JPH0873932A - Method for heat-treating steel for machine structure - Google Patents
Method for heat-treating steel for machine structureInfo
- Publication number
- JPH0873932A JPH0873932A JP23403894A JP23403894A JPH0873932A JP H0873932 A JPH0873932 A JP H0873932A JP 23403894 A JP23403894 A JP 23403894A JP 23403894 A JP23403894 A JP 23403894A JP H0873932 A JPH0873932 A JP H0873932A
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- Prior art keywords
- steel
- heat treatment
- machine structure
- hot
- hot water
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Heat Treatment Of Steel (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、熱間鍛造した機械構造
用鋼材の熱処理方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment method for hot forged machine structural steel.
【０００２】[0002]
【従来の技術】従来、熱間鍛造した機械構造用鋼材の材
質を改質、すなわち、硬化処理するための熱処理方法と
して、 (1) 再加熱した後、焼入れ、焼もどし処理を行う方法 (2) 熱間鍛造時の自熱を利用した焼入れ、焼もどし処理
を行う方法 (3) 非調質鋼（バナジウム鋼）を用いた析出硬化による
方法 (4) 高炭素量の鋼材を用い、熱間鍛造時の自熱を利用し
た鍛造自熱調質による方法 等が採用されている。2. Description of the Related Art Conventionally, as a heat treatment method for modifying, that is, hardening treatment of the material of a hot forged machine structural steel material, (1) a method of carrying out quenching and tempering treatment after reheating (2) ) A method of quenching and tempering using self-heating during hot forging (3) A method of precipitation hardening using non-heat treated steel (vanadium steel) (4) Using a high carbon content steel For example, a method of tempering forging by using self-heating during forging is adopted.
【０００３】ところで、上記(1)〜(4)の熱処理に要する
コストは、一般的には、(1)＞(2)＞(3)＞(4)の順となる
が、(1)及び(2)の焼入れ、焼もどし処理を行う方法の場
合、処理コストが高くなるほか、焼入れを行う場合の水
温又は油温の精密な制御が必要になる等、均質な材質を
得るためには、高度な処理技術及び設備を必要とすると
いう問題点を有していた。また、(3)の非調質鋼（バナ
ジウム鋼）を用いる方法及び(4)の高炭素量の鋼材を用
いる方法は、処理コストは低廉にできるものの、材料の
硬度や引張強度を上げようとすると、被切削性や靭性が
著しく損なわれることになるとともに、特に、(3)の非
調質鋼（バナジウム鋼）を用いる方法の場合、材料自体
のコストが高くなるという問題点を有していた。By the way, the costs required for the above heat treatments (1) to (4) are generally in the order of (1)>(2)>(3)> (4). In the case of the method of performing quenching and tempering of (2), in addition to increasing the processing cost, it is necessary to precisely control the water temperature or oil temperature when performing quenching, in order to obtain a homogeneous material, It had a problem that it required advanced processing technology and equipment. In addition, although the treatment cost can be reduced by the method of using non-heat treated steel (vanadium steel) of (3) and the method of using steel material of high carbon content of (4), it is attempted to increase the hardness and tensile strength of the material. Then, the machinability and toughness are significantly impaired, and in particular, in the case of the method (3) using the non-heat treated steel (vanadium steel), the cost of the material itself is high. It was
【０００４】[0004]
【発明が解決しようとする課題】本発明は、上記従来の
熱間鍛造した機械構造用鋼材の熱処理方法の有する問題
点を解決し、材料の被切削性や靭性を損なうことなく、
所定の硬度や引張強度を得ることができ、かつ処理コス
トの低廉な全く新規な機械構造用鋼材の熱処理方法を提
供することを目的とする。SUMMARY OF THE INVENTION The present invention solves the problems of the conventional heat treatment method for hot forged machine structural steel, and does not impair the machinability and toughness of the material.
It is an object of the present invention to provide a completely new heat treatment method for a steel material for machine structural use, which can obtain predetermined hardness and tensile strength and has a low treatment cost.
