Fe-1.3Mn-Si계 引拔鋼線의 工程變數와 機械的 特性의 相關性에 관한 硏究

Abstract

Heat treatment tests and microstructural changes were observed for deformed PC(pre-stressed concrete) steel rods using cold drawing equipment and continuous high-frequency induction heating and cooling facility. In order to improve the wear resistance performance of the pinch roller, a pinch roller with a VC(vanadium carbide) coating layer applied using the TD(thermal diffusion) coating method was manufactured and abrasion resistance test was performed. In addition, the optimal shape of the drawing die was calculated through finite element analysis, and the drawing die was manufactured, and then applied to the production of deformed PC steel bars and verified by measuring production until the die wear limit was reached. The heat treatment and microstructure of the deformed PC steel bar was analyzed to analyze the process conditions of high frequency induction heating heat treatment applied to the 9.2 mm diameter deformed PC steel bar to secure the high frequency induction heating heat treatment conditions applicable to the 8.8 mm diameter deformed PC steel bar. Heat treatment test and microstructure analysis were performed to obtain high frequency induction heating heat treatment conditions with the same mechanical properties as 9.2mm deformed PC steel bars. As a result of the G3 current value and line speed change test, it was shown that the change of the line speed compared to the current value greatly affects the mechanical properties of the product, and the optimal value is the G3 current of 98A and the line speed of 48m/min. In the case of Specimen 2 to which the optimal value was applied, a microstructure similar to that of the existing product (ø9.2 mm PC steel bar) was observed, and the tensile strength was 1,455 MPa, which satisfies the product's allowable value (1,420 MPa). The characteristics of abrasion resistance by thermal diffusion surface treatment of a pinch roller, a Fe-13Cr-based cold alloy tool steel, were analyzed and reviewed. The rate of formation of the VC (vanadium carbide) coating layer was checked, the coating layer was formed with an effective thickness, and the specific abrasion amount of the base material and the VC coating layer was measured, and the effect was verified by applying a pinch roller to which the VC coating layer was applied to the production facility for the deformable PC steel bar. did When the VC layer is formed by the TD coating method, which is immersed in molten vanadium at 1,000°C to improve the abrasion resistance of pinch rollers applied to the production of deformed PC steel bars, the VC layer formation rate is 0.6-0.9㎛/hr and immersion for 10 hours A VC layer of 8 μm was produced. The specific wear amount of the base material and the VC layer was 2.02x10-4mm2/N and 0.73x10-4mm2/N, respectively, and the abrasion amount of the VC layer was only 36% worn compared to the base material. When the pinch roller to which the VC layer is applied is applied to an induction heat treatment machine that manufactures a deformed PC steel bar, twice the wear resistance performance of the base material was confirmed. The optimal design of the drawing die mold was verified through finite element analysis of the AP angle (Approach angle). By checking the AP angle of the Japanese-made drawing die for PC steel bar, the optimal design method of the drawing die mold was derived through molding analysis, and the effect was obtained by using the cold drawing facility of Taekwang Metal Co., Ltd. and continuous high frequency induction heating and cooling facility. was verified. The AP angles of Japanese-made PC steel bar drawing dies were 7.34° and 2.62° for AP #1 and AP #2, respectively. As a result of calculating the stress through finite element analysis for the model to which AP #1 and AP #2 were applied ±0.5°, AP #1, which is a model to which +0.5° was applied, was designed at 7.84° and AP #2 at 3.11°. The lowest stress was calculated at , and its value was 253.8 MPa, which is a 9% decrease compared to the previous model. As a result of trial production of a 9.2mm deformed PC steel bar by applying a new drawing die with optimized AP angle, it was calculated that productivity improvement by 45% and die consumption reduction by 26% are possible. As a result of trial production of an 8.8mm deformed PC steel bar by applying a new drawing die with an optimized AP angle, it was calculated that productivity can be improved by 49% and die consumption can be reduced by 28%.

