Tomiharu Matsushita

Femoral component made of Ti-15Mo-5Zr-3Al alloy in total hip arthroplasty

We have developed a femoral component made of Ti-15Mo-5Zr-3Al alloy for total hip prostheses. In vitro mechanical experiments showed that this alloy had better mechanical properties than Ti-6Al-4V alloy with respect to yield strength, tensile strength, elongation, and reduction of area. The elastic modulus of the Ti-15Mo-5Zr-3Al alloy was lower than and its fatigue properties were superior to those of the Ti-6Al-4V alloy. Intraosseous implantation experiments in vivo revealed favorable bone formation around the implants made of Ti-15Mo-5Zr-3Al in rat tibia and no inflammatory responses to the implant. Ti-15Mo-5Zr-3Al alloy appears to be a suitable material for the femoral components of total hip prostheses.

Improvement of equipment for close-tolerance forging and extrusion in Japan

Abstract Nowadays, there is heavy demand for net or near net shape forming in mechanical working technology, in which both heavy and light weight products have dimensional tolerances of about one thousandth of the sizes of the worked material. In this paper, the factors affecting the accuracy of the product are discussed generally, with emphasis being given to the achieving of high dimensional accuracy in hot forging and extrusion. The important factors are the temperature rise in the worked material and the working tools. To meet the demand for higher dimensional accuracy, it is very important in forging and extrusion that the press has high rigidity and that movable members should be guided with good dynamic accuracy. Furthermore, it is essential to be able to predict the deformation of the press frame and of the tooling and the temperature distribution within the tools and the worked materials.

Hot Hydrostatic Extrusion of Steel

Three kinds of steel, 0.40% carbon steel, Cr-Mo case hardening steel and 304 stainless steel, are hydrostatically extruded at high temperatures up to 1300°C.

Hydrostatic extrusion of round and shaped tubes

Abstract The manufacture of tubes of round and of complicated shape by cold or hot hydrostatic extrusion is investigated with regard to the extrusion pressure, the tool arrangements and the productivity attainable with hydrostatic extrusion. The pressures required to extrude round tubes are 3 to 20% higher than those required for rods of aluminium, aluminium alloy, copper, carbon steel, zircaloy and stainless steel. For shaped tubes having complicated profiles, the extrusion pressures are 10 to 40% higher than those for rods. Three kinds of tool arrangement for tube extrusion are proposed for increasing the production rate and reducing manufacturing costs. They use, respectively, a mandrel fixed to the connecting cylinder, a travelling mandrel not supported by the billet end and a floating-tipped mandrel in which the floating tip behaves similarly to the floating plug in tube drawing. By employing these tool arrangements, disadvantages of the conventional fixed and travelling mandrels can be eliminated. The assessment of the production rate copper tube that could possibly be attained by using hot hydrostatic extrusion is also compared with that for the conventional tube manufacturing process. The opinion is advanced that a large number of drawing and tube reducing passes could be eliminated by applying hot hydrostatic extrusion. Eccentricities of tubes as extruded range from 2 to 3%.