JP2001335838A - Method for producing heat-treated member - Google Patents
Method for producing heat-treated memberInfo
- Publication number
- JP2001335838A JP2001335838A JP2000154000A JP2000154000A JP2001335838A JP 2001335838 A JP2001335838 A JP 2001335838A JP 2000154000 A JP2000154000 A JP 2000154000A JP 2000154000 A JP2000154000 A JP 2000154000A JP 2001335838 A JP2001335838 A JP 2001335838A
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- Prior art keywords
- heat
- carbon
- treated member
- steel
- tempering
- Prior art date
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- Heat Treatment Of Articles (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、熱処理部材の製造
方法に関する。The present invention relates to a method for manufacturing a heat-treated member.
【０００２】[0002]
【従来の技術】鉄鋼部材は、圧延のままで使用されるも
のもあるが、耐摩耗性（硬さ）、強度、靱性が要求され
る部材は、熱処理を施して使用される。このように、熱
処理を施して使用される鉄鋼部材を熱処理部材という。
熱処理部材の代表的なものとしては、図４に示す油圧シ
ョベルおよびブルドーザーなどの建設機械の無限軌道帯
２０に使用される履板２１、リンク２２、ピン２３、ブ
ッシュ２４、ならびに図５、図６に示すブルドーザーな
どの建設機械３０および除雪機械３２に使用される刃先
３１などがあり、その他、各種産業機械に使用される機
械構造用部品の多くは熱処理部材である。従来の熱処理
部材の製造方法は、図２に示す、低炭素鋼および中炭素
鋼を素材とし熱処理として焼入れ・焼もどしを施す方法
と、図３に示す、低炭素ボロン鋼を素材とし熱処理とし
て焼入れのみを施す方法（特開平１１−１４０５４０
号）とがある。図２に示す方法は、鉄鋼材料を所定形状
に成形して素材を成形する工程１１と、素材に熱処理を
施す工程１２とからなり、熱処理は、「焼入れ」という
工程と「焼もどし」という工程との２工程からなり、焼
入れと焼もどしがかならず組になっていた。焼入れと焼
もどしの２工程の熱処理が必要な理由はつぎの通りであ
る。一般に、熱処理部材では、耐摩耗性（硬さ）および
強度と靱性とは相反する特性である。焼入れだけでは、
耐摩耗性（硬さ）および強度は大幅に向上するが、靱性
が著しく低い。「焼入れ」という熱処理の後に「焼もど
し」という熱処理を施すことによって、焼入れままのも
のに比べて、耐摩耗性（硬さ）および強度は若干低下す
るが、靱性が大幅に向上し、必要な耐摩耗性（硬さ）お
よび強度と靱性とが確保される。すなわち、焼入れと焼
もどしの２工程の熱処理を施さないと、必要な耐摩耗性
（硬さ）および強度と靱性は確保されない。図３に示す
方法は、低炭素ボロン鋼材料を所定形状に成形して素材
を成形する工程１３と、素材に「焼入れ」のみからなる
熱処理を施す工程１４とからなり、熱処理工程１４は、
「焼入れ」のみで「焼もどし」を省略したものであっ
た。材料に低炭素ボロン鋼（炭素量が０．０５〜０．３
０重量％）を選択することにより、焼入れままで金属組
織が低炭素マルテンサイトの単一組織となり、「焼入
れ」・「焼もどし」が施された金属組織と同じとなり、
焼もどしを省略できることを見出し、特開平１１−１４
０５４０号の発明に到ったのであった。これにより、低
炭素ボロン鋼の場合は、熱処理に要する工数、時間、設
備が大幅に削減された。2. Description of the Related Art Some steel members are used as they are rolled. However, members requiring wear resistance (hardness), strength and toughness are subjected to heat treatment. The steel member used after being subjected to the heat treatment is referred to as a heat-treated member.
