200932390 九、發明說明 【發明所屬之技術領域】 本發明係關於適用於Cr系合金鋼的加工之披覆超硬 柱塞以及使用其之冷抽拉方法，詳而言之，係關於耐熔執 性（seizure resistance)及耐摩耗性優異的披覆超硬柱塞 以及使用其之冷抽拉方法。 φ 【先前技術】 冷抽拉加工是適用於，在核能用配管和高溫高壓鍋爐 等的用途所使用之要求高尺寸精度之鋼管的精加工。在採 用該冷抽拉加工的情況，是將素管的一端施以縮徑而形成 頸縮部，接著將素管施以酸洗後進行潤滑處理，再將頸縮 部用冷抽拉機的夾頭夾持住，而隨著載具（carriage )的 移動將素管施以抽拉而加工成目標尺寸。 第1圖係用來槪略說明藉由冷加工來將素管施以縮徑 φ 及壁厚減少加工的方法。在將素管3施以抽拉加工時，是 將柱塞1以相對於模具2及素管3形成同心狀的方式插入 素管3的內部，並將柱塞1的一端用心軸4保持後，將素 管3朝箭頭方向施以抽拉。 這時，被施以抽拉之素管3的外面，是藉由模具2擠 壓而進行縮徑，另一方面，素管3的內面，是沿著柱塞的 平行部la受到拘束而進行壁厚減少加工。因此，抽拉加 工後的目標尺寸當中，外徑尺寸是依模具孔徑來決定，內 徑尺寸是依柱塞平行部la的直徑來決定。 -4- ❹ 200932390 在第1圖所示的冷抽拉加工，隨著素管全;I 度變長（例如，20m/抽拉道次），由於維持在ϋ 成與素管間的摩擦變大，當素管和模具或柱塞5 無法減少的情況，摩擦熱會集中於局部而發生熔 因此，在碳鋼和合金鋼的冷抽拉加工，如传 或柱塞和被加工管間之摩擦，以降低抽拉工具的 止熔執的發生，這點是相當重要的。基於此觀爵 拉工具（模具或柱塞）的材質和形狀、潤滑劑的 拉速度和抽拉排程的最佳化等等，已有各種的提 例如，本申請人提出，在抽拉加工時使用 超合金作爲R型模具及柱塞的材質，又爲了減值 的摩擦，是在柱塞表面施加二層披覆而構成抽g 照日本特開平07-60335號公報）。 具體而言，若R型模具和素管的接觸角超3 管外面之熔執發生率急劇增加，而接觸角在40 素管外面就不會發生熔執，因此採用：施加二層 硬柱塞、被加工管和模具的接觸角爲40°以下的 【發明內容】 如前述般，作爲冷加工之抽拉工具，大多是 合金。該超硬合金，是將硬質的金屬碳化物粉东 而製得的合金，一般指的是將WC (碳化鎢）和 劑（binder )的鈷混合而施以燒結者，按照其用 I之加工長 Ϊ面壓而造 :間的摩擦 執現象。 f減輕模具 J摩耗而防 ^，針對抽 丨選擇、抽 案。 WC-Co 系 i與素管間 :工具（參 I 40。，素 °以下時， ^披覆的超 R型模具 使用超硬 施以燒結 作爲黏結 途，爲了 -5- 200932390 提昇材料特性可加入TiCN (氮化鈦碳）、TaC (碳化鉬） 等。 在抽拉加工，由於超硬合金在高溫時的硬度降低程度 小而非常不容易摩耗，因此是作爲汎用的抽拉工具的材料 ’又在與素管內面間發生明顯摩擦的柱塞，其主流是使用 在工具表面披覆TiCN (氮化鈦碳）硬質物質而構成的超 硬柱塞。通常，TiCN的披覆，是利用CVD (化學氣相成 φ 長）或pVD (物理氣相成長）來形成。 對於碳鋼或低合金鋼製的素管施以抽拉加工的情況， 在素管的去鱗皮（descaling )處理是使用硫酸洗，在潤滑 處理則是進行磷酸鹽皮膜處理之化成處理。具體的酸洗及 潤滑處理的順序，是在去鱗皮後，將素管的內外表面用鹼 性脫脂劑洗淨後用水洗淨，將該素管浸漬於磷酸鹽處理浴 以在內外表面形成磷酸鹽皮膜的底材。接著進行中和處理 ，而形成以硬脂酸鈉爲主成分之金屬皂層。 0 另一方面，對於Cr含量5質量％以上的高Cr系合金 鋼製的素管施以抽拉加工的情況，由於磷酸鹽處理不容易 進行反應，如後述的化成處理所說明的，並非在素管形成 磷酸鹽皮膜的底材，而是將素管浸漬於草酸鹽處理浴而在 內外表面形成草酸鹽皮膜的底材後，再形成以硬脂酸鈉爲 主成分之金屬皂層。 然而，對於作爲潤滑皮膜的底材是形成草酸鹽皮膜之 Cr系合金鋼施以抽拉加工的情況’若使用在表面披覆 TiCN之超硬柱塞，已知會發生TiCN膜的剝離而使柱塞壽 200932390 命明顯減低。而且’抽拉加工後的鋼管上時常發生熔執， 而會造成製品產率降低及抽拉加工的效率變差。 本發明是有鑑於上述抽拉加工的問題點而開發完成者 ，其目的是舉了提供一種披覆超硬柱塞以及使用其之冷抽 拉方法，對於作爲潤滑皮膜的底材是形成草酸鹽皮膜之Cr 系合金鋼製的素管施以抽拉加工的時’藉由使用在表面披 覆TiAIN膜之超硬柱塞，以在抽拉加工時防止熔執的發生 φ 而延長柱塞壽命，而能以高效率來製造高品質的冷加工用 製品。 本發明人等爲了解決上述課題’是使用各種的披覆超 硬柱塞，區分成作爲潤滑皮膜的底材是形成磷酸鹽皮膜的 素管和作爲潤滑皮膜的底材是形成草酸鹽皮膜的素管，並 隨著抽拉加工的進行而觀察超硬柱塞表面的披覆膜的舉動 〇 將作爲潤滑皮膜的底材是形成草酸鹽皮膜的素管，使 φ 用披覆TiCN之超硬柱塞施以抽拉加工時，草酸鹽皮膜會 造成TiCN膜的腐蝕，而容易發生TiCN膜的剝離。 相對於此，雖然不一定有理論根據，但若在抽拉加工 使用披覆TiAIN的超硬合金，即使在將作爲潤滑皮膜的底 材是形成草酸鹽皮膜的素管施以抽拉加工的情況，仍不會 在TiAIN膜發生腐蝕，而能抑制抽拉加工時之熔執，而謀 求柱塞壽命的延長。 本發明是有鑑於上述見解而開發完成者，其要旨是包 括下述（1)的披覆超硬柱塞以及（2)的冷抽拉方法。 200932390 (1) 一種披覆超硬柱塞，其特徵在於：係使用於作 爲化成處理所獲得之潤滑皮膜的底材是形成草酸鹽皮膜之 Cr系合金鋼的冷抽拉，其表面披覆氮化鈦鋁（TiAIN )膜 〇 該披覆超硬柱塞，氮化鈦鋁（TiAIN )膜的厚度宜爲 3 〜1 0 μ m 〇 (2) —種冷抽拉方法，其特徵在於：作爲對Cr系合 φ 金鋼構成的被加工管實施的化成處理，經過除去管表面的 氧化鱗皮及銹之酸洗步驟、在中和後的管表面形成草酸鹽 皮膜的步驟、以及在前述草酸鹽皮膜上形成潤滑層的步驟 之後，將披覆著3〜1 Ομιη厚的氮化鈦鋁（TiAIN )膜之披 覆超硬柱塞插入前述被加工管的內面，施以縮徑及壁厚減 少加工。 本發明所規定之「Cr系合金鋼」，例如爲JIS G 3462 、STBA25〜26之合金鋼鋼管，能以Cr含量5〜9質量％的 φ 鋼種作爲代表對象。其對象也可以是高Cr含量的鋼種， 其代表例包括：Cr含量12〜14質量％的相當於SUS420的 13Cr鋼、Cr含量18〜2 0質量％的相當於SUS3 04的不鏽鋼 。使用這些鋼種經由抽拉加工而得之鋼管，可適用於鍋爐 的加熱器管、空氣預熱器等，或是化學工業、石油工業的 熱交換器、冷凝管、觸媒管等。 依據本發明的披覆超硬柱塞，即使是將Cr系合金鋼 或不鏽鋼製的作爲潤滑皮膜底材是形成草酸鹽皮膜的素管 施加抽拉加工的情況，披覆於表面的TiAIN並不會發生剝 200932390 離’而能防止抽拉加工時發生熔執，可謀求柱塞壽命的延 長’且以高效率來製造出尺寸精度優異的高品質的冷加工 製品。 【實施方式】 本發明的披覆超硬柱塞之對象鋼種，是以Cr含量 5〜20質量％爲代表之Cr系合金鋼和不鏽鋼（以下總稱爲 ❹ 「Cr系合金鋼」）’但素管的製造方法並沒有特別的限定 。通常之無縫鋼管用的素管，係採用生產效率優異的芯棒 式無縫管軋（mandrel mill)製造法，而藉由熱壓延來製 造。 「Cr系合金鋼」素管，用來讓素管軟化的熱處理，例 如是在800 °C的退火條件下進行。供抽拉加工的素管，是 在進行素管軟化後，馬上用酸洗來實施去鱗皮處理以將素 管的內外表面的鱗皮除去，接著實施潤滑處理。 φ 第2圖係顯示可適用於本發明的素管之化成處理的步 驟例。首先’在第1處理步驟是進行酸洗，以將隨著素管 軟化而附著於表面之氧化鱗皮除去。通常，酸洗用的酸是 使用硫酸（1 0〜1 3 % )，其管理項目是游離酸度和鐵濃度。 關於酸洗條件’是以處理溫度爲室溫，浸漬時間3 0分鐘 爲標準。在酸洗後，進行水洗（例如數分鐘左右）以將殘 留於表面的酸除去。 在上述酸洗步驟後’接著將素管浸漬於氫氧化鈉溶液 而進行中和。經由該中和能讓素管表面穩定化。然後，在 -9- 200932390 第2處理步驟，是浸漬於草酸鹽處理浴，以在素管表面形 成草酸鹽皮膜的底材。所使用的草酸鹽處理浴，是將草酸 的全酸度控制在9〜12 point左右，關於處理條件，是以處 理溫度80°C，浸漬時間5分鐘爲標準。該草酸鹽皮膜處理 後，進行溫水洗淨（例如，以處理溫度50°C進行數分鐘左 右）。 若素管的鋼種爲碳鋼或低合金鋼（例如Cr含量爲2 0 質量％以下），一般是進行磷酸鹽皮膜處理以在素管表面 形成磷酸鹽皮膜，但若處理鋼的Cr含量超過5質量％，將 無法充分地形成磷酸鹽皮膜的底材。