1310708 (1) 九、發明說明 【發明所屬之技術領域】 本發明係關於附錨固部的鋼筋的製造方法，更具體而 言，是關於製造如下的附錨固部的鋼筋的方法，該鋼筋具 有由一體形成在鋼筋的端部的擴徑部構成的錨固部。 【先前技術】 以往，用於鋼筋混凝土結構的鋼筋是將其端部彎曲成 u字形或L字形等來作爲錨固部，藉由該錨固部來對於其 他的鋼筋或混凝土進行固定。 但是，爲了增大對於混凝土的固定強度，對於端部彎 曲成U字形或L字形等的結構的鋼筋’必須加大U字形 或L字形等的部分，因此體積增大，很難在狹窄的場所進 行施工，並且，存在著：鋼筋端部的彎曲加工困難、成本 趨高的問題。 針對於這些問題，本案的申請人等曾經提出了如下的 附錨固部的鋼筋，該鋼筋係藉由對鋼筋的端部進行高溫镦 鍛加工而形成有如釘子的頭部那種形狀的擴徑部，將此作 爲錨固部（請參照專利文件1 )。 第3圖（a)是專利文獻1中前述的的附錨固部的鋼 筋的槪略側面圖，第3圖（b )是表示該附錨固部的鋼筋 的端部的槪略剖面圖，第3圖（c )是第3圖（b )中的X-X剖面線的箭頭方向的剖面圖。 該附錨固部的鋼筋1 A，在具有一定外徑的通常部分 -5- (2) 1310708 1 a的兩端部，係分別藉由高溫镦锻加工形成圓板形的擴徑 部1 b來作爲錨固部。該擴徑部1 b與以往的將鋼筋端部彎 曲成U字形或L字形的錨固部相比較，即使外部尺寸較小 也可確保很大的作用面積，因此，可增大相對於其他的鋼 筋或混凝土的固定強度。並且，由於擴徑部1 b與通常部 分la係形成完整一體的結構（以無接縫的方式形成）， 因此，擴徑部1 b與通常部分1 a的連接強度很大。所以， 根據使用了該附錨固部的鋼筋1A的鋼筋混凝土結構，係 可形成強度很大的結構體。 在第3圖中，lba是擴徑部lb的端面（外側端面）， 端面lba是與鋼筋1A的軸線方向直交的圓形的平面。端 面lba的直徑是通常部分la的外徑D的2.5倍左右。 在第3圖中，1 bb是擴徑部形成面（內側端面），擴 徑部形成面1 bb是相對於鋼筋1 A的軸線方向呈傾斜（形 成鈍角0 )地擴大的圓錐狀的面。 第4圖（a)和（b)是表示製造第3圖所示的附錨固 部的鋼筋1 A時的高溫镦鍛加工製程的槪略剖面圖。 首先，如第4圖（a )所示，利用具有感應線圏7的 加熱裝置將具有一定外徑D的鋼筋1的端部區域加熱到容 易塑性變形的溫度。在此，將端部區域的加熱的溫度係 8 00〜1 000 °C左右（請參照專利文獻1的段落0014 )。 然後’在與加熱後的端部區域相鄰接的位置上，利用 衝壓機的夾鉗（省略其圖示）握持住鋼筋1，將該鋼筋1 的端面按壓在模8的成形面8 a上，如第4圖（b )所示， -6- (3) 1310708 藉由衝壓機將軸線方向的壓縮力p施加在鋼筋1上’以壓 縮端部區域。藉由這種操作’鋼筋1的端部區域會以其外 徑增大（擴徑）的方式進行塑性變形’而形成圓板狀的擴 徑部1 b，可製造出在通常部分1 a的端部形成有擴徑部1b 的附錨固部的鋼筋1 A。 在第4圖中，8 aa是設置在成形面8a的中央的隆起部 ，在使鋼筋1的端部區域塑性變形時’藉由隆起部8 aa可 促進鋼筋材料朝向相對於軸線方向的直角方向（半徑方向 )外方流動。 而且，本案的申請人等也曾經提出了用於大量生産上 述具有錨固部的附錨固部的鋼筋的加工裝置（請參照專利 文獻2)。 在該加工裝置上，設置了具備加熱頭和變壓器的加熱 裝置，前述的加熱頭係由加熱鋼筋的端部區域的感應線圈 所形成；前述的變壓器係保持該加熱頭，同時，向其供給 高頻電流。藉由該加熱裝置，鋼筋的端部區域被加熱到適 合高溫镦鍛加工的溫度（例如：800〜1 3 00 °C )(請參照 專利文獻2的段落0030)。 專利文獻1 :日本特開2000-25 7209號公報。 專利文獻2:日本特開2000-288676號公報。 〔發明所欲解決之課題〕 但是，專利文獻1和專利文獻2所公開的技術，即， 藉由對鋼筋的端部進行高溫镦鍛加工而呈一體地形成作爲 (4) 1310708 錨固部的擴徑部的技術，具有以下（1)〜（3)的問題。 (1 )在藉由高溫镦锻加工形成擴徑部時，在以一定的溫 度加熱鋼筋的整個端部區域的情況下，形成具有預定的形 狀的擴徑部是困難的，該擴徑部例如：係由與鋼筋的軸線 方向直交的直徑爲2.5D左右的圓形的端面（第3圖中的 端面1 ba )，和以對鋼筋的軸線方向形成直角或鈍角的方 式擴大的擴徑部形成面（第3圖中的擴徑部形成面lbb) 所構成的。 亦即，在將鋼筋的整個端部區域加熱到8 0 〇〜1 〇 0 0 °c ，以進行高溫镦鍛加工的情況下，在端部區域中的特別需 要很大的塑性變形量的部分，具體而言，是對於在從鋼筋 的端面起算的軸線方向的離開距離爲2D以內的部分，熱 量不足，而不易使得該部分塑性變形（朝對於軸線方向成 直角的方向鼓出），而如第5圖所示般地，所形成的擴徑 部1 b ’係成爲球狀或橢圓球狀，無法形成具有直徑爲2.5 D 左右的圓形端面的結構。 並且，如果將鋼筋的整個端面區域加熱到1300 °C左右 ，來進行高溫镦鍛加工，則在該端部區域將會産生挫曲現 象（Buckling )，而成爲不定形狀，很難形成預定形狀的 擴徑部。 (2 )如果將端部區域加熱到高溫（例如：1 3 00 °C )，來 進行高溫镦锻加工，則所形成的擴徑部的表面，具體而言 ，是上述擴徑部形成面，有時將會變成粗糙面，有時會在 擴徑部形成面上産生毛髮狀的細小損傷，亦即所謂的毛細 -8 - (5) 1310708 裂紋（hair crack )。 即使擴徑部形成面變成粗糙面，或者在擴徑部形成面 上産生毛細裂紋，雖然作爲附錨固部的鋼筋，在性能上沒 有問題，但是會導致在外觀上、商品價値上的降低。 因此，需要使用高溫加工性優異的鋼筋（母材），才 能夠達成：即使以高溫加熱以進行高溫镦鍛加工，擴徑部 形成面也不會變成粗糙面或者在擴徑部形成面上不産生毛 細裂紋之效果。 (3 )在使用異型條鋼作爲鋼筋，在其端部進行高溫镦鍛 加工以形成擴徑部時，藉由壓縮使得異型條鋼的節與節接 近’其結果，被兩個節所夾住的部分在擴徑部形成面以及 在通常部分與擴徑部形成面的交界（擴徑部的根部）處， 變成如同切槽部的形狀，該部分在使用環境下有成爲脆性 斷裂的起點之虞。因此，尤其希望以異型條鋼作爲母材的 附·錨固部的鋼筋保有優異的韌性（尤其是在低溫下的韌性 【發明內容】 本發明的第一目的，是提供：附錨固部的鋼筋的製造 $法’該方法可確實地形成具有適當形狀的擴徑部來作爲 銷固部。 本發明的第二目的，是提供：附錨固部的鋼筋的製造 力法’該錨固部具有高強度和良好的韌性，同時，作爲錨 固部的擴徑部的表面（擴徑部形成面）不會成爲粗糙面， -9- (6) 1310708 在擴徑部形成面上不産生毛細裂紋。 本發明的第三目的，是提供：可製造韌性（尤其是低 溫韌性）良好的附錨固部的鋼筋的方法。 本發明之附錨固部的鋼筋的製造方法，包括如下製程 ，即’將鋼筋的端部區域加熱，並實施高溫镦鍛加工，以 在軸線方向上壓縮被加熱的該端部區域，使其塑性變形以 增大外徑（擴徑），藉此，一體地形成作爲錨固部的擴徑 部，其特徵在於： 以如下方式進行加熱而實施高溫镦鍛加工，即，使前 述的鋼筋的端部區域的溫度隨著接近端面而連續地或階段 性地升高’從前述的鋼筋的端面起算在軸線方向離開2. OD (D爲鋼筋的外徑）的部分的溫度（τ 1 )大於等於1 3 0 0 °C ’未達該鋼筋材料的熔點，從前述的鋼筋的端面起算在軸 線方向離開5 · 〇D的部分的溫度（T2 )，大於等於該鋼筋 材料的A c 3相變溫度、小於等於1 2 0 0 °C。 構成藉由本發明的製造方法所獲得的附錨固部的鋼筋 的擴徑部（錨固部）的端面，是直徑爲2.0D至2.8D、尤 其是以2.5D至2.8D的圓形爲佳。 在本發明的製造方法中，前述的鋼筋係使用這樣的條 鋼爲佳，該條鋼含有c: 0.10〜0.30質量％、Μη: 〇·5〇〜 1 _5 〇質量％、S i :小於等於〇 · 5 〇質量％、ρ :小於等於 〇_〇5質量％、S :小於等於〇.05質量％、Cu :小於等於 〇·1〇質量％ ’其餘部分爲Fe以及不可避免的雜質。1310708 (1) EMBODIMENT OF THE INVENTION [Technical Field] The present invention relates to a method of manufacturing a steel bar with an anchor portion, and more particularly to a method of manufacturing a steel bar with an anchor portion having the following An anchor portion formed integrally with an enlarged diameter portion at an end portion of the reinforcing bar. [Prior Art] Conventionally, a reinforcing bar for a reinforced concrete structure has an end portion bent into a U-shape or an L-shape as an anchor portion, and the anchor portion is used to fix other steel bars or concrete. However, in order to increase the fixing strength to the concrete, the steel bar having a structure in which the end portion is bent into a U shape or an L shape must have a U-shaped or L-shaped portion, so that the volume is increased and it is difficult to be in a narrow place. Construction is carried out, and there is a problem that the bending of the end portion of the steel bar is difficult and the cost is high. In response to these problems, the applicant of the present invention has proposed a steel bar with an anchor portion which is formed by a high-temperature upsetting process on the end portion of the steel bar to form an enlarged diameter portion having a shape like a nail head. This is used as an anchor (refer to Patent Document 1). Fig. 3(a) is a schematic side view showing the reinforcing bar of the anchoring portion described above in Patent Document 1, and Fig. 3(b) is a schematic cross-sectional view showing the end portion of the reinforcing bar of the anchoring portion, and 3rd. Fig. (c) is a cross-sectional view taken along line XX of Fig. 3(b) in the direction of the arrow. The reinforcing bar 1 A of the anchoring portion is formed at both ends of the normal portion -5-(2) 1310708 1 a having a certain outer diameter by a high-temperature upsetting process to form a disk-shaped enlarged diameter portion 1 b. As an anchor. The enlarged diameter portion 1 b can secure a large working area even when the external size is small as compared with the conventional anchor portion in which the end portion of the reinforcing bar is bent into a U shape or an L shape. Therefore, the reinforcing member can be enlarged relative to the other reinforcing bars. Or the fixed strength of concrete. Further, since the enlarged diameter portion 1b and the normal portion la are integrally formed (separately formed), the connection strength between the enlarged diameter portion 1b and the normal portion 1a is large. Therefore, according to the reinforced concrete structure using the reinforcing bar 1A with the anchor portion, a structure having a large strength can be formed. In Fig. 3, lba is an end surface (outer end surface) of the enlarged diameter portion 1b, and the end surface 1ba is a circular plane orthogonal to the axial direction of the reinforcing bar 1A. The diameter of the end face lba is about 2.5 times the outer diameter D of the usual portion la. In Fig. 3, 1 bb is a diameter-enlarged portion forming surface (inner end surface), and the enlarged-diameter portion forming surface 1 bb is a