| Sandvik nanoflex is a new type of quasicrystal reinforced maraging steel,the tensile strength of which can reach more than 3000 MPa.However,till now there is little research about its deformation and heat treatment.Therefore,the deformation and heat treatment process optimization of this steel has been studied in this work.The Design-Expert was used to study the effects of processing deformation,solid solution temperature,aging temperature and time on the OOCr12Ni9Mo4Cu2 martensitic steel performance.The theoretical optimal process parameters are:85%cold deformation,solid solution at 1021?for 1 h,and aging at 474.25? for 171.6 min(about 3 h).The theoretical optimized hardness would reach 663 HV.The results of validation tests coincided well with the theoretical calculation values.The average measured microhardness was 632 HV,when the cold deformation was 85%,solid solution at 1021? for 1h,and aging at 474? for 171 min.theory of optimal value of the error rate between calculation and test was just 4.6%,less than 5%.At the same time,SPSS software was used to analyze the influence of Ti and Mo on the microhardness of this steel which has been treat under solution 1 h at 1050 ?,aging 3 h under 475 ?,and one regression equation was developed:H=459.402 +133.236Ti%+3.518Mo% in which,H is the microhardness(HV),Ti%and Mo%are the composition weight percent(wt%)of Ti and Mo respectivly.This equation had a good agreement with the previous test results from other researcher.The microstructure and performance have also been investigated by using DTA,SEM,XRD and tensile tests.quasicrystal precipitated phase with the diameter of about 20-30nm was observed after aging at 475?,leading to higher tensile strength compared with the sample after aging at 550?,in which more residual austenite and higher percentage elongation were observed. |
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