Research On Tool-chip Stick Welding And Stick Welding Surface Dynamic Characteristics For Cutting2.25Cr1Mo0.25V

Tube section material2.25Cr1Mo0.25V is a key part of hydrogenation reactor,which is widely used in coal chemical industry, petrochemical, high efficient andclean energy and other fields. The2.25Cr1Mo0.25V is typical of difficultmaterials.Because of large cracks, oxide skin, slag inclusion, sand inclusion andresidual uneven in the surface of work piece in rough forging process, it is happenedthat cutting force and cutting temperature is increasing resulting in bond breakage oftools, which reduces the service life of tools and decreases the production efficiency.This study relies on the National Natural Science Foundation of China "The researchon the sticking failure mechanism of tools when cutting the tube section materialswith high efficiency and heavy duty"(Project No.51075109). This paper aims atsolving the problem of the bond breakage of tools in the process of cutting tubesection material2.25CrlMo0.25V, with cutting experiments and diffusionexperiments as the basis, and analyzes tool-chip stick welding process, conditions toreveal the mechanism of stick welding and obtains the mechanical properties of thesurface after stick welding happened.First, experiments of cutting2.25CrlMo0.25V and diffusion experiments of toolYT15and high strength steel are established, this article analyzes the stick weldingprocess and conditions of tool-chip from a macro and micro perspective, andanalyzes influencing factors of diffusion which basing on element diffusion intool-chip stick welding process, and computes the diffusion coefficient and diffusionactivation energy which representatives element diffusion capacity,and drewelement diffusion curve in the tool substrate material to reveal the diffusion rulesbetween tool-chip and element.Second, this article analyzes the formation of concentration changes stick welding layer according to the adhesion state and changes of elemental concentration,to obtain the relationship between initial element concentration and diffused elementconcentration in stick welding layers. This article analyses stick welding layers fromthe point of element concentration. Each element concentration of stick weldinglayers is obtained basing on a known of components of tools and chip. Then we canbuild material models of stick welding layers by simulation software to predict itsphysical properties and compare with the performance of tools.Finally, this article analyzed the change of tool stick welding surfacemechanical properties, made a finite element simulation of mechanical stress andthermal stress field in stick welding layers and diffusion layers of tools, obtained thestress distribution, built the stress distribution model of tool stick welding layers, anddetermined distribution regularity and characteristics of normal stress and shearstress; This article analyzed the binding force between stick welding layers and tools,and analyzed the change regulations of the binding force with changing of crack andelement diffusion.