Abstract: Spherical graphite cast iron utilized to prepare a lapping tool is manufactured by casting a molten composition into a mold cavity, and by chilling one side of the resulting casting thereby causing unidirectional solidification, the one side being used as the operating surface of the lapping tool. The molten composition consists essentially of 3.0-3.8 wt. % of carbon, 2.0-2.9 wt. % of silicon, 0.3-0.9 wt. % of manganese, less than 0.05 wt. % of phosphorus, less than 0.03 wt. % of sulfur, 0.2-1.0 wt. % of nickel, 0-0.8 wt. % of copper, 0.05-0.5 wt. % of molybdenum, 0.03-0.09 wt. % of magnesium and the balance of iron. The lapping tool made of this casting has a percentage of sphericity of higher than 80%, graphite particle diameter of less than 100 microns, a density of graphite particles of larger than 70/mm.sup.2, and a Vickers hardness of larger than 200.

Abstract: This invention relates to a heavy wall monolithic iron pipe comprising nodular graphite in the outer portion of its wall and flake or quasi-flake graphite in the inner portion of its wall and a method for making said pipe. The central portion of the wall of the pipe may be a combination of nodular graphite and flake or quasi-flake graphite.

Abstract: Castings made from aluminum and its alloys have at least one face including at least one region of wear-resistant zones. These castings are formed by a controlled distribution of zones hardened by local melting effect. The zones, no matter what their length and shape, have a width and depth between 3 and 150 .mu.m and the surface fraction or percentage of the zones for the wear-resistant region is between 5 and 60%.

Abstract: A process for increasing surface hardness of a heat-hardenable steel disk, along an annular band intermediate the disk central and edge portions, is disclosed. The process contemplates selecting a first position on the surface of the intermediate annular band. The process contemplates next rapidly heating at the first position a minor portion of the disk surface in relation to the remainder of the disk so as to cause the minor portion to increase in temperature to an elevated temperature ranging from 1400 to 1600 degrees Fahrenheit in a time period of 0.3 to 0.7 seconds. The disk is heated in a manner such that substantially no heat diffuses from the thus-heated portion of the disk to the remainder thereof. The process next contemplates rapidly terminating the heating step to allow the remainder of the steel disk to serve as a heat sink to rapidly cool the thus-heated portion from the elevated temperature to less than 1000 degrees Fahrenheit in 0.

Abstract: In order to prevent the formation of fissures or tears in the walls of cylinders of an internal combustion engine, hardening tracks (4) generated by a carbon dioxide laser, are placed parallel to each other at an angle of inclination (.alpha.) with respect to the axis (3) of the wall of the cylinder or cylinder liner, and spaced from each other by a distance (X) which is greater than twice the distance (k) between the maxima (9, 10) of tension resulting in the operation of the ICE from the edges of the hardening track, thereby satisfying the condition: X is greater than 2.times.k.