JPH0137453B2 - - Google Patents
Info
- Publication number
- JPH0137453B2 JPH0137453B2 JP25462386A JP25462386A JPH0137453B2 JP H0137453 B2 JPH0137453 B2 JP H0137453B2 JP 25462386 A JP25462386 A JP 25462386A JP 25462386 A JP25462386 A JP 25462386A JP H0137453 B2 JPH0137453 B2 JP H0137453B2
- Authority
- JP
- Japan
- Prior art keywords
- tempering
- circumferential surface
- inner circumferential
- track
- temperature
- 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.)
- Expired
Links
- 238000000034 method Methods 0.000 claims description 36
- 238000010438 heat treatment Methods 0.000 claims description 35
- 230000006698 induction Effects 0.000 claims description 25
- 238000005496 tempering Methods 0.000 claims description 25
- 238000010791 quenching Methods 0.000 claims description 11
- 230000000171 quenching effect Effects 0.000 claims description 10
- 238000001816 cooling Methods 0.000 claims description 7
- 229910000851 Alloy steel Inorganic materials 0.000 claims description 6
- 229910052799 carbon Inorganic materials 0.000 claims description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 5
- 239000000047 product Substances 0.000 description 20
- 230000002093 peripheral effect Effects 0.000 description 19
- 239000013078 crystal Substances 0.000 description 10
- 229910001566 austenite Inorganic materials 0.000 description 8
- 238000007670 refining Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 239000000523 sample Substances 0.000 description 5
- 238000009826 distribution Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 229910000712 Boron steel Inorganic materials 0.000 description 1
- 241001311547 Patina Species 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- YWGOMNFRIAWRHU-UHFFFAOYSA-N [B].[C].[Cr] Chemical compound [B].[C].[Cr] YWGOMNFRIAWRHU-UHFFFAOYSA-N 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
- C21D9/14—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes wear-resistant or pressure-resistant pipes
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
Description
［産業上の利用分野］
本発明は、装軌車両等に用いる履帯ブツシユの
熱処理方法に関するものである。
［従来の技術］
装軌車両などに用いる履帯１は、第１図に示す
ように、シユー２、シユー締付けボルト３、シユ
ー締付けナツト４、リンク５および６、ブツシユ
７、ダストシール８、ピン９をもつてその一単位
が構成されている。履帯１に用いられるブツシユ
７は、第２図に示すように、その内周表面７ａお
よび外周表面７ｂに耐摩耗性が要求されるととも
に、ブツシユ７に加わる負荷に耐えるための強
度、靫性、疲労強度が要求される。したがつて、
従来から履帯用ブツシユには上記の要求品質を満
足させるため熱処理が施されている。
従来の熱処理方法には、(イ)肌焼鋼（たとえば
JIS：SCM415、420）を素材とし、これを浸炭焼
入れした後に焼もどしする方法（特公昭52−
34806号公報）や、(ロ)中炭素低合金鋼（たとえば
JIS：SCM435、SCM440、JIS：SCr435にＢを添
加したもの）を素材として、これを調質して肉厚
の中心部に柔らかい延性部を作り、その後外周、
内周の両側に高周波焼入れを施し、さらにその後
焼もどしする方法（特開昭59−77979号公報の従
来技術の説明）、などがある。
しかし、上記調質を含む(ロ)の方法においては、
中炭素低合金鋼を加熱炉内においてAc3点以上の
温度に加熱し、油焼入れを行つた後600℃前後の
温度で焼もどしすることによつて調質を行なつて
いるため、処理時間が長かつたり、処理工程が多
いなど、作業能率が悪いという欠点があつた。
そこで、これを改善するために、素材の調質を
