Kanichi Hatsukano

Microstructure and Mechanical Properties of Mg Alloy Sheets Produced by Twin Roll Caster

Mg-Al-Zn alloys containing 0.5% Ca were strip cast into sheets with a thickness of about 1.0mm by twin roll caster. It is found that the addition of Ca to Mg95Al5-XZnX (wt%)alloys prevents the oxidation and burning of molten, and makes the melting and casting easy. The as-cast Mg96Al4Zn0.5Ca0.5 alloy sheet has few cracks at the edge. With increasing Zn content, the generation of cracks occurs more markedly. The as-cast alloys have equiaxed grains with an average grain size of 10 μm. A fine microstructure is obtained. All the samples consist of single hcp-Mg phase. The yield and ultimate tensile strength of the as-cast sheets are in the range of 180 to 200 MPa and 265 to 275 MPa, respectively. The alloy Mg95Al2Zn2.5Ca0.5 shows an elongation of 21% as well as a high strength of 275 MPa. The annealing at 400 °C causes an improvement of elongation to 24% and 30% for Mg96Al4Zn0.5Ca0.5 and Mg95Al2Zn2.5Ca0.5,respectively. A further enhancement of mechanical properties is expected by an appropriate thermomechanical treatment. The as-cast Mg96Al4Zn0.5Ca0.5 sheet was deep drawn at 250°C and a drawing ratio of 2.0 without cracking . In summery, the Ca added Mg alloys are suitable for the production of Mg alloy sheets by strip casting and the cast alloy sheet have high strength with ductility and good formability

Recycling of Stainless Steel Grinding Sludge

Stainless steel sludge is generated as a waste in the grinding process, and the possibility of recycling stainless steel is considered here. Generally, stainless steel grinding sludge ranging about 10,000 are generated per a year in Japan, and most of it is discarded or re-melted with scrap steel. In this study, we considered the possibility of using the stainless steel sludge as metal powder for MIM or raw material for metal foam. For the MIM process, the metal powder will need some improvement, and flotation and spheroidizing processes of the sludge are necessary. For fabrication of the metal foam, untreated sludge can be used, and steel foam about 90% porosity is produced.

Warm Lateral Extrusion of Magnesium Wrought Alloy by Using Multi-Axes Material Testing Machine

The Formability of magnesium wrought alloys, AZ61 and AZ31 were investigated . First, the cylinder compression tests were carried out at room temperature and elevated temperatures. Then, the possibility of applying the warm lateral extrusion of the AZ61 and AZ31 alloys were examined under several conditions by using the multi-axes material testing machine. A cylindrical billet coated with molybdenum disulfide lubricant was set in the horizontal die cavity and the billet was heated up to the extrusion temperature, and then extruded laterally under the two horizontally advancing punches. Furthermore, lateral extrusion with counteracting pressure on the end of branches by using two punches methods was tried to reduce the extrusion temperature and sound products was obtained around 190°C.