摘要:
PROBLEM TO BE SOLVED: To improve the strength and the strain straightening of a material for soft-nitriding crankshaft at still more. SOLUTION: The blank for soft-nitriding crankshaf has the composition of a prescribed mass% of C, Si, Mn, Cu, Ni, Cr, V, S, s-Al, Ca, N and the balance Fe with inevitable impurities, and ferrite+pearlite structures, and after producing the steel having the above condition, a hot-forging is applied and thereafter, a normalizing treatment is applied in the temperature range of 780-850°C to the heat-forged material. Afterward, a strain straightening processing for correcting the bending caused by the soft-nitriding treatment is applied. COPYRIGHT: (C)2010,JPO&INPIT
摘要:
[Problems] To provide a process for production wherein a compound layer formed on a surface of an iron and steel material by nitriding treatment is prevented from being oxidized by induction quenching, so that unevenness in film thickness between different portions of an oxidization-inhibiting film may not easily occur, with the result that a nitrogen-containing compound layer obtained after high-frequency heating may uniformly remain. [Means for solving] A process for duplex heat treatment of combined nitriding treatment and induction quenching treatment on an iron and steel material, further comprising a chemical conversion treatment step for forming a chemical conversion film on a nitrogen compound layer formed on the iron and steel material by the nitriding treatment, after the nitriding treatment and before the induction quenching treatment.
摘要:
PROBLEM TO BE SOLVED: To provide a process of producing steel member which hardly causes film thickness irregularity of an oxidation-preventive film depending on a portion of a steel member and, as a result, allows a nitrogen-containing compound layer obtained after high-frequency heating to evenly remain, as a method of preventing oxidation of a compound layer due to high-frequency hardening, the compound layer being formed on the surface of a steel material by nitriding. SOLUTION: The process of producing steel member by which the steel material is subjected to combined heat treatment comprising a combination of nitriding and high-frequency hardening is characterized in that a chemical conversion treatment process for forming a chemical conversion coating film on a nitrogen compound layer formed on steel by the nitriding is further included before the high-frequency hardening after the nitriding. COPYRIGHT: (C)2011,JPO&INPIT