RESEACH ON LUBRICATION IN HOT EXTRUSION OF G3 CORROSION RESISTANT Ni–BASED ALLOY TUBE I. Establishment and Application of Glass Lubricating Film Thickness Model
WANG Baoshun, LIN Ben, ZHANG Maicang, DONG Jianxin
School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083
Cite this article:
WANG Baoshun LIN Ben ZHANG Maicang DONG Jianxin. RESEACH ON LUBRICATION IN HOT EXTRUSION OF G3 CORROSION RESISTANT Ni–BASED ALLOY TUBE I. Establishment and Application of Glass Lubricating Film Thickness Model. Acta Metall Sin, 2011, 47(3): 367-373.
Abstract In the hot extrusion of steel, adequate lubrication can be obtained by placing a glass pad made of compacted glass powder in front of the billet. During the extrusion, the glass pad progressively melts in thin layer, allowing lubrication to be maintained over the entire stroke. However, the thickness of glass pad in a single operation is markedly depends on the process parameters and glass properties. Therefore, the mechanism of glass lubrication film forming and film thickness calculation model has been investigated during hot extrusion of G3 nickel–based alloy tube. Furthermore, combined with FEM code, the operation variables and viscosity of glass lubricant have been systematically researched in the hot extrusion of G3 alloy tube which is conducted on the 6000 t horizontal extrusion press. The results showed that the processing parameters can be optimized using the thickness formulation of lubrication film and glass pad during a single press operation. Moreover, under the prctically technical parameters of hot extrusion G3 alloy tube, the requirements of glass viscosity are s follows: softening temperature about 720 ℃; the viscosity coefficient ranges −0.05 ℃−1 to −0.04 ℃−1 when temperature is between 720 and 800 ; the viscosity ranges 25 Pa·s to 200 Pa·s uring the hot working temperature 1100—1200 ℃.
