Abstract: The composition of a hard-facing welding material to be overlaid onto a cast iron base metal followed by a supercooling treatment for hardening must lie above a line LA in a Schaeffler's structure diagram which is represented by a Cr equivalent and a Ni equivalent. On the other hand, if the base metal is preheated, the carbon precipitation line will be at the Ni equivalent of 34 (LC1), and the Cr equivalent will thus be above 4. However, if the Cr equivalent is above 4, there will occur cracks after welding (examples in which cracks occurred are shown by square marks represented by a in FIG. 1). As a solution, the carbon precipitation line was raised up to the Ni equivalent of 38 without preheating the base metal, and the Cr equivalent of the welding material was made to be 4 or less.

Abstract: A welding material for hard-facing which is to be hardened by a supercooling treatment after overlaying onto a cast iron base metal has a basic component composition which meets, in an overlaid condition, both a first condition and a second condition. The first condition is that a nickel (Ni) equivalent and a chromium (Cr) equivalent fall within that region to be defined in Schaeffler's structure diagram in which a difference in hardness before and after the supercooling treatment is a predetermined value or above. The second condition is that a starting temperature of martensitic transformation is a predetermined temperature or below.

Abstract: A mold casting process comprises, after pouring of a molten metal into a mold, rapidly cooling that surface layer of a cast product which is in contact with a mold, and releasing the resulting product from the mold when the surface layer thereof has been converted into a shell-like solidified layer. Such process is used for casting a mechanical part blank and apparatus for carrying out the process is provided.

Abstract: A mold casting process comprises, after pouring of a molten metal into a mold, rapidly cooling that surface layer of a cast product which is in contact with a mold, and releasing the resulting product from the mold when the surface layer thereof has been converted into a shell-like solidified layer. Such process is used for casting a mechanical part blank and apparatus for carrying out the process is provided.

Abstract: Disclosed is a control apparatus for correcting the measurement of flow rates for use with a turbine-type flow meter in which the rotation of a turbine rotating in response to the flow velocity of fluid to be measured is detected to produce pulses which are, in turn, integrated to measure the flow rate of the fluid. The apparatus operates to obtain a value representing the rate of reduction in the flow rate from the pulse cycle in order to detect a first time at which the reduction rate increases above a first predetermined value and a second time at which the reduction rate decreases below a second predetermined value, produce a correction value on the basis of the pulse cycle at the second time and the time lag between the first and second times, and integrate pulses other than those generated in the period of time between the first and second times, adding the correction value from the correction value producing means to the integrated value.

Abstract: A mold casting process comprises, after pouring of a molten metal into a mold, rapidly cooling that surface layer of a cast product which is in contact with a mold, and releasing the resulting product from the mold when the surface layer thereof has been converted into a shell-like solidified layer. Such process is used for casting a mechanical part blank and apparatus for carrying out the process is provided.

Abstract: A method for manufacturing a metal sintered body disclosed herein is characterized by the use of steps of: mixing 70 to 90 weight % of self-fluxing alloy powder and 10 to 30 weight % of metal powder of high melting point having a higher melting point than that of the self-soluble metal powder and in which the self-fluxing alloy powder is liable to be deposited thereon to obtain a metal powder having a sintering property; using a material in which 1 to 10 weight % of plastic binder is kneaded with the metal powder having a sintering property to obtain a molded body having a predetermined shape; and sintering the molded body at a temperature in excess of a liquid phase line of the self-fluxing alloy powder.

Abstract: A surface-chiseling machine for refractory, concrete or other materials is disclosed, which includes a piston having at its one end a step portion and on a side periphery at its other end a through-hole, and a cylinder forming a first air chamber on a closed side of the step portion of the piston, forming an exhaust channel communicated with the through-hole of the piston and having an air hole for feeding a compressed air to the first air chamber. The cylinder at its rear end is closed with a back head for forming therein a second air chamber, while at its front end is closed with a front head which is provided with a plurality of chisel-inserting holes, into which are inserted chisels with their rear ends being contactable directly with a front face of the piston for providing a striking action on the chisels.