因此，本發明所採用 的化成處理，其前提是在第2處理步驟進行草酸鹽皮膜處 理。 然後，在第3處理步驟，讓所形成的草酸鹽皮膜和皂 系潤滑劑反應，以在表面形成潤滑層。作爲形成潤滑層的 處理，一般是讓硬脂酸鈉和草酸鹽皮膜反應來形成金屬皂 ❺ 層’但本發明的製造方法並不偏限於此。形成潤滑層的處 理條件’疋以處理溫度80C，浸漬時間15分鐘爲標準。 將經由上述第1〜第3處理步驟實施化成處理後的素管施以 乾燥。 本發明的披覆超硬柱塞，本體是由WC-Co系、或是 WC-TiCN-TaC-Co系的合金基體所構成，在其表面披覆 T i A1N (氮化鈦鋁）膜。所披覆的膜，可利用c V D (化學 氣相成長）或P V D (物理氣相成長）來形成，但並不侷限 於此，可藉由慣用的條件來披覆於基體表面。 -10- 200932390 在管的冷抽拉加工，由於加工範圍遍及素管的全長， 其加工長度超過20m/抽拉道次（pass)，比起其他的冷加 工（例如衝壓加工等）是在極嚴苛條件下的冷加工。因此 ，在進行管的抽拉加工時，爲了確保耐摩耗性，以往是使 用在表面披覆TiCN (氮化鈦碳）膜的超硬柱塞。 然而，在將「Cr系合金鋼」素管施以抽拉加工的情況 ，如前述般，作爲化成處理所獲得之潤滑皮膜的底材是形 0 成草酸鹽皮膜。將這種素管使用披覆TiCN膜的超硬柱塞 進行抽拉加工時，草酸鹽皮膜會造成TiCN膜的腐蝕，而 容易發生TiCN膜的剝離，因此抽拉加工後的鋼管上時常 發生熔執現象。 相對於此，在將「Cr系合金鋼」素管施以抽拉加工的 情況，若使用披覆TiAIN膜的超硬柱塞，草酸鹽皮膜並不 會造成披覆膜的腐蝕，而能顯著減少披覆膜的剝離。如此 般’ TiAIN膜對於草酸鹽皮膜具有耐蝕性的舉動，雖然技 φ 術上的理由尙不明確，但這是本發明人等進行各種深入的 探討所獲得的新發現。 本發明的披覆超硬柱塞，宜在其基體表面形成 3〜ΙΟμιη厚的TiAIN膜。TiAIN膜的厚度未達3μπι時耐摩 耗性不足，抽拉加工後的鋼管上容易發生熔執。另一方面 ’若其厚度超過1〇μηι，由於披覆過厚而變得較脆，披覆 膜容易發生缺陷。 本發明之冷抽拉方法，其特徵在於：作爲對「Cr系合 金鋼」構成的被加工管實施的化成處理，經過除去管表面 -11 - 200932390 的氧化鱗皮及銹之酸洗步驟、在中和後的管表面形成草酸 鹽皮膜的步驟、以及在前述草酸鹽皮膜上形成潤滑層的步 驟之後，將披覆著3〜ΙΟμιη厚的TiAIN膜之披覆超硬柱塞 插入前述被加工管的內面，施以縮徑及壁厚減少加工。 在本發明的冷抽拉方法，在將「Cr系合金鋼」素管施 以抽拉加工的情況，藉由使用TiAIN膜的披覆超硬柱塞， 比起習知的TiCN膜的披覆超硬柱塞，可提昇耐熔執性及 耐摩耗性，並大幅延長柱塞壽命，同時可防止在抽拉加工 發生熔執。 以下根據實施例來具體說明本發明的效果。 〔實施例〕 (實施例1 ) 作爲實施例1的供試素管是準備：使用JIS STAB26 (9Cr-lMo鋼）作爲鋼材，藉由曼內斯曼（Mannesmann) Q 之芯棒式無縫管軋法實施精加工壓延而製得的管。該素管 ，爲了施以素管軟化而.用輥膛爐（roller hearth kiln)實 施800 °C xlO分鐘的熱處理，接著藉由酸洗將素管內外表 面的鱗皮除去，再實施潤滑處理。 抽拉加工前之具體的化成處理，是使用硫酸（10~13 % )於室溫（處理溫度）進行30分鐘（處理時間）的酸洗 ，經由水洗、中和後，以處理溫度爲75~85°C的狀態進行 5分鐘（處理時間）的草酸鹽皮膜處理，接著在75〜85 °C (處理溫度）讓硬脂酸鈉和草酸鹽皮膜反應15分鐘而形 -12- 200932390 成金屬巷層。 抽拉加工排程，是將素管尺寸設定爲外徑34.0mmx壁 厚3.3mm，將抽拉尺寸設定爲外徑25.80mmx壁厚2.60mm ，並將下述（1 )式所示的截面減少率Rd設定爲40·5% °200932390 IX. INSTRUCTIONS OF THE INVENTION [Technical Field] The present invention relates to a coated superhard plunger suitable for processing of Cr-based alloy steel and a cold drawing method using the same, and more particularly, relates to a resistance to melting A super-hard plunger with excellent seizure resistance and abrasion resistance and a cold drawing method using the same. φ [Prior Art] The cold drawing process is a finishing process for steel pipes requiring high dimensional accuracy for use in nuclear power piping and high-temperature high-pressure boilers. In the case of using the cold drawing process, one end of the element tube is reduced in diameter to form a necking portion, and then the acid tube is subjected to pickling and then lubricated, and then the neck portion is cooled by a cold drawing machine. The collet is clamped and the desired size is processed by pulling the plain tube with the movement of the carriage. Fig. 1 is a schematic view for explaining a method of applying a reduced diameter φ and a wall thickness reduction by cold working. When the drawing tube 3 is subjected to the drawing process, the plunger 1 is inserted into the inside of the element tube 3 so as to be concentric with respect to the mold 2 and the element tube 3, and one end of the plunger 1 is held by the mandrel 4 , the tube 3 is pulled in the direction of the arrow. At this time, the outer surface of the drawing tube 3 is pressed by the die 2 to reduce the diameter, and the inner surface of the element tube 3 is restrained by the parallel portion 1a of the plunger. Wall thickness reduces processing. Therefore, among the target sizes after the drawing, the outer diameter is determined by the hole diameter of the mold, and the inner diameter is determined by the diameter of the parallel portion la of the plunger. -4- ❹ 200932390 The cold drawing process shown in Fig. 1 is completed with the prime tube; the I degree becomes longer (for example, 20m/draw path), because the friction