Study On Die Forging Process Of Valve Of 21-4N Engine

Engine is the heart of the car,valve is an important part,the quality of valve directly affects the performance of the engine.At present,the valve forming process is mainly die forging.Die forging is easy to operate,easy to realize mechanization,low labor intensity,high production accuracy,high production efficiency,can produce more complex shape parts.5Cr21Mn9Ni4N(21-4N)is the preferred material for engine valves due to its superior chemical stability,corrosion resistance,high strength and excellent impact resistance.However,due to its great strength,it is a difficult material to deform,and its plastic deformation process is more complex.In the process of die forging,if the process parameters are not properly controlled,forming defects will easily occur,resulting in high scrap rate,high cost and other problems.Therefore,this study studied the die forging process of 21-4N valves to meet the requirements of low cost,high productivity and high quality.Firstly,the Gleeble-1500 D thermal simulation test machine conducted isothermal thermal compression test on 21-4N and studied its thermal deformation behavior.Based on the experimental data,the constitutive model of 21-4N based on Arrhenius equation and the thermal processing diagram with true strain of 0.2,0.4 and 0.6 were established,and the conditions suitable for 21-4N thermal deformation were determined.Then,using Deform software to simulate the forging process of 21-4N engine valves,the forming mechanism of 21-4N engine valves was revealed.The influence law of blank size parameters and die forging process parameters on die forging forming results was studied.The damage evolution rule and the size difference between the blank and the standard part were obtained by statistics.Finally,the process parameters were verified by experiments and qualified valve forgings were obtained.In this paper,the engine valve of die forging forming process was studied,discussed the influence law of process parameters on the valve forming quality,determines the 21-4N heat resistant steel engine valve of the optimum parameters of the die forging forming technology,the results for the 21-4N heat engine valve steel die forging forming technology,provides a theoretical basis for the reference for the mass production.Figure 46;Table 14;Reference 67...