Representative examples of the heat treatment member include a track plate 21, a link 22, a pin 23, a bush 24 used in an endless track belt 20 of a construction machine such as a hydraulic shovel and a bulldozer shown in FIG. 4, and FIGS. And a blade 31 used for a construction machine 30 such as a bulldozer and a snow removal machine 32, and many other machine structural parts used for various industrial machines are heat-treated members. Conventional methods for manufacturing heat-treated members include a method shown in FIG. 2 in which low carbon steel and medium carbon steel are used as materials and quenching and tempering are performed as heat treatment, and a method shown in FIG. (Japanese Unexamined Patent Publication No. 11-140540)
No.). The method shown in FIG. 2 includes a step 11 of forming a material by shaping a steel material into a predetermined shape, and a step 12 of performing a heat treatment on the material. The heat treatment includes a step of “quenching” and a step of “tempering”. Quenching and tempering were always in pairs. The reason why two steps of heat treatment of quenching and tempering are required is as follows. In general, in a heat-treated member, wear resistance (hardness) and strength and toughness are contradictory characteristics. Just quenching,
Abrasion resistance (hardness) and strength are greatly improved, but toughness is significantly lower. By performing a heat treatment called "tempering" after a heat treatment called "quenching", the abrasion resistance (hardness) and strength are slightly reduced as compared with the as-quenched one, but the toughness is greatly improved and the necessary Abrasion resistance (hardness) and strength and toughness are ensured. That is, unless two heat treatments of quenching and tempering are performed, the required wear resistance (hardness), strength, and toughness cannot be secured. The method shown in FIG. 3 includes a step 13 of forming a material by shaping a low-carbon boron steel material into a predetermined shape, and a step 14 of subjecting the material to a heat treatment consisting only of “quenching”.
"Quenching" was omitted, and "tempering" was omitted. Low carbon boron steel (carbon content 0.05-0.3)
0% by weight), the metal structure becomes a single structure of low-carbon martensite as-quenched, and becomes the same as the metal structure subjected to “quenching” and “tempering”,
They found that tempering could be omitted.
The invention of No. 0540 has been reached. As a result, in the case of low-carbon boron steel, the number of steps, time, and equipment required for heat treatment were significantly reduced.
【０００３】[0003]
【発明が解決しようとする課題】しかし、従来の熱処理
部材の製造方法には、つぎの問題がある。 中炭素鋼を素材とした熱処理部材の場合は、焼入れ
のみのままでは、靱性（シャルピー衝撃値）が低く、熱
処理部材としては使用できないので、焼入れ・焼もどし
の熱処理を施さなければならず、熱処理の工数、時間、
設備が低炭素ボロン鋼の焼入れのみ品より多く必要とな
る。 低炭素ボロン鋼を素材とした熱処理部材の場合は、 −１．炭素量が０．０５〜０．３０重量％のため、さ
らに強度、耐摩耗性が必要な部材への適用ができない。
たとえば、低炭素ボロン鋼で炭素量が０．３０％の場合
（熱処理工程：焼入れのみ）、つぎの機械的性質が最大
であり、これ以上の強度、耐摩耗性が得られない。 硬さ：ＨＲＣ５０（耐摩耗性の要因） 引張強さ：１６０Ｋｇ／ｍｍ2 （強度の要因） −２．上記−１の理由により、低炭素鋼から中炭素
鋼への材料変更無しには、更なる厚さ減少、軽量化をは
かることができない。熱処理で焼入れと焼もどしの２工
程が必要となるので、工数、時間、設備が大となり、コ
ストアップを招く。本発明の目的は、 従来の中炭素鋼を素材とし焼入れ・焼もどしの熱処
理を施す場合に比べて熱処理の工数、時間、設備を削減
でき、 従来の低炭素ボロン鋼を素材とし焼入れのみの熱処
理を施す場合に比べて耐摩耗性（硬さ）および強度を向
上できかつ必要な靱性を確保できる、熱処理部材の製造
方法を提供することにある。However, the conventional method for manufacturing a heat-treated member has the following problems. In the case of a heat-treated member made of medium carbon steel, if only quenching is used, the toughness (Charpy impact value) is low and it cannot be used as a heat-treated member. Therefore, quenching and tempering heat treatment must be performed. Man-hours, time,
The equipment requires more quenching than low carbon boron steel. In the case of a heat-treated member made of low-carbon boron steel, -1. Since the carbon content is 0.05 to 0.30% by weight, it cannot be applied to members that require further strength and wear resistance.
