Abstract: A method for producing a titanium foil according to the present invention includes an electrodeposition step of performing electrolysis with electrodes including an anode and a cathode using a molten salt bath comprising titanium ions and having at least one molten chloride to deposit metal titanium onto an electrolytic surface of the cathode, wherein the electrodeposition step includes maintaining a ratio of a molar concentration of titanium ions to the total molar concentration of metal ions in the molten salt bath at 7% or more, and maintaining a temperature of the molten salt bath at 510° C. or less, and conducting a current to the electrodes under conditions where a continuous stop time of current conduction is less than 1.0 second, a current density is 0.10 A/cm2 or more and 1.0 A/cm2 or less, and a time for electrodepositing the metal titanium onto the electrolytic surface of the cathode is 120 minutes or less.

Abstract: A method for producing suspension parts via preforming the workpiece by roll forming. The sectional area and length of the workpiece are calculated. In the former step, more than one orthogonal cross-section is acquired from the suspension part of aluminum alloy, and the sectional area is converted into the area of a circle. An imaginary area is calculated by adding to the converted area an adequate amount of flash. In the latter step, a circular truncated cone is defined from two adjacent imaginary circles and the length of the imaginary center line between the two adjacent imaginary circles. A solid of revolution is defined by connecting these circular truncated cones, and the volume of the suspension part of aluminum alloy is substituted by the volume of the solid of revolution. The value obtained by dividing the sectional area of the workpiece by the volume is regarded as the-length of the workpiece.

Abstract: A method for determining the dimensions of the workpiece that can be roll-formed for preforming. A method for producing suspension parts via preforming the workpiece by roll forming.

Abstract: Agitation shafts provided with agitation vanes at lower portions thereof are fastened rotatably to the outer circumferential surface of a support cylinder to form a soft ground hardening machine. Connecting means are provided between upper and lower portions of the support cylinder. The connect-means are adapted to be tensed and slackened for eliminating the inclination of the machine in operation. In a soft ground hardening method using this machine, the inclination thereof can be eliminated as the direction in which the machine is inserted into or withdrawn from the soft ground is measured momentarily.

Abstract: Agitation shafts provided with agitation vanes at lower portions thereof are fixed rotatably around a support cylinder to form a soft ground hardening machine. A direction control unit is provided at a lower portion of the support cylinder so as to control the direction in which the machine is inserted into and withdrawn from the soft ground. In a method of hardening the soft ground by using this machine, the direction in which the machine is inserted into and withdrawn from the soft ground is controlled as the direction in which the machine is being inserted into or withdrawn from the soft ground is measured.