工業用純鈦冷軋薄板開發

Development of Industrial Cold Rolled Titanium Sheet

洪胤庭(I.T. Hong) ； 張孝慈(H.T. Chang) ； 伍昭憲(C.H. Wu) ； 余育陞(Y.S. Yu)

《鑛冶：中國鑛冶工程學會會刊》 61卷4期 (2017/12) Pp. 60-76

https://doi.org/10.30069/MM.201712_61(4).0006

摘要

本研究針對純鈦熔煉、軋延及熱處理各項生產細節進行研究，並將研究成果落實於生產現場，成功開發出工業用冷軋鈦捲，供給國內各產業使用。此外，本研究使用EBSD分析各種不同製程之鈦板，探討軋延量與熱處理條件對純鈦板顯微組織、集合組織、異向性與r 值的影響，並進一步分析冷軋後純鈦形成雙晶之晶粒取向差角度及極圖，釐清純鈦冷軋後雙晶與差排的形成機制。研究結果發現真空電弧熔煉之熔煉參數會影響熔煉後鑄錠表面缺陷及氧氮微量元素偏析程度，進一步影響最終鍛打後鈦胚品質與成分。為獲得較佳之鈦板表面品質及細緻晶粒，鈦捲熱軋時，鈦胚加熱溫度需控制於930℃、粗完軋溫度需控制在750~850℃、精完軋溫度需控制在650~750℃、盤捲溫度＞600℃。鈦捲進行冷軋時，冷軋每道次軋延量不宜超過20%，且軋速不宜超過80mpm，以避免鈦捲與軋輥產生熱粘，導致表面品質不良。冷軋完畢後鈦捲再經連續退火酸洗獲得完全再結晶之亮皮冷軋鈦捲。EBSD分析結果顯示，純鈦HCP中的c軸方向是影響鈦板異向性與r值（深冲特性）的重要因素。一般熱軋厚板或熱軋薄板具{10-10}＜11-20＞及{11-20}＜10-10＞兩種會使c軸平行於TD(板寬方向)的集合組織，因此熱軋厚板與熱軋薄板之異向性較大，且r值較低。透過適當冷軋及熱處理，使鈦板{10-10}＜11-20＞及{11-20}＜10-10＞ 集合組織消失，形成{-2115}＜01-10＞及{10-13}＜2-1-10＞兩種c軸較垂直板面的集合組織，則可改善鈦板之異向性，並提高r值（高深冲性）。本研究開發之冷軋純鈦薄板，已供給國內建築、民生餐具、能源、石化等領域，重要應用實績有: 台北大巨蛋鈦屋頂與帷幕牆（施工中）、國內民生鈦餐具、板式熱交換器與台塑、長春等公司之化工桶槽，已銷售約1100 噸，為國內輕金屬產業創造逾10億元產值。

關鍵字

純鈦 ； 冷軋 ； 集合組織 ； 異向性 ； r值

並列摘要

Pure titanium was widely used for petrochemical, architecture, aerospace, energy, ocean industry because of its low density, outstanding corrosion resistance, favorable mechanical properties, good weldability and excellent forming property. This research studied the melting, rolling and heat-treatment process of pure titanium and successfully developed the cold rolled titanium coil. A series of microstructural observations, texture analysis, mechanical property measurements were conducted to study how rolling and heat-treatment process affect the properties of microstructure, texture, anisotropy property and r-value (Lanford value) of titanium sheets. We also investigated the out-orientation angle and pole figure of twin crystal of cold rolled titanium sheet to clarify the deform mechanism and dislocation. Our results showed that the melting parameters of VAR affect the defect morphology and the segregation degree of oxygen and nitrogen, thereby affected the quality and composition of titanium slab. The finishing rolling temperature must be maintained at 900~930°C and the heating temperature of titanium slab at 650~750°C to obtain quality surface and fine grain. The reduction rate of cold roll pass should not surpass 20% and the rolling speed should be under 80MPM to avoid roughing up the surface of titanium cold rolled sheet. Results of EBSD analysis showed the direction of c-axis was the key factor of anisotropy of titanium sheet. The anisotropy of hot rolled titanium plate and sheet were more obvious than cold rolled sheet, because their c-axis was parallel to the transverse direction. After proper cold rolling and heat-treatment, the c-axis tended to be vertical to normal plane of titanium sheet resulting in cold rolled titanium sheet equipped with high r value and low anisotropy property. The cold rolled titanium sheet/coil was successfully developed for architecture, civil, energy and petrochemical industry worth more than 1 billion NTD.

並列關鍵字

pure titanium ； cold rolling ； texture ； anisotropy