STEEL FOR CUTTING TOOL EXCELLENT IN TOUGHNESS, WEAR RESISTANCE AND SOFTENING RESISTANCE

• Main Author: MAEDA MASAHITO
• Format: Patent
• Language: English; Japanese
• Published: 26.10.2017
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; METALLURGY; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PROBLEM TO BE SOLVED: To provide a steel for a cutting tool having wear resistance for a cutting tool, hardly softening by heat generation due to working in use and excellent in toughness.SOLUTION: The steel is provided that contains, by mass%, C:0.45 to 0.60%, Si:0.50 to 1.20%, Mn:≤0.60%, Ni:1.50 to 2.10%, Cr:4.50 to 6.00%, Mo+W/2:1.00 to 2.00%, V+Nb/2:0.50 to 1.50%, Al:0.01 to 0.03%, N:0.0100 to 0.0300% and the balance Fe with inevitable impurities. In the steel, an area ratio of a micro structure of carbide and nitride with a length of 1 μm or more is 0.1 to 1.0%, the number of carbide and nitride having an area of 30 μmor more is 20/mmor less. The steel satisfies formula T=315-392×{(C%)+6/7(N%)}-52×(Si%)-24×(Mn%)-14×(Cr%)+49×{(Mo%)+(W%)/2}≥20 and formula S=(Ni+Mo+W/2+V+Nb/2)≥0.57.SELECTED DRAWING: None 【課題】 刃物用の耐摩耗性を有し、使用時の加工発熱で軟化しにくく靭性に優れた刃物用鋼を提供する。【解決手段】質量％で、Ｃ：０．４５〜０．６０％、Ｓｉ：０．５０〜１．２０％、Ｍｎ：≦０．６０％、Ｎｉ：１．５０〜２．１０％、Ｃｒ：４．５０〜６．００％、Ｍｏ＋Ｗ／２：１．００〜２．００％、Ｖ＋Ｎｂ／２：０．５０〜１．５０％、Ａｌ：０．０１〜０．０３％、Ｎ：０．０１００〜０．０３００％を含有し、残部Ｆｅおよび不可避不純物からなる鋼で、長さ１μｍ以上の炭化物および窒化物のミクロ組織の面積率が０．１〜１．０％、３０μｍ2以上の面積を有する炭化物および窒化物の個数が２０個／ｍｍ2以下、式Ｔ＝３１５−３９２×｛（Ｃ％）＋６／７（Ｎ％）｝−５２×（Ｓｉ％）−２４×（Ｍｎ％）−１４×（Ｃｒ％）＋４９×｛（Ｍｏ％）＋（Ｗ％）／２｝≧２０、式Ｓ＝（Ｎｉ＋Ｍｏ＋Ｗ／２＋Ｖ＋Ｎｂ／２）≧０．５７である鋼。【選択図】 なし