Numerical Simulation Of Induction Hardening Strengthening Of The Valve Body Of High-pressure Piston Pump

In the fracturing pump used in oil mining,the valve body is an important part of the one-way valve system.In the process of use,the inclined conical surface(the contact surface between valve body and valve seat)will appear plastic deformation,fragmentation and erosion wear problems,which puts forward higher requirements for its surface strength.As an efficient and environmentally friendly heat treatment,induction hardening is suitable for the surface strengthening of a large number of parts.With the deepening of the research on electromagnetic induction heating theory,the numerical simulation analysis of induction hardening has been widely used under the support of computer numerical simulation technology.The numerical simulation of induction hardening can not only obtain the change law of temperature field,electromagnetic field and phase transition during heating and cooling process under different process parameters.It can also provide guidance on the design parameters such as the use of magnetic body and the selection of air gap.Combined with the problems encountered in the actual production and use of highpressure piston pump valve body,this paper is mainly divided into the following parts:(1)By referring to the references,this paper comprehensively analyzes the status quo of the research on the reliability of the valve body,the phase transition in the process of electromagnetic induction heating and quenching,and puts forward the research content and research route of this paper.Based on Maxwell equations and Fourier heat transfer law,this paper establishes a mathematical model of electromagnetic field and temperature field,which lays a theoretical foundation for the research of this paper.(2)The influences of the use of guiding magnets and heating time on the electromagnetic field and temperature field in the induction heating process of valve body were studied,and the temperature field values obtained under the above different parameters were put into the JMAK phase transformation model derived from the austenite expansion experiment data to calculate the austenitizing process curve with time at each point,and the process parameters meeting the hardening layer thickness were obtained.(3)The influences of the selection of coolant,cooling time and material composition on the cooling rate,phase microstructure distribution,hardening layer distribution and surface hardness during the quenching process of valve body were studied.The results show that extending the heating time can increase the thickness of hardened layer and reduce the surface hardness.The surface hardness is positively correlated with the heat transfer coefficient of coolant.(4)The hardness simulation results were put into the erosion wear calculation model,the flow field and proppant motion state were studied,and the relationship between erosion rate and surface hardness was established.The results show that the erosion of the inclined cone in valve body is mainly concentrated on the edge of the inclined cone.The erosion rate of inclined conical surface has a linear relationship with surface hardness.Based on the electromagnetic thermal coupling theory,this paper completed the numerical simulation study of the complete process of induction hardening of high-pressure piston pump,and established the relationship model between the surface hardness of quenching and erosion rate of quenching.The research results provide some technical support for the optimization of quenching process parameters.It is beneficial to shorten the R&D cycle and has important research significance.