between the ϋ and the 管 tube is maintained. Large, when the tube and the mold or the plunger 5 cannot be reduced, the frictional heat will concentrate on the local part and melt. Therefore, in the cold drawing process of carbon steel and alloy steel, such as transfer or between the plunger and the tube being processed It is quite important to rub to reduce the occurrence of the melting of the pulling tool. Based on the material and shape of the grenade pulling tool (mold or plunger), the pulling speed of the lubricant and the optimization of the drawing schedule, etc., various proposals have been made, for example, the applicant proposes that in the drawing process In the case of using a superalloy as the material of the R-type mold and the plunger, and for the friction of the reduction, a two-layer coating is applied to the surface of the plunger to form a pumping g. Japanese Patent Laid-Open No. Hei 07-60335. Specifically, if the contact angle of the R-shaped mold and the plain tube exceeds the outside of the 3 tubes, the incidence of melting increases sharply, and the contact angle does not occur outside the 40-tube tube. Therefore, the application uses two layers of hard plungers. The contact angle of the tube to be processed and the mold is 40° or less. [Invention] As described above, the drawing tool as a cold working is often an alloy. The super-hard alloy is an alloy obtained by mixing a hard metal carbide powder, and generally refers to a method in which a cobalt of WC (tungsten carbide) and a binder is mixed and applied to a sinter, and processed according to the use thereof. The long face is pressed and created: the friction between the two. f Reduce the mold J wear and prevent ^, select and draw for the pumping. WC-Co between i and the tube: tool (refer to I 40., below the prime °, ^ super-R-type mold coated with super hard and applied as a bonding method, for the purpose of -5 - 200932390 TiCN (titanium nitride carbon), TaC (molybdenum carbide), etc. In the drawing process, since the hardness of the super hard alloy at a high temperature is small and it is not easy to wear, it is a material for a general-purpose drawing tool. In the case of a plunger that is significantly rubbed against the inner surface of the element tube, the mainstream is a super-hard plunger formed by coating a hard material of TiCN (titanium nitride carbon) on the surface of the tool. Usually, the coating of TiCN is by CVD. (Chemical gas phase is φ long) or pVD (physical vapor phase growth) is formed. For the case where the carbon tube or the low alloy steel tube is subjected to the drawing process, the descaling treatment in the tube is The use of sulfuric acid washing, in the lubrication treatment is the chemical treatment of the phosphate film treatment. The specific pickling and lubrication treatment in the order of descaling, the inner and outer surfaces of the tube are washed with alkaline degreaser and water Wash, immerse the tube in phosphorus The salt treatment bath forms a substrate of a phosphate film on the inner and outer surfaces, and then is subjected to a neutralization treatment to form a metal soap layer containing sodium stearate as a main component. 