Novel Carburization Phenomenon for Steel and its Practical Use

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05045
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26030:Composite materials and interfaces-related
• Research Institution: Kurume National College of Technology
• Principal Investigator: MORIZONO Yasuhiro 久留米工業高等専門学校, 材料システム工学科, 教授 (70274694)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 純鉄 / 鉄粉 / グラファイト粉 / 熱処理 / 炭素拡散

Outline of Final Research Achievements

A pure iron plate was embedded in mixtures of iron and graphite powders and then held in the temperature range of 1073-1273 K in the atmosphere. After the heat treatment, the plate had metallic luster and a pearlite structure was observed in the vicinity of the iron surface. This indicates that carbon atoms resulting from the graphite powder diffused into the plate. In this process, the addition of iron powder to graphite powder is indispensable. Therefore, when the plate was heat-treated in only graphite powder, carburization did not occur and an oxide film was formed on the iron surface. In addition, the amount of carbon diffused into the plate was significantly affected by the size of iron powder.

Free Research Field

材料組織制御学

Academic Significance and Societal Importance of the Research Achievements

鋼の浸炭は，その表面から炭素を拡散浸透させた後，焼入れ・焼戻しを行うことで表面部を硬化させる技術であり，耐摩耗性や耐疲労性の向上が求められる歯車などの機械部品によく適用される。工業的には，高炭素含有の浸炭用ガスの中で加熱・保持する「ガス浸炭」が主流となっている。我々の研究グループは，この浸炭が鉄粉とグラファイト粉を混ぜた粉末を使えば，大気中で加熱するだけで容易に達成できることを見出した。本研究課題では，新しい浸炭技術としての利用を目指して，その詳細を調査した。