mechanical properties has been developed in order to cut the cost and enlarge the application of ADI. The helical bevel gears were made of the new-developed Mn-Cu alloyed ADI. The microstructure and mechanical properties of the standard sample were investigated by optical microscope (OM), scanning electron microscope (SEM) and performance measurement. The results showed that after a series of treatments, the mechanical properties (Rm 1 007.4 to 1 200 MPa, A 5.2% to 8.8%, HRC 32 to HRC 35, αK 70 to 120 J/cm2) of the Mn-Cu alloyed ADI standard sample could reach European standard EN1564-97/ EN-CJS-1000-5. The surface hardness after helical bevel gears meshing was significantly increased due to the formation of martensite. The bench test and traffic running testing results suggested that the new Mn-Cu alloyed ADI with ultimate life and median life respectively exceeding 30×104 and 50×104 times could replace 20CrMnTi forged steel for manufacturing the EQ140 helical bevel gears.
Austempered ductile iron (ADI) has several advantages of replacing cast steel and forged steel in many engineering fields. A new Mn-Cu alloyed ADI with excellent mechanical properties has been developed in order to cut the cost and enlarge the application of ADI. The helical bevel gears were made of the new-developed Mn-Cu alloyed ADI. The microstructure and mechanical properties of the standard sample were investigated by optical microscope (OM), scanning electron microscope (SEM) and performance measurement. The results showed that after a series of treatments, the mechanical properties (Rm 1 007.4 to 1 200 MPa, A 5.2% to 8.8%, HRC 32 to HRC 35, αK 70 to 120 J / cm2) of the Mn-Cu alloyed ADI standard sample could reach European standard EN1564 -97 / EN-CJS-1000-5. The surface hardness after helical bevel gears meshing was significantly increased due to the formation of martensite. The bench test and traffic running testing results suggested that the new Mn-Cu alloyed ADI with ultimate l ife and median life were exceeding 30 × 104 and 50 × 104 times could replace 20CrMnTi forged steel for manufacturing the EQ140 helical bevel gears.