Study On Super High Managanese Steel With Trace Boron

Super-high manganese steel with boron a new antifriction material, this is studied in this thesis. It is obtained by increasing alloying elements such as Mn, C and adding alloying elements such as B, Cr, Re to general high manganese steel Mn13.In order to remedy the applied insufficiency of general high manganese steel such as without enough abrasion resistance as a result of inadequate deformation hardens at low stress or low impact, easily happen low temperature brittleness rupture at the condition of chilliness(-20--40℃).This thesis has selected five boron content of super-high manganese steel with trace boron. There are AO:O,A1:0.0015%,A2:0.003%,A3:0.0045%,A4:0.006%.The sample were carried out water toughening at different temperature(1080℃,1100℃,1120℃,1140℃) and then were carried out abrasive wear experiment under the low impact.By use OLYPUS metallographic miacroscope,HRBV-187.5 sclerometer,JB-301 impact test machine,SSX-550 scanning electron microscope, TECNAI G2 20 transmission electron microscope and ZQS-2000 instrument of the alloy heat check and line contracts to investigate:(1) The effect of boron content and main alloying elements content on mechanical properties of super-high manganese steel with trace boron; (2) The heat treatment handicraft studies of super-high manganese steel with trace boron; (3) The effect of boron content and main alloying elements content on casting properties of super-high manganese steel with trace boron; (4) The effect of boron content on austenite organize and carbide; (5) The low temperature toughness and ductile-to-brittle transition temperature; (6) The effect of boron, chromium and other micro-alloy elements on wear resistance and the mechanism.The result shows that fluidity obviously decreases with the boron content increasing from 0 to 0.006%,the fluidity decreases from 573mm to 347mm, reduced 39.4%.The linear shrinkage of AO is 2.1002% that is the lowest which firstly increases and then decreases with the increasing of boron content, the most of linear shrinkage is 2.3645% at A2.The first crystal organizes become big with the increasing of boron content. There are more carbides in the casting organize of super-high manganese steel with boron. After water toughening at equal temperature the carbide in microstructure gradually increase with the increasing of boron content, with the water toughening temperature heightening from 1080℃to 1140℃the amount of carbides firstly decrease then increase at equal boron content. The normal temperature impact toughness of sample firstly augment then decrease with the increasing of boron content and water toughening temperature, the impact toughness value is 168-191 J/cm2.The ductile-to-brittle transition temperature is-70℃of super-high manganese steel with boron, enhancing its using dependability. The degree of hardness changes between HBS202-218 but the change is not big. Under low impact abrasive wear and after water toughening at equal temperature, the wear resistance of super-high manganese steel gradually enhance, at the same boron content the wear resistance firstly increase then decrease with the rising of water toughening temperature, the changing scope is 1.09-1.98.Study indicated that the super-high manganese steel with boron 0.003% has the best combination property after 1100℃water toughening:HBS=215,αK=191J/cm2,the relative wear resistance is 1.46.The ductile-to-brittle transition temperature is-70℃,it reduces 30℃compare to general high manganese steel.