For example, when the carbon content of low-carbon boron steel is 0.30% (heat treatment step: only quenching), the following mechanical properties are maximum, and further strength and wear resistance cannot be obtained. Hardness: HRC50 (factor of wear resistance) Tensile strength: 160 kg / mm 2 (factor of strength) -2. Due to the reason -1, the thickness cannot be reduced and the weight cannot be reduced without changing the material from low carbon steel to medium carbon steel. Since two steps of quenching and tempering are required in the heat treatment, the number of steps, time, and equipment are increased, and the cost is increased. An object of the present invention is to reduce the number of steps, time, and equipment of heat treatment as compared with the case where a conventional medium carbon steel is used as a material and heat treatment for quenching and tempering is performed. An object of the present invention is to provide a method for manufacturing a heat-treated member, which can improve abrasion resistance (hardness) and strength as well as secure required toughness as compared with the case of applying heat treatment.
【０００４】[0004]
【課題を解決するための手段】上記目的を達成する本発
明はつぎの通りである。 （１） 炭素量が０．３０１〜０．５０重量％の中炭素
ボロン鋼からなる材料を所定形状に成形して素材とする
工程と、該素材に焼入れのみからなり焼もどしを省略し
た熱処理を施す工程と、からなる熱処理部材の製造方
法。 （２） 前記中炭素ボロン鋼は、炭素量が０．３０１〜
０．３４重量％である（１）記載の熱処理部材の製造方
法。 （３） 前記中炭素ボロン鋼は、ボロン量が０．０００
１〜０．０１００重量％である（１）記載の熱処理部材
の製造方法。 （４） 前記中炭素ボロン鋼は、ボロン量が０．０００
５〜０．００３０重量％である（３）記載の熱処理部材
の製造方法。The present invention to achieve the above object is as follows. (1) Forming a material made of medium carbon boron steel having a carbon content of 0.301 to 0.50% by weight into a predetermined shape to obtain a material, and performing a heat treatment consisting only of quenching and omitting tempering. And a step of producing a heat-treated member. (2) The medium carbon boron steel has a carbon content of 0.301 to
The method for producing a heat-treated member according to (1), wherein the amount is 0.34% by weight. (3) The medium carbon boron steel has a boron content of 0.000.
The method for producing a heat-treated member according to (1), wherein the content is 1 to 0.0100% by weight. (4) The medium carbon boron steel has a boron content of 0.000.
The method for producing a heat-treated member according to (3), wherein the content is 5 to 0.0030% by weight.
【０００５】上記（１）〜（４）の熱処理部材の製造方
法では、熱処理を施す工程において、素材に焼入れのみ
からなる熱処理を施すので、従来の焼入れと焼もどしの
２工程からなる熱処理に比べて焼もどしの工程が省略さ
れており、焼もどしの工程分、工数、時間が削減される
ほか、焼もどしの設備が不要となり、その結果、熱処理
部材の製造コストを低減することができる。また、素材
の炭素量が０．３０１〜０．５０重量％であるから、低
炭素鋼に比べて、熱処理後の硬さ、強度が向上し、更な
る板厚減少、軽量化をはかることができる。従来、中炭
素鋼は焼入れのままでは靱性が低く熱処理部材としては
使用できないとされてきたが、使用実績からの必要靱性
の限度の究明とボロン添加量による靱性アップにより、
中炭素低合金鋼でも、焼入れままで、すなわち焼もどし
を省略できることがわかった。すなわち、シャルピー衝
撃値が５Ｋｇ・ｍ／ｃｍ2 以上、破壊靱性値が２５０Ｋ
ｇ／ｍｍ1.5 以上であれば、使用中の折損事故は皆無で
あることが究明され、この条件は材料を中炭素ボロン鋼
（ボロン量：０．０００１〜０．０１００重量％）とす
れば焼入れのみで（焼もどしを省略しても）満足できる
ことが試験により確かめられ、本発明に到った。上記
（２）の熱処理部材の製造方法では、炭素量が０．３０
１〜０．５０重量％では、焼入れままでは、低炭素マル
テンサイト組織と中炭素マルテンサイト組織の混合組織
であるが、炭素量を０．３０１〜０．３４重量％とした
ので、低炭素マルテンサイト組織を多く存在させること
ができ、低炭素鋼の靱性を多く残すことができ、ボロン
添加により比較的容易に、必要靱性を確保することがで
きる。上記（３）の熱処理部材の製造方法では、ボロン
を０．０００１〜０．０１００重量％添加しているの
で、必要靱性を確保することができる。上記（４）の熱
処理部材の製造方法では、ボロンを０．０００５〜０．
００３０重量％添加しているので、必要靱性を確保する
ことができる。ボロンを添加する理由は、焼入れ性の確
保および高硬度域における靱性確保である。焼入れ性に
ついて説明すると、低炭素鋼および中炭素鋼の炭素量が
少ない領域では、焼入れ工程で熱処理部材の芯部まで硬
化しにくいという問題があるので、ボロンを０．０００
１〜０．０１００重量％、さらに望ましくは０．０００
５〜０．００３０重量％添加して必要な焼入れ性を確保
する。これにより、高周波焼入れのように表面層のみを
焼入れ硬化する場合のみならず、芯部まで焼入れ硬化す
る必要がある一般の熱処理部材にも、本発明方法を適用
することができる。大型の熱処理部材で、ボロンのみで
は必要な焼入れ性を確保することが困難な場合には、ボ
ロンに加えて、焼入れ性を向上せしめる他の元素（成
分）であるＭｎ、Ｃｒ、Ｍｏなどを添加してもよい。ボ
ロンを添加するもう一つの理由は、高硬度域（ＨＲＣ４
０程度以上）における靱性確保である。以上のように、
素材に中炭素系のボロン鋼を用いることにより、焼入れ
のみで（焼もどしを施さなくても）、必要な硬さ、強