省略した履帯ブツシユの高周波誘導加熱焼入れ方
法、「履帯用ブツシユおよびその生産方法」が、
本特許出願人により、特願昭57−179980号で提案
されている（特開昭59−77979号公報）。
［発明が解決しようとする課題］
しかしながら、上記特願昭57−179980号発明に
おいても、外周側の高周波焼入れ、内周側の
高周波焼入れ、焼もどしの３工程が必要であつ
た。そこで、さらに少ない工程で処理でき、しか
もブツシユの耐摩耗性や疲労強度、靫性を劣化さ
せない熱処理方法の開発が望まれる。
本発明の目的は、特願昭57−179980号発明よ
り、さらに処理工程が少なく、しかも耐摩耗性、
疲労強度、靫性を劣化させない、履帯ブツシユの
熱処理方法を提供することにある。
［課題を解決するための手段］
上記目的を達成するための本発明に係る履帯ブ
ツシユの熱処理方法は、中炭素低合金鋼を素材と
する履帯ブツシユに、外周表面のみから、内周表
面をAc3点直上の温度にする高周波誘導加熱およ
び冷却を施して履帯ブツシユの肉厚全体を焼入れ
し、その後焼もどしする熱処理方法からなる。
上記熱処理方法において、焼もどしは、加熱炉
内にて150〜250℃に焼もどしするか、あるいは、
内周表面から高周波誘導加熱によつて内周側を加
熱して焼もどしするか、によつて行なわれる。
内周表面からの高周波誘導加熱による焼もどし
をする場合は、外周側は、内周側を焼もどしする
ときの伝導熱を利用し、内周側より低い温度で焼
もどしする。
［作用］
特願昭57−179980号公報の従来の熱処理方法に
よつて製造されたブツシユは、炉中焼もどしのた
め内周、外周表面の硬さは同じで、HRC50〜62程
度の硬さにあり、耐摩耗性が優れていると同時
に、肉厚中央部はHRC20〜40程度の硬さになつて
おり、ブツシユ全体の靫性を保つのに役立つてい
る。当該ブツシユの内周、外周表面付近の旧オー
ステナイト結晶粒度は生産性を考慮し、実用上問
題ない範囲（結晶粒度番号７程度、JISG0551に
よる）になつている。
これに対し、本発明に係る履帯ブツシユの熱処
理方法では、外周表面のみからの、高周波誘導加
熱および冷却のため、焼入れ加熱段階において、
外周表面から内周表面に温度勾配がつき、加熱外
周表面から最も離れた内周表面の温度を、変態温
度Ac3点直上の温度にコントロールできる。これ
によつて内周表面付近の旧オーステナイト結晶粒
の粗大化を抑制し微細化をはかることができる。
したがつて、本発明の熱処理方法によつて得られ
るブツシユの内周表面付近の旧オーステナイト結
晶粒は微細で、これによつて靫性と疲労強度が向
上する。
さらに、本発明の熱処理方法は、外周表面のみ
から加熱して冷却する焼入れ方法であるから、ブ
ツシユの内周表面付近には圧縮の残留応力が付与
される。この圧縮残留応力によつて疲労強度が向
上する。
本発明の熱処理方法では高周波焼入れ前の調質
工程はなく、かつ高周波焼入れ工程における内周
側からの焼入れ工程もないために、前記特願昭57
−179980号発明にくらべても内周側の高周波焼入
れ工程分、工程削減がはかられている。
本発明によつて製造されたブツシユは、外周表
面からの加熱、冷却による焼入れを経て製造さ
れ、全肉厚がHRC50〜62程度に硬化する。これは
表面の耐摩耗性には非常によいが、靫性が犠牲に
なるので、上記の結晶粒の微細化で、実用上問題
ない程度に靫性をカバーしている点が特徴であ
る。
［実施例］
以下に、本発明の履帯ブツシユの熱処理方法に
係る望ましい実施例を、第３図ないし第７図を参
照して説明する。
本発明を工程順に説明する。
第１工程
中炭素低合金鋼を素材とする筒状の履帯ブツシ
ユを機械加工して用意する。試験には、中炭素低
合金鋼として第１表に示す中炭素クロム・ボロン
鋼を用い、供試材を作成した。
[Industrial Application Field] The present invention relates to a method for heat treating track bushings used in tracked vehicles and the like. [Prior Art] As shown in FIG. 1, a crawler track 1 used for a tracked vehicle etc. includes a shoe 2, a shoe tightening bolt 3, a shoe tightening nut 4, links 5 and 6, a bush 7, a dust seal 8, and a pin 9. One unit is made up of the following. As shown in FIG. 2, the bushing 7 used in the crawler track 1 is required to have wear resistance on its inner circumferential surface 7a and outer circumferential surface 7b, as well as strength, toughness, and strength to withstand the load applied to the bushing 7. Fatigue strength is required. Therefore,
Conventionally, bushings for crawler tracks have been subjected to heat treatment in order to satisfy the above-mentioned quality requirements. Conventional heat treatment methods include (a) case hardening steel (e.g.
JIS: SCM415, 420) is used as a material, and the method is to carburize and quench the material and then temper it (Special Publication Act 1977-
34806) and (b) medium carbon low alloy steel (e.g.