conical surface which is inclined with respect to the axial direction of the reinforcing bar 1 A (forming an obtuse angle 0). Fig. 4 (a) and (b) are schematic cross-sectional views showing a high temperature upsetting process in the case of manufacturing the reinforcing bar 1 A with the anchor portion shown in Fig. 3. First, as shown in Fig. 4(a), the end portion of the reinforcing bar 1 having a certain outer diameter D is heated to a temperature at which plastic deformation is easily performed by a heating device having an induction coil 7. Here, the heating temperature of the end portion is about 00 to 1 000 °C (refer to paragraph 0014 of Patent Document 1). Then, at the position adjacent to the heated end region, the reinforcing bar 1 is held by the clamp of the press (not shown), and the end face of the reinforcing bar 1 is pressed against the forming surface 8a of the die 8. Above, as shown in Fig. 4(b), -6-(3) 1310708 applies a compressive force p in the axial direction to the reinforcing bar 1 by a press to compress the end region. By this operation, the end portion of the reinforcing bar 1 is plastically deformed so that its outer diameter is increased (expanded diameter) to form a disk-shaped enlarged diameter portion 1 b, which can be manufactured in the normal portion 1 a. The end portion is formed with a reinforcing bar 1 A with an anchor portion of the enlarged diameter portion 1b. In Fig. 4, 8 aa is a ridge portion provided at the center of the forming surface 8a, and when the end portion of the reinforcing bar 1 is plastically deformed, 'the bulge portion 8 aa can promote the direction of the reinforcing bar material at a right angle with respect to the axial direction. (Radius direction) Flows outside. Moreover, the applicant of the present invention has also proposed a processing apparatus for mass-producing the above-described reinforcing steel portion having an anchor portion (refer to Patent Document 2). The processing apparatus is provided with a heating device including a heating head and a transformer, wherein the heating head is formed by an induction coil that heats an end portion of the reinforcing bar; and the transformer maintains the heating head and supplies the heating head high. Frequency current. With this heating device, the end portion of the reinforcing bar is heated to a temperature suitable for high-temperature upsetting processing (for example, 800 to 1 300 ° C) (refer to paragraph 0030 of Patent Document 2). Patent Document 1: Japanese Laid-Open Patent Publication No. 2000-25 7209. Patent Document 2: Japanese Laid-Open Patent Publication No. 2000-288676. [Problems to be Solved by the Invention] However, the techniques disclosed in Patent Document 1 and Patent Document 2 are integrally formed as a (4) 1310708 anchor portion by performing high-temperature upsetting processing on the end portion of the reinforcing bar. The technique of the diameter section has the following problems (1) to (3). (1) When the enlarged diameter portion is formed by high-temperature upsetting, when the entire end portion of the reinforcing bar is heated at a constant temperature, it is difficult to form the enlarged diameter portion having a predetermined shape, for example, the enlarged diameter portion is : a circular end surface (the end surface 1 ba in FIG. 3 ) having a diameter of about 2.5D orthogonal to the axial direction of the reinforcing bar, and an enlarged diameter portion formed by expanding a right angle or an obtuse angle in the axial direction of the reinforcing bar The surface (the enlarged diameter portion forming surface lbb in Fig. 3) is constituted. That is, in the case where the entire end portion of the reinforcing bar is heated to 80 〇 to 1 〇0 0 °c for high-temperature upset processing, a portion requiring a large amount of plastic deformation in the end portion is particularly required. Specifically, for a portion within a distance of 2D from the axial direction from the end face of the reinforcing bar, the amount of heat is insufficient, and the portion is not easily plastically deformed (bulging in a direction at right angles to the axial direction), and As shown in Fig. 5, the enlarged diameter portion 1b' is formed in a spherical shape or an elliptical shape, and a circular end surface having a diameter of about 2.5 D cannot be formed. Further, if the entire end face region of the reinforcing bar is heated to about 1300 °C for high-temperature upsetting, a buckling phenomenon (Buckling) will occur in the end portion, and it becomes an indefinite shape, and it is difficult to form a predetermined shape. Expansion section. (2) When the end region is heated to a high temperature (for example, 1 3 00 ° C) to perform high temperature upsetting, the surface of the enlarged diameter portion formed is specifically the enlarged diameter forming surface. Sometimes it will become a rough surface, and sometimes a hair-like fine damage will be generated on the surface of the enlarged diameter portion, that is, a so-called capillary -8 - (5) 1310708 hair crack. Even if the enlarged diameter portion forming surface becomes a rough surface or a capillary crack is generated on the enlarged diameter portion forming surface, the reinforcing steel as the anchoring portion has no problem in performance, but it causes a decrease in appearance and commercial price. Therefore, it is necessary to use a steel bar (base metal) excellent in high-temperature workability, and it can be achieved that even if it is heated at a high temperature for high-temperature upsetting, the enlarged diameter forming surface does not become rough or does not form on the enlarged diameter forming surface. The effect of capillary cracks. (3) When the profiled steel is used as the steel bar and the high temperature upsetting process is performed at the end portion to form the enlarged diameter portion, the section and the section of the profiled steel are brought close by compression, and the result is sandwiched by the two sections. The portion of the enlarged diameter portion forming surface and the boundary between the normal portion and the enlarged diameter portion forming surface (the root portion of the enlarged diameter portion) becomes like the shape of the groove portion, and this portion has a starting point of brittle fracture in the use environment. Hey. Therefore, it is particularly desirable to maintain excellent toughness (especially toughness at low temperatures) of the steel bar with the profiled steel as the anchoring portion of the base