度、靱性を確保することができる。In the method of manufacturing a heat-treated member according to the above (1) to (4), in the step of performing the heat treatment, the material is subjected to a heat treatment consisting only of quenching, which is compared with the conventional heat treatment consisting of two steps of quenching and tempering. Since the tempering process is omitted, the tempering process, man-hours, and time are reduced, and the tempering equipment is not required. As a result, the manufacturing cost of the heat-treated member can be reduced. Further, since the carbon content of the material is 0.301 to 0.50% by weight, the hardness and strength after heat treatment are improved, and further reduction in thickness and weight can be achieved as compared with low carbon steel. it can. Conventionally, medium carbon steel has been considered to have low toughness as it is hardened and cannot be used as a heat-treated member.However, by investigating the limit of required toughness from actual use results and increasing the toughness by adding boron,
It has been found that even with a medium carbon low alloy steel, quenching can be omitted as it is, that is, tempering can be omitted. That is, the Charpy impact value is 5 kg · m / cm 2 or more, and the fracture toughness value is 250 Kg.
When the g / mm is 1.5 or more, it is determined that there is no breakage accident during use. This condition is quenched if the material is medium carbon boron steel (boron amount: 0.0001 to 0.0100% by weight). It was confirmed by a test that satisfactory results were obtained only by omitting the tempering, and the present invention was reached. In the method (2) for manufacturing a heat-treated member, the carbon content is 0.30.
At 1 to 0.50% by weight, the as-quenched alloy has a mixed structure of a low carbon martensite structure and a medium carbon martensite structure. However, since the carbon content is set to 0.301 to 0.34% by weight, low carbon martensite is used. A large number of site structures can be present, the toughness of the low-carbon steel can be retained, and the required toughness can be relatively easily secured by adding boron. In the method (3) for producing a heat-treated member, since 0.0001 to 0.0100% by weight of boron is added, necessary toughness can be secured. In the method for manufacturing a heat-treated member according to the above (4), the amount of boron is set to 0.0005 to 0.5.
Since 0030% by weight is added, necessary toughness can be secured. The reason for adding boron is to ensure hardenability and toughness in a high hardness region. Explaining the hardenability, in a region where the carbon content of the low carbon steel and the medium carbon steel is small, there is a problem that it is difficult to harden to the core of the heat-treated member in the hardening process.
1 to 0.0100% by weight, more preferably 0.000%
The necessary hardenability is secured by adding 5 to 0.0030% by weight. Thus, the method of the present invention can be applied to not only a case where only the surface layer is quenched and hardened as in induction hardening, but also a general heat-treated member which needs to be hardened and hardened to the core. If it is difficult to secure the necessary hardenability with boron alone in a large heat-treated member, Mn, Cr, Mo, etc., which are other elements (components) that improve the hardenability, are added in addition to boron. May be. Another reason for adding boron is in the high hardness region (HRC4
(About 0 or more). As mentioned above,
By using a medium-carbon boron steel as a material, necessary hardness, strength, and toughness can be ensured only by quenching (without tempering).
