35Mn2 Steel's Mechanism Study Of Caustic Brittlement

The petroleum is one kind of non-renewable resources, in order to most effectively enhance the petroleum's recovery ratio, Daqing area opens A-S-P experimental plot. A-S-P is a way of tertiary oil recovery technology. Compared to the water drive, A-S-P technique can make the petroleum's recovery ratio be enhanced to 20%~25%. Because it uses alkali (NaOH) to drive the oil, and simultaneously along with the well depth, the subsurface temperature is increased up generally to 100℃. Therefore, working in this kind of environment, the oil tube, the oil extraction rod (part of materials are 35Mn2 steel) appear more broken phenomenon. At present, A-S-P technique is only studied to its effect of driving oil in domestic and foreign country. But research report is really few to the tube's caustic brittlement's behavior among ASP. Thus, studying 35Mn2 steel's corrosion mechanism in the hot strong alkali medium may provide the basis for the reasonable material selected as well as the anticorrosion measure, simultaneously may reduce the security accident's occurrence, also bring certain economic efficiency and the social efficiency for the oil industry.In addition, as the important part of oil and gas well, thimble's anti-cracking should be improved in the process of perforation. Because of perforation, the body must withstand the impact load with an enormous strain rate. When certain critical condition can be achieved, thimble appears the cracking. Therefore under the high rate of strain, studying the caustic brittlement's influence on 35Mn2 steel's dynamic fracture may provide certain reference for the petroleum thimble's safe handling.Through the electrochemistry experiment and the impact experiment, the article studies 35Mn2 steel's impact ductility and proves that hydrogen-induced-cracking is 35Mn2 steel caustic brittlement's main mechanism. Moreover, through the Hopkinson experiment, the caustic brittlement has little influence on the 35Mn2 steel's dynamic fracture toughness under the high rate of strain.