JP2009125752A - Method for heating raw material billet for hot forging - Google Patents
Method for heating raw material billet for hot forging Download PDFInfo
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- JP2009125752A JP2009125752A JP2007300777A JP2007300777A JP2009125752A JP 2009125752 A JP2009125752 A JP 2009125752A JP 2007300777 A JP2007300777 A JP 2007300777A JP 2007300777 A JP2007300777 A JP 2007300777A JP 2009125752 A JP2009125752 A JP 2009125752A
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- 238000010438 heat treatment Methods 0.000 title claims abstract description 242
- 238000000034 method Methods 0.000 title claims abstract description 44
- 238000005242 forging Methods 0.000 title claims abstract description 35
- 239000002994 raw material Substances 0.000 title abstract description 7
- 239000000463 material Substances 0.000 claims abstract description 116
- 238000001816 cooling Methods 0.000 claims abstract description 21
- 230000002093 peripheral effect Effects 0.000 claims abstract description 9
- 239000007788 liquid Substances 0.000 claims description 8
- 239000002826 coolant Substances 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 3
- NJPPVKZQTLUDBO-UHFFFAOYSA-N novaluron Chemical compound C1=C(Cl)C(OC(F)(F)C(OC(F)(F)F)F)=CC=C1NC(=O)NC(=O)C1=C(F)C=CC=C1F NJPPVKZQTLUDBO-UHFFFAOYSA-N 0.000 description 7
- 230000005855 radiation Effects 0.000 description 5
- 238000002791 soaking Methods 0.000 description 4
- 238000009529 body temperature measurement Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 229910000975 Carbon steel Inorganic materials 0.000 description 2
- 239000010962 carbon steel Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 102200082816 rs34868397 Human genes 0.000 description 2
- 230000005611 electricity Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Abstract
Description
この発明は、鍛造用素材ビレットを、鍛造後に要求される材質特性に対応した温度分布を付して加熱する方法に関する。 The present invention relates to a method for heating a forging material billet with a temperature distribution corresponding to the material characteristics required after forging.
従来、熱間鍛造用素材は、その温度分布にバラツキがある場合、素材の各部位の変形能が異なって高寸法精度で鍛造することが難しいため、熱間鍛造では、一般に素材は目標温度に均一加熱され、段付き形状などの異形状の素材についても均一に加熱されるように工夫がなされている（例えば、特許文献１参照）。
前記素材ビレットを目標温度に均一に加熱した場合、鍛造後の機械的性質などの材質特性も、鍛造品（as-forged）の各部位でほぼ均一となる。このため、鍛造品の各部位で異なった材質特性が要求される場合には、鍛造後、鍛造品に部分的熱処理を施すなどして、要求特性を満たすような対応がなされていた。しかし、このような対応では、熱処理コストを要する上に、鍛造品の生産性低下をもたらす。 When the material billet is uniformly heated to the target temperature, the material properties such as mechanical properties after forging are also substantially uniform in each part of the forged product (as-forged). For this reason, when different material properties are required in each part of the forged product, measures have been taken to satisfy the required properties by, for example, subjecting the forged product to partial heat treatment after forging. However, such measures require heat treatment costs and reduce the productivity of forged products.
そこで、この発明の課題は、鍛造最終製品の各部位で異なった材質特性が要求される場合、素材ビレットに、その異なる材質特性に対応した温度分布をつけることにより、熱処理コストの低減と生産性の向上を可能とする加熱方法を提供することである。 Therefore, the object of the present invention is to reduce the heat treatment cost and productivity by providing the material billet with a temperature distribution corresponding to the different material characteristics when different material characteristics are required in each part of the final forged product. It is providing the heating method which makes improvement possible.
前記の課題を解決するために、この発明では以下の構成を採用したのである。 In order to solve the above problems, the present invention employs the following configuration.
請求項１に係る熱間鍛造用素材ビレットの加熱方法は、熱間鍛造工程における素材ビレットの加熱方法であって、前記素材ビレットを、熱間鍛造した熱間鍛造品に要求される材質特性に応じて、その外周側に軸方向に配置した加熱手段または加熱手段と冷却手段により、軸方向に温度分布をつけて目標鍛造温度に加熱することを特徴とする熱間鍛造用素材ビレットの加熱方法。 The method for heating a material billet for hot forging according to claim 1 is a method for heating a material billet in a hot forging process, and the material properties required for a hot forged product obtained by hot forging the material billet. Accordingly, the heating method of the raw billet for hot forging is characterized by heating the target forging temperature with a temperature distribution in the axial direction by the heating means or the heating means and the cooling means arranged in the axial direction on the outer peripheral side. .
このように、熱間鍛造品の各部位に要求される材質特性に対応して、素材ビレットを、予め温度分布をつけて目標温度に加熱するようにすれば、要求材質特性を満たすため、熱間鍛造後に部分的な熱処理を施さずに済み、熱処理コストの低減および生産性の向上に寄与する。 In this way, if the material billet is heated to the target temperature with a temperature distribution in advance corresponding to the material properties required for each part of the hot forged product, It is not necessary to perform partial heat treatment after the forging, which contributes to reduction of heat treatment cost and improvement of productivity.
請求項２に係る熱間鍛造用素材ビレットの加熱方法は、前記軸方向の温度分布を、前記加熱手段または前記加熱手段と冷却手段により、素材ビレットにおける加熱部位からの軸方向の熱伝導またはこの熱伝導と強制冷却とを利用してつけることを特徴とする。 The method for heating a hot billet material billet according to claim 2 is characterized in that the temperature distribution in the axial direction is measured by the heating means or the heating means and the cooling means in the axial direction from the heating part in the material billet or It is characterized by being attached using heat conduction and forced cooling.