【０００６】[0006]
【発明の実施の形態】本発明実施例の熱処理部材の製造
方法は、図１に示すように、炭素量が０．０３０１〜
０．５０重量％、ボロン量が０．０００１〜０．０１０
０重量％の中炭素ボロン鋼（表１に示す実施例の場合
は、ボロンに加えて１．０重量％程度のマンガンが添加
されているので、中炭素マンガン・ボロン鋼ともいう）
からなる材料を所定形状に成形して素材とする工程１
と、該素材に焼入れのみからなる熱処理を施す工程２
と、からなる。素材の中炭素ボロン鋼の炭素量は、０．
３０１〜０．３４重量％であることがより望ましい。ま
た、素材の中炭素ボロン鋼のボロン量は、０．０００１
〜０．０１００重量％、望ましくは０．０００５〜０．
００３０重量％である。素材の組成は、表１に示す通り
である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a method of manufacturing a heat-treated member according to an embodiment of the present invention has a carbon content of 0.0301 to 0.031.
0.50% by weight, the amount of boron is 0.0001 to 0.010
0% by weight of medium carbon boron steel (in the case of the examples shown in Table 1, since about 1.0% by weight of manganese is added in addition to boron, it is also called medium carbon manganese-boron steel)
1 of forming a material consisting of
And a step 2 of subjecting the material to a heat treatment consisting only of quenching.
And consisting of The carbon content of the material medium carbon boron steel is 0.
More preferably, it is 301 to 0.34% by weight. The boron content of the medium carbon boron steel is 0.0001.
-0.0100% by weight, preferably 0.0005-0.5%.
0030% by weight. The composition of the material is as shown in Table 1.
【０００７】[0007]
【表１】 [Table 1]
【０００８】材料の素材への成形は、圧延、鍛造、鋳造
などの成形方法の何れによってもよい。熱処理部材の代
表的なものとしては、従来と同様、図４に示す油圧ショ
ベルおよびブルドーザーなどの建設機械の無限軌道帯２
０に使用される履板２１、リンク２２、ピン２３、ブッ
シュ２４ならびに図５に示すブルドーザーなどの建設機
械３０および図６に示す除雪ドーザーなどの除雪機械３
２に使用される刃先３１などがあり、その他、各種産業
機械に使用される機械構造用部品の多くは熱処理部材で
ある。また、成形とは、熱処理部材の形状への成形であ
る。The molding of the material into the material may be performed by any of molding methods such as rolling, forging, casting and the like. As a typical example of the heat-treated member, the crawler belt 2 of a construction machine such as a hydraulic shovel and a bulldozer shown in FIG.
5, a construction machine 30 such as a bulldozer shown in FIG. 5 and a snow removal machine 3 such as a snow removal dozer shown in FIG.
2, there is a blade edge 31 and the like, and in addition, most of the machine structural parts used in various industrial machines are heat-treated members. Forming is forming the heat-treated member into a shape.
【０００９】熱処理工程２が焼入れ工程のみからなると
いうことは、熱処理工程２は、焼入れ工程を含むが、焼
もどし工程（低温焼もどし工程または高温焼もどし工
程）を含まないことを意味する。すなわち、素材を焼入
れしたままで熱処理部材として使用する。焼入れは従来
の中炭素（合金）鋼の焼入れと同じである。すなわち、
焼入れは、上記素材をＡｃ3 変態点以上の温度（たとえ
ば、約９００℃）に加熱して均一なオーステナイト組織
とし、加熱直後に上記素材を約２００℃以下まで急冷す
ることにより、行う。焼もどしは行わない。The fact that the heat treatment step 2 comprises only a quenching step means that the heat treatment step 2 includes a quenching step but does not include a tempering step (low-temperature tempering step or high-temperature tempering step). That is, the material is used as a heat-treated member while being quenched. Quenching is the same as conventional hardening of medium carbon (alloy) steel. That is,
Quenching is performed by heating the material to a temperature equal to or higher than the Ac 3 transformation point (for example, about 900 ° C.) to form a uniform austenite structure, and immediately cooling the material to about 200 ° C. or less immediately after heating. No tempering is performed.