JIS: SCM435, SCM440, JIS: SCr435 with B added) is used as a material, tempered to create a soft ductile part in the center of the wall thickness, and then the outer periphery,
There is a method in which both sides of the inner periphery are subjected to induction hardening and then tempered (description of the prior art in JP-A-59-77979). However, in method (b), which includes the above-mentioned tempering,
Since medium-carbon low-alloy steel is heated in a heating furnace to a temperature of Ac 3 or higher, oil quenched, and then tempered at a temperature of around 600℃, the processing time is reduced. The disadvantage was that the process was long and required many processing steps, resulting in poor work efficiency. Therefore, in order to improve this, a high-frequency induction heating quenching method for track bushings that omits material refining, ``Crawler bushings and their production method'', has been developed.
This was proposed by the applicant of this patent in Japanese Patent Application No. 179980/1983 (Japanese Patent Application Laid-open No. 77979/1982). [Problems to be Solved by the Invention] However, the invention of Japanese Patent Application No. 57-179980 also requires three steps: induction hardening on the outer circumferential side, induction hardening on the inner circumferential side, and tempering. Therefore, it is desired to develop a heat treatment method that can be processed in fewer steps and that does not deteriorate the wear resistance, fatigue strength, or patina of the bush. The object of the present invention is to have fewer processing steps than the invention of Japanese Patent Application No. 57-179980, and to provide wear resistance and
An object of the present invention is to provide a heat treatment method for track bushings that does not deteriorate fatigue strength and toughness. [Means for Solving the Problems] A heat treatment method for a track bushing according to the present invention to achieve the above-mentioned object is to apply Ac to a track bushing made of medium carbon low alloy steel from only the outer circumferential surface to the inner circumferential surface. It consists of a heat treatment method that hardens the entire thickness of the track bushing by applying high-frequency induction heating and cooling to a temperature just above three points, and then tempering it. In the above heat treatment method, tempering is performed by tempering at 150 to 250°C in a heating furnace, or
This is done by heating and tempering the inner circumferential side by high-frequency induction heating from the inner circumferential surface. When tempering is performed by high-frequency induction heating from the inner circumferential surface, the outer circumferential side is tempered at a lower temperature than the inner circumferential side, using conductive heat when tempering the inner circumferential side. [Function] Bushes manufactured by the conventional heat treatment method disclosed in Japanese Patent Application No. 57-179980 have the same hardness on the inner and outer surfaces due to furnace tempering, and have an H R C of about 50 to 62. It is hard and has excellent abrasion resistance, and at the same time, the thick central part has a hardness of about H R C 20 to 40, which helps maintain the shine of the entire bushing. Considering productivity, the prior austenite crystal grain size near the inner and outer peripheral surfaces of the bushing is within a range that does not cause any practical problems (crystal grain size number approximately 7, according to JISG0551). On the other hand, in the heat treatment method for track bushings according to the present invention, in the quenching heating stage, due to high frequency induction heating and cooling from only the outer peripheral surface,
There is a temperature gradient from the outer circumferential surface to the inner circumferential surface, and the temperature of the inner circumferential surface farthest from the heated outer circumferential surface can be controlled to a temperature just above the transformation temperature Ac. This makes it possible to suppress coarsening of prior austenite crystal grains in the vicinity of the inner circumferential surface and to achieve refinement.
Therefore, the prior austenite crystal grains in the vicinity of the inner circumferential surface of the bush obtained by the heat treatment method of the present invention are fine, thereby improving the toughness and fatigue strength. Furthermore, since the heat treatment method of the present invention is a hardening method that heats and cools only the outer circumferential surface, compressive residual stress is imparted to the vicinity of the inner circumferential surface of the bush. This compressive residual stress improves fatigue strength. In the heat treatment method of the present invention, there is no thermal refining process before induction hardening, and there is no hardening process from the inner peripheral side in the induction hardening process.
Compared to the invention of No.-179980, the process is reduced by the induction hardening process on the inner circumferential side. The bush manufactured according to the present invention is manufactured through hardening by heating and cooling from the outer circumferential surface, and is hardened to a total wall thickness of approximately H R C 50 to 62. Although this is very good for surface wear resistance, it comes at the expense of toughness, so the feature is that the above-mentioned refinement of the crystal grains covers the toughness to the extent that there is no problem in practical use. [Embodiments] Hereinafter, preferred embodiments of the method for heat treatment of track bushings of the present invention will be described with reference to FIGS. 3 to 7. The present invention will be explained step by step. 1st step A cylindrical track bushing made of medium carbon low alloy steel is machined and prepared. For the test, test materials were prepared using medium carbon chromium boron steel shown in Table 1 as medium carbon low alloy steel.