material. [Inventive] The first object of the present invention is to provide a steel bar with an anchor portion. The method of manufacturing the method can reliably form an enlarged diameter portion having an appropriate shape as a pinned portion. A second object of the present invention is to provide a method for producing a reinforcing bar with an anchoring portion which has high strength and In addition, the surface of the enlarged diameter portion of the anchor portion (the enlarged diameter portion forming surface) does not become a rough surface, and -9-(6) 1310708 does not cause capillary cracks on the enlarged diameter portion forming surface. A third object is to provide a method for manufacturing a steel bar with an anchorage portion having good toughness (especially low temperature toughness). The method for manufacturing a steel bar with an anchor portion of the present invention includes the following process, that is, 'the end region of the reinforcing bar Heating and performing high temperature upsetting processing to compress the heated end portion in the axial direction to plastically deform to increase the outer diameter (expanding diameter), thereby integrally forming as an anchor The enlarged diameter portion of the solid portion is characterized in that the high temperature upsetting processing is performed by heating as follows, that is, the temperature of the end portion region of the reinforcing steel bar is continuously or stepwisely increased as approaching the end surface. The end face of the above-mentioned steel bar is calculated from the axial direction of the portion of the OD (D is the outer diameter of the steel bar). The temperature (τ 1 ) is greater than or equal to 1 3 0 0 ° C 'the melting point of the steel bar material is not reached, from the aforementioned steel bar The end face is calculated from the temperature (T2) of the portion away from 5 · 〇D in the axial direction, and is equal to or greater than the A c 3 phase transition temperature of the reinforcing bar material, and is less than or equal to 1 2 0 0 ° C. The composition is obtained by the manufacturing method of the present invention. The end face of the enlarged diameter portion (anchor portion) of the reinforcing bar with the anchor portion is preferably a diameter of 2.0D to 2.8D, particularly a circle of 2.5D to 2.8D. In the manufacturing method of the present invention, the aforementioned It is preferable to use such a steel bar which contains c: 0.10 to 0.30% by mass, Μη: 〇·5〇~1 _5 〇 mass%, S i : less than or equal to 〇·5 〇 mass%, ρ: less than Equivalent to 〇_〇5 mass%, S: less than or equal to 〇.05 mass%, Cu: small It is equal to 〇·1〇% by mass. The rest is Fe and unavoidable impurities.
並且，上述鋼筋中含有的Μη和C的質量比例（Mn/C -10- (7) (7)Further, the mass ratio of Μη and C contained in the above-mentioned steel bars (Mn/C -10- (7) (7)
1310708 )是大於等於3.0，尤其是大於等於3.5更好< 並且’上述鋼筋是由異型條鋼所形成的爲 本發明的附錨固部的鋼筋，是藉由本發明 而得到’本發明的製造方法包括如下製程，艮丨 端部區域加熱，並實施高溫鐵鍛加工，以在朝 縮被加熱的該端部區域，使其塑性變形而擴徑 體地形成作爲錨固部的擴徑部，而且是以如τ 熱’即，使前述的鋼筋的端部區域的溫度隨著 連續地或階段性地升高，從前述的鋼筋的端面 方向離開2.0D的部分的溫度（T1)大於等於 達該鋼筋材料的熔點，從前述的鋼筋的端面赶 向離開5.0D的部分的溫度（T2 )，大於等於 的A c 3相變溫度、小於等於1 2 0 0 °C。 〔發明之效果〕 (1)根據本發明（技術方案1〜3)的製造戈 體形成具有適當形狀之可作爲錨固部之擴徑窗 地製造將這樣的擴徑部作爲錨固部的鋼筋（防 筋）。 亦即，由於溫度（T1 )大於等於1 3 00 °C， 特別需要大的塑性變形量的部分，也就是從銅 算向軸線方向的離開距離爲2.0D以內的部分 熱量’使該部分容易塑性變形，藉由這樣，可 狀的擴徑部，例如：由直徑爲2.0D至2.8D的 佳。 的製造方法 ，將鋼筋的 線方向上壓 ，藉此，一 方式進行加 接近端面而 起算在軸線 1 3 00°C，未 算在軸線方 該鋼筋材料 法’係可一 ，而可確實 錨固部的鋼 所以可對於 筋的端面起 供給充分的 形成預定形 圓形的端面 -11 - (8) 1310708 (或具有與其相同程度的面積的任意形狀的端 部形成面所構成的擴徑部，前述的擴徑部形成 鋼筋的軸線方向呈直角或鈍角地擴大。 並且，由於溫度（T2)大於等於該鋼筋材 相變溫度、小於等於1 200°C，所以可使從鋼筋 的在軸線方向的離開距離爲2.0D至5.OD的部 ，而確實地進行塑性變形。 (2 )根據本發明（技術方案4 )的製造方法， 用之條鋼是含有特定的比例的C和Μη的條鋼 製造兼備高強度和良好的韌性的附錨固部的鋼 並且，由於將所使用的條鋼的Cu和S的 定得較低，因此，高溫加工性優異，即使加熱 1 300°C的溫度，進行高溫镦锻加工時所形成的 面（擴徑部形成面）也不會成爲粗糙面，不會 成面上産生毛細裂紋。 (3 )根據本發明（技術方案5〜6 )的製造方 韌性（尤其是低溫韌性）良好的附錨固部的鋼 即，由於使用鋼筋中含有的Μη和C的 Mn/C )大於等於3.0、將容易産生脆性斷裂的 例限制得相對較低的條鋼，因此，可形成韌性 部的鋼筋。 因此，即使是在擴徑部形成面上具有類似 狀的鋼筋，也可以防止將該部分作爲起點的脆 事。 面）和擴徑 面係相對於 料的A c 3的 的端面起算 分不會挫曲 作爲鋼筋使 ，因此，可 筋。 含有比例規 到大於等於 擴徑部的表 在擴徑部形 法，可製造 筋。 質量比例（ C的含有比 好的附錨固 切槽部的形 性斷裂之情 -12- (9) 1310708 【實施方式】 〔用以實施本發明的最佳形態〕 以下，就本發明進行詳細說明。 本發明的附錨固部的鋼筋的製造方法包括如下製程’ 即，將鋼筋的端部區域予以加熱，實施高溫镦鍛加工，在 軸線方向上壓縮被加熱的端部區域，使其塑性變形以使其 外徑增大（擴徑），藉此，一體地形成擴徑部來作爲錨固 部。 可只在鋼筋的一端部進行高溫镦锻加工，也可在兩端 部都進行高溫镦鍛加工。 對本發明的製造方法中使用的「鋼筋」沒有特別的限 制，可使用以往衆所周知的條鋼。鋼筋的外徑D例如爲 1 0〜40mm左右。 鋼筋可以是圓條鋼，也可以是異型條鋼，但本發明的 製造方法尤其適合於使用異型條鋼的情況。 鋼筋的「端部區域」是在高溫镦鍛加工中被加熱的區 域，是指在：將鋼筋的端面作爲起點，將從端面起算離開 5D〜7D的位置作爲終點時，從起點到終點的區域。 「局溫镦鍛加工」是如下的加工方法，即，將鋼筋的 端部區域予以加熱，同時，在軸線方向上壓縮該端部區域 ，使其塑性變形以使其擴徑。 加熱鋼筋的端部的方法沒有特別限制，但基於可局部 快速地加熱鋼筋的觀點，最好是使用高頻感應加熱方法。 在本發明的製造方法中，在進行高溫镦鍛加工時，對 -13- (10) 1310708 鋼筋的端部區域的加熱溫度是隨著接近鋼筋的端面而連續 或階段性地升高，因此，鋼筋的端面也變成最高溫。 在此’端部區域的溫度可藉由紅外線放射溫度計等進 行測定。 ' 在本發明的製造方法中（高溫镦鍛加工），從鋼筋的 ' 端面起在軸線方向離開2.0D的部分的溫度（T1)大於等 於1 300°C ’未達該鋼筋材料的熔點。 I 藉由這樣，可對於特別要求大的塑性變形量的部分， 即，從鋼筋的端面起的離開距離爲2.0D以內的部分（端 面附近的鋼筋材料）供給充分的熱量，使該部分容易塑性 變形（相對於軸線方向朝向直角方向鼓出）。 在溫度（T1)未達1 3 00 °C的情況下，不容易使從鋼筋 的端面起算的離開距離爲2.0D以內的部分產生塑性變形 ’不能形成預定形狀的擴徑部（請參照後述的比較例1〜3 )° φ 在本發明的製造方法中，從鋼筋的端面起算在軸線方 向離開5.0D的部分的溫度（T2)，大於等於該鋼筋材料 的A c 3相變溫度，小於等於1 2 0 〇。<：。 藉由這樣’可以確實地使從鋼筋的端面起算的離開距 離爲2 · 0 D至5 · 0 D的部分不挫曲地產生塑性變形。 在溫度（T2 )未達該鋼筋材料的ac3相變溫度的情況 下’不容易使從鋼筋的端面起算的離開距離爲2.0D至 5 · 〇D的部分產生塑性變形。另—方面，在該溫度（τ2 ) 超過1 200 t：的情況下’在該部分容易産生挫曲現象（請參 -14- (11) 1310708 照後述的比較例4) 0 藉由高溫镦锻加工形成的擴徑部，係由與鋼筋的軸線 方向直交的端面、和相對於鋼筋的軸線方向形成直角或鈍 角地擴展的擴徑部形成面所構成的。 擴徑部的端面形狀沒有特別限制’可以例舉：圓形、 橢圓形、長方形、膠囊形等。在進行高溫镦鍛加工時，藉 由利用壓模來限制擴徑部的外周面’可容易形成具有橢圓 形、長方形、膠囊形等的端面的擴徑部。 在擴徑部的端面爲圓形的情況下，其直徑係以2.0D 至2 · 8 D爲宜，2 · 5 D至2.8 D更好。直徑過小的擴徑部不能 充分發揮相對於其他鋼筋、混凝土的錨固定功能。另一方 面，超過直徑2.8D的擴徑部所形成的附錨固部的鋼筋不 能充分對應過密的鋼筋配置。 並且，在擴徑部的端面爲圓形以外的形狀的情況下， 該端面的面積最好與直徑爲2.0D至2_8D的圓處於相同程 度。 以下，佐以附圖，就本發明的製造方法中的高溫镦鍛 加工的一例進行說明。 第1圖（a)〜（d)是表示本發明的製造方法中的高 溫镦鍛加工的製程的槪略剖面圖。 首先，如第1圖（a )所示’設置由感應線圈2 〇形成 的加熱頭’以包圍外徑爲D的鋼筋！ 〇的端部區域（在以 細面10A爲起點’以從_面i〇A起算在軸線方向離開7D 的位置爲終點時’從起點到終點的區域）的方式，藉由高 -15- (12) 1310708 頻感應加熱法來加熱該端部區域。 在此，將構成加熱頭的感應線圈20捲繞成錐形，使 其內周與鋼筋10的外周面之間的距離係越接近鋼筋10的 端面10A越短。 第2圖是表示在藉由第1圖（a)所示的感應線圈20 加熱鋼筋1 〇的端部區域時，從端面1 〇 A起算的離開距離 與該部分上的鋼筋溫度的關係的示意圖。 如第1圖（a )所示，藉由設置錐形的感應線圈20， 進行加熱，可以使得鋼筋1 〇的端部區域的溫度分佈係$ 爲：該端部區域的各部分的溫度隨著接近端面10A而連續 升高。 並且，在端部區域的各部分上，藉由調整感應線圈2〇 的內周和鋼筋1 〇的外周面之間的距離，可控制各部分的 溫度。 另外’溫度控制方法並不局限於這些方法。 在鋼筋10的端部區域中，從端面10A起算在軸線方 向離開2_0D的部分12藉由感應線圈2〇進行加熱，該部 分12的溫度（T1 )大於等於130(rc、未達該鋼筋材料的 熔點（控制在該範圍內）。 並且’從端面1〇Α起算在軸線方向離開5_0D的部分 1 5藉由感應線圈2〇進行加熱，該部分15的溫度（τ2 ) 大於等於鋼筋材料的Ac3相變溫度、小於等於1 200 °C (控 制在該範圍內）。 然後’從具有上述的溫度分佈並被加熱的端部區域使 -16- 30 (13) 1310708 感應線圈20退避，然後，如第1圖（b )所示，將壓模 的成形面31按壓在鋼筋10的端面上，在鋼筋10上施 軸線方向的壓縮力P以壓縮端部區域。藉此，在鋼筋 的端部區域進行塑性變形（相對於軸線方向朝向直角方 鼓出），其外徑增大（擴徑）。 在此，壓縮速度雖然是依鋼筋10的外徑D而不同 但是以3.0〜10.0mm/s爲宜，5.0〜8.0mm/s更好。 在壓縮速度過低的情況下，在進行壓縮操作中，端 區域的溫度降低，變形阻力上升，很難產生塑性變形（ 成擴徑部）。另一方面，在壓縮速度過高的情況下，在 行壓縮操作中容易産生挫曲現象。 