請求項３に係る熱間鍛造用素材ビレットの加熱方法は、前記軸方向の温度分布を、前記加熱手段に対して、素材ビレットを軸方向に相対的に移動させることによりつけることを特徴とする。 The method for heating a hot billing material billet according to claim 3 is characterized in that the temperature distribution in the axial direction is applied by moving the material billet in the axial direction relative to the heating means. .
このように、軸方向の温度分布を、単に加熱部位からの熱伝導によって、もしくは熱伝導と強制冷却によってつけることにより、または素材ビレットを加熱手段に対して相対的に移動させる操作を加えてつけることにより、大掛かりな加熱装置を必要とせず、簡便に素材ビレットの軸方向に温度分布をつけることができる。 In this way, the temperature distribution in the axial direction is simply applied by heat conduction from the heating site, or by heat conduction and forced cooling, or by adding an operation of moving the material billet relative to the heating means. Thus, a temperature distribution can be easily provided in the axial direction of the billet without requiring a large heating device.
請求項４に係る熱間鍛造用素材ビレットの加熱方法は、前記素材ビレットを、前記加熱手段から一旦出した後、所要の時間後に前記加熱手段に入れて再加熱することを特徴とする。 The method for heating a hot billing material billet according to claim 4 is characterized in that after the material billet is once taken out of the heating means, it is put into the heating means and reheated after a predetermined time.
このように、素材ビレットを加熱手段に対して出し入れして加熱することにより、加熱部位の断面内の温度差を小さくして均熱度を向上させることができる。 In this way, the material billet is taken in and out of the heating means and heated, so that the temperature difference in the cross section of the heated part can be reduced and the soaking degree can be improved.
請求項５に係る熱間鍛造用素材ビレットの加熱方法は、前記加熱手段が、高周波加熱コイルまたはガスバーナである加熱方法である。 The method for heating a hot billet billet according to claim 5 is a heating method in which the heating means is a high-frequency heating coil or a gas burner.
このように、誘導加熱、またはガスによる直接加熱のいずれの方法によっても、前記軸方向の温度分布をつけることができる。 Thus, the axial temperature distribution can be set by any method of induction heating or direct heating by gas.
請求項６に係る熱間鍛造用素材ビレットの加熱方法は、前記冷却手段が、冷却媒体として、気体もしくは液体または気液混合物をノズルから噴出する強制冷却装置である加熱方法である。 The heating method of the hot forging material billet according to claim 6 is a heating method in which the cooling means is a forced cooling device that ejects gas, liquid, or gas-liquid mixture as a cooling medium from a nozzle.
このように、冷却媒体として、気体もしくは液体または気液混合媒体を用いることにより、素材ビレットの前記熱伝導による温度上昇を簡便に調節して、所要の温度分布をつけて目標鍛造温度に加熱することができる。 As described above, by using a gas, liquid, or gas-liquid mixed medium as a cooling medium, the temperature rise due to the heat conduction of the material billet is easily adjusted, and the target forging temperature is heated with a required temperature distribution. be able to.
請求項７に係る熱間鍛造用素材ビレットの加熱方法は、前記素材ビレットが丸素材であり、その直径がΦ１００ｍｍ以下であることを特徴とする。 The method for heating a hot billing material billet according to claim 7 is characterized in that the material billet is a round material and the diameter thereof is Φ100 mm or less.
本願発明では、上述のように、要求材質特性に対応した温度分布を、素材ビレットの軸方向に付けるため、長時間の加熱は好ましくない。素材ビレットの直径がΦ１００ｍｍよりも大きくなると、素材表面と中心の温度差、すなわち断面内の温度分布が大きくなり、この温度分布を改善して目標鍛造温度範囲に収めるためには、長時間の加熱が必要となることによる。 In the present invention, as described above, since a temperature distribution corresponding to the required material characteristics is applied in the axial direction of the material billet, heating for a long time is not preferable. When the diameter of the material billet is larger than Φ100 mm, the temperature difference between the material surface and the center, that is, the temperature distribution in the cross section increases, and in order to improve this temperature distribution and keep it within the target forging temperature range, heating for a long time Is required.
請求項８に係る熱間鍛造用素材ビレットの加熱方法は、前記素材ビレットの加熱過程で、温度分布をつける素材ビレットの各部位の温度を測定し、この測定温度に基づいて、前記加熱手段または加熱手段と冷却手段の出力を制御することを特徴とする。 The method of heating a material billet for hot forging according to claim 8 measures the temperature of each part of the material billet that gives a temperature distribution in the heating process of the material billet, and based on the measured temperature, the heating means or The output of the heating means and the cooling means is controlled.
このようにすれば、素材ビレットの各部位の温度を実測することにより、所要の温度分布をつけて、目標鍛造温度に精度よく制御することができる。 If it does in this way, by measuring the temperature of each site | part of a raw material billet, a required temperature distribution can be attached and it can control to target forging temperature accurately.
請求項９に係る熱間鍛造用素材ビレットの加熱方法は、前記素材ビレットの加熱過程で、温度分布をつける素材ビレットの加熱部位の温度を測定し、この測定温度に基づいて、前記素材を前記軸方向に相対的に移動させるタイミングを制御することを特徴とする。 The method of heating a material billet for hot forging according to claim 9 measures the temperature of the heated part of the material billet that gives a temperature distribution in the heating process of the material billet, and based on the measured temperature, the material is It is characterized by controlling the timing of relative movement in the axial direction.
このように、素材ビレットの加熱部位の温度を実測することにより、素材ビレットを軸方向に相対移動させるタイミングを精度よく把握することができる。なお、前記加熱手段もしくは加熱手段と冷却手段の出力を制御する場合、または素材ビレットを軸方向に相対移動させるいずれの場合も、素材ビレット各部位の温度は、非接触式温度計、接触温度計または熱電対のいずれでも測定でき、測定する部位に応じて、これらの測温手段を使い分けることができる。 Thus, by actually measuring the temperature of the heated part of the material billet, it is possible to accurately grasp the timing at which the material billet is relatively moved in the axial direction. In addition, when controlling the output of the heating means or the heating means and the cooling means, or when the material billet is relatively moved in the axial direction, the temperature of each part of the material billet is a non-contact type thermometer or contact thermometer. Either a thermocouple or a thermocouple can be measured, and these temperature measuring means can be used properly according to the part to be measured.