0 On the other hand, the Cr content is 5 mass% or more. In the case where the alloy tube made of the Cr-based alloy steel is subjected to the drawing process, the reaction is not easily performed by the phosphate treatment, and as described in the chemical conversion treatment described later, the substrate of the phosphate film is not formed in the plain tube, but the element is After the tube is immersed in the oxalate treatment bath to form a substrate of the oxalate film on the inner and outer surfaces, a metal soap layer containing sodium stearate as a main component is formed. However, the oxalic acid is formed as a substrate for the lubricating film. When the Cr-based alloy steel of the salt film is subjected to drawing processing, it is known that the peeling of the TiCN film occurs when the TiCN film is coated with TiCN, and the plunger life is significantly reduced. The steel pipe often undergoes melting, which results in a decrease in the yield of the product and a decrease in the efficiency of the drawing process. The present invention has been developed in view of the above problems of the drawing process, and the object thereof is to provide A super-hardened plunger and a cold drawing method using the same, when the substrate used as the lubricating film is a vacuum tube made of a Cr-based alloy steel forming an oxalate film, by using a drawing process The super-hard squeezing of the TiAIN film is used to prevent the occurrence of the φ during the drawing process, and the life of the plunger is prolonged, and the high-quality cold-worked product can be manufactured with high efficiency. The subject 'is to use a variety of super-hardened plungers, and the substrate that is used as the lubricating film is a thin tube that forms a phosphate film and a substrate that is a lubricating film is a thin tube that forms an oxalate film. The process of drawing and observing the coating film on the surface of the super-hard plunger will be used as the substrate of the lubricating film to form the acid tube of the oxalate film, so that the φ is coated with the super-hard plunger coated with TiCN. During processing, the oxalate film causes corrosion of the TiCN film, and peeling of the TiCN film is liable to occur. On the other hand, although it is not necessarily theoretically based, if a TiAIN-coated superhard alloy is used in the drawing process, even if the substrate which is a lubricating film is a sulfate film forming a sulphate film, the drawing is performed. In the case, corrosion of the TiAIN film is still not caused, and the melting of the drawing process can be suppressed, and the life of the plunger is prolonged. The present invention has been developed in view of the above findings, and the gist of the present invention is to include a superhard plunger having the following (1) and a cold drawing method (2). 200932390 (1) A coated superhard plunger characterized in that the substrate used for the lubricating film obtained by the chemical conversion treatment is a cold drawing of a Cr-based alloy steel forming an oxalate film, and the surface thereof is covered. Titanium aluminum nitride (TiAIN) film, the superhard plunger is coated, and the thickness of the titanium nitride (TiAIN) film is preferably 3 to 10 μm 〇(2) - a cold drawing method, characterized in that: a chemical conversion treatment for a tube to be processed including Cr-based φ gold steel, a step of removing the oxidized scale and the rust by the surface of the tube, a step of forming an oxalate film on the surface of the tube after neutralization, and After the step of forming a lubricating layer on the oxalate film, a superhard plunger coated with a titanium nitride (TiAIN) film having a thickness of 3 to 1 Ομηη is inserted into the inner surface of the processed tube, and is shrunk. Diameter and wall thickness reduce processing. The "Cr-based alloy steel" specified in the present invention is, for example, an alloy steel pipe of JIS G 3462 and STBA 25 to 26, and can be represented by a steel of φ having a Cr content of 5 to 9 mass%. The object may be a steel having a high Cr content, and