Abstract:
본 발명은 저 변형량에서 나노 결정립을 가지는 티타늄 합금을 제조하고, 보다 우수한 강도를 가지도록 하는 것이다. 초기 미세조직을 미세한 층 구조로 이루어진 마르텐사이트로 유도한 후 변형량, 변형율속도, 변형온도 등이 미세조직 변화에 미치는 영향을 관찰하여 공정 변수를 최적화시켜 저 변형량에서 나노 결정립 티타늄 합금을 제조하는 것을 특징으로 한다.
Abstract:
본 발명은 저주기 피로 수명을 향상시킬 수 있는 마그네슘 합금 가공재의 제조방법을 제공하기 위한 것으로써, 마그네슘 합금 가공재를 제조하는 방법에 있어서, 가공을 마친 마그네슘 합금 가공재에 선압축변형(pre-straining)을 행하는 것을 포함하는 선압축변형을 이용하여 저주기 피로 수명이 향상된 마그네슘 합금 가공재의 제조방법에 관한 것이다.
Abstract:
PURPOSE: A method for increasing fatigue strength of magnesium alloy processing materials is provided to prevent the reduction of strength by removing twin crystal in a material by applying pre-tension of 1~10% to an magnesium alloy extruding or rolling material. CONSTITUTION: A method for increasing fatigue strength of magnesium alloy processing materials is as follows. A magnesium alloy processing material is pre-tensioned. Twin crystal of 10~12 existing in the magnesium alloy processing material is removed through pre-tensile stress. The pre-tensile stress is performed in a strain rate of 1~10%.
Abstract:
PURPOSE: A high-strength and high-Mn steel wire rod with excellent cold forging property, a manufacturing method thereof, and a bolt manufacturing method using the same are provided to reduce the weight of parts by excluding a heat treatment process and utilizing the steel wire rod for the parts. CONSTITUTION: A method for manufacturing a high-strength and high-Mn steel wire rod with excellent cold forging property comprises the steps of: heating steel including Mn of 12-25wt.% to 1100-1250°C, hot rolling the heated steel at 700-1100°C, cooling the hot rolled steel below 200°C, and cold caliber-rolling or drawing the steel into a steel wire rod. [Reference numerals] (AA) Temperature(°C); (BB) 1200°C heating; (CC) 1100°C hot rolling; (DD) Cold caliber-rolling or drawing; (EE) Time(t)
Abstract:
PURPOSE: A method for increasing fatigue strength of magnesium alloy processing materials is provided to prevent the reduction of strength by removing twin crystal in a material by applying pre-tension of 1~10% to an magnesium alloy extruding or rolling material. CONSTITUTION: A method for increasing fatigue strength of magnesium alloy processing materials is as follows. A magnesium alloy processing material is pre-tensioned. Twin crystal of 10~12 existing in the magnesium alloy processing material is removed through pre-tensile stress. The pre-tensile stress is performed in a strain rate of 1~10%.
Abstract:
본 발명은 저주기 피로 수명을 향상시킬 수 있는 마그네슘 합금 가공재의 제조방법을 제공하기 위한 것으로써, 마그네슘 합금 가공재를 제조하는 방법에 있어서, 가공을 마친 마그네슘 합금 가공재에 선압축변형(pre-straining)을 행하는 것을 포함하는 선압축변형을 이용하여 저주기 피로 수명이 향상된 마그네슘 합금 가공재의 제조방법에 관한 것이다. 마그네슘 합금 가공재(wrought magnesium alloy), 저주기 피로 수명(low-cycle fatigue life), 선압축변형(pre-straining), 쌍정(twin)
Abstract:
본 발명은 냉간 압조성이 우수하여, 볼트 제조시 구상화 열처리 및 퀀칭-템퍼링 처리가 필요치 않은 고강도 고망간 강선재와 이를 제조하는 방법 및 상기 강선재를 이용한 볼트의 제조방법을 제공한다. 본 발명은 망간(Mn) 12~25중량%를 포함하는 강을 1100~1250℃로 가열하는 단계; 상기 가열된 강을 700~1100℃에서 열간 압연하는 단계; 및 상기 열간 압연된 강을 200℃이하의 온도로 냉각하고, 냉간 공형 압연 또는 인발하여 강선재를 제조하는 단계를 포함하는 냉간 압조성이 우수한 고강도 고망간 강선재의 제조방법과 이를 통해 제조된 강선재 및 이를 이용한 볼트의 제조방법을 제공한다.
Abstract:
PURPOSE: A method for manufacturing magnesium alloy worked material having improved low-cycle fatigue life using pre-straining is provided to improve the stability of components and enlarge the application area of magnesium alloy worked material by the improvement of fatigue characteristic. CONSTITUTION: A method for manufacturing magnesium alloy worked material having improved low-cycle fatigue life using pre-straining comprises following steps. A pre-straining process is performed in magnesium alloy worked material. Twin crystals are created on the magnesium alloy worked material. The pre-straining process is performed at the deformation ratio 1~15%. The low cycle fatigue life is improved since the pre-straining process is performed.
Abstract:
PURPOSE: A method for increasing the fatigue life of surface-nitrified steel is provided to maintain abrasion resistance and to prevent the fatigue life due to fine cracks and pores formed on a compound layer. CONSTITUTION: A method for increasing the fatigue life of surface-nitrified steel is as follows. A nitrified steel compound layer is removed by a grinding, cutting and milling process. A compound layer is removed to range where a hardened layer is maintained.
Abstract:
PURPOSE: A method for producing nano-crystalline titanium alloy at low strain rate is provided to increase the strength, yield strength and tensile strength of nano-crystalline titanium alloy without the decrease of ductility. CONSTITUTION: A method for producing nano-crystalline titanium alloy at low strain is as follows. Martensite structure is rolled in deformation temperature of 575~625°C, strain velocity of 0.07~0.13, and strain rate of 0.9~1.8. The Martensite structure is segmented into fine coaxial structures.