Abstract: In a slide ring seal assembly having slide rings comprised of a casting material for running gears of track-laying vehicles and construction machinery, the improvement being slide rings composed of a gray cast iron alloy having a pearlitic matrix structure having lamellar separation of graphite therein, having a hardness value of at least 110 HRB, and being composed of:2.99 weight percent of carbon;4.61 weight percent of silicon;0.77 weight percent of manganese;0.53 weight percent of phosphorus;0.039 weight percent of sulfur;1.7 weight percent of chromium;0.81 weight percent of vanadium;1.86 weight percent of copper; andiron as remainder.

Abstract: A wear resistant cast iron alloy having a great strength for the manufacture of wear resistant machine parts having a tempered structure with embedded graphite spheroids formed in very fine form by the decomposition of ledeburite. The alloy has a spheroid number of 300,000 to 900,000/cm.sup.2 and is comprised of 1.5 to 3.0% carbon, 3.0 to 6.0% silicon, 0.1 to 2.0% manganese, 0.05 to 0.5% phosphorus, up to a maximum of 0.15% sulfur, 0.1 to 1.0% chromium, 0 to 3.5% vanadium, 0.1 to 2.5% molybdenum, 0.1 to 3.0% nickel and/or cobalt, 0.1 to 3.5% copper, 0.1 to 2.5% tungsten, 0.1 to 1.0% titanium, niobium and/or tantalum, up to a maximum of 0.15% magnesium, and up to a maximum of 0.15% nitrogen. A method is provided for producing a cast piece of the cast iron alloy.

Abstract: A friction stressed machine part of cast iron with a ledeburitic-containing bearing surface contains 0.1 to 10 area percent of predominantly nodular-shaped graphite in the ledeburitic-containing bearing surface. A number of methods for producing such a machine part are provided, including, casting the machine part against a quenching plate so that it hardens in a mottled manner in the region of the bearing surface.