この発明では、熱間鍛造品で、要求される各部位の材質特性に応じて、素材ビレットを、その軸方向に予め温度分布をつけて目標温度に加熱するようにしたので、熱間鍛造後に、各部位で異なる要求材質特性を満たすための部分的な熱処理を施さずに済み、熱処理コストの低減および生産性の向上に寄与する。 In the present invention, in the hot forged product, according to the required material properties of each part, the material billet is preheated in the axial direction and heated to the target temperature, so after hot forging This eliminates the need for partial heat treatment to satisfy different required material properties at each part, thereby contributing to reduction in heat treatment cost and improvement in productivity.
また、素材ビレットにおける軸方向の熱伝導を利用し、素材ビレット各部位の温度を実測して、加熱手段もしくは加熱手段と冷却手段の出力を制御し、または素材ビレットを高周波コイルなどの加熱手段に対して、軸方向に相対的に移動させる、または出し入れするタイミングを決定するようにしたので、大掛かりな加熱手段や冷却手段を必要とせず、簡便かつ精度よく、要求材質特性に応じた軸方向の温度分布をつけることができる。 In addition, by utilizing the heat conduction in the axial direction of the material billet, the temperature of each part of the material billet is measured, the output of the heating means or the heating means and the cooling means is controlled, or the material billet is used as a heating means such as a high frequency coil. On the other hand, since the relative movement in the axial direction or the timing for taking in and out is determined, large heating means and cooling means are not required, and the axial direction according to the required material characteristics is simple and accurate. A temperature distribution can be given.
以下に、この発明の実施形態を添付の図１から図３に基づいて説明する。 Embodiments of the present invention will be described below with reference to the accompanying FIGS.
図１は、本願発明の素材ビレットの加熱方法を実施するために必要な加熱装置を、模式的に示したものである。直径Ｄｓ、長さＬｓの素材ビレット１は、エアシリンダなどの駆動手段２によって、昇降可能な台座３の上に、素材ビレット１の下端面Ｓｂの温度を測定するための空間部４を設けて、支持部材５を介して載置されている。加熱手段として、コイル内径Ｄｃおよび軸方向のコイル長さＬｃの高周波コイル６が素材ビレット１の外周側に配置され、コイル内径Ｄｃは、直径Ｄｓの素材ビレット１がその軸方向に相対的に移動できる大きさに形成されている。コイル長さＬｃは、通常、高温加熱部１ａの軸方向の長さすなわち加熱領域をＨＬとして、（ＨＬ−５ｍｍ）よりも長く形成されていればよい。これは、加熱領域ＨＬが高周波加熱コイルかから５ｍｍ程度突出していても、この突出域まで目標温度ＴＨａまで加熱されることによる。台座３には、素材ビレット１の軸方向の移動量を検知するための検針７が付設され、この検針７に近接して移動量の目盛板８が設置されている。台座３の昇降量すなわち素材ビレット１の軸方向の移動量は、この検針７と目盛板８により読み取ることができる。このように、素材ビレット１は、高温加熱部１ａからの軸方向の熱伝導により低温加熱部１ｂが加熱されて、所要の温度分布を実現することが可能となる。そして、必要に応じて加熱手段である高周波加熱コイル６に対して、素材ビレット１を軸方向に移動させて、または高周波コイル６に対して軸方向に移動させて一旦コイルの外に出した後、所要の時間経過後にコイル内に入れる出し入れを伴って、それぞれ加熱することができる。この素材ビレットを高周波加熱コイル６に対して軸方向に相対移動させて温度分布をつける加熱方法は、素材ビレット１が長尺の場合にとくに適した加熱方法である。また、前記高周波加熱コイル６の図示下方側に、高周波コイル６で直接加熱されない非加熱部（低温加熱部１ｂ）の温度制御を行なうために、気体や液体または気液混合ミストなど、これらの混合物を冷却媒体とする強制冷却装置を配置することもできる。なお、前記空間部４は必ずしも設ける必要はなく、この空間部４に相当するスペースに、ステンレス鋼などの熱伝導率が大きい非磁性金属部材、または熱伝導が小さい耐火物部材を敷くことにより、低温加熱部１ｂからのこれらの部材への熱移動量を変化させて、素材１の軸方向の温度分布を調節することができる。すなわち金属部材を敷く場合には熱移動量が大きくなって素材ビレット１の軸方向の温度分布を急峻側に調節することができ、逆に、耐火物部材を敷く場合には熱移動量が小さくなるため、素材ビレット１の軸方向の温度分布を緩慢側に調節することができる。この場合の低温加熱部１ｂの温度は、その外周面（側面）について測定することができる。さらに、素材ビレット１は移動させず、高周波加熱コイル６の方を軸方向に移動させて、温度分布をつけるようにすることもできる。上記の素材ビレットを軸方向に移動させる（高周波加熱コイルからの出し入れする場合を含む）加熱する方法は、素材ビレットの温度上昇曲線（温度上昇推移）を制御する場合などにも活用できる。そして、加熱手段として、前記高周波加熱コイル６の代わりに、対向する一対のガスバーナを複数対、素材ビレットの周方向および軸方向に配置し、ガス流量を調整することにより、加熱温度を制御することも可能である。この場合、軸方向に配置するガスバーナの容量を変化させて配置することもできる。前記高温加熱部１ａは、必ずしも素材ビレット１の上部に限るものではなく、鍛造品の形状や要求される材質特性によって、素材ビレット１の中央部や下部を加熱することも可能である。 FIG. 1 schematically shows a heating apparatus necessary for carrying out the heating method for a billet of the present invention. The material billet 1 having a diameter Ds and a length Ls is provided with a space 4 for measuring the temperature of the lower end surface Sb of the material billet 1 on a pedestal 3 that can be raised and lowered by a driving means 2 such as an air cylinder. It is placed via the support member 5. As a heating means, a high-frequency coil 6 having a coil inner diameter Dc and an axial coil length Lc is arranged on the outer peripheral side of the material billet 1, and the coil inner diameter Dc is moved relative to the material billet 1 having a diameter Ds in the axial direction. It is formed in a size that can be done. Coil length Lc is usually the length or the heating region in the axial direction of the high temperature heating portion 1a as H L, it may be formed longer than (H L -5mm). This is because even if the heating region HL protrudes from the high frequency heating coil by about 5 mm, the heating region HL is heated to the target temperature THa. The pedestal 3 is provided with a meter reading 7 for detecting the amount of movement of the billet 1 in the axial direction, and a scale plate 8 for the amount of movement is provided in the vicinity