a representative example thereof includes a 13Cr steel having a Cr content of 12 to 14% by mass and a stainless steel equivalent to SUS3 04 having a Cr content of 18 to 20% by mass. The steel pipe obtained by the drawing process using these steel types can be applied to a heater tube of a boiler, an air preheater, or the like, or a heat exchanger of a chemical industry or a petroleum industry, a condenser pipe, a catalyst pipe, or the like. According to the superhard plunger of the present invention, even if a Cr-based alloy steel or a stainless steel is used as the lubricating film substrate, the alloy tube forming the oxalate film is subjected to drawing processing, and TiAIN is applied to the surface. It does not cause the peeling of 200932390, and it can prevent the melt-flow at the time of a drawing process, and can extend the life of a plunger, and manufacture the high-quality cold-processed product which is excellent in dimensional precision by high efficiency. [Embodiment] The object steel of the super-hardened plunger of the present invention is a Cr-based alloy steel and stainless steel (hereinafter collectively referred to as "Cr-based alloy steel") represented by a Cr content of 5 to 20% by mass. The method of manufacturing the tube is not particularly limited. A plain tube for a seamless steel pipe is usually produced by hot rolling using a mandrel mill manufacturing method which is excellent in productivity. The "Cr-based alloy steel" tube is a heat treatment for softening the tube, for example, under an annealing condition of 800 °C. The plain tube for the drawing process is subjected to descaling treatment by pickling immediately after softening of the tube to remove the scale on the inner and outer surfaces of the tube, followed by lubrication treatment. Fig. 2 is a view showing an example of a process for forming a chemical tube which can be applied to the present invention. First, in the first treatment step, pickling is performed to remove the oxidized scale which adheres to the surface as the element tube softens. Usually, the acid used for pickling is sulfuric acid (10 to 13%), and its management items are free acidity and iron concentration. Regarding the pickling conditions, the treatment temperature was room temperature, and the immersion time was 30 minutes. After pickling, water washing (e.g., several minutes) is carried out to remove the acid remaining on the surface. After the above pickling step, the acid tube was then immersed in a sodium hydroxide solution to carry out neutralization. The neutralization of the surface of the tube can be stabilized by this neutralization. Then, in the second treatment step of -9-200932390, it is immersed in an oxalate treatment bath to form a substrate of an oxalate film on the surface of the element tube. The oxalate treatment bath used was controlled to have a total acidity of about 9 to 12 points, and the treatment conditions were as follows: a treatment temperature of 80 ° C and an immersion time of 5 minutes. After the oxalate film is treated, it is washed with warm water (for example, at a treatment temperature of 50 ° C for several minutes). If the steel of the element tube is carbon steel or low-alloy steel (for example, the Cr content is 20% by mass or less), the phosphate film is generally treated to form a phosphate film on the surface of the tube, but if the Cr content of the treated steel exceeds 5 The mass% will not sufficiently form the substrate of the phosphate film. Therefore, the chemical conversion treatment employed in the present invention is premised on the oxalate coating treatment in the second treatment step. Then, in