並且，壓縮行程式以 2.0D至 4.0D爲宜，2.5D 3 . 5 D更好。 在此，壓縮鋼筋10的端部區域的壓模30，具有可 制所形成的擴徑部的端面的成形面31和可限制所形成 擴徑部的外周面（一部分擴徑部形成面）的圓筒形的成 面32。藉由這樣，如第1圖（c)所示，可藉由壓模30 成形面3 2來限制鋼筋材料相對於鋼筋1 〇的軸線方向朝 直角方向外方的流動。 然後如第1圖（d )所示，使壓模3 0退避。 藉由這樣，可製造出：擴徑部102與用於保持外徑 的鋼筋的通常部分101 —體形成的附錨固部的鋼筋100 前述的擴徑部1 02係由··與鋼筋的軸線方向直交的直徑 2.5 D左右的圓形端面1 02 A、和相對於鋼筋的軸線方向 加 10 向 部 形 進 至 限 的 形 的 向 D 5 爲 以 -17- (14) 1310708 $成鈍角的方式擴大的圓錐形的擴徑部形成 琰的。 在本發明的製造方法中，鋼筋最好使用 以下稱爲「特定的條鋼」），即，含有C : 龜％、Μη: 0.50〜1.50質量％、Si:小於等 %、P :小於等於〇. 0 5質量％、S :小於等ΐ 、Cu :小於等於0.10質量％，其餘部分爲 k 免的雜質。 特定條鋼中的C (碳）的含有比例爲0. %、最好爲0.15〜0.25質量％。如果C的 G· 1 0質量％，則所製得的附錨固部的鋼筋不 度。另一方面，如果C的含有比例超過0.: 所製得的附錨固部的鋼筋的韌性降低，容易 〇 特定條鋼中的Μη (錳）的含有比例爲 I 量％、最好爲0.60〜1.40質量％。如果Μη 達0.50質量％，則所製得的附錨固部的鋼 的強度。另一方面，如果Μη的含有比例超: ，則所製得的附錨固部的鋼筋的韌性降低， 斷裂，並且，所製得的附錨固部的鋼筋的焊 特定條鋼中的S i (矽）的含有比例小於 量％、最好小於等於0.35質量％。如果Si 過0.5 0質量％，則具有助長所製得的附錨 脆化的趨勢。 面1 0 2 B所構 這樣的條鋼（ 0.10〜0-30 質 i於0 · 5 0質量 令0.0 5質量％ F e以及不可避 1 0〜0.30質量 含有比例未達 具有充分的強 5 〇質量％，則 産生脆性斷裂 0.50〜1.50 質 的含有比例未 筋不具有充分 過1.50質量％ 容易産生脆性 接性降低。 t等於0.50質 的含有比例超 固部的鋼筋的 -18- (15) 1310708 特定條鋼中的P (磷）的含有比例小於等於〇 . 〇 5質量 %、最好小於等於0.04質量％。p的含有比例超過〇·〇5 質量％的條鋼的高溫镦锻加工性差，並且，所製得的附錨 固部的鋼筋的低溫韌性降低。 特定條鋼中的S (硫）的含有比例小於等於〇.〇5質量 %、最好小於等於0.04質量％。S的含有比例超過〇.〇5 質量％的條鋼的高溫加工性差，有時所形成的擴徑部的表 面（擴徑部形成面）成爲粗糙面，或者在擴徑部形成面上 産生毛細裂紋。 特定條鋼中的Cu (銅）的含有比例小於等於0.1 0質 量％、最好小於等於0.08質量％。Cu的含有比例超過 〇. 1 〇質量％的條鋼的高溫加工性差，有時所形成的擴徑部 的表面（擴徑部形成面）成爲粗糙面，或者在擴徑部形成 面上産生毛細裂紋。 在本發明的製造方法所使用的特定條鋼中，Μη和C 的質量比例（Mn/C )最好是大於等於3.0，大於等於3 . 5 更好。如果比例（Mn/C )未達3.0，則所製得的附錨固部 的鋼筋的韌性降低。 〔實施例〕 以下，就本發明的實施例進行說明，但本發明並不局 限於這些實施例。 <實施例1 -19- (16) 1310708 具有下列表1所示的組成，藉由利用具有第1圖（a )所示形狀的感應線圏（20 )的加熱裝置，加熱由Ac3相 變溫度（計算値）爲809 °C、外徑D (公稱直徑）=2 5mm 的異型條鋼（特定的條鋼）所構成的鋼筋的一端上的端部 區域（長度=7D )，使其以端部區域的溫度分佈是隨著接 近鋼筋的端面而連續升高。 在藉由紅外線放射溫度計分別測定從該鋼筋的端面起 算離開2 · 0D的部分的溫度（T 1 )、以及從該鋼筋的端面 起算離開5.0D的部分的溫度（T2 )時，溫度（T1 )爲 1 3 5 0 °C、溫度（T2 )爲 100〇°C。 之後，立即使感應線圈20從端部區域退避，將第1 圖（b)〜（d)所示的壓模30的成形面31按壓在鋼筋的 端面上’向鋼筋施加軸線方向的壓縮力，以壓縮該端部區 域。在此，壓縮速度爲5.0mm/s。 其結果，可使端部區域’尤其是從鋼筋的端面起算的 離開距離爲2.0D以內的部分是很低的變形阻力，而可容 易地塑性變形（相對於鋼筋的軸線方向朝向直角方向鼓出 )。另外，藉由構成壓模30的直徑爲2.5D的圓筒形的成 形面3 2限制因爲塑性變形所引起的鋼筋材料的流動。然 後使壓模3 0退避，取出附錨固部的鋼筋。 <實施例2〜4 > 除了以使溫度（T1 )和溫度（T 2 )成爲下表i所示的 數値的方式改變加熱條件以外，其他的條件都與實施例1 -20- (17) 1310708 相同地製造附錨固部的鋼筋。 <實施例5〜1 0 > 除了根據下表1改變鋼筋（異型條鋼）的組成以外， 其他的條件都與實施例1相同地製造附錨固部的鋼筋。 <比較例1〜4 > I 除了以使溫度（T1)和溫度（T2)成爲下表1所示的 數値的方式改變加熱條件以外，其他的條件都與實施例1 相同地試製了附錨固部的鋼筋。 在此，比較例1是溫度（T1 )未達1 3 00°C、溫度（T2 )未達鋼筋材料的Ac3相變溫度的比較例。 比較例2和比較例3是溫度（T1 )未達1 300 °C的比較 例。 比較例4是溫度（T 2 )超過1 2 0 0 °C的比較例。 <高溫镦鍛加工> 關於藉由實施例1〜1 〇所製得的附錨固部的鋼筋、以 及藉由比較例1〜4所進行的高溫镦鍛加工而製得的各種 鋼筋，藉由目視觀察其端部形狀’以此來評斷高溫镦鍛加 工性。評斷標準如下。將其結果同時表示在表1中。 (評斷標準） “〇，，：預定形狀的擴徑部（由直徑爲2 · 5 D的圓形端面、 -21 - (18) 1310708 和相對於鋼筋的軸線方向形成鈍角地進行擴大的擴徑部形 成面所構成的擴徑部）與鋼筋的通常部分是形成一體。 “ X A ” ：形成第5圖所示的球形或橢球形的擴徑部，該擴徑 部的端面的直徑大於等於1 · 3 D、小於等於1 . 8 d。 “XXA” ：形成第5圖所示的球形或橢球形的擴徑部，該擴 徑部的端面的直徑未達1.3D。 “xB” ：端部區域發生挫曲’不能形成預定形狀的擴徑部。 _ “ X C ” ：不能形成擴徑部（塑性變形）。 <擴徑部形成面的表面狀態（鋼筋的高溫加工性）> 關於藉由實施例1〜1 0所製得的各附錨固部的鋼筋， 藉由目視來觀察擴徑部形成面的表面狀態，根據以下標準 進行評斷。將其結果问時表示在表1中。 (評斷基準） | “〇”：沒有異常。 “△R” ：粗糙面。 “△H” ：只確認到一點毛細裂紋。 · “xH” ：確認到毛細裂紋。 <拉伸試驗（強度和韌性）> 關於藉由實施例1〜10所製得的各附錨固部的鋼筋， 在—40°c的低溫條件下進行拉伸試驗（拉伸速度=l〇mm/s )、測定拉伸強度，確認斷裂部位。將其結果同時表示在 -22- 1310708 (20)13107081310708) is greater than or equal to 3.0, especially greater than or equal to 3.5. < and 'the above-mentioned reinforcing bar is a reinforcing bar which is formed of a profiled steel and is an anchoring portion of the present invention, and is obtained by the present invention. Including the following process, the end region is heated, and a high-temperature iron forging process is performed to plastically deform the end portion which is heated toward the contraction to form an enlarged diameter portion as an anchor portion, and For example, if the temperature of the end region of the aforementioned reinforcing bar is continuously or stepwise increased, the temperature (T1) of the portion which is separated from the end face of the reinforcing bar by 2.0D is greater than or equal to the reinforcing bar. The melting point of the material, from the end face of the aforementioned steel bar to the temperature (T2) of the portion leaving 5.0D, the phase change temperature of A c 3 or more, equal to or lower than 1 2 0 0 °C. [Effects of the Invention] (1) According to the manufacturing method of the present invention (claims 1 to 3), a reinforcing rod having an appropriately shaped shape as an anchor portion is formed to form a reinforcing bar having such an enlarged diameter portion as an anchor portion (prevention Reinforcement). That is, since the temperature (T1) is greater than or equal to 1 300 °C, a portion requiring a large amount of plastic deformation, that is, a portion of the heat from the copper to the axial direction within a distance of 2.0 D, makes the portion easy to plastic. The deformation, by which the shape-enlarged diameter portion is, for example, preferably has a diameter of 2.0D to 2.8D. The manufacturing method is to press the reinforcing wire in the direction of the line, thereby, in one way, adding the approaching end face and starting at the axis 1 300 ° C, the steel bar method is not counted in the axis, but the anchoring portion can be surely Therefore, it is possible to supply a sufficient diameter-forming end surface -11 - (8) 1310708 (or an end portion forming surface having an arbitrary shape with an area of the same degree) to the end surface of the rib, the aforementioned The diameter-enlarged portion of the enlarged diameter portion is expanded at a right angle or an obtuse angle. Further, since the temperature (T2) is equal to or higher than the phase transition temperature of the steel member, and is less than or equal to 1,200 ° C, the axial direction of the steel bar can be removed. The distance is from 2.0D to 5.OD, and the plastic deformation is surely performed. (2) According to the manufacturing method of the present invention (claim 4), the steel bar is made of a steel bar containing a specific ratio of C and Μη. Steel with anchorage of high strength and good toughness. Since the steel and the S of the steel to be used are set to be low, the high-temperature workability is excellent, and the temperature is high even when the temperature is 1,300 ° C. upsetting The surface (the enlarged diameter portion forming surface) formed during the forging process does not become a rough surface, and no capillary crack is formed on the surface. (3) Manufacturing toughness according to the present invention (claims 5 to 6) (especially Low-temperature toughness) A steel having a good anchorage portion, which is a steel strip having a Mn/C ratio of Μη and C contained in the steel bar, which is 3.0 or more, and which is liable