【表】
第２工程
履帯ブツシユの供試材を、筒状体の外周表面の
みから、周波数2.5KHzの高周波誘導電流によつ
て加熱する。このとき、高周波条件を調整して、
内周表面付近の温度を、変態点Ac3点直上の温度
にする。加熱直後、外周表面のみから冷却し、外
周表面から全肉厚にわたつて焼入れする。その結
果、第２表に示すように内周表面付近の旧オース
テナイト結晶粒が、微細になる。[Table] 2nd step The sample material of the track bushing is heated only from the outer circumferential surface of the cylindrical body using a high-frequency induced current with a frequency of 2.5 KHz. At this time, adjust the high frequency conditions and
The temperature near the inner peripheral surface is set to just above the transformation point Ac3 . Immediately after heating, it is cooled only from the outer peripheral surface and hardened over the entire wall thickness from the outer peripheral surface. As a result, as shown in Table 2, the prior austenite crystal grains near the inner peripheral surface become fine.
【表】
上表より明らかなように、内周表面付近の結晶
粒度番号は、9.4であり、従来の前記結晶粒度番
号７に比べて、さらに微細化されている。
第３工程
焼入れ後の供試材を、焼もどしする。焼もどし
には、150〜250℃の炉中焼もどしと、内周表面か
らの高周波誘導加熱による焼もどしとの、２つの
方法が適用でき、何れの方法によつてもよい。
試験では、炉中で200℃に焼もどしする炉中焼
もどしを用いた。150〜250℃の範囲は、焼入れに
よる実用上の有効硬さをそこなわずに焼もどしで
きる範囲である。その結果の供試材の厚さ方向の
硬さ分布を第３図に示してある。第３図に示すよ
うに、外周表面、芯部、内周表面ともほぼ同一硬
さが得られた。ロツクウエル硬さでHRC50近傍以
上は、ブツシユの内周表面、外周表面に十分な耐
摩耗性を与える硬さである。
内周表面からの高周波誘導加熱による焼もどし
を適用する場合は、内周表面を200〜250℃程度に
加熱し、外周側は内周側を焼もどすときの伝導熱
を利用して、内周側より低い温度（約170℃）に
焼もどしする。このとき得られる硬さは、内周表
面でHRC50〜60であり、外周表面は焼入れのまま
の硬さが保持できる。
第４図は、同一化学成分、同一炉中焼もどしに
おける本発明品と従来品との疲労特性比較を示し
ている。第４図から、本発明方法によつて得られ
るブツシユの疲労特性が、調質後高周波焼入れ焼
もどし品および調質なし高周波焼入れ焼もどし品
と、ほぼ同等であることが判明する。第６図は、
高荷重域の亀裂発生繰返し数と内周表面付近の旧
オーステナイト結晶粒度番号との関係を示してい
る。第６図から結晶粒が微細であると、高荷重域
の亀裂発生繰返し数が多くなる、すなわち亀裂が
発生しにくくなることが判明する。第６図はま
た、本発明品の旧オーステナイト結晶粒度番号が
９以上で、従来の、調質後高周波焼入れ炉中焼も
どし品の7.1、調質なし高周波焼入れ焼もどし品
の6.9に比べて、結晶粒度番号が大、すなわち結
晶粒が微細化され、耐亀裂発生に対しては従来品
より優れていることを示している。
さらに、外周表面のみからの加熱冷却による焼
入れと、焼もどし工程を経た供試材には、内周表
面付近に圧縮残留応力が生じている。第７図は、
本発明品の残留応力分布を示している。第７図か
ら、本発明品の内周表面付近の残留応力が圧縮に
なつていることが判明する。
第４工程
焼もどしされた供試材の外周表面のみを位上研
摩加工し、最終製品を得る。
本発明の方法は、上記の第２工程および第３工
程にわたつて存在する。
［発明の効果］
本発明の履帯ブツシユの熱処理方法によるとき
は、次にあげる効果が得られる。
イ 外周表面のみからの高周波誘導加熱および冷
却による焼入れとその後の焼もどしの組合せに
よつて、高周波焼入れ前の調質工程、高周波焼
入れ時の内周側の高周波焼入れ工程を省略する
ことができ、熱処理工数の低減をはかることが
できる。
ロ 焼入れによつて全肉厚がHRC50〜62程度に硬
化されており、内周表面、外周表面の耐摩耗性
を良好にすることができる。
ハ 全肉厚硬化にもかかわらず、外周表面のみか
らの、内周表面をAc3点直上の温度にする高周
波誘導加熱によつて、内周表面付近の旧オース
テナイト結晶粒の粗大化を抑制して微細化で
き、疲労強度、靫性を従来品に比べて遜色ない
程度またはそれ以上に向上させることができ
る。
ニ 外周表面のみからの加熱および冷却による焼
入れと、その後の焼もどしの組合せによつて、
内周表面付近に圧縮残留応力が生成し、疲労強
度が向上する。[Table] As is clear from the above table, the grain size number near the inner peripheral surface is 9.4, which is even finer than the conventional grain size number 7. Third step: Temper the sample material after quenching. Two methods can be applied to the tempering: tempering in a furnace at 150 to 250°C and tempering by high-frequency induction heating from the inner circumferential surface, and either method may be used. In the test, furnace tempering, in which the material is tempered in a furnace at 200°C, was used. The range of 150 to 250°C is the range in which tempering can be performed without damaging the practically effective hardness due to quenching. The resulting hardness distribution in the thickness direction of the sample material is shown in FIG. As shown in FIG. 3, almost the same hardness was obtained for the outer circumferential surface, core portion, and inner circumferential surface. A Rockwell hardness of around H R C50 or higher is a hardness that provides sufficient wear resistance to the inner and outer peripheral surfaces of the bush. When applying tempering by high-frequency induction heating from the inner circumferential surface, the inner circumferential surface is heated to about 200 to 250℃, and the outer circumference is heated to about 200 to 250℃, and the inner circumference is