Research On Plastic Flow And Precise Forming Technology Of Oil Drilling Parts

With global energy supply shortage, the major industrial countries are stepping up to the drilling of the underground energy and mining production, so the demand of key components for oil drilling tools also increases.Key components of oil drilling tools are consumable industrial products. General assignments of the drilling are at thousands of meters below with bad work environment and complex stress conditions.The distort, tensile, compression and other complex force are applied on it. So the new forming technology is particularly important.This article selected the oil drill pipe joint as the research object, its material is 37CrMnMo medium carbon low-alloy steel Joint is the drill pipe’s important connecting parts, it often should be removed in the process of drilling, by tong twisted together, and complicated stress conditions.The traditional forming technology is half free forging forming which with low dimensional precision,large material consumption, high energy consumption and internal metal streamline vulnerable to damage.Represented by warm extrusion of precision plastic forming is a kind of no less cutting plastic forming method,the forging of high precision, and can remove after machining process,improve internal metal streamline distribution status and the forging quality and mechanics performance improved significantly.This paper used the precision plastic forming technology, which can improve the forging size precision and material utilization, improve the quality of forgings, reduce energy consumption.Through the thermal physics experiment, analyzed the rheological properties of the material of Oil drill pipe joint at high temperature, and it was concluded that the deformation temperature (T)and strain rate (V)on the influence law of metal flow stress (σ).On this basis, according to the Arrhenius equation and the analysis of hot compression data to get stress index n= 6.56091642 and thermal activation energy Q= 284.039529KJ/mol, established the 37CrMnMo steel flow stress constitutive equation at high temperature.Analyzed the forming process of oil drill pipe joint, and determined the parting surface, machining allowance, tolerance, the draft Angle and radius of the key forming parts, establish proper physical model.From the key parameters of pre blocking shape and even skin position, in order to solve forgings insufficient filling, metal flow resistance is big and forging internal temperature distribution.From the deformation temperature(T), extrusion speed(V), corner radius of steps (r),to obtain forging forming law, improve the quality of forgings, reduce the forming load.Based on the rigid visco-plastic finite element method (fem), the precision plastic forming process of oil drill pipe joint was simulated.Compared and analyzed the temperature field, stress and strain field, metal flow situation, the streamline distribution inside the metal and load conditions of forgings, so select the optimal shape of preformed blocking and the even skin position.Researched the influence of process parameters on the quality of forgings in the process of precision plastic forming of the oil drill pipe joint.By orthogonal experiment, analyzed the influence of component forming temperature (T),speed (V) and corner radius of steps (r) on the maximum equivalent stress, load and the temperature field.By the analysis of the range and comprehensive balance analysis method, we obtained impact Significance determination of various parameters in 37CrMnMo’s warm extrusion precision forming of the oil drill pipe joint and the optimal process parameters combination:the temperature is 780℃, the extrusion speed is 30 mm/s, the corner radius of steps is 4 mm.Analyzed the simulation results at optimal conditions and applied to practical production, experimented on the analysis result to verification, the results showed that the product which under the condition conforms to the actual requirements.In this paper, researched on process optimization and forging quality in the actual production of the oil drill pipe joint can provide the theory basis and the instruction for improving the forgings organization performance and further change the forming process.