For common titanium tee pipe fittings, because of their small diameter and thin wall, parts are required to withstand high pressure. Casting is difficult and its quality can not be guaranteed. If two straight pipes are welded to form, because the welding seam is the space intersection line of two cylinders, it is very difficult to grasp the blanking and welding operation. Moreover, the size of the parts is small, and the welding quality of the inner wall can not be maintained easily. Casting and welding, even if their shape can be manufactured, are unavoidable due to the inclusion of pore slag during the process, and process defects are not allowed for medium and high-pressure piping.
Technicians have envisaged using die forging or radial extrusion process to make T-shaped solid bad material first and then drilling holes in horizontal and vertical directions. However, the experimental results show that the quality of titanium tee pipe is not easy to maintain. In addition, the process has disadvantages such as many processing procedures, large equipment required, and low utilization of metal materials.
Finally, the technician decides to use the straight tube extrusion forming, put the straight tube blank filled with filler into the die cavity, close the upper and lower die, and then push with the same diameter Jack (2 pieces) at the same speed from both sides. The titanium tube in the die cavity will inevitably produce plastic deformation under the pressure of both ends. Upsetting or extrusion along radial holes in the die.
Upsetting deformation is impossible because the tube is filled with incompressible filler. Therefore, the straight tube is extruded with the filler from the radial hole opened in the die under pressure.
In order to prevent the extruded radial pipe from bursting under the internal pressure of the filler, an ejector rod is installed in the radial bore of the die, and sufficient pressure is applied to the extruded radial branch pipe.
When the extruded branch reaches the dimension requirement, the required titanium tee pipe can be obtained by opening the die and removing the packing. Practice shows that the extruded tee pipe has the same wall thickness in three directions, little upsetting deformation, and 2-3 times the diameter of the pipe as high as the extruded part. In addition, due to the simultaneous movement of filler and titanium tube in the mold cavity, there are no mechanical scratches on the inner wall of the tube, and the dimensions and quality meet the requirements of the drawings.