of the meter reading 7. The raising / lowering amount of the pedestal 3, that is, the movement amount of the material billet 1 in the axial direction can be read by the meter reading 7 and the scale plate 8. As described above, the billet 1 can realize the required temperature distribution by heating the low temperature heating portion 1b by the heat conduction in the axial direction from the high temperature heating portion 1a. Then, the material billet 1 is moved in the axial direction with respect to the high-frequency heating coil 6 which is a heating means as required, or is moved out of the coil once in the axial direction with respect to the high-frequency coil 6. Each of them can be heated with taking in and out of the coil after the required time has elapsed. The heating method for making the temperature distribution by moving the billet relative to the high-frequency heating coil 6 in the axial direction is a heating method particularly suitable when the billet 1 is long. Moreover, in order to perform temperature control of the non-heating part (low temperature heating part 1b) which is not directly heated by the high frequency coil 6 on the lower side of the high frequency heating coil 6, the mixture thereof such as gas, liquid or gas / liquid mixed mist It is also possible to arrange a forced cooling device using as a cooling medium. The space portion 4 is not necessarily provided, and a space corresponding to the space portion 4 is laid with a nonmagnetic metal member having a high thermal conductivity, such as stainless steel, or a refractory member having a low heat conductivity, The temperature distribution in the axial direction of the material 1 can be adjusted by changing the amount of heat transfer from the low-temperature heating unit 1b to these members. That is, when a metal member is laid, the amount of heat transfer is increased, and the temperature distribution in the axial direction of the material billet 1 can be adjusted to a steep side. Conversely, when a refractory member is laid, the amount of heat transfer is small. Therefore, the temperature distribution in the axial direction of the material billet 1 can be adjusted to the slow side. In this case, the temperature of the low-temperature heating unit 1b can be measured on the outer peripheral surface (side surface). Furthermore, the material billet 1 is not moved, but the high-frequency heating coil 6 can be moved in the axial direction to give a temperature distribution. The heating method of moving the material billet in the axial direction (including the case where the material billet is moved in and out of the high-frequency heating coil) can be used for controlling the temperature rise curve (temperature rise transition) of the material billet. And as a heating means, instead of the high-frequency heating coil 6, a plurality of pairs of gas burners facing each other are arranged in the circumferential direction and the axial direction of the material billet, and the heating temperature is controlled by adjusting the gas flow rate. Is also possible. In this case, the gas burner arranged in the axial direction can be arranged by changing its capacity. The high-temperature heating unit 1a is not necessarily limited to the upper part of the material billet 1, and the central part and the lower part of the material billet 1 can be heated depending on the shape of the forged product and the required material properties.
図２（ａ）および(ｂ)は、本願発明の加熱方法により、素材ビレット１の軸方向に温度分布をつける一例を模式的に示したものである。また、図３は、素材ビレットの軸方向に温度分布をつける前記の加熱方法における温度制御の流れを示したものである。この加熱方法では、鍛造後すなわち鍛造品各部位での要求材質特性に応じて、素材ビレット１の図示上部側は、例えば、被削性向上を目的とした結晶粒粗大化のために高温加熱を、同図示下部側は、例えば、高強度を目的とした結晶粒微細化のための低温加熱をそれぞれ行う。まず、高周波加熱コイル６の図示下側の端部コイルが、素材ビレット１の高温加熱部１ａと低温加熱部１ｂの境界Ｂ付近に位置するように、駆動装置２により台座３を昇降させる。そして、高温加熱部の目標加熱温度ＴＨａに対して、高周波コイル６の電流および電圧を設定し、通電する（Ｓ１０）。高温加熱部１ａの温度ＴＨは、高周波加熱により均一に加熱される軸方向の中央部Ｃの温度を放射温度計などの測温手段により測定する（Ｓ２０）。高温加熱部の温度ＴＨが、図２（ｂ）に模式的に示したように、高温側目標温度ＴＨａに到達すると（Ｓ３０）、高周波コイル６の通電量をＯＮ−ＯＦＦ制御または通電量（出力）自体を制御する(Ｓ４０)。そして、図２（ｂ）に模式的に温度推移を示したように、高温加熱部１ａからの軸方向の熱伝導により加熱される低温加熱部１ｂの最も温度が低い下端面Ｓｂの中央部Ｅの温度ＴＬを接触式温度計により測定する（Ｓ５０）。この低温加熱部１ｂが目標加熱温度ＴＬａに到達しているかどうかを判定し（Ｓ６０）、到達した時点で、所要の温度分布をつけた目標鍛造温度への加熱が終了したと判断し、高周波加熱コイル６の電源をＯＦＦにする（Ｓ７０）。このときの素材ビレット１の温度分布は、図２（ａ）に模式的に示したような近似温度分布で表すことができ、低温加熱部１ｂでは軸方向に温度勾配が存在する。このため、低温加熱部１ｂが高強度を目的としている場合には、この温度勾配の高温側（高温加熱部１ａとの境界域Ｂ）が目標強度を満たすように、低温加熱部１ｂの温度測定位置における目標温度ＴＬａを設定することが望ましい。