Study On The Creep Effect On Interference Of Extrusion Container With Consideration Of Working Conditions

Large extrusion container is the key part of extrusion machine,which is the most expensive extrusion tool,its life directly affect the quality economic costs of the extrusion production.The key to the design of the extrusion cylinder is the design of the size and the amount of interference,check condition is the peak stress less than the allowable stress.The practice shows,the extrusion cylinder in the harsh conditions of high temperature and pressure,the amount of interference of the extrusion cylinder will be reduced due to the creep properties of the material,which will lead to the deterioration of the stress of the cylinder,even lead to loose,misplacement and inner cylinder being pressed,resulting in cylinder failure.At present,the research on the law of the variation of the amount of interference is very limited at home and abroad.In this paper,the relationship between the interference and creep is studied in three-layer cylinder.Mainly works are as follows:1)Based on the thick-walled cylinder theory and Lamé formula,applying DDM method to obtain the stress distribution of the combined extrusion cylinder.2)Based on the work of others,the formula for calculating the relationship between the creep deformation of the material and the variation of the amount of interference in the extrusion cylinder is derived by the constitutive equation of Norton-Bailey.3)The finite element simulation applying Deform soft is performed to obtain the load-time boundary in the extrusion process.4)The creep behavior of H13,H11 and 5CrNiMo and steel was obtained by creep test,and the constitutive equation of materials were obtained based on the constitutive equation of Norton-Bailey.5)Based on creep theory,three main factors affecting the amount of interference are discussed,including structure size,stress and extrusion time.6)The effect of creep of material on the amount of interference under different material combination in the extrusion cylinder is analyzed and compared.In summary,this paper mainly adopts the combination of experimental and theoretical analysis to study the creep effect on interferences of extrusion container with consideration of working conditions.The research results can provide some theoretical guidance for the design of the extrusion cylinder.