【０００５】[0005]
【課題を解決するための手段】上記目的を達成するた
め、本発明の機械構造用鋼材の熱処理方法は、熱間鍛造
した機械構造用鋼材を熱間のオーステナイト化状態で９
８〜１００℃の熱湯に浸漬して機械構造用鋼材の温度を
熱湯の温度近傍まで冷却することを要旨とする。上記機
械構造用鋼材としては、各種の機械構造用炭素鋼鋼材や
機械構造用合金鋼、例えば、ニッケルクロム鋼鋼材、ニ
ッケルクロムモリブデン鋼鋼材、クロム鋼鋼材、クロム
モリブデン鋼鋼材などを用いることができる。In order to achieve the above object, the heat treatment method for a steel for machine structural use according to the present invention is performed by hot forging a machine structural steel in a hot austenitized state.
The gist is to immerse in a hot water of 8 to 100 ° C. and cool the temperature of the steel for machine structure to a temperature close to the temperature of the hot water. As the steel material for machine structure, various carbon steel materials for machine structure or alloy steel for machine structure, for example, nickel chrome steel material, nickel chrome molybdenum steel material, chrome steel steel material, chrome molybdenum steel material, etc. can be used. .
【０００６】[0006]
【作用】熱間鍛造した機械構造用鋼材を冷却することな
く熱間のオーステナイト化状態のままで９８〜１００℃
の熱湯に浸漬して、機械構造用鋼材の表面が常に蒸気膜
で覆われた状態で機械構造用鋼材の温度を熱湯の温度９
８〜１００℃近傍まで冷却する。この場合において、機
械構造用鋼材の冷却媒体として９８〜１００℃の熱湯を
使用することにより、従来の熱処理方法において冷却媒
体として使用している冷水又は油水の場合のような精密
な温度制御が不要となり、また、冷却時、機械構造用鋼
材の表面が常に蒸気膜で覆われた状態に保持されること
と合わせて、安定した状態で熱処理を行うことができ
る。Operation: Hot forging machine structural steel is not cooled but is hot austenitized at 98 to 100 ° C.
Immersed in the hot water of the machine structure, the temperature of the steel for the machine structure is 9
Cool to near 8-100 ° C. In this case, by using hot water of 98 to 100 ° C. as the cooling medium of the steel for machine structure, precise temperature control is not required unlike the case of cold water or oil water used as the cooling medium in the conventional heat treatment method. Further, during cooling, the surface of the steel material for machine structure is always kept in a state of being covered with the vapor film, and the heat treatment can be performed in a stable state.
【０００７】[0007]
【実施例】以下、本発明を実施例に基づいて説明する。
図１は、一般的な機械構造用炭素鋼鋼材であるＳ４０Ｃ
炭素鋼鋼材を使用し、熱間鍛造により図２に示す形状の
フランジ部Ｆとシャフト部Ｓとからなるスピンドルナッ
クル１を成形した後、このスピンドルナックル１を冷却
することなくそのまま熱間のオーステナイト化状態の温
度、本実施例においては約８５０℃の温度で、９８〜１
００℃の熱湯に浸漬して、スピンドルナックル１の表面
が常に蒸気膜で覆われた状態でスピンドルナックル１の
温度を熱湯の温度近傍まで冷却した場合の連続冷却変態
図（Ｃ．Ｃ．Ｔ．曲線）を示す。EXAMPLES The present invention will be described below based on examples.
Fig. 1 shows S40C which is a general carbon steel material for machine structure.
A carbon steel material is used to form a spindle knuckle 1 including a flange portion F and a shaft portion S having a shape shown in FIG. 2 by hot forging, and then the spindle knuckle 1 is hot austenitized without being cooled. 98-1 at the temperature of the state, in this example at a temperature of about 850 ° C.
Continuous cooling transformation diagram (C.C.T.C.) when the temperature of the spindle knuckle 1 is cooled to near the temperature of the hot water while the surface of the spindle knuckle 1 is always covered with a vapor film by being immersed in hot water of 00.degree. Curve).