また、低温加熱部１ｂの温度測定を、素材ビレット１の側面で行なう場合には、下端面Ｓｂから軸方向に１ｍｍ以上、（Ｌｓ／２−１）ｍｍ以下の所要の位置で温度測定をすることができる。そして、素材ビレット１を速やかに加熱装置から取り出して、鍛造装置へ供給する（Ｓ８０）。一方、低温加熱部１ｂが目標加熱温度ＴＬａに到達していない場合（Ｓ６０）、高周波加熱コイル６のＯＮ−ＯＦＦ制御または出力制御により、高温加熱部１ａの温度を目標加熱温度ＴＨａに保持しながら、所定の時間Ｓ後（Ｓ秒後）に（Ｓ９０）、再度低温加熱部１ｂの温度ＴＬを測定する（Ｓ５０）。以下、低温加熱部１ｂが目標加熱温度ＴＬａに到達するまで、これらのステップを繰り返す。 2A and 2B schematically show an example in which a temperature distribution is provided in the axial direction of the material billet 1 by the heating method of the present invention. FIG. 3 shows the flow of temperature control in the above heating method for providing a temperature distribution in the axial direction of the billet. In this heating method, after the forging, that is, according to the required material characteristics in each part of the forged product, the upper part of the material billet 1 shown in the drawing is heated at a high temperature for the purpose of, for example, grain coarsening for the purpose of improving machinability. The lower side of the figure performs, for example, low-temperature heating for refining crystal grains for the purpose of high strength. First, the pedestal 3 is moved up and down by the drive device 2 so that the lower end coil of the high-frequency heating coil 6 is positioned in the vicinity of the boundary B between the high-temperature heating unit 1a and the low-temperature heating unit 1b of the material billet 1. And the electric current and voltage of the high frequency coil 6 are set with respect to the target heating temperature THa of a high temperature heating part, and it supplies with electricity (S10). The temperature TH of the high-temperature heating unit 1a is measured by temperature measuring means such as a radiation thermometer at the temperature in the central portion C in the axial direction that is uniformly heated by high-frequency heating (S20). When the temperature TH of the high temperature heating part reaches the high temperature side target temperature THa as schematically shown in FIG. 2B (S30), the energization amount of the high frequency coil 6 is controlled by ON-OFF control or energization amount (output). ) Itself is controlled (S40). Then, as schematically shown in FIG. 2 (b), the central portion E of the lower end surface Sb having the lowest temperature of the low temperature heating unit 1b heated by the axial heat conduction from the high temperature heating unit 1a. The temperature TL is measured with a contact-type thermometer (S50). It is determined whether or not the low-temperature heating unit 1b has reached the target heating temperature TLa (S60), and when it reaches, it is determined that the heating to the target forging temperature with the required temperature distribution has been completed, and high-frequency heating is performed. The power supply of the coil 6 is turned off (S70). The temperature distribution of the material billet 1 at this time can be expressed by an approximate temperature distribution as schematically shown in FIG. 2A, and a temperature gradient exists in the axial direction in the low-temperature heating unit 1b. For this reason, when the low temperature heating part 1b aims at high intensity | strength, the temperature measurement of the low temperature heating part 1b is carried out so that the high temperature side (boundary area B with the high temperature heating part 1a) of this temperature gradient may satisfy | fill target intensity | strength. It is desirable to set the target temperature TLa at the position. When the temperature of the low-temperature heating unit 1b is measured on the side surface of the material billet 1, the temperature is measured at a required position of 1 mm or more and (Ls / 2-1) mm or less in the axial direction from the lower end surface Sb. be able to. Then, the billet 1 is quickly taken out from the heating device and supplied to the forging device (S80). On the other hand, when the low temperature heating unit 1b has not reached the target heating temperature TLa (S60), the temperature of the high temperature heating unit 1a is maintained at the target heating temperature THa by ON-OFF control or output control of the high frequency heating coil 6. After a predetermined time S (after S seconds) (S90), the temperature TL of the low-temperature heating unit 1b is measured again (S50). Hereinafter, these steps are repeated until the low-temperature heating unit 1b reaches the target heating temperature TLa.