to cause brittle fracture, is limited to a relatively low strip steel, and thus can be formed. Reinforcement of the tough part. Therefore, even if a reinforcing bar having a similar shape is formed on the enlarged diameter forming surface, it is possible to prevent the portion from being a brittle matter as a starting point. The surface and the expanded surface are not frustrated relative to the end face of the material A c 3 as a reinforcing bar, and therefore, can be reinforced. A table containing a proportionally larger than or equal to the enlarged diameter portion can be manufactured by expanding the diameter portion. Mass ratio (the content ratio of C is better than that of a good anchoring groove portion -12-(9) 1310708 [Embodiment] [Best Mode for Carrying Out the Invention] Hereinafter, the present invention will be described in detail. The method for manufacturing the steel bar with the anchor portion of the present invention includes the following process: that is, heating the end portion of the steel bar, performing high temperature upsetting processing, compressing the heated end portion in the axial direction, and plastically deforming it. By increasing the outer diameter (expanding the diameter), the enlarged diameter portion is integrally formed as an anchor portion. High-temperature upsetting processing can be performed only at one end portion of the reinforcing bar, and high-temperature upsetting processing can be performed at both end portions. The "reinforcing bar" used in the production method of the present invention is not particularly limited, and conventionally known steel bars can be used. The outer diameter D of the reinforcing bar is, for example, about 10 to 40 mm. The reinforcing bar may be round steel or may be Shaped steel, but the manufacturing method of the present invention is particularly suitable for the case of using a profiled steel bar. The "end region" of the steel bar is a region heated in the high temperature upsetting process, and refers to: The surface is used as the starting point, and the area from the start point to the end point when the position from 5D to 7D is taken as the end point. The "local temperature upset processing" is a processing method in which the end portion of the reinforcing bar is heated while The end portion is compressed in the axial direction to be plastically deformed to expand the diameter. The method of heating the end portion of the reinforcing bar is not particularly limited, but based on the viewpoint of locally heating the reinforcing bar quickly, it is preferable to use high frequency induction. Heating method. In the manufacturing method of the present invention, when performing high temperature upset processing, the heating temperature of the end region of the -13-(10) 1310708 steel bar is continuously or stepwisely increased as approaching the end surface of the steel bar. Therefore, the end surface of the reinforcing bar also becomes the highest temperature. The temperature of the end portion can be measured by an infrared radiation thermometer or the like. 'In the manufacturing method of the present invention (high-temperature upsetting processing), from the 'end face of the reinforcing bar The temperature (T1) of the portion leaving the 2.0D in the axial direction is greater than or equal to 1 300 ° C. 'The melting point of the reinforcing steel material is not reached. I. By this, a plasticity which is particularly demanding is required. The portion of the shape, that is, the portion within the distance of 2.0D from the end face of the reinforcing bar (the reinforcing material near the end face) is supplied with sufficient heat to make the portion easily plastically deformed (bulging toward the direction perpendicular to the axial direction) When the temperature (T1) is less than 1 3 00 °C, it is not easy to plastically deform the portion from the end surface of the steel bar to a distance of 2.0 D. The diameter-enlarged portion of the predetermined shape cannot be formed (please refer to the following) Comparative Example 1 to 3) ° φ In the manufacturing method of the present invention, the temperature (T2) of the portion which is separated from the end face of the reinforcing bar by 5.0D in the axial direction is equal to or higher than the A c 3 phase transition temperature of the reinforcing bar material, which is smaller than It is equal to 1 2 0 〇. <: By this, it is possible to surely make the plastic deformation of the portion from the end face of the reinforcing bar of 2·0 D to 5 · 0 D without buckling. In the case where the temperature (T2) does not reach the ac3 phase transition temperature of the reinforcing bar material, it is not easy to plastically deform the portion from the end face of the reinforcing bar to a distance of 2.0D to 5 · 〇D. On the other hand, in the case where the temperature (τ2 ) exceeds 1 200 t: 'the buckling phenomenon is likely to occur in this portion (refer to Comparative Example 4 described later in the case of 14-(11) 1310708) 0 The enlarged diameter portion formed by the machining is constituted by an end surface that is orthogonal to the axial direction of the reinforcing bar and an enlarged diameter portion forming surface that expands at a right angle or an obtuse angle with respect to the axial direction of the reinforcing bar. The shape of the end face of the enlarged diameter portion is not particularly limited, and examples thereof include a circular shape, an elliptical shape, a rectangular shape, and a capsule shape. When the high-temperature upset processing is performed, the outer peripheral surface of the enlarged diameter portion is restricted by the stamper, and the enlarged diameter portion having an end surface such as an elliptical shape, a rectangular shape, or a capsule shape can be easily formed. In the case where the end face of the enlarged diameter portion is circular, the diameter is preferably 2.0D to 2·8 D, and more preferably 2·5 D to 2.8 D. The enlarged diameter portion with too small diameter cannot fully exert the anchor fixing function with respect to other steel bars and concrete. On the other hand, the reinforcing bars of the anchoring portion formed by the enlarged diameter portion exceeding the diameter of 2.8D cannot sufficiently correspond to the excessively dense reinforcing bar configuration. Further, in the case where the end surface of the enlarged diameter portion has a shape other than a circular shape, the area of the end surface is preferably the same as the circle having a diameter