冷間 引拔 設備와 連續 高周波 誘導加熱 및 冷却 設備를 이용하여 異形 PC(Pre-stressed Concrete) 鋼棒에 대한 熱處理 試驗과 微細組織 變化를 觀察하였으며, 핀치 롤러의 耐 磨耗 性能 向上을 위하여 TD(Thermal Diffusion) 코팅法을 利用하여 VC(Vanadium Carbide) 코팅층이 적용된 핀치 롤러를 製作 및 耐磨耗 試驗을 實施하였다. 또한 有限 要素 解析(Finite Element Analysis)을 통하여 引拔 다이스의 최적 形狀을 計算하여 引拔 다이스를 製作 후, 異形 PC 鋼棒 生産에 適用하여 다이스 磨耗 限界 到達까지의 生産量 測定으로 檢證하였다. 異形 PC 鋼棒에 대한 熱處理와 微細組織은 直徑 9.2mm 異形 PC 鋼棒에 적용되고 있는 高周波 誘導加熱 熱處理의 工程 條件을 參考하여 直徑 8.8mm 異形 PC 鋼棒에 적용할 수 있는 高周波 誘導 加熱 熱處理 條件을 확보하기 위하여 熱處理 試驗과 微細組織 分析을 시행하여 直徑 9.2mm 異形 PC 鋼棒과 同一 機械的 特性을 갖는 高周波 誘導 加熱 熱處理 條件을 구하였다. G3 電流 값 및 線束(선속)변경 試驗 結果, 電流 값 대비 線速도 변경이 製品의 機械的인 特性에 많은 영향을 끼치며, 최적값은 G3 電流 98A 및 線速 48m/min인 것으로 나타났다. 최적값이 적용된 경우, 기존 제품(ø9.2mm PC 鋼棒)과 유사한 微細組織이 觀察되며 引張强度는 1,455MPa로 제품의 허용값(1,420MPa)을 충족하였다. Fe-13Cr계 냉간합금 공구강인 핀치롤러의 熱擴散(Thermal diffusion) 表面處理에 의한 耐磨耗性에 대한 特性을 分析, 檢討하였다. VC(Vanadium carbide) 코팅층의 生成 速度를 確認하여 유효한 두께로 코팅층을 形成시켰으며, 母材와 VC 코팅층의 比 磨耗 量을 測定하고 VC 코팅층이 적용된 핀치 롤러를 異形 PC 鋼棒 製造 設備에 적용해 그 效果를 檢證하였다.異形 PC 鋼棒 生産에 적용되는 핀치 롤러의 耐 磨耗 性能 向上을 위한 1,000℃ 바나듐(Vanadium) 용탕에 沈積시키는 TD 코팅 方法에 의한 VC 층을 生成할 경우, 0.6-0.9㎛/hr의 VC 층 生成 速度를 보이며 10시간 沈積時 8㎛의 VC 층이 生成 되었다. 母材와 VC 층의 比 磨耗量은 각각 2.02x10-4mm2/N와 0.73x10-4mm2/N으로, VC 층의 磨耗 量은 母材 대비 36%만 磨耗 되었다. VC 층이 적용된 핀치롤러를 異形 PC 鋼棒을 製造하는 誘導 加熱 熱處理 設備에 適用 시 母材 대비 2배의 耐 磨耗 性能이 확인되었다. 인발 다이스 금형의 최적 설계는 AP angle(Approach angle)에 대한 유한요소해석을 통하여 검증하였다. 日本産 異形 PC 鋼棒用 引拔 다이스에 대한 AP angle을 확인하며 成形 解釋을 통한 引拔 다이스 金型의 최적 설계 방안을 도출하여 태광금속(주)의 冷間引拔 設備와 連續 高周波 誘導 加熱 및 冷却 設備를 使用하여 그 效果를 檢證하였다. 일본産 異形 PC 鋼棒 引拔 다이스의 AP angle은 AP #1과 AP #2는 각각 7.34°, 2.62°로 測定되었다. AP #1과 AP #2를 각각 ±0.5°를 적용한 모텔을 有限 要素 解析(유한 요소 해석)을 통하여 應力을 계산한 결과, +0.5°가 적용된 모델인 AP #1은 7.84°, AP #2는 3.11°로 설계된 모델에서 가장 낮은 應力이 계산되었으며 그 값은 기존 모델 대비 9% 감소한 253.8 MPa였다. AP angle이 최적화된 新規 引拔 다이스를 適用하여 9.2mm 異形 PC 鋼棒을 시험 생산한 결과 生産性 向上 45% 및 다이스 消耗量 減少 26%가 가능할 것으로 計算되었다. AP angle이 최적화된 신규 引拔 다이스(DIES)를 적용하여 8.8mm 異形 PC 鋼棒을 試驗 生産한 결과 生産性 向上 49% 및 다이스 消耗量 減少 28%가 가능할 것으로 計算되었다.