| 摘要 |
PURPOSE:To improve strength and wear resistance and to produce crank shafts, etc. in a good yield of production in the stage of producing said parts, by combining the selection of compsn. for soft nitriding steel to be used as a material and a specific heat treatment. CONSTITUTION:Steel contg. <0.5% C, <0.5% Cr, <0.2% Al, <0.3% V is used as a material in the stage of producing parts required to have strength and abrasion resistance such as crankshafts, connecting rods, chassis spindles, torsion bars, etc. for automobiles. The above-mentioned parts are made of such steel and are annealed at the temp. of the Ac1 transformation point or below or are slowly cooled or held at an equal temp. after hot forging to deposit part of the V incorporated therein. The parts are further subjected to a soft nitriding treatment to form a hardened layer of 300Hv hardness at 0.02-0.15mm. depth. The crankshafts and other automotive parts having excellent strength and abrasion resistance are produced. |