of 2.0D to 2_8D. Hereinafter, an example of high-temperature upsetting processing in the production method of the present invention will be described with reference to the drawings. Fig. 1 (a) to (d) are schematic cross-sectional views showing a process of high temperature upset processing in the production method of the present invention. First, as shown in Fig. 1(a), the heating head formed by the induction coil 2 is placed to surround the steel bar having the outer diameter D. The end region of the crucible (the region from the starting point to the end point when the position from the _ plane iA is calculated as the starting point from the _ plane i 〇A from the _ plane i 〇A), by the height -15- (12 1310708 Frequency induction heating to heat the end region. Here, the induction coil 20 constituting the heating head is wound into a tapered shape such that the distance between the inner circumference and the outer peripheral surface of the reinforcing bar 10 is shorter as it approaches the end surface 10A of the reinforcing bar 10. Fig. 2 is a view showing the relationship between the distance from the end face 1 〇A and the temperature of the reinforcing bar on the portion when the end portion of the reinforcing bar 1 is heated by the induction coil 20 shown in Fig. 1(a). . As shown in Fig. 1(a), by providing a tapered induction coil 20, heating is performed so that the temperature distribution of the end portion of the reinforcing bar 1 is: the temperature of each portion of the end portion is It rises continuously close to the end face 10A. Further, the temperature of each portion can be controlled by adjusting the distance between the inner circumference of the induction coil 2 和 and the outer circumferential surface of the reinforcing bar 1 各 in each portion of the end portion. Further, the temperature control method is not limited to these methods. In the end region of the reinforcing bar 10, the portion 12 which is spaced apart from the end face 10A and which is separated from the 2_0D in the axial direction is heated by the induction coil 2A, and the temperature (T1) of the portion 12 is greater than or equal to 130 (rc, which does not reach the reinforcing bar material) Melting point (controlled within this range) and 'the portion 15 which is separated from the end face 1 by 5_0D in the axial direction is heated by the induction coil 2〇, and the temperature (τ2) of the portion 15 is equal to or larger than the Ac3 phase of the reinforcing bar material. Variable temperature, less than or equal to 1 200 ° C (controlled within this range). Then 'from the end region with the above temperature distribution and being heated, the -16 - 30 (13) 1310708 induction coil 20 is retracted, and then, as in 1(b), the molding surface 31 of the stamper is pressed against the end surface of the reinforcing bar 10, and a compressive force P in the axial direction is applied to the reinforcing bar 10 to compress the end region. Thereby, the end portion of the reinforcing bar is performed. The plastic deformation (bulging out at a right angle with respect to the axial direction) increases the outer diameter (expanded diameter). Here, although the compression speed is different depending on the outer diameter D of the steel bar 10, it is preferably 3.0 to 10.0 mm/s. , 5.0~8.0mm/s is better. At compression speed When the degree is too low, in the compression operation, the temperature in the end region is lowered, the deformation resistance is increased, and plastic deformation (increase in diameter) is hard to occur. On the other hand, when the compression speed is too high, the line is in progress. In the compression operation, buckling is likely to occur. Further, the compression stroke type is preferably 2.0D to 4.0D, and 2.5D 3.5D is more preferable. Here, the stamper 30 of the end portion of the compressed steel bar 10 can be made. The molding surface 31 of the end surface of the enlarged diameter portion to be formed and the cylindrical surface 32 which can restrict the outer circumferential surface (the surface of the enlarged diameter portion) of the enlarged diameter portion are formed. Thus, as shown in Fig. 1 (c) ), the flow of the reinforcing bar material outward in the direction perpendicular to the axial direction of the reinforcing bar 1 ′ can be restricted by the forming surface 32 of the stamper 30. Then, as shown in Fig. 1(d), the stamper 3 0 is made. By doing so, it is possible to manufacture the reinforcing bar 100 with the anchor portion formed by the expanded portion 102 and the normal portion 101 of the reinforcing bar for holding the outer diameter. The aforementioned enlarged diameter portion 102 is composed of steel bars a circular end face of about 2.5 D in diameter in the direction of the axis, and a relative length of the steel bar The direction of the axis plus the direction of the 10th direction into the limit is D 5 which is a conical enlarged diameter portion which is enlarged by an angle of -17-(14) 1310708 $. In the manufacturing method of the present invention It is preferable to use the following "specific strip steel", that is, C: turtle %, Μη: 0.50 to 1.50 mass%, Si: less than equal %, P: less than or equal to 〇. 0 5 mass%, S : less than equal ΐ, Cu: less than or equal to 0.10% by mass, and the rest is k-free impurities. The content ratio of C (carbon) in the specific steel is 0.%, preferably 0.15 to 0.25 mass%. If G·10% by mass of C, the resulting anchorage of the anchor portion is inferior. On the other hand, if the content ratio of C exceeds 0.: The toughness of the steel bar with the anchor portion obtained is lowered, and the content ratio of Μ (manganese) in the specific steel bar is easily 1% by mass, preferably 0.60~ 1.40% by mass. If Μη is 0.50% by mass, the strength of the steel with the anchor portion is obtained. On the other hand, if the content ratio of Μη exceeds:, the toughness of the obtained steel bar with the anchor portion is lowered, broken, and the S i (矽) in the specific steel strip of the obtained steel bar with the anchor portion is obtained. The content ratio is less than the amount %, preferably less than or equal to 0.35 mass%. If Si exceeds 0.50% by mass, it tends to promote the embrittlement of the anchor. Face 1 0 2 B is constructed such a strip (0.10~0-30 quality i at 0 · 50 0 mass order 0.0 5 mass % F e and unavoidable 1 0~0.30 mass content ratio is not sufficient to have a strong 5 〇 quality %, the brittle fracture is 0.50~1.50. The proportion of the unflavored material is not more than 1.50% by mass. It is easy to produce the brittleness. The t-equal to the 0.50 quality of the steel with the proportion of the over-solid part is -18- (15) 1310708 specific The content ratio of P (phosphorus) in the steel bar is less than or equal to 〇. 