Research On Mechanical Properties And Wear Mechanism Of Austenitic-based Wear-Resistant Steel

In this paper,Hadfield high manganese steel,0Cr17Ni10Mn5Mo2 stainless steel and0Cr19Ni9 stainless steel were taken as the research objects,and the effects of forging welding and thermomechanical treatment on the microstructure,mechanical properties and wear resistance of cast Hadfield high manganese steel were studied.Then,Hadfield high manganese steel,0Cr17Ni10Mn5Mo2 stainless steel and 0Cr19Ni9 stainless steel reached the same hardness level through deformation treatment The differences of microstructure,conventional mechanical properties and work hardening ability of the three tested steels were analyzed,and the differences of friction and wear properties of the three tested steels under different loads were compared.By analyzing the changes of friction coefficient,wear surface morphology,surface roughness,surface and subsurface microstructure and wear debris composition in the wear process of the test steel,the key factors affecting the friction coefficient and wear resistance were found out,and then the methods to improve the wear resistance of austenite based wear resistant steel were explored.The results show that forging welding and thermomechanical treatment(FW & TMCP)can refine the grain size,reduce the void defects and make the microstructure more compact.The tensile strength,yield strength,elongation and work hardening rate of FW & TMCP high manganese steel are increased,which indicates that forging welding and thermomechanical treatment significantly improve the strength plasticity and work hardening ability of cast Hadfield high manganese steel.Compared with the cast Hadfield high manganese steel,FW & TMCP high manganese steel has smaller wear loss,higher wear surface hardness and less plastic deformation under the same wear load,which means higher overall wear resistance.With the increase of friction load,the friction coefficient of two kinds of high manganese steel decreases gradually.The results show that the friction coefficient of the cast high manganese steel is less than that of FW & TMCP high manganese steel under the same load,and the morphology of the two kinds of high manganese steel changes from debris accumulation to furrow and spalling,so the phenomenon of adhesive wear to abrasive wear appears in the wear process of the two kinds of high manganese steel.At the same hardness level,the forged Hadfield high manganese steel and0Cr17Ni10Mn5Mo2 stainless steel are all austenite,but the grains of forged Hadfield high manganese steel are larger and there are deformation bands.The grain size of0Cr17Ni10Mn5Mo2 stainless steel is fine and uniform.0Cr19Ni9 stainless steel is austenite and a little ferrite with fine grains.The yield strength of forged Hadfield high manganese steel is low,which indicates that its resistance to plastic deformation is small.The plastic toughness of 0Cr19Ni9 stainless steel is the best.The work hardening ability of forged Hadfield high manganese steel is the best.The tensile fracture surfaces of the three tested steels show dimple morphology,which is ductile fracture.Because the yield strength of the two kinds of stainless steels is larger,they show cup-shaped shear fracture.There are fine grain strengthening,twin strengthening and dislocation strengthening in the two kinds of stainless steels,which make them have higher yield strength and better plastic toughness.0Cr17Ni10Mn5Mo2 stainless steel has the best wear resistance at the same hardness level.The wear resistance of 0Cr19Ni9 stainless steel is slightly lower than that of forged Hadfield high manganese steel.With the increase of applied load,the average friction coefficients of the three tested steels increase.At the same loading,the roughness of forged Hadfield high manganese steel is the largest,which leads to the largest average friction coefficient.With the increase of applied load,the forging Hadfield high manganese steel changes from a small amount of debris accumulation and furrow to furrow and a small amount of spalling,which indicates that the wear mechanism is adhesive wear to abrasive wear.0Cr17Ni10Mn5Mo2 stainless steel and0Cr19Ni9 stainless steel show pitting,furrow and flake spalling,which indicates that the wear mechanism is adhesive wear and abrasive wear.The dislocation density and twin density of 0Cr17Ni10Mn5Mo2 stainless steel lead to better wear resistance.The grains of the two kinds of stainless steel are fine and uniform,and there are twins,which indicates that the existence of fine grain strengthening makes the wear resistance of the two kinds of stainless steel better.Therefore,at the same hardness level,the main factors affecting the wear resistance of austenitic based wear-resistant steel are grain size,dislocation and twin after removing the influence of hardness.In the mechanical properties,the influence of yield strength is greater than that of plasticity and toughness,and the influence of processing hardening ability is smaller.