the third treatment step, the formed oxalate film and the soap-based lubricant are reacted to form a lubricating layer on the surface. As the treatment for forming the lubricating layer, sodium stearate and the oxalate film are generally reacted to form a metal soap layer. However, the production method of the present invention is not limited thereto. The treatment conditions for forming the lubricating layer were measured at a treatment temperature of 80 C and an immersion time of 15 minutes. The element tube which has been chemically processed through the above-described first to third processing steps is dried. The superhard plunger of the present invention is composed of a WC-Co system or a WC-TiCN-TaC-Co alloy substrate, and is coated with a TiA1N (titanium aluminum nitride) film. The film to be coated may be formed by c V D (chemical vapor phase growth) or P V D (physical vapor phase growth), but is not limited thereto, and may be coated on the surface of the substrate by a conventional condition. -10- 200932390 In the cold drawing process of the tube, the processing length exceeds the full length of the tube, and the processing length exceeds 20m/passage, which is extremely strict compared to other cold processing (such as press processing). Cold working under severe conditions. Therefore, in order to ensure wear resistance during pipe drawing, a super-hard plunger which is coated with a TiCN (titanium nitride carbon) film has been conventionally used. However, in the case where the "Cr-based alloy steel" tube is subjected to the drawing process, as described above, the substrate of the lubricating film obtained by the chemical conversion treatment is a form of oxalate film. When the alloy tube is drawn by a super-hard plunger coated with a TiCN film, the oxalate film causes corrosion of the TiCN film, and the peeling of the TiCN film is liable to occur, so that the steel pipe after the drawing process often occurs. The phenomenon of melting. On the other hand, when the "Cr-based alloy steel" tube is subjected to the drawing process, if the super-hard plunger coated with the TiAIN film is used, the oxalate film does not cause corrosion of the coating film, but Significantly reduce the peeling of the drape. As a result of the fact that the 'TiAIN film has corrosion resistance to the oxalate film, the reason for the technical advantage is not clear, but this is a new discovery obtained by the present inventors in various in-depth discussions. In the coated superhard nip of the present invention, it is preferable to form a TiAIN film having a thickness of 3 to ΙΟμη on the surface of the substrate. When the thickness of the TiAIN film is less than 3 μm, the abrasion resistance is insufficient, and the steel pipe after the drawing process is liable to be melted. On the other hand, if the thickness exceeds 1 〇μηι, the coating is too brittle and becomes brittle, and the coating film is prone to defects. The cold drawing method according to the present invention is characterized in that, as a chemical conversion treatment for a pipe to be processed which is composed of "Cr-based alloy steel", a pickling step of removing oxidized scales and rust on the surface of the pipe -11 - 200932390 is performed. a step of forming an oxalate film on the surface of the neutralized tube, and a step of forming a lubricating layer on the oxalate film, and inserting a superhard plunger coated with a TiAIN film having a thickness of 3 to 插入μη into the aforementioned The inner surface of the processing tube is subjected to reduction in diameter and wall thickness to reduce processing. In the cold drawing method of the present