〇5 mass%, preferably less than or equal to 0.04 mass%. The high-temperature upsetting processability of the steel having a content ratio of p exceeding 〇·〇5 mass% is poor, and The low-temperature toughness of the obtained steel bar with the anchor portion is reduced. The content ratio of S (sulfur) in the specific steel bar is less than or equal to 〇.〇5 mass%, preferably less than or equal to 0.04 mass%. The content ratio of S exceeds 〇 〇5% by mass of the steel bar is inferior in high-temperature workability, and the surface of the enlarged diameter portion (the enlarged diameter portion forming surface) may be a rough surface or a capillary crack may be formed on the enlarged diameter portion forming surface. Cu (copper) content is less than 0.10 mass%, preferably 0.08 mass% or less. The content of Cu is more than 0.1% by mass. The high-temperature workability of the steel bar is poor, and the surface of the enlarged diameter portion (the expanded diameter forming surface) may be formed. It is a rough surface or a capillary crack is formed on the surface of the enlarged diameter portion. In the specific steel used in the production method of the present invention, the mass ratio (Mn/C) of Μη and C is preferably 3.0 or more, greater than or equal to Preferably, if the ratio (Mn/C) is less than 3.0, the toughness of the obtained steel bar with the anchor portion is lowered. [Embodiment] Hereinafter, an embodiment of the present invention will be described, but the present invention It is not limited to these embodiments. <Example 1 -19- (16) 1310708 The composition shown in the following Table 1 is obtained by heating using the induction coil (20) having the shape shown in Fig. 1(a). a device for heating an end region (length) on one end of a reinforcing bar composed of a profiled steel (specific bar) having an Ac3 phase transition temperature (calculated 値) of 809 ° C and an outer diameter D (nominal diameter) = 2 5 mm =7D ), so that the temperature distribution in the end region is close to the steel bar The end face is continuously raised. The temperature (T 1 ) of the portion which is separated from the end face of the reinforcing bar by the infrared radiation thermometer, and the temperature of the portion which is separated from the end face of the reinforcing bar by 5.0D (T2) are respectively measured by the infrared radiation thermometer. When the temperature (T1) is 1 3 50 ° C and the temperature (T2) is 100 ° C. Immediately thereafter, the induction coil 20 is retracted from the end region, and the first graph (b) to (d) are used. The forming surface 31 of the stamper 30 is pressed against the end surface of the reinforcing bar to apply a compressive force in the axial direction to the reinforcing bar to compress the end region. Here, the compression speed is 5.0 mm/s. As a result, the end portion "especially the portion within a distance of 2.0D from the end face of the reinforcing bar is a very low deformation resistance, and can be easily plastically deformed (bumping in a direction perpendicular to the axial direction of the reinforcing bar) ). Further, the flow of the reinforcing bar material due to plastic deformation is restricted by the cylindrical shaped surface 3 2 constituting the stamper 30 having a diameter of 2.5D. Then, the stamper 30 is retracted, and the reinforcing bar with the anchor portion is taken out. <Examples 2 to 4 > Other conditions were the same as in Example 1 -20- except that the heating conditions were changed such that the temperature (T1) and the temperature (T 2 ) became the number 値 shown in the following table i. 17) 1310708 The steel bars with anchors are manufactured identically. <Examples 5 to 10> The steel bars with anchor portions were produced in the same manner as in Example 1 except that the composition of the steel bars (shaped bars) was changed according to the following Table 1. <Comparative Examples 1 to 4 > I Other conditions were the same as in Example 1 except that the heating conditions were changed so that the temperature (T1) and the temperature (T2) became the number shown in Table 1 below. Reinforcement with anchorage. Here, Comparative Example 1 is a comparative example in which the temperature (T1) is less than 1 3 00 ° C and the temperature (T2) is less than the Ac3 phase transition temperature of the reinforcing bar material. Comparative Example 2 and Comparative Example 3 are comparative examples in which the temperature (T1) is less than 1 300 °C. Comparative Example 4 is a comparative example in which the temperature (T 2 ) exceeded 1 2 0 0 °C. <High-temperature upsetting processing> Various reinforcing bars obtained by the reinforcing bars of the anchor portions obtained in Examples 1 to 1 and the high-temperature upsetting processing by Comparative Examples 1 to 4 were used. The shape of the end portion was visually observed to judge the high-temperature upsetting processability. The criteria for judgment are as follows. The results are shown in Table 1 at the same time. (Criteria for Judgment) "〇,,: Expanded diameter portion of a predetermined shape (a circular end surface having a diameter of 2 · 5 D, -21 - (18) 1310708, and an expanded diameter which is formed at an obtuse angle with respect to the axial direction of the reinforcing bar The enlarged diameter portion formed by the portion forming surface is integrally formed with the normal portion of the reinforcing bar. "XA": a spherical or ellipsoidal enlarged diameter portion shown in Fig. 5 is formed, and the diameter of the end surface of the enlarged diameter portion is equal to or greater than 1 · 3 D, less than or equal to 1.8 d. "XXA": The spherical or ellipsoidal enlarged diameter portion shown in Fig. 5 is formed, and the diameter of the end face of the enlarged diameter portion is less than 1.3D. "xB": end portion The area buckling 'cannot form a diameter-enlarged portion of a predetermined shape. _ "XC": The enlarged diameter portion (plastic deformation) cannot be formed. <The surface state of the enlarged diameter portion forming surface (high-temperature workability of the steel bar)> The steel bars of the respective anchor portions obtained in Examples 1 to 10 were visually observed for the surface state of the enlarged diameter portion forming surface, and were judged according to the following criteria. The results are shown in Table 1. Judgment benchmark) | “〇”: No abnormality. “△R”: Thick "△H": Only a slight capillary crack was confirmed. "xH": capillary crack was confirmed. <Tensile test (strength and toughness)> Regarding each of the examples obtained by Examples 1 to 10 The steel bar of the anchoring portion was subjected to a tensile test at a low temperature of -40 ° C (stretching speed = l 〇 mm / s), the tensile strength was measured, and the fracture site was confirmed. The result was also expressed at -22 - 1310708 ( 20) 1310708