次に、高温加熱部１ａの温度ＴＨが目標加熱温度ＴＨａに到達していない場合（Ｓ３０）、高周波加熱コイル６の通電を継続しながら、低温加熱部１ｂの温度ＴＬを測定する（Ｓ１００）。そして、低温加熱部１ｂが目標加熱温度ＴＬａに到達しているかどうかを判定する（Ｓ１１０）。目標加熱温度ＴＬａに到達している場合、低温加熱部１ｂの下端面Ｓｂの前記位置Ｅの温度を測定しながら、必要に応じて、前述の冷却手段により、その出力を制御して低温加熱部１ｂの表面を強制冷却し、低温加熱部１ｂの下端面Ｓｂの温度を目標加熱温度ＴＬａに保持する（Ｓ１２０）。さらに、高温加熱部１ａの温度ＴＨが所定の加熱時間内に目標加熱温度ＴＨａに到達するように、高周波加熱コイル６の電流・電圧設定値を上げ（Ｓ１３０）、所定の時間Ｓ後（Ｓ秒後）に（Ｓ１４０）、高温加熱部１ａの温度ＴＨを再度測定する（Ｓ２０）。そして、高温加熱部１ａの温度ＴＨが目標加熱温度ＴＨａに到達すると、既に低温加熱部１ｂは目標加熱温度ＴＬａに到達しているため、高周波コイル６の電源をＯＦＦにするとともに、低温加熱部１ｂの表面の強制冷却を終了し、素材ビレット１を速やかに加熱装置から取り出して、鍛造装置へ供給する（Ｓ８０）。前記ステップＳ１１０で、低温加熱部１ｂが目標加熱温度ＴＬａに到達していない場合、高周波加熱コイル６の通電を継続し、所定の時間Ｓ後（Ｓ秒後）に（Ｓ１４０）、高温加熱部１ａの温度ＴＨを再度測定する（Ｓ２０）。以下、高温加熱部１ａおよび低温加熱部１ｂがそれぞれ目標加熱温度ＴＨａおよびＴＬａに到達するまで、上記のステップが繰り返される。なお、高温加熱部１ａの温度ＴＨを測定した後（Ｓ２０）、高温加熱部１ａの温度が目標温度ＴＨａに到達する前に、必要に応じて、素材１を一旦高周波コイル６の外（下方または上方）に引き出して、所要時間が経過した後、高周波加熱コイル６の内に入れて、再加熱することにより、素材ビレット１の温度分布、とくに高温加熱部１ａの断面内の温度差を小さくして均熱度を向上させることができる。 Next, when the temperature TH of the high temperature heating unit 1a has not reached the target heating temperature THa (S30), the temperature TL of the low temperature heating unit 1b is measured while energization of the high frequency heating coil 6 is continued (S100). And it is determined whether the low temperature heating part 1b has reached | attained target heating temperature TLa (S110). If the target heating temperature TLa has been reached, the temperature at the position E of the lower end surface Sb of the low-temperature heating unit 1b is measured and the output is controlled by the cooling means as necessary to control the output of the low-temperature heating unit. The surface of 1b is forcibly cooled, and the temperature of the lower end surface Sb of the low-temperature heating unit 1b is maintained at the target heating temperature TLa (S120). Further, the current / voltage set value of the high-frequency heating coil 6 is increased so that the temperature TH of the high-temperature heating unit 1a reaches the target heating temperature THa within a predetermined heating time (S130), and after a predetermined time S (S seconds). After (S140), the temperature TH of the high-temperature heating unit 1a is measured again (S20). When the temperature TH of the high-temperature heating unit 1a reaches the target heating temperature THa, the low-temperature heating unit 1b has already reached the target heating temperature TLa, so that the power of the high-frequency coil 6 is turned off and the low-temperature heating unit 1b The surface is forcedly cooled, and the billet 1 is quickly removed from the heating device and supplied to the forging device (S80). If the low-temperature heating unit 1b has not reached the target heating temperature TLa in step S110, the energization of the high-frequency heating coil 6 is continued, and after a predetermined time S (after S seconds) (S140), the high-temperature heating unit 1a. The temperature TH is again measured (S20). Hereinafter, the above steps are repeated until the high temperature heating unit 1a and the low temperature heating unit 1b reach the target heating temperatures THa and TLa, respectively. In addition, after measuring the temperature TH of the high temperature heating unit 1a (S20), before the temperature of the high temperature heating unit 1a reaches the target temperature THa, the material 1 is temporarily removed from the high frequency coil 6 (downward or After the required time elapses, it is placed in the high frequency heating coil 6 and reheated to reduce the temperature distribution of the material billet 1, particularly the temperature difference in the cross section of the high temperature heating part 1 a. The soaking degree can be improved.
直径がΦ５０ｍｍおよびΦ１０５ｍｍで、長さが１００ｍｍの炭素鋼（Ｓ４５Ｃ）の素材ビレットを、結晶粒粗大化を目的として高温加熱部の目標加熱温度ＴＨａ≧１１００℃、高強度化を目的として低温加熱部の目標加熱温度ＴＬａ≦７００℃として、内径１１０ｍｍ、長さ５０ｍｍの高周波加熱コイルで、図１および図２（ａ）に示した加熱装置および加熱方法により、素材ビレット１の上端面Ｓｔから軸方向に所定の位置までの加熱位置を１８０sec加熱した。No.3およびNo.4の素材ビレット（Φ５０ｍｍ）については、２段階加熱を行なった。すなわち、No.3素材ビレットでは、第１段階で素材ビレット１の上端面から２５ｍｍまでの加熱位置を９０ｓ加熱した後、第２段階では、台座３（図１参照）を上昇させて、前記上端面Ｓｔから５０ｍｍの位置までの加熱位置を９０ｓ加熱し、第１および第２段階合計で、１８０ｓの加熱を行なった。高温加熱部１ａの温度は、前記加熱位置の軸方向の中央部（上端面Ｓｔから２５ｍｍの位置）の表面（外周面）温度を放射温度計により測定し、中心温度は、予め取付けた熱電対により測定した。一方、高温加熱部１ａからの軸方向の熱伝導により加熱される低温加熱部１ｂの温度については、下端面Ｓｂから軸方向に２．５ｍｍ入った位置の表面（外周面）温度を放射温度計により、中心温度を予め取付けた熱電対により測定した。なお、本実施例では低温加熱部の強制冷却は行なっていない。 A billet of carbon steel (S45C) having a diameter of Φ50 mm and Φ105 mm and a length of 100 mm, a target heating temperature THa ≧ 1100 ° C. of a high-temperature heating unit for the purpose of grain coarsening, and a low-temperature heating unit for the purpose of increasing strength A high-frequency heating coil having an inner diameter of 110 mm and a length of 50 mm with a target heating temperature of TLa ≦ 700 ° C., and the axial direction from the upper end surface St of the material billet 1 by the heating apparatus and heating method shown in FIGS. The heating position up to a predetermined position was heated for 180 seconds. No. 3 and No. 4 material billets (Φ50 mm) were subjected to two-stage heating. That is, in the No. 3 material billet, the heating position from the upper end surface of the material billet 1 to 25 mm is heated for 90 s in the first stage, and then the base 3 (see FIG. 1) is raised in the second stage, The heating position from the end face St to the position of 50 mm was heated for 90 s, and heating was performed for 180 s in total in the first and second stages. The temperature of the high-temperature heating part 1a is measured by measuring the surface (outer peripheral surface) temperature of the central part (position 25 mm from the upper end surface St) in the axial direction of the heating position with a radiation thermometer. It was measured by. On the other hand, for the temperature of the low temperature heating part 1b heated by the axial heat conduction from the high temperature heating part 1a, the surface (outer peripheral surface) temperature at a position 2.5 mm in the axial direction from the lower end surface Sb is the radiation thermometer. The center temperature was measured with a thermocouple attached in advance. In this embodiment, forced cooling of the low temperature heating part is not performed.
