号数 ばね論文集48号(2003年)
ページ数 pp.7-14
種類 論文
論文名 高腐食疲労ばね用鋼の冷間コイルばねへの適用
Title Application of High Corrosion Fatigue Strength Spring Material to Cold-Formed Coil Spring
著者 吉川 英利・榊原 隆之・脇田 将見
Author Hidetoshi YOSHIKAWA, Takayuki SAKAKIBARA, Masami WAKITA
抄録  近年,懸架ばねとして軽量化と高い腐食疲労強度を合わせ持つ熱間成形ばねが提案されている. 弊社のSUP190を用いた熱間成形ばねを提案している. 一方で,懸架ばねの熱間成形によるものから冷間成形によるものへ移行している. 冷間成形ばねには,高い成形性,形状自由度をもっている特徴がある.冷間ばね材は短時間熱処理により得られる. 短時間熱処理は微細な組織,結晶粒そして脱炭が少ないという特徴がある. そこで,我々は冷間ばねと短時間熱処理の特徴に注目した. そして,我々は熱間ばね材であるSUP190を短時間熱処理に適応させるという観点で開発を行った. しかし,SUP190は高合金鋼であるために変態点の変化や炭化物の固溶に関する検討が必要である. よって,我々は熱間加工シミュレーターによる熱処理について基礎評価を重点的に行った. それに加えて,実炉における熱処理の評価を行い,さらにばね特性についても評価した.
Abstract Weight reduction and high capacity of corrosion fatigue strength have been demanded for suspension springs from hot-formed coiling process. We suggested SUP190 for the hot-formed coil springs for this purpose. On the other hand, shift from the hot-formed coil springs to cold-formed coil springs has been proceeding recently, because the cold-formed coil springs have advantage of high formability and high shape freedom. The cold-formed coil spring materials are generally obtained by the quick heat treatment. The quick heat treatment have the advantage of fine structure, fine austenitic grain and minimum decarburization. We focused on the advantage of the cold-formed coil springs made of material processed by the quick heat treatment. In the meanwhile, we have further developed a means of applying the quick heat treatment to the hot-formed coil spring materials of SUP190. However since SUP190 is alloy steel, it is necessary to consider the change of transformation temperature and solid solution of carbides. Therefore, we concentrated on the basic evaluation for heat treatment by using the hot-working simulator. In addition ,the evaluation of the heat treatment in production furnace and the examination of spring characteristic were conducted.
著者の所属 中央発條(株)
Belonging CHUO SPRING CO., LTD
Key Words Short period heat treatment, High corrosion fatigue strength, Cold-formed coil spring, Decarburization