【０００８】機械構造用鋼材を冷却することなく熱間の
オーステナイト化状態のままで９８〜１００℃の熱湯に
浸漬して、機械構造用鋼材の表面が常に蒸気膜で覆われ
た状態で機械構造用鋼材の温度を熱湯の温度９８〜１０
０℃近傍まで冷却すると、水焼入れと完全焼なましのほ
ぼ中間の冷却速度（対数時間軸）を有することが明らか
となった。The mechanical structure steel material is immersed in hot water of 98 to 100 ° C. in the hot austenitized state without cooling, and the mechanical structure steel material surface is always covered with a vapor film. The temperature of the steel material is 98 to 10
It became clear that when cooled to near 0 ° C., it had a cooling rate (logarithmic time axis) that was almost intermediate between water quenching and complete annealing.
【０００９】このようにして熱処理を行ったスピンドル
ナックルの性状を調べるため、硬さ試験及び金属組織の
顕微鏡による写真撮影を行った。In order to investigate the properties of the spindle knuckle thus heat-treated, a hardness test and a microscopic photograph of the metal structure were taken.
【００１０】図３は、スピンドルナックル１のシャフト
部Ｓの図２におけるＩーＩ断面のブリネルくぼみ径［Ｈ
ＢＤ］を示し、（ａ）は本発明の機械構造用鋼材の熱処
理方法を実施した場合を、（ｂ）はそのまま空冷（完全
焼なまし）した場合を示す。この図からも明らかなよう
に、本発明の機械構造用鋼材の熱処理方法を実施した場
合、スピンドルナックル１のシャフト部Ｓの中心部Ｓo
で４．１０［ＨＢＤ］（２２８［ＨＶ］）、周辺部Ｓc
で４．００〜３．９５［ＨＢＤ］（２４１〜２４７［Ｈ
Ｖ］）の硬度が得られ、そのまま空冷（完全焼なまし）
した場合のスピンドルナックルのシャフト部Ｓの中心部
Ｓoで４．４０［ＨＢＤ］（１９６［ＨＶ］）、周辺部
Ｓcで４．４０［ＨＢＤ］（１９６［ＨＶ］）の硬度と
比較して、実用上十分な硬度となっていることがわかっ
た。FIG. 3 is a Brinell recess diameter [H] of the shaft portion S of the spindle knuckle 1 taken along the line II in FIG.
BD], (a) shows a case where the heat treatment method for a steel material for machine structure of the present invention is carried out, and (b) shows a case where it is air-cooled (completely annealed) as it is. As is clear from this figure, when the heat treatment method for steel for machine structure of the present invention is carried out, the central portion So of the shaft portion S of the spindle knuckle 1 is
4.10 [HBD] (228 [HV]), peripheral area Sc
4.00 to 3.95 [HBD] (241 to 247 [H
V]) hardness is obtained, and it is air-cooled as it is (completely annealed)
Compared with the hardness of 4.40 [HBD] (196 [HV]) at the central portion So of the shaft portion S of the spindle knuckle and 4.40 [HBD] (196 [HV]) at the peripheral portion Sc, It was found that the hardness was practically sufficient.
