Study On The Key Technology Of Producing For300M Aircraft Landing Gear Outer Cylinder Forging

The landing gear is one of the key components on the aircraft. It is the mainstructural parts for gliding on the ground when taking off or landing. The aircraft landinggear is used to support the weight of the aircraft, to absorb collision energy, so it shouldhave comprehensive mechanical performance, such as high strength, high toughness.Subjected to the poor apparatus conditions and lacking technical capacity, domesticlanding gear manufacturing has low material utilization, long production cycles and highcosts. Large overall refinement is the development trend of the outer cylinderforgings.Good preform shape design is the key to ensuring an overall shape forgings, anda subsequent heat treatment after forging is a necessary means to achieve the mechanicalproperties of forgings. The preform forging shape of the outer cylinder and300M heattreatment process parameters were studied with a combination method of numerical andexperimental in this paper.In this paper, the structural characteristics of the300M outer cylinder forgings wasanalyzed. non-contour shape and contour shape of the preform preform was designedbased on the same volume method. Using rigid-plastic finite element theory, with aplatform of finite element analysis software Deform-3D, the two different shapedpreform forgings of the outer cylinder were numerical simulated.The final formingprocess, local forming process, forming load, the deformation uniformity, streamlinedistribution, flash distribution were comparatively analyzed on how the two differentshaped preform to form the final forgings. The results showed that the preform of contourshape in forming forgings was better then non-contour.In this paper, the impact of the size parameters of the contour shape preform onmolding the final forging was discussed. The influence of the long straight length of thecontour shape preform on forming forging fly edge was studied.The impact on formingthe forging V-shaped transition was studied. The angle of V-shaped parts on formingforging was studied. The results showed that when the volume of the contour shape of thepreform was0.177m3, the length was1340mm, the length of the long straight section is 795mm～845mm, V-shaped angle is90°, the forging can ensure good shape.In this paper, the heat treatment process parameters of300M high strength low alloysteels were studied. Effects of quenching holding temperature, quenching holding time,tempering holding temperature, tempering holding time, the number of tempering on themicrostructure and hardness were studied. The optimum heat treatment processparameters of300M low alloy high strength steel was determined as925℃normalizing,60min holding temperature870℃quenching,2h holding temperature300℃, temperingtwice.By the use of finite element simulation software Deform-3D, simulating the heatingprocess of the outer cylinder forging heat treatment to determine the outer cylinderforging heating specification, which normalizing heating, forging into the furnace600℃,925℃insulation175min, quenching heating, forging into the furnace600℃,170minholding870℃, tempering heating, forging into the furnace20℃,250min holding,tempering twice.