HIGH STRENGTH COMPONENT AND METHOD FOR MANUFACTURING THE SAME

• Main Authors: HAMADA YUKI, HIGUCHI SHIGEKI, INOUE KEISUKE
• Format: Patent
• Language: English; Japanese
• Published: 07.10.2021
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

To provide a high strength component excellent in static torsional strength and torsional fatigue strength.SOLUTION: A high strength component consisting of steel having a predetermined component composition includes a carburizing and quenching layer on a surface layer part and has 0.80 μm or less of the arithmetic average roughness (Ra) of the surface, 1200-1650 MPa of a compressive residual stress and 490 HV or more of an equivalent hardness H defined by the following formula (1) on the basis of a hardness distribution from the surface to the inner center. H=Σ(Ki×Hi)/ΣKi .. the formula (1), where, Σ(Ki×Hi) is a value obtained by totaling the product of an area Ki (mm2) in a small region divided in the cross section of an object to be measured and a representative hardness Hi (HV) in the small region over the total small regions, and ΣKi is the area (mm2) of the total small regions.SELECTED DRAWING: None 【課題】静ねじり強度およびねじり疲労強度に優れた高強度部品を提供する。【解決手段】高強度部品は、所定の成分組成を有する鋼からなり、表層部に浸炭焼入れ層を有する。表面の算術平均粗さ（Ｒａ）が０．８０μｍ以下、圧縮残留応力が１２００〜１６５０ＭＰａで、更に、前記表面から内部中心までの硬さ分布に基づき下記式（１）で定義される相当硬さＨが４９０ＨＶ以上である。Ｈ＝Σ（Ｋi×Ｈi）／ΣＫi・・式（１）、但し、Σ（Ｋi×Ｈi）は、測定対象の断面内にて区画された小領域の面積Ｋi（ｍｍ2）と該小領域の代表硬さＨi（ＨＶ）の積を全小領域について合計したもの、ΣＫiは、全小領域の面積（ｍｍ2）である。【選択図】 なし