Structural Damage And Mechanical Behavior Of H13 Co-based Alloy Steel Cladding Under Cyclic Loading In Forging

In hot forging operations,the die surface and the nearest surface layers are subjected to coupled mechanical and prolonged high temperature above 700?thermal cycles which significantly influence their service life.Die failure is caused by different phenomena:wear,plastic deformation and thermo-mechanical fatigue.Reduced the service life of the forging die will affect the economic failure of forging die forging products will also reduce the size of the appearance thus affecting the quality forgings,resulting in greater economic losses.Therefore,a series of research has been started to prolong the life of die.For green remanufacturing of failure of hot forging die,repaired and modified with advanced surface strengthening technology to realize regeneration.Compared to traditional methods,which is cannot effective repair the hot forging die,Plasma Arc Surfacing?PAS?has been developed that is applied to overlap metal cladding in die surface layer,that modification features more efficiency,less pollution and energy consumption.By PAS for the preparation of the functionally graded materials?FGM?die,Which is both to solve the problem of combining dissimilar materials,and proposed graded structure can effectively alleviate differences in physical and chemical properties.Through PAS surfacing the Co-based alloy powder and the transition layer of W6Mo5Cr4V2 powder at H13,and this article analyzes the design of composition,microstructure and properties of surfacing alloy layer.Then choice the optimized process parameters,which is preparing for Co-based overlap welding.Then the FGM samples,bimetal sample will be tested by optical microscope,micro-hardness and EDS microstructure,then analyzes the hardness distribution and elemental analysis.The three types of samples were processed?8×12mm compression cylinder-like with numerical-controlled machine tool,which in Gleeble-3500 thermal-performing multiple cycles of compression test on simulation machine,the deformation rates is0.01s^-1,0.1s^-1 to simulate the forging process the impact of the size of the different forging equipment.Compressed sample cycle sample preparation and were observed after the cyclic compression microstructure,hardness and conduct EDS spectrum analysis test.The results of multi-pass compression cycle three types of samples showed that the deformation rate?=0.01s^-1 the maximum stress of homogeneous specimen,bimetal and functionally graded mental is 239MPa,310MPa and 317MPa.The maximum stress of deformation rate?=0.1s^-1 forging die homogeneous specimen was 288MPa,bimetal specimen was maximum stress 343MPa,the maximum stress functionally graded mental specimen was 386MPa.The results showed that when the strain rate must be in the same amount of deformation of functionally graded forging die stress is greater than the deformation of the bimetal forging die is greater than the homogeneous heat mode.Same sample at different strain rates,in the same amount of deformation,the stress of the specimen should increase as the rate increases.Using DEFORM finite element analysis software to simulate the performance of three types of samples at high temperatures in the compressed state,the simulate results show that the load-stroke curve and sample results,and further described in the service state forging cycle,functionally graded forging die compared to bimetal homogeneous forging die can be effective resistance their poor service status.Through PAS method to manufacture multilayer metal die with functionally graded materials structure,experiments and simulations proved that this design can effectively extend the service life.