Temper to a lower temperature than the other side (approximately 170℃). The hardness obtained at this time is H R C50 to 60 on the inner peripheral surface, and the hardness of the outer peripheral surface can be maintained as hardened. FIG. 4 shows a comparison of fatigue properties between the product of the present invention and a conventional product with the same chemical composition and tempering in the same furnace. From FIG. 4, it is clear that the fatigue properties of the bushes obtained by the method of the present invention are almost the same as those of the products subjected to induction quenching and tempering after thermal refining and the products subjected to induction quenching and tempering without refining. Figure 6 shows
It shows the relationship between the number of crack initiation cycles in the high load region and the prior austenite grain size number near the inner peripheral surface. It is clear from FIG. 6 that when the crystal grains are fine, the number of repetitions of crack generation in the high load region increases, that is, it becomes difficult for cracks to occur. Figure 6 also shows that the prior austenite grain size number of the product of the present invention is 9 or more, compared to 7.1 for the conventional product that has been induction quenched and tempered in an induction quenching furnace after heat refining, and 6.9 for the product that has been induction quenched and tempered without heat refining. The crystal grain size number is large, meaning the crystal grains are refined, indicating that the product is superior to conventional products in terms of resistance to cracking. Furthermore, compressive residual stress is generated in the vicinity of the inner circumferential surface of the sample material that has been quenched by heating and cooling only from the outer circumferential surface and has undergone a tempering process. Figure 7 shows
It shows the residual stress distribution of the product of the present invention. It is clear from FIG. 7 that the residual stress near the inner peripheral surface of the product of the present invention is compressive. Fourth step: Only the outer peripheral surface of the tempered sample material is polished to obtain a final product. The method of the present invention includes the above-mentioned second and third steps. [Effects of the Invention] When the method of heat treating a track bushing of the present invention is used, the following effects can be obtained. (b) By combining hardening by high-frequency induction heating and cooling from only the outer peripheral surface and subsequent tempering, it is possible to omit the refining process before induction hardening and the induction hardening process on the inner peripheral side during induction hardening, It is possible to reduce the number of heat treatment steps. (b) The entire wall thickness is hardened to about H R C50 to 62 by quenching, and the wear resistance of the inner and outer peripheral surfaces can be improved. C. Despite full wall thickness hardening, coarsening of prior austenite crystal grains near the inner circumferential surface is suppressed by high-frequency induction heating from the outer circumferential surface only to bring the inner circumferential surface to a temperature just above the Ac 3 point. It is possible to improve the fatigue strength and toughness to a level comparable to or even higher than that of conventional products. D. By a combination of quenching by heating and cooling only from the outer peripheral surface and subsequent tempering,
Compressive residual stress is generated near the inner peripheral surface, improving fatigue strength.
