Research On Composition And Heat Treatment Of Medium-carbon-low-alloy Cast Steel

Each year, a third to half of the world’s material will be consumed because of wear.At the present, wear-resisting material is the most widely used, so the research of wearresistant steel is very important to enhance the performance of materials.This article based on mining with wear-resisting pipe as the research object,withmedium carbon alloy steel as the foundation to study a new type of wear resistantsteel.This article design four different chemical composition test of steel, and the fourkinds of test steel under the condition of invariable in C and Mn element by changingthe elemental composition of Si,Cr,Mo to contrast test of the metallographic structureand mechanical properties of steel after rolling.Select the kind which one own the bestperformance indexes to test the subsequent heat treatment experiment.This article testthe experiment respectively in50min,80min,110min,140min quenching heatpreservation time,800℃,850℃,900℃and950℃quenching heating temperature,300℃,340℃,380℃,420℃,460℃tempering temperature,then measuring the impact ofthe steel properties and the hardness value, using the wear testing machine to measurethe wear-resisting performance of the test steel, using the metallographic microscope tomeasure the microstructure of test steel, using scanning electron microscope to observethe impact fracture surface morphology and wear morphology of the test steel. Bycomparing the performance indexes under different heat treatment process to determinethe reasonable heat treatment process system.Using the test technology for industrialmanufacture.Based on the study of the microstructure and mechanical properties of the differentcontent of alloy wear-resistant steel which one is rolling state, the results showedthat:the organization of the no.1test steel in rolling state which one own C0.30%,Si0.73%,Mn1.38%,Cr0.91%,Mo0.32%is plate strip martensite+bainite+a small amountof pearlite, Rockwell hardness is48HRC,-20℃low temperature impact work of 17J.After comparison,the no.1test steel own the best properties.So the no.1test steelcan be used by the customs.Through the study of the heat treatment of the no.1test steel,I found that theoptimum heat treatment temperature of the steel is:quenching temperature is850℃,tempering temperature is420℃.After the heat treatment process, the hardness ofthe steel grade is46HRC,impact value is64J,based on the impact fracture scanningelectron microscopy analysis, I found a lot of toughening nest.After the wear test, I used the scanning electron microscopy to observe themorphology of impact fracture,then I found that test steel wear resistance is basicdirectly proportional to the hardness of the steel.I used the composition of the no.1test steel wear-resistant steel to conduct theindustrial trial production, after the measure I found the size is precision and mechanicalproperties all meets the requirement of the customs.Through the experiment, a wearresistant steel pipe with good comprehensive mechanical properties was obtained.