invention, in the case where the "Cr-based alloy steel" tube is subjected to the drawing process, the super hard plunger is coated by using the TiAIN film, compared with the conventional TiCN film. The ultra-hard plunger improves the resistance to wear and abrasion and greatly extends the life of the plunger while preventing the melt-out in the drawing process. The effects of the present invention will be specifically described below based on examples. [Examples] (Example 1) The test tube of Example 1 was prepared by using JIS STAB26 (9Cr-lMo steel) as a steel material, and a mandrel-type seamless tube of Mannesmann Q. The rolling method is a tube obtained by finishing calendering. In order to apply the softening of the tube, the tube was subjected to a heat treatment at 800 °C for 10 minutes using a roller hearth kiln, and then the scales on the inner and outer surfaces of the tube were removed by pickling, followed by lubrication treatment. The specific chemical conversion treatment before the drawing process is pickling using sulfuric acid (10 to 13%) at room temperature (treatment temperature) for 30 minutes (treatment time), and after washing and neutralizing, the treatment temperature is 75~. The oxalate film treatment was carried out for 5 minutes (treatment time) at 85 ° C, and then sodium stearate and oxalate film were reacted at 75 to 85 ° C (treatment temperature) for 15 minutes to form -12-200932390 Metal lanes. The drawing process schedule is to set the size of the element tube to an outer diameter of 34.0 mmx and a wall thickness of 3.3 mm, and to set the drawing size to an outer diameter of 25.80 mmx and a wall thickness of 2.60 mm, and to reduce the cross section shown by the following formula (1). Rate Rd is set to 40.5% °
Rd={(D〇-Di)/D〇}x 1 00(%)...(1) 其中，D。：加工前截面積（mm2) ，Di :加工後截面 積（mm2 ) φ 依第1圖所示的構造進行抽拉加工’模具是使用超硬 模具，抽拉用柱塞區分成：TiAlN膜的披覆超硬柱塞（本 發明例）和Ti CN膜的披覆超硬柱塞（比較例）’調查各 別的柱塞壽命。 柱塞壽命，是由各別的每1個披覆超硬柱塞的抽拉總 計長度（m)來判斷，其判斷基準爲是否發生熔執或披覆 剝離。 第3圖係顯示實施例1的柱塞壽命的調查結果。從第 0 3圖的結果可明顯看出，使用本發明例之TiAlN膜的披覆 超硬柱塞的情況，柱塞壽命爲抽拉總計長度2900m，相對 於此，使用比較例之TiCN膜的披覆超硬柱塞的情況，柱 塞壽命僅達抽拉總計長度1 000m。 (實施例2 ) 作爲實施例2的供試素管是準備：使用相當於JIS SU S3 04的不鏽鋼作爲鋼材，藉由曼內斯曼之芯棒式無縫 管軋法實施精加工壓延而製得的管。該素管，爲了施以素 -13- 200932390 管軟化而用輥膛爐實施1230 °Cx2分鐘的熱處理’接著藉 由酸洗將素管內外表面的鱗皮除去，再藉由化成處理來實 施潤滑處理。 抽拉加工排程，是將素管尺寸設定爲外徑54.0mmx壁 厚7.9mm，將抽拉尺寸設定爲外徑44.50mmx壁厚6.30mm ，並將上述（1 )式所示的截面減少率Rd設定爲33.9%。 和實施例1同樣的，模具是使用超硬模具，抽拉用柱 塞區分成：TiAIN膜的披覆超硬柱塞（本發明例）和TiCN 膜的披覆超硬柱塞（比較例），調查各別的柱塞壽命。 結果，使用本發明例之TiAIN膜的披覆超硬柱塞的情 況，柱塞壽命爲抽拉總計長度1 8000m，相對於此，使用 比較例之TiCN膜的披覆超硬柱塞的情況，柱塞壽命僅達 抽拉總計長度7 4 0 0 m。 根據實施例1、2的結果可知，在將作爲化成處理所 獲得的潤滑皮膜的底材是形成草酸鹽皮膜之Cr系合金鋼 施以抽拉加工時，藉由使用TiAIN膜的披覆超硬柱塞，可 發揮優異的耐熔執性及耐摩耗性，能有效防止抽拉加工所 發生之熔執現象，而能大幅延長柱塞壽命。 依據本發明的披覆超硬柱塞，即使是將Cr系合金鋼 製的作爲潤滑皮膜底材是形成草酸鹽皮膜的素管施加抽拉 加工的情況，披覆於表面的TiAIN並不會發生剝離，可發 揮優異的耐熔執性及耐摩耗性，能有效防止抽拉加工所發 生之熔執現象，而能大幅延長柱塞壽命。 使用該柱塞之冷抽拉方法所製得的鋼管，尺寸精度優 -14- 200932390 異而成爲高品質的冷加工製品，且能以高效率來製造，因 此適用於作爲冷精加工之無縫鋼管。 【圖式簡單說明】 第1圖係用來槪略說明藉由冷抽拉將素管施以縮徑及 壁厚減少加工的方法。 第2圖係適用於本發明的對象素管之化成處理的步驟 ❹例。 第3圖係實施例1的柱塞壽命的調查結果。 第4圖係實施例2的柱塞壽命的調查結果。 【主要元件符號說明】 1 :柱塞 1 a :柱塞的平行部 2 :模具 〇 3 :素管 4 :心軸 -15-Rd={(D〇-Di)/D〇}x 1 00(%)...(1) where D is. : Cross-sectional area before processing (mm2), Di: Cross-sectional area after processing (mm2) φ Pulling processing according to the structure shown in Fig. 1 'The mold is a super-hard mold, and the plunger is divided into: TiAlN film. The super-hard plunger (inventive example) and the coated ultra-hard plunger (Comparative Example) of the Ti CN film were used to investigate the respective plunger life. The plunger life is judged by the total length (m) of the drawing of each of the super-hardened plungers, and the criterion is whether or not the melting or the coating is peeled