【００１０】表１の化学組成をもつ圧延鋼を材料（中炭
素ボロン鋼）として、実際に焼入れのみの（焼もどしを
省略した）熱処理を施して熱処理部材を製造し、機械的
特性を調べてみた。結果を表２に示す。表２には、従来
の中炭素鋼（中炭素マンガン鋼）の圧延→焼入れ・焼も
どしを施した熱処理部材、および従来の中炭素鋼（中炭
素マンガン鋼）の圧延→焼入れままの熱処理部材、従来
の中炭素鋼（中炭素マンガン・ボロン鋼）の圧延→焼入
れ・焼もどしを施した熱処理部材、従来の低炭素ボロン
鋼の圧延→焼入れままの熱処理部材、従来の低炭素ボロ
ン鋼の圧延→焼入れ・焼もどしを施した熱処理部材、の
機械的特性を調査または調査で得られないものは試験し
て、その結果を比較のために、併せ示してある。Using a rolled steel having the chemical composition shown in Table 1 as a material (medium carbon boron steel), a heat-treated member is manufactured by actually performing heat treatment only for quenching (omitting tempering), and examining mechanical properties. saw. Table 2 shows the results. Table 2 shows that the heat-treated parts of the conventional medium-carbon steel (medium-carbon manganese steel) rolled → quenched and tempered, and the conventional heat-treated parts of the medium-carbon steel (medium-carbon manganese steel) rolled → as-quenched, Rolling of conventional medium-carbon steel (medium-carbon manganese-boron steel) → heat treatment of quenched and tempered steel, rolling of conventional low-carbon boron steel → heat-treated member of as-quenched steel, rolling of conventional low-carbon boron steel → The mechanical properties of the quenched and tempered heat-treated members, which were not obtained by the investigation or investigation, were tested and the results are also shown for comparison.
【００１１】[0011]
【表２】 [Table 2]
【００１２】本発明品である、中炭素ボロン鋼を素材と
し焼入れのみの熱処理を施した熱処理部材の、表面付近
の完全焼入れ部の金属組織は、中炭素マルテンサイト組
織（ただし、炭素量が０．３０近傍では低炭素マルテン
サイトと中炭素マルテンサイトとの混合組織）であり、
この完全焼入れ部の機械的性質は、表２に示すように、
硬さがＨＲＣ５０〜５５、強度が１７５〜１８５Ｋｇ／
ｍｍ2 、靱性がシャルピー衝撃値で５〜７Ｋｇ・ｍ／ｃ
ｍ2 、また破壊靱性値で２５０〜３００Ｋｇ／ｍｍ1.5
である。[0012] The metal structure of the completely quenched portion near the surface of the heat-treated member of the present invention, which is made of medium-carbon boron steel and heat-treated only by quenching, has a medium-carbon martensite structure (provided that the carbon content is 0%). Around 30. a mixed structure of low carbon martensite and medium carbon martensite)
As shown in Table 2, the mechanical properties of the completely quenched part
Hardness is HRC50-55, strength is 175-185Kg /
mm 2 , Toughness is 5-7 kg · m / c in Charpy impact value
m 2 , and 250 to 300 kg / mm 1.5 in fracture toughness.
It is.
【００１３】これに対し、従来の中炭素鋼（中炭素マン
ガン鋼）を素材とする熱処理部材は、焼入れ・焼もどし
（高温焼もどし）を施した熱処理部材で、シャルピー衝
撃値で３〜８Ｋｇ・ｍ／ｃｍ2 、また破壊靱性値で２０
０〜２５０Ｋｇ／ｍｍ1.5 であり、焼入れままの熱処理
部材で、シャルピー衝撃値で１〜３Ｋｇ・ｍ／ｃｍ2、
また破壊靱性値で１５０〜２５０Ｋｇ／ｍｍ1.5 である
ので、必要な靱性値（シャルピー衝撃値で５Ｋｇ・ｍ／
ｃｍ2 以上、破壊靱性値で２５０Ｋｇ／ｍｍ1. 5 以上）
を満足できない。本発明品は、必要靱性５Ｋｇ・ｍ／ｃ
ｍ2 および必要破壊靱性値２５０Ｋｇ／ｍｍ1.5 が確保
されている。On the other hand, a conventional heat-treated member made of medium-carbon steel (medium-carbon manganese steel) is a heat-treated member subjected to quenching and tempering (high-temperature tempering), and has a Charpy impact value of 3 to 8 kg. m / cm 2 , and a fracture toughness of 20
0 to 250 Kg / mm 1.5, which is a heat-treated as-quenched member, and has a Charpy impact value of 1 to 3 Kg · m / cm 2 ,
Further, since the fracture toughness value is 150 to 250 kg / mm 1.5 , the required toughness value (5 kg / m
cm 2 or more, 250Kg / mm 1. 5 or more in fracture toughness value)
Cannot be satisfied. The product of the present invention has a required toughness of 5 kg · m / c.
m 2 and a required fracture toughness value of 250 kg / mm 1.5 are secured.
