AUTOMOBILE UNDER CARRIAGE AND DRIVE MECHANISM PARTS, EXCELLENT IN FATIGUE CHARACTERISTIC, AND THEIR PRODUCTION

• Main Authors: SHIRAGAMI TETSUO, MIWA JIRO, FUKUI YOSHIMITSU, SANPEI TETSUYA, SHIROI YUKIYASU, GOTO MASAKI, TANIGUCHI YOICHI, KATO KINYA, EHATA AKIRA
• Format: Patent
• Language: English
• Published: 29.07.1997
• Edition: 6
• 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; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; PUNCHING METAL; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; VEHICLE SUSPENSION ARRANGEMENTS; VEHICLES IN GENERAL; WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS ORPROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL

PROBLEM TO BE SOLVED: To provide automobile under carriage and drive mechanism parts, produced by means of cold forging and excellent in fatigue characteristic, and their production. SOLUTION: These parts are composed of a steel material which contains, by weight, 0.19-0.39% C, <=0.10% Si, 0.3-1.4% Mn, <=0.01% P, <=0.015% S, 0.020-0.070% Al, <=0.0050% N, and <=0.0015% O and in which C equivalent, represented by (C equivalent)=C+(Si/24)+(Mn/6), is regulated to 0.37-0.49% and also the value of Al/N and the fraction of ferrite are regulated to 8-15 and <=50%, respectively. These parts are produced by subjecting this steel material to cold working including punching under the condition of 1/d>2.5, where (1) is the depth of hole and (d) is the inside diameter of hole, by cold extrusion.