【００１１】図４及び図５は、スピンドルナックル１に
本発明の機械構造用鋼材の熱処理方法を実施した場合の
金属組織を示す顕微鏡写真であり、図４（ａ）はフラン
ジ部Ｆの表面部Ｆ1、（ｂ）はその内部Ｆ2、図５（ａ）
はシャフト部Ｓの表面部Ｓ1、（ｂ）はその内部Ｓ2の金
属組織を示す。また、図６及び図７は、スピンドルナッ
クル１をそのまま空冷（完全焼なまし）した場合の金属
組織を示す顕微鏡写真であり、図６（ａ）はフランジ部
Ｆの表面部Ｆ1、（ｂ）はその内部Ｆ2、図７（ａ）はシ
ャフト部Ｓの表面部Ｓ1、（ｂ）はその内部Ｓ2の金属組
織を示す。この図からも明らかなように、本発明の機械
構造用鋼材の熱処理方法を実施した場合、そのまま空冷
（完全焼なまし）した場合と比較して、フェライト（写
真の白色部分）が少なく、かつ、均質な結晶構造となっ
ていることがわかった。FIGS. 4 and 5 are photomicrographs showing the metallographic structure of the spindle knuckle 1 when the heat treatment method for steel for machine structural use of the present invention is carried out, and FIG. F1, (b) is the inside F2, Fig. 5 (a)
Shows the metal structure of the surface S1 of the shaft S, and (b) shows the metal structure of the inside S2. 6 and 7 are photomicrographs showing the metal structure when the spindle knuckle 1 is air-cooled (completely annealed) as it is, and FIG. 6 (a) is a surface portion F1 of the flange portion F, (b). Shows the inside F2, FIG. 7 (a) shows the surface S1 of the shaft S, and FIG. 7 (b) shows the metal structure of the inside S2. As is clear from this figure, in the case where the heat treatment method for a steel material for machine structure of the present invention was carried out, as compared with the case where it was air-cooled (completely annealed) as it was, less ferrite (white portion in the photograph), and It was found that the crystal structure was homogeneous.
【００１２】このように、機械構造用鋼材に対して本発
明の機械構造用鋼材の熱処理方法を実施した場合に、実
用上十分な硬度と均質な結晶構造を得ることができるの
は、機械構造用鋼材の冷却媒体として９８〜１００℃の
熱湯を使用することにより、冷却時、機械構造用鋼材の
表面が常に蒸気膜で覆われた状態に保持され、これにに
より、安定した状態で熱処理が行われるためである。As described above, when the heat treatment method for a steel for mechanical structure of the present invention is applied to the steel for mechanical structure, it is possible to obtain a practically sufficient hardness and a homogeneous crystal structure. By using hot water of 98 to 100 ° C. as a cooling medium of the steel material for use in steel, the surface of the steel material for machine structure is always kept in a state of being covered with a vapor film during cooling, which allows heat treatment in a stable state. This is done.
【００１３】本実施例においては、機械構造用鋼材とし
て一般的な機械構造用炭素鋼鋼材であるＳ４０Ｃ炭素鋼
鋼材を使用したが、これに限定されるものではなく、本
発明の機械構造用鋼材の熱処理方法は、各種の機械構造
用炭素鋼鋼材や機械構造用合金鋼、例えば、ニッケルク
ロム鋼鋼材、ニッケルクロムモリブデン鋼鋼材、クロム
鋼鋼材、クロムモリブデン鋼鋼材などの熱処理に広く使
用することができる。In the present embodiment, S40C carbon steel, which is a general carbon steel for machine structure, is used as the steel for machine structure, but it is not limited to this, and the steel for machine structure of the present invention is not limited to this. The heat treatment method can be widely used for heat treatment of various carbon steel materials for machine structures and alloy steels for machine structures, for example, nickel chrome steel materials, nickel chrome molybdenum steel materials, chrome steel steel materials, chrome molybdenum steel materials, etc. it can.
【００１４】また、対象となる物品も、本実施例のスピ
ンドルナックル１に限定されず、熱間鍛造して成形され
る歯車等、機械構造用の物品に広く使用することができ
る。Further, the target article is not limited to the spindle knuckle 1 of the present embodiment, and can be widely used for mechanical structural articles such as gears formed by hot forging.
【００１５】そして、本発明の機械構造用鋼材の熱処理
方法によれば、熱処理により材料の被切削性や靭性を損
なうことがないため、熱処理後に切削加工等の機械加工
を行う物品の熱処理に特に適しているということができ
る。Further, according to the heat treatment method for a steel for machine structural use of the present invention, the machinability and the toughness of the material are not impaired by the heat treatment, so that it is particularly suitable for heat treatment of an article to be subjected to machining such as cutting after the heat treatment. It can be said that it is suitable.
