This application relates to a method of manufacturing a knife using a multilayer material. In one aspect, the method includes preparing a multilayer material for manufacturing a knife, and heating and then forging the multilayer material to form a knife-shaped structure including a blade part and a handle part. The method also includes grinding the blade part to form a sharpened knife-edge and applying mud, including kaolin and white clay, to an entire surface of the knife-shaped structure and removing the mud applied to the blade part. The method further includes heating the knife-shaped structure applied with the mud, and quenching the heated knife-shaped structure through oil-cooling. The method further includes etching a surface of the quenched knife-shaped structure to form a pattern on the surface and grinding the surface-etched knife-shaped structure to form a knife having a final shape.

A method for manufacturing a forged steel roll comprises: casting, by the ESR method, a steel ingot which contains, by mass %, C: 0.3% or more, Si: 0.2% or more, Cr: 2.0-13.0% and Mo: 0.2% or more, and further contains Bi at 10-100 ppm by mass; and forging the steel ingot to manufacture the roll. According to this method, since freckle defects can be sealed near the center of the steel ingot, the roll can be stably used over a long period of time.

The present invention provides a high quality material for ring rolling. The material includes radially outer and inner peripheral surfaces. In the material, a center of gravity on a half section is located so as to be closer to the outer peripheral surface in contact with a main roll than a center of the half section in a thickness direction, a shape of the half section includes a height reducing portion having a height from a center line dividing the half section into halves in a height direction, this height is gradually reduced toward the inner peripheral surface in contact with a mandrel roll, and the shape is formed in a substantially linear symmetry such that the center line is a symmetric axis. A height of the inner peripheral surface is from 20% to 50% of a maximum height of the material.

An improved forging process includes the steps of pre-heating the top and bottom dies of a forging press to a specified temperature, and maintaining both dies at the specified temperature during subsequent forging operation with closed-loop temperature control systems. The top and bottom forging dies are each coupled to a dedicated thermic fluid heater, the temperature of each die is individually measured and compared to a respective target temperature, and the respective thermic fluid heaters are controlled in relation to detected deviations of the measured temperatures from the target temperatures. Compressor wheel preforms produced according to this process consistently exhibit primarily radial grain orientations that exactly match the expected values.

The present invention relates to a heat-resistant Ti alloy having excellent high-temperature strength and a process for producing the same. More particularly, the present invention relates to a heat-resistant Ti alloy having a composite structure having an equiaxed phase and grains containing an acicular phase inside thereof, and a process for producing the same.

The invention relates to a method for producing a ring-shaped or plate-like element, in particular for a metal-sealing material-feedthrough, in particular for devices which are subjected to high pressures, preferably igniters for airbags or belt tensioning devices, whereby a blank, especially in the embodiment of a wire-shaped material is provided and the blank is subjected to processing so that a feedthrough-opening can be incorporated into a ring-shaped or plate-like element created from the blank.

Methods of refining the grain size of a titanium alloy workpiece include beta annealing the workpiece, cooling the beta annealed workpiece to a temperature below the beta transus temperature of the titanium alloy, and high strain rate multi-axis forging the workpiece. High strain rate multi-axis forging is employed until a total strain of at least 1 is achieved in the titanium alloy workpiece, or until a total strain of at least 1 and up to 3.5 is achieved in the titanium alloy workpiece. The titanium alloy of the workpiece may comprise at least one of grain pinning alloying additions and beta stabilizing content effective to decrease alpha phase precipitation and growth kinetics.

A method of manufacturing an annular material includes: a forging process of making a discoid forged material by forging an alloy material; and a ring rolling process of making an annular material by performing ring rolling on an annular intermediate made by forming a through-hole in the forged material. In the forging process, hot forging which achieves an absolute value 1 of a strain in a circumferential direction of the forged material that is greater than or equal to 0.3, an absolute value h of a strain in a height direction of the forged material that is greater than or equal to 0.3, and a ratio h/1 between the absolute values of the strains that is in a range of 0.4 to 2.5 is performed at least two or more times.

A method for manufacturing a ring-shaped member includes preparing a workpiece, pressing a first member against the workpiece to form a depression having a depth in an axial direction in the workpiece, punching out a bottom portion of the depression in the workpiece using a second member, and deforming a circumferential wall in accordance with relative movement between the workpiece and a third member.