Study On Heat Treatment Process And Properties Of 10CrMnMoSi Duplex Steel In Bifurcation Bifurcation Of Six - Stage Branch Well

According to the finite element analysis results of six branch wells bifurcation device, as well as the bifurcation device design, material selection and preparation process requirement, this paper explores heat treatment system and the change of organization structure and performance of10CrMnMoSi ferrite martensite dual phase steel.This paper analyzes the structure and mechanical properties of lOCrMnMoSi ferrite martensite dual phase steel after the subcritical quenching at different temperatures from730℃to850℃with OM, SEM, EDS, micro hardness tester and universal testing machine and other modern analysis methods. Dual phase steel pipe after heat treatment is expaned to30%, and studies the structure, mechanical performance change of dual phase steel after successful expansion. By the autoclave test and electrochemical test, researches dual phase steel corrosion behavior after expansion. The results are as follow:1)10CrMnMoSi transforms to ferrite and martensite after the subcritical quenching at different temperatures. The quenching temperature rises, the martensitic transforms from long and narrow island distribution to lath martensite and ferrite fibrous coexist; At the same time, the martensite content increases from10.29%at730℃to61.22%at850℃; Martensite and ferrite grain size decrease with the increase of quenching temperature, and the ferrite grain size reduces from14.20um to2.72um, the martensite size decreases from5.35um to2.11μm.2) With the increase of quenching temperature, the yield strength, tensile strength of dual phase steel generally show an upward trend; the elongation general trend performance is the dorp; the yield ratio increases at first and then decreases; the fracture morphology changes from the initial typical ductile fracture to brittle fracture; the hardness of ferrite gradually ups, from171.86HV at730℃to255.63HV at850℃;And the hardness of martensite gradually reduces, from707.17HV to479.35HV.3) With the Hollomon stress strain model, Crussard-Jaoul analysis (referred to C-J analysis) and amended C-J (as amended Swift equation) analysis methods investigate the work hardening behavior of10CrMnMoSi dual phase steel. By the relationship between the amended C-J analysis model and Hollomon stress-strain, obtains the m1, m2and n1, n2value of samples. After quenching at790℃, the sample’s n1, n2values are relatively larger. And with the increase of quenching temperature, the volume fraction of martensite rises, ferrite martensite dual phase steel’s "turning strain point" is gradually moving to the left.4) The dual phase steel, quenching at the750℃,770℃,790℃, expand to30%successful without cracking. Due to the effect of work hardening, the yield strength and tensile strength of dual phase steel rise significantly after expansion, and the elongation falls off. And dual phase steel shows strong brittleness tendency.5) The corrosion behavior of duplex steel10CrMnMoSi shows that the corrosion resistance of dual phase steel after inflation is below than before. When the quenching temperature is790℃, the corrosion rate of the sample after expansion is the lowest, and the corrosion resistance is the best.