Processing and Microstructural Evolution of Superalloy Inconel 718 during Hot Tube Extrusion

The processing parameters of tube extrusion for superalloy Inconel 718 (IN 718), such as slug temperature, tools temperature, choice of lubricant, extrusion ratio and extrusion speed, were determined by experiment in this paper. An appropriate temperature range recommended for the slug is 1080-1120℃, and the temperature range recommended for the tools is 350-500℃. The microstructural evolution of superalloy IN 718 during tube extrusion was analyzed. With the increase of the deformation the cross crystal grains were slightly refined. While the vertical crystal grain is elongated evidently and the tensile strength increased along the axial rake. Glass lubricants have to be spread on the slug surface after being heated to 150-200℃, vegetable oil or animal oil can be used as the lubricant on the surface of the tools to reduce the extrusion force remarkably.

Texture evolution and mechanical anisotropy of an ultrafine/nano-grained pure copper tube processed via hydrostatic tube cyclic expansion extrusion

Texture evolution and mechanical anisotropic behavior of an ultrafine-grained(UFG)pure copper tube processed by recently introduced method of hydrostatic tube cyclic expansion extrusion(HTCEE)was investigated.For the UFG tube,different deformation behavior and a significant anisotropy in tensile properties were recorded along the longitudinal and peripheral directions.The HTCEE process increased the yield strength and the ultimate strength in the axial direction by 3.6 and 1.67 times,respectively.Also,this process increased the yield strength and the ultimate strength in the peripheral direction by 1.15 and 1.12 times,respectively.The ratio of ultimate tensile strength in the peripheral direction to that in the axial direction,as a criterion for mechanical anisotropy,are 1.7 and 1.16 for the as-annealed coarse-grained and the HTCEE processed UFG tube,respectively.The results are indicative of a reducing effect of the HTCEE process on the mechanical anisotropy.Besides,after HTCEE process,a low loss of ductility was observed in both directions,which is another advantage of HTCEE process.Hardness measurements revealed a slight increment of hardness values in the peripheral direction,which is in agreement with the trend of tensile tests.Texture analysis was conducted in order to determine the oriental distribution of the grains.The obtained{111}pole figures demonstrate the texture evolution and reaffirm the anisotropy observed in mechanical properties.Scanning electron microscopy micrographs showed that different modes of fracture occurred after tensile testing in the two orthogonal directions.

Industrial Elaboration by Extrusion of PVC Tubes Loaded with Micronized Dura Palm Kernel Shell Powder

We present in this work how to use the dura palm kernel shell powders as loads for the elaboration by extrusion of PVC tubes. The transformation of dura palm kernel shells into micronized shell powder as well as its characterization was the subject of recent work. We carried out, the formulations by using the industrial scales of precision, the mixtures of the instrants with an industrial machine of mark HENSHLLE N˚2 MAIN 570762, the routine tests by ATG/DSC then by IRTF, the extrusion of the tubes with an extruder twin-screw with 9 rooms of transformation finally the tests of conformity by the observations and the analyses. We obtained for the formulations the dosage of 0%, 4.01%, 12.54%, 23.03%, 32.01%, 38.01%, 51.02% representing the percentage of hull powder in the mixture, the machine mixing gave perfectly homogeneous powders, the routine tests showed that the hull powder keeps all its properties until the end of the shaping whatever the percentage of hulls contained in the PVC, the extrusion gave tubes for each formulation and the conformity tests gave perfectly round tubes of diameter 90 × 82 mm, a coloration going from white grey at 0% to dark black at 51.02% showing the influence of the carbon black and the color of the shell powder according to its proportion. The infrared of the tubes obtained shows for each formulation a variation of the CH2 and CH bonds and a decrease of the −OH bonds. The thermogravimetric analyses and the differential calorimetric analyses of the tubes of each formulation, show each time that the quantity of shell powders in the mixture influences the PVC tubes obtained. Thus, we obtain a variation of the phase temperatures according to the dosage, giving from 108.72˚C to 76.56˚C for the glass transition temperature and from 494.71˚C to 414.56˚C for the melting temperature, at the DSC and a progressive decrease of the mass following the heat absorption with each time 4 phases instead of 5 for the unloaded PVC tubes at the ATG according to the dosage.