表１に示した測温値から、素材ビレットの直径がΦ５０ｍｍの場合には、第１段階のみで１８０ｓの加熱を行なう場合（No.1）、第１段階および第２段階の２段加熱を行なった場合のいずれも、高温加熱部からの軸方向の熱伝導を利用して、要求材質特性（結晶粒粗大化と高強度化）に応じて、軸方向に温度分布をつけて前記の目標鍛造温度に加熱できることがわかる。１段階加熱の場合（No.1）と２段階加熱の場合（No.3,No.4）を比較すると、高温加熱部１ａでの加熱状態は同様であるが、２段階加熱の方が低温加熱部１ｂの温度をより低くでき、素材ビレット１の軸方向により大きい温度分布をつける必要がある場合に適している。一方、素材ビレット１の直径がΦ１０５ｍｍの場合、断面寸法が大きいために、高温加熱部１ａにおいて、加熱中における表面から中心部への熱伝導が十分ではないことによって中心部の温度が低く、高温加熱部１ａの全断面内で目標加熱温度を満足していない。これに伴って、軸方向の熱伝導により加熱される低温加熱部１ｂも表面から中心部への熱伝導が十分でなく、表面温度の高い状態が残存し、低温加熱部１ｂでも全断面内で目標加熱温度を満足していない。 From the temperature measurement values shown in Table 1, when the diameter of the billet is Φ50 mm, when heating for 180 s only in the first stage (No. 1), two-stage heating in the first stage and the second stage is performed. In any case, the above-mentioned target is obtained by applying a temperature distribution in the axial direction according to the required material characteristics (grain coarsening and high strength) using the axial heat conduction from the high-temperature heating section. It can be seen that it can be heated to the forging temperature. Comparing the case of one-step heating (No. 1) and the case of two-step heating (No. 3, No. 4), the heating state in the high-temperature heating section 1a is the same, but the two-step heating is lower in temperature. This is suitable when the temperature of the heating unit 1b can be lowered and a larger temperature distribution is required in the axial direction of the material billet 1. On the other hand, when the diameter of the material billet 1 is Φ105 mm, since the cross-sectional dimension is large, in the high-temperature heating part 1a, the heat conduction from the surface to the center part during heating is not sufficient, the temperature of the center part is low, and the high temperature The target heating temperature is not satisfied within the entire cross section of the heating unit 1a. Along with this, the low-temperature heating part 1b heated by the axial heat conduction also has insufficient heat conduction from the surface to the center part, and the surface temperature remains high, and even the low-temperature heating part 1b is within the entire cross section. The target heating temperature is not satisfied.
なお、高温加熱部の加熱は、高周波加熱コイルに限らず、素材ビレットの周りに、対向する１対のバーナーを、必要に応じて周方向および軸方向に複数対配置して、高温加熱部の加熱手段とすることもできる。また、軸方向に配置するバーナーの容量を変化させることもできる。さらに、素材ビレットの軸方向につける温度分布の基準となる要求材質特性は、必ずしも結晶粒度の粗大化や高強度に限らず、例えば、Ｖ、Ｎｂ、Ｔｉなどの元素の添加による析出強化を利用した高強度化の場合などにも、軸方向に温度分布をつけて目標鍛造温度に加熱することが必要となり、上記加熱方法を適用することができる。 The heating of the high-temperature heating unit is not limited to the high-frequency heating coil, and a plurality of pairs of opposing burners are arranged around the material billet in the circumferential direction and the axial direction as necessary, It can also be a heating means. Moreover, the capacity | capacitance of the burner arrange | positioned to an axial direction can also be changed. Furthermore, the required material properties that are the basis for the temperature distribution applied in the axial direction of the billet are not necessarily limited to coarse crystal grains and high strength. For example, precipitation strengthening by adding elements such as V, Nb, and Ti is used. Also in the case of increasing the strength, it is necessary to heat the target forging temperature with a temperature distribution in the axial direction, and the above heating method can be applied.