【００１６】また、本発明の機械構造用鋼材の熱処理方
法は、冷却時、機械構造用鋼材の表面を常に蒸気膜で覆
った状態に保持し、安定した状態で熱処理を行うため、
機械構造用鋼材の種類が決まれば、物品の形状にはほと
んど左右されずに、熱処理後の材料の性状が決定され
る。したがって、一般的な機械構造用炭素鋼鋼材を使用
する場合には、使用する鋼材の種類（Ｓ１０Ｃ〜Ｓ５８
Ｃ）を適宜選択することによって、物品が必要とする硬
度を容易に得ることができる。Further, according to the heat treatment method for steel for machine structure of the present invention, during cooling, the surface of the steel for machine structure is always kept in a state of being covered with a vapor film and the heat treatment is carried out in a stable state.
Once the type of machine structural steel material is determined, the properties of the material after heat treatment are determined almost without being influenced by the shape of the article. Therefore, when a general carbon steel material for machine structure is used, the type of steel material to be used (S10C to S58).
By appropriately selecting C), the hardness required for the article can be easily obtained.
【００１７】[0017]
【発明の効果】本発明によれば、機械構造用鋼材の冷却
媒体として９８〜１００℃の熱湯を使用することによ
り、従来の熱処理方法において冷却媒体として使用され
ている冷水又は油水の場合のような精密な温度制御が不
要となり、また、冷却時、機械構造用鋼材の表面は常に
蒸気膜で覆われた状態に保持されることと合わせて、安
定した状態で熱処理を行うことができる。これにより、
材料の被切削性や靭性を損なうことなく、所定の硬度や
引張強度を得ることができ、かつ処理コストを低廉にす
ることができる。EFFECTS OF THE INVENTION According to the present invention, by using hot water of 98 to 100 ° C. as a cooling medium for steel for machine structural use, cold water or oil water used as a cooling medium in the conventional heat treatment method can be used. In addition to the need for precise temperature control, the surface of the steel for machine structural use is always kept covered with a vapor film during cooling, and heat treatment can be performed in a stable state. This allows
Predetermined hardness and tensile strength can be obtained without impairing the machinability and toughness of the material, and the processing cost can be reduced.
【図１】本発明の機械構造用鋼材の熱処理方法の連続冷
却変態図（Ｃ．Ｃ．Ｔ．曲線）を示す。1 shows a continuous cooling transformation diagram (CCT curve) of a heat treatment method for a steel material for machine structure of the present invention.
【図２】本発明の機械構造用鋼材の熱処理方法を実施し
たスピンドルナックルを示す図である。FIG. 2 is a view showing a spindle knuckle subjected to a heat treatment method for a steel material for machine structure of the present invention.
【図３】図２のスピンドルナックルのシャフト部のＩ−
Ｉ断面のブリネルくぼみ径を示し、（ａ）は本発明の機
械構造用鋼材の熱処理方法を実施した場合を、（ｂ）は
そのまま空冷（完全焼なまし）した場合を示す。[Fig. 3] I- of the shaft portion of the spindle knuckle of Fig. 2.
The Brinell indentation diameter of the I cross section is shown, (a) shows the case where the heat treatment method of the steel for machine structural use of the present invention was carried out, and (b) shows the case where it was air cooled (completely annealed) as it was.
【図４】スピンドルナックルに本発明の機械構造用鋼材
の熱処理方法を実施した場合のフランジ部の金属組織を
示す顕微鏡写真であり、（ａ）はその表面部（図２のＦ
1）を、（ｂ）はその内部（図２のＦ2）を示す。FIG. 4 is a micrograph showing a metallographic structure of a flange portion when a heat treatment method for a steel material for machine structure of the present invention is applied to a spindle knuckle, (a) of the surface portion (F of FIG. 2).
1) and (b) show the inside (F2 in FIG. 2).
