MANUFACTURING METHOD FOR FORGING MATERIAL FOR CARBURIZATION

• Main Authors: TAKAO RYOTA, FUKUDA NAOKI, SUGIURA TAKAYOSHI, SHIMADA TAKEYUKI
• Format: Patent
• Language: English; Japanese
• Published: 07.10.2021
• Subjects: ALLOYS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; FERROUS OR NON-FERROUS ALLOYS; FORGE FURNACES; FORGING; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; HAMMERING; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; PRESSING METAL; PUNCHING METAL; RIVETING; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS

To provide a manufacturing method of a forging material for carburization enabling crystal grains to be more effectively prevented from coarsening at carburization even when adopting a warm forging operation.SOLUTION: A manufacturing method of a forging material for carburization comprises: preparing a blank which contains 0.12-0.28% of C, 0.90% or less of Si, 0.30-1.00% of Mn, 0.035% or less of P, 0.010-0.045% of S, 0.40-2.00% of Cr, 0.003-0.060% of Al, 0.0030-0.0100% of N, at least one of 0.01-0.10% of Nb and 0.01-0.15% of Ti, 0-0.60% of Mo and 0.0005-0.0050% of B as optional elements, and satisfies the expression 1: 0.8Ti+Nb≥0.045 and expression 2: S≥0.206Ti+0.0086; rolling the blank at temperatures of 1,100-1,250°C; cooling the blank to 600°C at 1.5°C/sec or more; and carrying out a warm forging operation at temperatures of 650-970°C by elevating the temperature to 400°C or more at 2.0°C/sec or more.SELECTED DRAWING: None 【課題】温間鍛造を採用する場合でも、従来よりも効果的に浸炭時の結晶粒粗大化を防止できる、浸炭用鍛造材の製造方法を提供すること。【解決手段】Ｃ：０．１２〜０．２８％、Ｓｉ：０．９０％以下、Ｍｎ：０．３０〜１．００％、Ｐ：０．０３５％以下、Ｓ：０．０１０〜０．０４５％、Ｃｒ：０．４０〜２．００％、Ａｌ：０．００３〜０．０６０％、Ｎ：０．００３０〜０．０１００％を含有し、Ｎｂ：０．０１〜０．１０％とＴｉ：０．０１〜０．１５％の少なくとも一方を含有し、任意元素としてＭｏ：０〜０．６０％とＢ：０．０００５〜０．００５０％を含有し、式１、２を満たす素材を１１００〜１２５０℃で圧延し、６００℃まで１．５℃／秒以上で冷却し、４００℃以上を２．０℃／秒以上で昇温して６５０〜９７０℃で温間鍛造を行う。式１：０．８Ｔｉ＋Ｎｂ≧０．０４５、式２：Ｓ≧０．２０６Ｔｉ＋０．００８６。【選択図】なし