【００１４】また、従来の中炭素ボロン鋼（中炭素マン
ガンボロン鋼）の素材に焼入れ・焼もどし（低温焼もど
し）を施した熱処理部材に比べても、本発明品では、焼
もどしで犠牲になる硬さ、引張強さの低下がないため、
硬さ、引張強さが向上するほか、焼もどしに要する工
数、時間、設備が不要となり、大幅なコスト低減をはか
ることができる。Further, compared with a conventional heat-treated member obtained by quenching and tempering (low-temperature tempering) a material of medium-carbon boron steel (medium-carbon manganese boron steel), the product of the present invention is sacrificed by tempering. Hardness and tensile strength do not decrease,
Hardness and tensile strength are improved, and man-hours, time, and equipment required for tempering are not required, so that significant cost reduction can be achieved.
【００１５】また、従来の低炭素ボロン鋼（低炭素マン
ガンボロン鋼）の圧延→焼入れ・焼もどし（低温焼もど
し）を施した熱処理部材は、硬さはＨＲＣ４２〜４９で
あり、引張強さは１３５〜１５５Ｋｇ／ｍｍ2 であり、
従来の低炭素ボロン鋼（低炭素マンガンボロン鋼）の圧
延→焼入れままの熱処理部材は、硬さはＨＲＣ４２〜４
９であり、引張強さは１３５〜１５５Ｋｇ／ｍｍ2 であ
るので、本発明品により硬さ（耐摩耗性）、強度が大幅
に向上することがわかる。そして、これによって、従来
に比べて、部材の厚さ低減、軽量化をはかることができ
る。[0015] Further, the hardness of the conventional heat-treated member obtained by rolling → quenching and tempering (low-temperature tempering) low carbon boron steel (low carbon manganese boron steel) is HRC 42 to 49 and tensile strength is 135-155 Kg / mm 2 ,
Rolling of conventional low-carbon boron steel (low-carbon manganese boron steel) → The hardness of the as-quenched heat-treated member is HRC42-4.
9 and a tensile strength of 135 to 155 kg / mm 2 , indicating that the hardness (wear resistance) and strength of the product of the present invention are significantly improved. As a result, the thickness and weight of the member can be reduced as compared with the related art.
【００１６】[0016]
【発明の効果】請求項１〜４の熱処理部材の製造方法に
よれば、熱処理を施す工程において、素材に焼入れのみ
からなる熱処理を施すので、従来の焼入れと焼もどしの
２工程からなる熱処理に比べて焼もどしの工程が省略さ
れており、焼もどしの工程分、工数、時間が削減される
ほか、焼もどしの設備が不要となり、その結果、熱処理
部材の製造コストを低減することができる。また、素材
の炭素量が０．３０１〜０．５０重量％であるから、低
炭素鋼に比べて、熱処理後の硬さ、強度が向上し、更な
る板厚減少、軽量化をはかることができる。請求項２の
熱処理部材の製造方法によれば、炭素量を０．３０１〜
０．３４重量％としたので、ボロン添加により比較的容
易に、必要靱性を確保することができる。請求項３の熱
処理部材の製造方法によれば、ボロンを０．０００１〜
０．０１００重量％添加しているので、必要靱性を確保
することができる。請求項４の熱処理部材の製造方法に
よれば、ボロンを０．０００５〜０．００３０重量％添
加しているので、必要靱性を確保することができる。According to the method for manufacturing a heat-treated member according to claims 1 to 4, in the heat-treating step, the material is subjected to a heat treatment consisting only of quenching, so that the conventional heat treatment consisting of quenching and tempering is performed. In comparison, the tempering process is omitted, and the tempering process, man-hours, and time are reduced, and the tempering equipment is not required. As a result, the manufacturing cost of the heat-treated member can be reduced. Further, since the carbon content of the material is 0.301 to 0.50% by weight, the hardness and strength after heat treatment are improved, and further reduction in thickness and weight can be achieved as compared with low carbon steel. it can. According to the method for manufacturing a heat-treated member of claim 2, the carbon content is set to 0.301 to
Since the content is 0.34% by weight, the required toughness can be relatively easily secured by adding boron. According to the method for manufacturing a heat-treated member according to claim 3, boron is added in an amount of 0.0001 to 0.0001.
