The Rare Earth In TD Processing Of 9SiCr Material Infiltration Mechanism And Process Research

Mold is an important and indispensable equipment in modern industrial production process.The quality of the mold directly affects the production efficiency and economic benefits of the product.With the continuous development of material science,there is many high hardness of metal materials in the field of mechanical processing.This makes the requirements for the performance of machining tools has got higher and higher,and mold is the most important machining tools in this industry.Because the mold in the process of work will suffer grreat impact and friction,what makes the mold damage or wear failure often occurs.So the service life of the mold has become an important indicator to measure the quality.Surface strengthening technology is an important means in the field of mechanical processing method.The technology in improving the surface performance and the service life of the mechanical parts plays an important position.TD salt-bath metallic cementation technology is one of the surface strengthening technology,compared with other surface strengthening technology,it can get higher hardness and better wear resistance of the cladding,and it can form stronger coating with substrate.TD technology was first proposed by the Japanese Toyota research center,and it had quickly attracted extensive attention.This technology has been widely applied in cold work die and surface strengthening of some mechanical parts abroad,and it received good results.In domestic TD technology because of suffering molten salt aging fast,processing equipment corrosion serious and deformation serious after machining parts processing such as problems,it cannot be widely used.Researchers at the present stage of process parameters of the salt bath heat treatment technology,processing equipment,coating growth mechanism and its organizational structure of research is not complete enough,which hindered the development of this technology in our country.Based on the TD salt-bath permeability vanadium of 9SiCr cold work die steel materials processing as the main line,the process parameters of this technique and technological process,coating structure and performance are analyzed.And through metallographic microscope,micro hardness meter and scanning electron microscope to analyzes vanadium salt bath permeability formation of the cladding of the structure,morphology,hardness distribution and element composition.By comparing the results of experimental study on the influence of salt bath permeability vanadium main process parameters and formula,and different temperature and holding time on the result of salt bath permeability vanadium,also studied the influence of-different rare earth contenting on TD processing.After research and analysis the following results are obtained:With anhydrous borax as base of salt of 9SiCr cold work die steel in salt bath vanadium permeability after processing can get a layer on the surface density of sample,continuous of vanadium carbide cladding,the coating layer has high hardness and wear resistance,and combined with the substrate good,not easy peeling;.By the same sample under different process temperature and same holding time permeability vanadium salt bath treatment,treated specimens were observed by metallographic microscope and to measure its coating thickness,and get the following results:If salt bath heat treatment temperature is higher,the formation of vanadium carbide cladding is thicker,and a linear relationship between the thickness of coating and temperature.In order to study the processing time on the result of salt bath permeability vanadium.,the author choose three different heat preservation time to do the contrast test under the same temperature.Conclusion is known by analyzing the resulting sample that the longer the cladding thickness is bigger,and two kinds of a numerical relationship of a quadratic function with the increase of time the growth rate is gradually reduced;Rare earth is added in the molten salt bath can rise to enhance the role of infiltration rate.When adding excessive amounts of rare earth hinder the growth of the coating can be created.