1? fe 擴徑部 的根部 Φ φ 啦 Φ 啦 姻 rT"1 m l 610 576 as 544 594 553 τ—^ g 612 614 I I I I 成面的表 面狀態 书Π e 〇 〇 〇 〇 〇 〇 ΔΗ ΔΗ △R 〇 1 1 1 1 鹅 高溫镦鍛 加工性 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 υ χχΑ < X Τ2 (°C) 1000 o OO 1000 1200 1000 1000 1000 1000 1000 1000 ο 00 1000 1000 i 1350 /—N Η Ρ o o ΓΛ ο ο Γ«"ί m m ΓΛ ΓΛ ο ΓΛ Ο ο ο 1250 Γ^ί S^， 1-^ 1—^ 1—M 1—^ r-H r-^ 1—Η 1—^ «—< si Μ 計算値 ro g oo g OO S 〇〇 g οο 1—H (M 00 814 816 卜 § η 00 Ο »—Η 00 S 00 S οο 809 S 00 < m II ^ 卜 ΓΛ ^sO Ό rn (Ν m 对_ i—Η 卜 oi 卜 卜 =3 U 0.08 0.08 0,08 1 0.08 0.06 0.07 0.13 1 ,0.11 0.08 0.07 0.08 0.08 0.08 0.08 C/3 0.022 <N S (Ν S (Ν S VO s s Ον Ο 00 ο m S ο S (Ν S S (Ν S CN S Μ 〇 ο Ο o o ο ο ο ο Ο C? ο Ο » (N s CN s (Ν S CN S CO s 00 s 寸 S 0.025 0.029 0.026 (Ν & (Ν S CS S fN S 堪 〇 〇 Ο Ο o o ο Ο Ο C5 ο •m ίΛ 0.20 宕 宕 寸 艺 0.20 0.21 0.23 宕 0.20 宕 宕 璨 o Ο Ο o o ο Ο Ο ο m £ 00 oo νο 00 Ό ΟΟ rN vo § 00 ο ίο Ό ΟΟ 00 ν〇 00 νο οο o o ο Ο O d ο Ο 5^ ο (J m (N CN CO (Ν m (Ν 卜 r~H 0.22 m (S 0.25 (Ν ΓΛ (Ν CN 〇 〇 Ο Ο o ο Ο o Ο ο Ο Ο iN ΓΛ ί〇 卜 00 ON ο 1—^ (Ν ΓΛ 寸 运 匡 匡 m 雩 Μ 蜀 習 辑 習 辑 辑 辑 辑 鎰 鎰 鎰 IK Μ κ IK 1¾ 駟 IK IK {W AJ ΛΛ ΛΛ J_J a_x -24- (21) 1310708 如表1所示，藉由實施例1〜1 〇所製得的附錨固部的 鋼筋，都是預定形狀的擴徑部與鋼筋的通常部分一體形成 的。因此，根據實施例1〜1 0的製造方法（加熱條件）， 可發揮良好的高溫镦鍛加工性。 而在藉由比較例1〜4來進行高溫镦鍛加工的鋼筋上 ，都未形成預定形狀的擴徑部，因此，根據比較例1〜4 的製造方法（加熱條件），不能發揮良好的高溫镦鍛加工 性。 藉由實施例1〜6以及實施例1 〇所製得的附錨固部的 鋼筋，由於使用Cu和S的含有比例低（Cu的含有比例小 於等於0.10質量％、S的含有比例小於等於0.05質量％ )的鋼筋來進行製造，因此擴徑部形成面的表面狀態良好 〇 藉由實施例1〜9所製得的附錨固部的鋼筋，由於使 用Μη和C的質量比例（Mn/C )大於等於3.0的鋼筋來進 行製造，因此強度高，同時，斷裂部位在於母材（通常部 分）上，即使在低溫條件下韌性也良好。 【圖式簡單說明】 第1圖是表示本發明的製造方法中的高溫镦鍛加工製 程的槪略剖面圖。 第2圖是表示在藉由第1圖（a)所示的感應線圈來 加熱鋼筋的端部區域時，從端面起算的離開距離與該部分 上的溫度的關係的示意圖。 -25- (22) 1310708 第3圖（a )是以往衆所周知的附錨固部的鋼筋的槪 略側視圖，第3圖（b )是該附錨固部的鋼筋的端部的槪 略剖面圖，第3圖（c )是第3圖（b )的X-X剖面線的箭 頭方向剖面圖。 第4圖（a)和（b)是表示製造第3圖所示的附錨固 部的鋼筋時的高溫鐵鍛加工製程的槪略剖面圖。 第5圖是橢球形的擴徑部形成在端部的鋼筋的槪略剖 面圖。 【主要元件符號說明】 1 0 :鋼筋 10A :端面 12:從端面10A起算在軸線方向離開2.0D的部分 1 5 :從端面1 0 A起算在軸線方向離開5.0 D的部分 20 :感應線圏 3 〇 :壓模 3 1 :成形面 3 2 :成形面 1〇〇 :鋼筋 101 :鋼筋的通常部分 1 0 2 :擴徑部 102A :圓形端面 102B :擴徑部形成面 P :壓縮力 -26-1? fe The root of the enlarged diameter Φ φ 啦 啦 r rT"1 ml 610 576 as 544 594 553 τ—^ g 612 614 IIII Surface state of the surface Π e 〇〇〇〇〇〇ΔΗ ΔΗ △R 〇 1 1 1 1 Goose high temperature upsetting processability χχΑ < X Τ 2 (°C) 1000 o OO 1000 1200 1000 1000 1000 1000 1000 1000 ο 00 1000 1000 i 1350 /—N Η oo oo ΓΛ ο ο Γ«"ί mm ΓΛ ΓΛ ο ΓΛ Ο ο ο 1250 Γ^ί S^, 1-^ 1—^ 1—M 1—^ rH r-^ 1—Η 1—^ «— < si Μ calculation 値ro g oo g OO S 〇〇g οο 1—H (M 00 814 816 § η 00 Ο »—Η 00 S 00 S οο 809 S 00 < m II ^ ΓΛ ΓΛ ^sO Ό Rn (Ν m vs _ i - Η oi 卜卜 = 3 U 0.08 0.08 0,08 1 0.08 0.06 0.07 0.13 1 ,0.11 0.08 0.07 0.08 0.08 0.08 0.08 C/3 0.022 <NS (Ν S (Ν S VO ss Ον Ο 00 ο m S ο S (Ν SS (Ν S CN S Μ 〇ο Ο oo ο ο ο ο Ο C? ο Ο » (N s CN s ( S CN S CO s 00 s 寸 S 0.025 0.029 0.026 (Ν & (Ν S CS S fN S 〇〇Ο oo oo ο Ο Ο C5 ο • m Λ Λ 0.20 宕宕 inch art 0.20 0.21 0.23 宕 0.20 宕宕璨o Ο oo oo ο Ο Ο ο m £ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 (Ν r r~H 0.22 m (S 0.25 (Ν 〇〇Ο 〇〇Ο Ν 〇〇Ο 〇〇Ο 〇〇Ο 00 N N 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00辑 辑 辑 镒镒镒 镒镒镒 κ κ IK IK 13⁄4 驷 IK IK {W AJ ΛΛ ΛΛ J_J a_x -24- (21) 1310708 As shown in Table 1, by the example 1~1 制The reinforcing bars of the anchoring portion are formed by integrally forming the enlarged diameter portion of the predetermined shape with the normal portion of the reinforcing bar. Therefore, according to the production methods (heating conditions) of Examples 1 to 10, good high-temperature upsetting processability can be exhibited. On the steel bars subjected to high-temperature upsetting by Comparative Examples 1 to 4, the enlarged diameter portions having a predetermined shape were not formed. Therefore, according to the production methods (heating conditions) of Comparative Examples 1 to 4, good high temperatures could not be exhibited. Upsetting processability. The steel bars with the anchor portions obtained in Examples 1 to 6 and Example 1 are low in the content ratio of Cu and S (the content ratio of Cu is 0.10% by mass or less, and the content ratio of S is 0.05 or less. %) of the steel bars are manufactured, so that the surface state of the enlarged diameter portion forming surface is good, and the steel bars with the anchor portions obtained by the embodiments 1 to 9 have a mass ratio (Mn/C) larger than that of the use of Μη and C. A steel bar equal to 3.0 is manufactured to have high strength, and at the same time, the fracture site is on the base material (usually), and the toughness is good even under low temperature conditions. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing a high-temperature upsetting processing process in the manufacturing method of the present invention. Fig. 2 is a view showing the relationship between the distance from the end face and the temperature at the end portion when the end portion of the reinforcing bar is heated by the induction coil shown in Fig. 1(a). -25- (22) 1310708 Fig. 3(a) is a schematic side view of a conventionally known steel bar with an anchor portion, and Fig. 3(b) is a schematic cross section of the end portion of the reinforcing bar with the anchor portion. Fig. 3(c) is a cross-sectional view taken along the line XX of Fig. 3(b). Fig. 4 (a) and (b) are schematic cross-sectional views showing a high-temperature iron forging process in the case of manufacturing a reinforcing bar with an anchor portion shown in Fig. 3. Fig. 5 is a schematic cross-sectional view showing the reinforcing bar formed at the end portion of the ellipsoidal enlarged diameter portion. [Description of main component symbols] 1 0 : Rebar 10A: End face 12: A portion that is separated from the axis D1 by 2.0D from the end face 10A: A portion 20 that exits 5.0 D in the axial direction from the end face 1 0 A: Induction wire 圏 3 〇: stamper 3 1 : forming surface 3 2 : forming surface 1 〇〇: reinforcing bar 101 : normal portion of reinforcing steel 1 0 2 : enlarged diameter portion 102A : circular end surface 102B : enlarged diameter forming surface P : compressive force -26 -