off. Fig. 3 is a view showing the results of investigation of the life of the plunger of Example 1. As is apparent from the results of Fig. 3, in the case of coating the superhard plunger using the TiAlN film of the present invention, the plunger life was a total drawing length of 2,900 m, whereas the TiCN film of the comparative example was used. In the case of a super-hard plunger, the plunger life is only up to a total length of 1 000 m. (Example 2) The test tube of Example 2 was prepared by using stainless steel equivalent to JIS SU S3 04 as a steel material, and performing finishing press rolling by Mannesmann's mandrel-type seamless tube rolling method. The tube that got. The tube is subjected to a heat treatment at 1230 ° C for 2 minutes in a roll crucible for the softening of the tube -13-200932390 tube. Then, the scale of the inner and outer surfaces of the tube is removed by pickling, and then the lubrication is performed by chemical conversion treatment. deal with. The drawing process schedule is to set the size of the element tube to an outer diameter of 54.0 mmx and a wall thickness of 7.9 mm, and to set the drawing size to an outer diameter of 44.50 mm x a wall thickness of 6.30 mm, and to reduce the section as shown in the above formula (1). Rd is set to 33.9%. In the same manner as in the first embodiment, the mold was a superhard mold using a superhard mold, and the plunger was divided into a superabrasive plunger (inventive example) of a TiAIN film and a superhard plunger coated with a TiCN film (Comparative Example). , investigate the individual plunger life. As a result, in the case of using the TiAIN film of the present invention to coat the super-hard plunger, the plunger life was a total draw length of 1 8000 m, whereas the case of using the TiCN film of the comparative example to coat the super-hard plunger was used. The plunger life is only up to a total length of 7 4 0 0 m. According to the results of Examples 1 and 2, when the substrate of the lubricating film obtained by the chemical conversion treatment is a Cr-based alloy steel forming an oxalate film, the coating is performed by using a TiAIN film. The hard plunger can exhibit excellent resistance to fusion and wear resistance, and can effectively prevent the occurrence of melting in the drawing process, and can greatly extend the life of the plunger. According to the coated super-hard nip of the present invention, even if the Cr-based alloy steel is used as the lubricating film substrate, the urethane film is drawn by the drawing process, and the TiAIN coated on the surface does not. When peeling occurs, excellent resistance to fusion and abrasion resistance can be exhibited, and the occurrence of the melting phenomenon in the drawing process can be effectively prevented, and the life of the plunger can be greatly extended. The steel pipe obtained by the cold drawing method of the plunger has a dimensional accuracy of -14-200932390, and is a high-quality cold-worked product, and can be manufactured with high efficiency, so it is suitable for use as a seamless steel pipe for cold finishing. . [Simple description of the drawing] Fig. 1 is a schematic diagram for explaining the method of reducing the diameter and the wall thickness by cold drawing. Fig. 2 is a diagram showing the steps of the chemical conversion treatment applied to the pixel tube of the present invention. Fig. 3 is a result of investigation of the plunger life of Example 1. Fig. 4 is a result of investigation of the plunger life of Example 2. [Description of main component symbols] 1 : Plunger 1 a : Parallel part of plunger 2 : Mold 〇 3 : Element tube 4 : Mandrel -15-