METHOD FOR MANUFACTURING BILLETS FOR PLATE SPRING STEEL

• Main Authors: KANG, SEOK EUN, YOON, WON GYU
• Format: Patent
• Language: English; Korean
• Published: 22.11.2001
• Edition: 7
• Subjects: CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; METALLURGY; PRETREATMENT OF RAW MATERIALS; PRODUCTION AND REFINING OF METALS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PURPOSE: A method is provided which not only maintains an equal level of fatigue life compared to a conventional method but also directly manufactures the molten steel into billets without passing through blooms by appropriately changing carburization and injection conditions of mole steel, thereby minimizing formation of scum in the billets. CONSTITUTION: In a billet manufacturing method by an open mold(2) comprising the processes of deoxidizing the molten steel(6) during tapping of molten steel for a pan spring from a ladle, and pouring the deoxidized molten steel into the mold in the atmosphere not using an immersion nozzle from a tundish(1), the method for manufacturing billets for plate spring steel is characterized in that the deoxidization is performed by injecting ferro silicon into the molten steel, and the pouring of the molten steel(6) is performed after maintaining a nitrogen atmosphere in a space between the tundish and the mold, wherein an amount of ferro silicon injected into the molten steel is selected in the range of 3.4 to 3.6 kg, and the nitrogen atmosphere in a space between the tundish and the mold(2) is made by supplying nitrogen into the inner space of the shielding material(4) through a nitrogen supply pipe(5) penetrating the heat resistant cloth(3) and shielding material after positioning a shielding material(4) with an inner space through which the molten steel passes between the lower part of the tundish(1) and the mold so that the molten steel discharged from the tundish is supplied into an injection hole of the mold, and covering the outer part of the shielding material with a heat resistant cloth(3). 본 발명은 판스프링용 강편(billet)의 제조방법에 관한 것이며; 그 목적은 강편내에 스컴(scum)발생을 최소화하여 기존의 것과 피로수명에 있어 동등한 수준을 유지하면서 대강편(bloom)을 거치지 않고 직접 강편으로 제조할 수 있는 방법을 제공함에 있다. 상기 목적달성을 위한 본 발명은 판스프링용 용강을 레들로 부터 출강중에 훼로실리콘으로 탈산처리하고, 탈산된 용강을 턴디쉬로 부터 침지노즐을 사용하지 않고 턴디쉬와 몰드 사이를 질소분위기로 한 후 몰드에 주입하는 판스프링강용 강편의 제조방법에 관한 것을 그 기술적 요지로 한다.