【図５】スピンドルナックルに本発明の機械構造用鋼材
の熱処理方法を実施した場合のシャフト部の金属組織を
示す顕微鏡写真であり、（ａ）はその表面部（図２のＳ
1）を、（ｂ）はその内部（図２のＳ2）を示す。FIG. 5 is a micrograph showing a metallographic structure of a shaft portion when a heat treatment method for steel for mechanical structure of the present invention is applied to a spindle knuckle, and (a) is a surface portion (S in FIG.
1) and (b) show the inside (S2 in FIG. 2).
【図６】スピンドルナックルをそのまま空冷（完全焼な
まし）した場合のフランジ部の金属組織を示す顕微鏡写
真であり、（ａ）はその表面部（図２のＦ1）を、
（ｂ）はその内部（図２のＦ2）を示す。FIG. 6 is a micrograph showing a metal structure of a flange portion when the spindle knuckle is air-cooled (completely annealed) as it is, (a) shows the surface portion (F1 of FIG. 2),
(B) shows the inside (F2 in FIG. 2).
【図７】スピンドルナックルをそのまま空冷（完全焼な
まし）した場合のシャフト部の金属組織を示す顕微鏡写
真であり、（ａ）はその表面部（図２のＳ1）を、
（ｂ）はその内部（図２のＳ2）を示す。FIG. 7 is a micrograph showing a metallographic structure of a shaft portion when the spindle knuckle is air-cooled (completely annealed) as it is, (a) shows the surface portion (S1 of FIG. 2),
(B) shows the inside (S2 of FIG. 2).
１ スピンドルナックル Ｆ フランジ Ｓ シャフト 1 Spindle Knuckle F Flange S Shaft
Claims (1)
ーステナイト化状態で９８〜１００℃の熱湯に浸漬して
機械構造用鋼材の温度を熱湯の温度近傍まで冷却するこ
とを特徴とする機械構造用鋼材の熱処理方法。1. A hot forged machine structural steel material is immersed in hot water at 98 to 100 ° C. in a hot austenitized state to cool the temperature of the mechanical structural steel material to a temperature close to that of the hot water. Heat treatment method for steel for machine structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23403894A JPH0873932A (en) | 1994-09-02 | 1994-09-02 | Method for heat-treating steel for machine structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23403894A JPH0873932A (en) | 1994-09-02 | 1994-09-02 | Method for heat-treating steel for machine structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0873932A true JPH0873932A (en) | 1996-03-19 |
Family
ID=16964598
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23403894A Pending JPH0873932A (en) | 1994-09-02 | 1994-09-02 | Method for heat-treating steel for machine structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0873932A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6468424A (en) * | 1987-09-07 | 1989-03-14 | Kobe Steel Ltd | Production of high-toughness non-tempered hot forging having excellent fatigue resistance and machinability |
| JPH0225516A (en) * | 1988-07-15 | 1990-01-29 | Nippon Steel Corp | Production of hot forged and non-refining part having little dispersion of mechanical characteristic |
| JPH04297548A (en) * | 1991-03-27 | 1992-10-21 | Kobe Steel Ltd | High strength and high toughness non-heat treated steel and its manufacture |
| JPH06228657A (en) * | 1993-02-01 | 1994-08-16 | Nippon Steel Corp | Production of hyper-eutectoid steel wire rod |
-
1994
- 1994-09-02 JP JP23403894A patent/JPH0873932A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6468424A (en) * | 1987-09-07 | 1989-03-14 | Kobe Steel Ltd | Production of high-toughness non-tempered hot forging having excellent fatigue resistance and machinability |
| JPH0225516A (en) * | 1988-07-15 | 1990-01-29 | Nippon Steel Corp | Production of hot forged and non-refining part having little dispersion of mechanical characteristic |
| JPH04297548A (en) * | 1991-03-27 | 1992-10-21 | Kobe Steel Ltd | High strength and high toughness non-heat treated steel and its manufacture |
| JPH06228657A (en) * | 1993-02-01 | 1994-08-16 | Nippon Steel Corp | Production of hyper-eutectoid steel wire rod |
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