直径がΦ９５ｍｍで、長さが１００ｍｍの炭素鋼（Ｓ４５Ｃ）の素材ビレットを、結晶粒粗大化のための高温加熱部における均熱化（ΔＴ≦５０℃）を目的として、内径１１０ｍｍ、長さ５０ｍｍの高周波加熱コイルで、図１および図２（ａ）に示した加熱装置および加熱方法により、素材ビレット１の上端面Ｓｔから軸方向に５０ｍｍまでの加熱位置を、合計１８０sec加熱した。No.1の素材ビレット１については、加熱開始後９０ｓ経過した時点で、エアシリンダ２により台座３を下降させて素材ビレット１の上端面Ｓｔを、一旦高周波加熱コイル６の外（下方）に５ｓ間出した後、台座３を上昇させて素材ビレット１を加熱開始時の位置に戻して、さらに９０ｓ、すなわち合計で１８０ｓ加熱した。No.２の素材ビレット１については、No.1の素材ビレット１と同様の加熱位置を、加熱開始時から、高周波加熱コイル６から出し入れせずに、１８０ｓ加熱した。高温加熱部１ａの温度は、前記加熱位置の軸方向の中央の位置（上端面Ｓｔから２５ｍｍの位置）で、表面（外周面）温度を放射温度計により測定し、中心温度は、予め取付けた熱電対により測定した。一方、高温加熱部１ａからの軸方向の熱伝導により加熱される低温加熱部１ｂの温度については、下端面Ｓｔから軸方向に２．５ｍｍ入った位置の表面（外周面）温度を放射温度計により、中心温度を予め取付けた熱電対により測定した。なお、本実施例では低温加熱部の強制冷却は行なっていない。表２に温度測定結果を示す。 A material billet of carbon steel (S45C) having a diameter of Φ95 mm and a length of 100 mm is used for the purpose of temperature equalization (ΔT ≦ 50 ° C.) in a high-temperature heating section for crystal grain coarsening, an inner diameter of 110 mm, and a length of 50 mm. The heating position from the upper end surface St of the material billet 1 to 50 mm in the axial direction was heated for a total of 180 seconds using the high frequency heating coil of FIG. 1 and the heating method and heating method shown in FIG. For the No. 1 material billet 1, 90 seconds after the start of heating, the pedestal 3 is lowered by the air cylinder 2 so that the upper end surface St of the material billet 1 is once outside (lower) the high frequency heating coil 6 for 5 s. After the removal, the pedestal 3 was raised and the material billet 1 was returned to the position at the start of heating, and further heated for 90 seconds, that is, 180 seconds in total. For the material billet 1 of No. 2, the same heating position as that of the material billet 1 of No. 1 was heated for 180 seconds without being taken in and out of the high-frequency heating coil 6 from the start of heating. The temperature of the high-temperature heating unit 1a is the center position in the axial direction of the heating position (position of 25 mm from the upper end surface St), the surface (outer peripheral surface) temperature is measured with a radiation thermometer, and the center temperature is attached in advance. Measured with a thermocouple. On the other hand, as for the temperature of the low temperature heating part 1b heated by the axial heat conduction from the high temperature heating part 1a, the surface (outer peripheral surface) temperature at a position 2.5 mm in the axial direction from the lower end surface St is a radiation thermometer. The center temperature was measured with a thermocouple attached in advance. In this embodiment, forced cooling of the low temperature heating part is not performed. Table 2 shows the temperature measurement results.
表２から、No.1およびNo.2素材ビレットの低温加熱部の表面温度および断面内温度差ΔＴ（＝表面温度−中心温度）は、ほぼ同様であるが、高温加熱部では、出し入れを行なったNo.1素材ビレットの断面内温度差ΔＴ＝３５℃に対して、出し入れを行なわずに加熱したNo.2素材ビレットではΔＴ＝８０℃と大きく、No.1素材ビレットの方が目標とした均熱化を達成できていることがわかる。このように、加熱過程で、素材ビレットを高周波加熱コイルから出し入れすることにより、高温加熱部の均熱化を実現することができる。 From Table 2, the surface temperature and the cross-sectional temperature difference ΔT (= surface temperature−center temperature) of the No. 1 and No. 2 billets are almost the same, but in the high temperature heating part, it is taken in and out. Compared to the temperature difference ΔT = 35 ° C in the cross section of the No.1 material billet, the No.2 material billet heated without taking in and out is as large as ΔT = 80 ° C. It can be seen that soaking has been achieved. In this way, it is possible to achieve soaking of the high-temperature heating section by taking the material billet into and out of the high-frequency heating coil during the heating process.
１：素材ビレット １ａ：高温加熱部 １ｂ：低温加熱部
２：駆動手段 ３：台座 ４：空間部
５：支持部材 ６：高周波加熱コイル ７：検針
８：目盛版
1: Material billet 1a: High temperature heating part 1b: Low temperature heating part 2: Driving means 3: Pedestal 4: Space part 5: Support member 6: High frequency heating coil 7: Meter reading 8: Scale plate
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| JP2012532028A (en) * | 2009-07-04 | 2012-12-13 | インダクトヒート インコーポレイテッド | Inductive electrical energy application for the production of deformed shafts with cylindrical components including crankshafts and camshafts that are non-integrally forged |
| CN106001345A (en) * | 2016-06-20 | 2016-10-12 | 安徽省瑞杰锻造有限责任公司 | Forging technology for Cr12MoV torsion rollers |
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|---|---|---|---|---|
| JPH04351241A (en) * | 1991-02-25 | 1992-12-07 | Kobe Steel Ltd | Method for plastic-working hard to-work material |
| JPH0776737A (en) * | 1993-09-07 | 1995-03-20 | Osaka Gas Co Ltd | Billet heating furnace |
| JP2001239345A (en) * | 2000-02-29 | 2001-09-04 | Sanyo Special Steel Co Ltd | Manufacturing method and apparatus for high precision inner surface deep-slot ring blank |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04351241A (en) * | 1991-02-25 | 1992-12-07 | Kobe Steel Ltd | Method for plastic-working hard to-work material |
| JPH0776737A (en) * | 1993-09-07 | 1995-03-20 | Osaka Gas Co Ltd | Billet heating furnace |
| JP2001239345A (en) * | 2000-02-29 | 2001-09-04 | Sanyo Special Steel Co Ltd | Manufacturing method and apparatus for high precision inner surface deep-slot ring blank |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2012532028A (en) * | 2009-07-04 | 2012-12-13 | インダクトヒート インコーポレイテッド | Inductive electrical energy application for the production of deformed shafts with cylindrical components including crankshafts and camshafts that are non-integrally forged |
| CN106001345A (en) * | 2016-06-20 | 2016-10-12 | 安徽省瑞杰锻造有限责任公司 | Forging technology for Cr12MoV torsion rollers |
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