Clarification of generation mechanism for residual stress field on quenched streel after carburizing by microscopic examination of hardened layer

2014 Fiscal Year Final Research Report

• Project/Area Number: 24560095
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Materials/Mechanics of materials
• Research Institution: Shizuoka University
• Principal Investigator: SAKAIDA Yoshihisa 静岡大学, 工学(系)研究科(研究院), 教授 (10334955)
• Co-Investigator(Renkei-kenkyūsha): HAYAKAWA Kunio 静岡大学, 工学部, 教授 (80283399)
• Research Collaborator: INAYAMA Tomohito ; NURAI Toshiyuki
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 後方電子線散乱回折法 / 局所方位差 / 領域平均 / 硬化層特性 / 硬化層深さ / 残留応力 / 変態塑性ひずみ / 浸炭焼入

Outline of Final Research Achievements

In this study, some quenched chromium-molybdenum steel after carburizing were used. Using the scanning electron microscope, the crystallographic orientation analysis was carried out on the cross-sectional hardened layer by EBSD (electron backscattering diffraction) technique. The correlations of the KAM (kernel average misorientation) distribution with the case depth and residual stress field were examined. As a result, the KAM distribution under the carburized surface was quite different from that of the interior below the case depth. By setting the threshold angle to 60 degrees, the KAM maps are meaningful data for the mixture of martensite and bainite grains. Furthermore, the case depth and the plateaued depth in the compressive residual stress near the carburized surface are predictable by calculating the area-average of the KAM maps.

Free Research Field

先進材（金属，セラミックス，骨）の変形・応力・破壊評価，電子顕微鏡やＸ線による非破壊評価法の開発