Study On Work Hardening And Impact Wear Behavior Of ZGMn13Cr2 Hadfield Steel Under Different Conditions

Hadfield manganese steels are widely used in many fields,such as mining machinery, railways, metallurgy, building materials due to its excellent work hardening ability. Work hardening mechanisms of High manganese steel differ from different working conditions. Compression test and impact wear test were carried out to invest the effect of strain rates, deformation strains, relative impact energies on microstructure evolution, mechanical properties and work hardening mechanisms of Hadfield steel under these two different working conditions. The mainly conclusions are as follows:True stress-strain curves, working hardening rate curves, microstructure of deformation zone were adopted to analyze the influence of strain rates, deformation strains on work hardening behavior of high manganese steel tested by Gleeble-3500 thermal simulator and the results are as follows:（1） High manganese steel was compressed under constant strain rate and strain stress increases with deformation strains increase. True stress-strain curves present a similar trend under different strain rates:it is elastic deformation stage when deformation strains increase from 0 to 0.05, strain stress increase linearly; it is linear hardening stage when deformation strains range from 0.05 to 0.3, the increase trend of strain stress slow down; it is parabolic hardening stage when deformation strains between 0.3 and 0.5. The same compressive strain corresponds to a larger true stress under a higher strain rate.（2） The microstructure of high manganese steel remain austenite matrix and a bit of carbide. No deformation-induced martensite is founded in these deformed samples with strain rate 0.1s^-1 and deformation strains range from 0 to 50%. The micro-hardness increase rapidly after compression deformation. When the amount of compression is 50%, the micro-hardness of sample increases from HV248.6（initial state） to HV560.8.（3） Numerous deformation bands appear in the matrix of high manganese steel at the compression deformation of 50% under different strain rates. Deformation bands intersect, tangle and isolate with each other which divide the matrix into different regions. Some deformation bands present ladder shaped under large cutting stress which result from cross slip. With the strain rate and deformation strain increasing, the density and the number of deformation bands increase. Work hardening mechanisms of Hadfield steel under this kind of compressive deformation are dislocation and twins.Impact wear test was carried out by MLD-10 abrasive wear testing machine to analyze the influence of relative impact energies, impact time on work hardening and impact wear behavior of high manganese steel. XRD,OP,TEM were adopted to discuss the work hardening and wear mechanism of high manganese steel. The results are as follows:（1） Numerous deformation bands appear in deformable layer of high manganese steel under impact loading. Deformation bands present parallel or ladder shaped and they intersect, tangle and isolate with each other which divide the matrix into different regions. With relative impact energies increasing, the density and the number of deformation bands increase and most dislocation is transformed from a flat plate arrangement into a great deal of high density dislocation entanglement. Furthermore, the amount and volume fraction of twins increase gradually.（2） The critical impact energy of high manganese steel is 200J/cm2. With relatively impact energy increasing, the thickness of deformable layer increase from 3000mm to 5500mm. The microstructure of high manganese steel remain matrix austenite and a bit of carbide. No deformation-induced martensite is founded in these impacted samples. Work hardening mechanisms of Hadfield steel under this kind of compressive deformation are dislocation and twins.（3） Wear mechanisms of high manganese differ from different relatively impact energies. When relative impact energies between 50J/cm2 and 100J/cm2,their wear mechanisms are cutting abrasive wear. When the relative impact energy is 200J/cm2, its wear mechanism is mainly plastic deformation wearing accompanied with parts of micro-cutting wear, When relative impact energies between 300J/cm2 and 400J/cm2, Matrix produce a large number of cracks, their wear mechanism are gouging abrasi mechanism and spalling fatigue.