Since 0.0100% by weight is added, required toughness can be secured. According to the method for manufacturing a heat-treated member according to the fourth aspect, since 0.0005 to 0.0030% by weight of boron is added, necessary toughness can be ensured.
【図１】本発明の一実施例の熱処理部材の製造方法の作
業工程図である。FIG. 1 is a work process diagram of a method for manufacturing a heat-treated member according to an embodiment of the present invention.
【図２】従来の低炭素鋼および中炭素鋼を素材とする熱
処理部材の製造方法の作業工程図である。FIG. 2 is a work process chart of a conventional method for manufacturing a heat-treated member made of low-carbon steel and medium-carbon steel.
【図３】従来の低炭素ボロン鋼を素材とする熱処理部材
の製造方法の作業工程図である。FIG. 3 is an operation process diagram of a conventional method for manufacturing a heat-treated member made of low-carbon boron steel.
【図４】無限軌道帯の一部の斜視図である。FIG. 4 is a perspective view of a part of the endless track belt.
【図５】建設機械の斜視図である。FIG. 5 is a perspective view of the construction machine.
【図６】除雪機械の斜視図である。FIG. 6 is a perspective view of the snow removing machine.
１ 素材の成形工程 ２ （焼もどし工程を含まない）熱処理工程 ２０ 無限軌道帯 ２１ 履板 ２２ リンク ２３ ピン ２４ ブッシュ ３０ 建設機械 ３１ 建設機械および除雪機械に使用される刃先 ３２ 除雪機械 Reference Signs List 1 material forming process 2 heat treatment process (not including tempering process) 20 endless track belt 21 footwear plate 22 link 23 pin 24 bush 30 construction machine 31 blade tip used for construction machine and snow removal machine 32 snow removal machine
───────────────────────────────────────────────────── フロントページの続き (72)発明者 杉山 大吾 東京都千代田区四番町５番地９ トピー工 業株式会社内 (72)発明者 井伊谷 和伸 東京都千代田区四番町５番地９ トピー工 業株式会社内 Ｆターム(参考） 2D015 KA01 4K042 AA25 BA01 BA02 BA03 CA02 DA01 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Daigo Sugiyama 5-9, Yonbancho, Chiyoda-ku, Tokyo Topy Industries Co., Ltd. (72) Inventor Kazunobu Iitani 5-9, Yonbancho, Chiyoda-ku, Tokyo Topy Industries F term in the company (reference) 2D015 KA01 4K042 AA25 BA01 BA02 BA03 CA02 DA01
Claims (4)
中炭素ボロン鋼からなる材料を所定形状に成形して素材
とする工程と、 該素材に焼入れのみからなり焼もどしを省略した熱処理
を施す工程と、からなる熱処理部材の製造方法。1. A process in which a material made of medium carbon boron steel having a carbon content of 0.301 to 0.50% by weight is formed into a predetermined shape to obtain a material, and the material is only quenched and tempering is omitted. Performing a heat treatment, and a method for producing a heat treated member.
０１〜０．３４重量％である請求項１記載の熱処理部材
の製造方法。2. The medium carbon boron steel has a carbon content of 0.3.
The method for producing a heat-treated member according to claim 1, wherein the amount is from 0.01 to 0.34% by weight.
０００１〜０．０１００重量％である請求項１記載の熱
処理部材の製造方法。3. The medium carbon boron steel according to claim 1, wherein the boron content is in the range of 0.1 to 0.5.
The method for producing a heat-treated member according to claim 1, wherein the content is 0001 to 0.0100% by weight.
０００５〜０．００３０重量％である請求項３記載の熱
処理部材の製造方法。4. The medium carbon boron steel according to claim 1, wherein the boron content is equal to or less than 0.1%.
The method for producing a heat-treated member according to claim 3, wherein the amount is from 0005 to 0.0030% by weight.
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|---|---|---|---|
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000154000A JP2001335838A (en) | 2000-05-25 | 2000-05-25 | Method for producing heat-treated member |
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| Publication Number | Publication Date |
|---|---|
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ID=18659162
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008074381A (en) * | 2006-03-28 | 2008-04-03 | Nisshin Steel Co Ltd | Caster and its manufacturing method |
-
2000
- 2000-05-25 JP JP2000154000A patent/JP2001335838A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008074381A (en) * | 2006-03-28 | 2008-04-03 | Nisshin Steel Co Ltd | Caster and its manufacturing method |
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