第１図は一般の履帯の分解斜視図、第２図は一
般の履帯ブツシユの縦断面図、第３図は本発明品
の断面硬さ分布図、第４図は本発明品と従来品
の、亀裂発生繰返し数一荷重特性の、比較図、第
５図は本発明品と従来品の圧壊荷重比較図、第６
図は本発明品と従来品の、旧オーステナイト結晶
粒度番号と荷重18.7ton（高荷重域）における亀裂
発生繰返し数特性の、比較図、第７図は本発明品
の残留応力分布図、である。
７……履帯ブツシユ。
Fig. 1 is an exploded perspective view of a general crawler belt, Fig. 2 is a vertical cross-sectional view of a general crawler bushing, Fig. 3 is a cross-sectional hardness distribution diagram of the product of the present invention, and Fig. 4 is a diagram of the cross-sectional hardness of the product of the present invention and the conventional product. Figure 5 is a comparison diagram of the crushing load of the product of the present invention and the conventional product.
The figure is a comparison diagram of the prior austenite grain size number and crack occurrence repetition rate characteristics at a load of 18.7 tons (high load area) between the inventive product and the conventional product. Figure 7 is the residual stress distribution diagram of the inventive product. . 7...Crawler bumps.
Claims (1)
に、外周表面のみから、内周表面をAc3点直上の
温度にする高周波誘導加熱および冷却を施して履
帯ブツシユの肉厚全体を焼入れし、その後焼もど
しすることを特徴とする履帯ブツシユの熱処理方
法。 ２ 前記焼もどしを、加熱炉内で150〜250℃の温
度で行なう特許請求の範囲第１項記載の履帯ブツ
シユの熱処理方法。 ３ 前記焼もどしを、内周表面からの高周波誘導
加熱により行なう特許請求の範囲第１項記載の履
帯ブツシユの熱処理方法。 ４ 内周側を焼もどしするときの伝導熱を利用
し、外周側を内周側より低い温度で焼もどしする
特許請求の範囲第１項記載の履帯ブツシユの熱処
理方法。[Scope of Claims] 1 A track bushing made of medium carbon low alloy steel is subjected to high frequency induction heating and cooling to bring the temperature of only the outer circumferential surface to the inner circumferential surface just above the Ac 3 point to increase the wall thickness of the track bushing. A heat treatment method for track bushings, which is characterized by quenching the entire body and then tempering it. 2. The method of heat treating a track bushing according to claim 1, wherein the tempering is performed in a heating furnace at a temperature of 150 to 250°C. 3. The method of heat treating a track bushing according to claim 1, wherein the tempering is performed by high-frequency induction heating from the inner circumferential surface. 4. The method of heat treating a track bushing according to claim 1, wherein the outer circumferential side is tempered at a lower temperature than the inner circumferential side by utilizing conductive heat when tempering the inner circumferential side.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25462386A JPS63109119A (en) | 1986-10-28 | 1986-10-28 | Method for heat treatment of caterpillar bush |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25462386A JPS63109119A (en) | 1986-10-28 | 1986-10-28 | Method for heat treatment of caterpillar bush |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63109119A JPS63109119A (en) | 1988-05-13 |
| JPH0137453B2 true JPH0137453B2 (en) | 1989-08-07 |
Family
ID=17267599
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25462386A Granted JPS63109119A (en) | 1986-10-28 | 1986-10-28 | Method for heat treatment of caterpillar bush |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63109119A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0270022A (en) * | 1988-09-05 | 1990-03-08 | Topy Ind Ltd | Heat treatment of bushing used for track of trackless vehicle |
| JPH02169375A (en) * | 1988-12-21 | 1990-06-29 | Topy Ind Ltd | Crawler bushing and manufacture thereof |
| JP6229226B2 (en) * | 2013-06-26 | 2017-11-15 | 高周波熱錬株式会社 | Heat treatment method |
| CN103540716A (en) * | 2013-09-22 | 2014-01-29 | 徐州徐工铁路装备有限公司 | Processing method of tread thermal treatment for caterpillar link |
-
1986
- 1986-10-28 JP JP25462386A patent/JPS63109119A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63109119A (en) | 1988-05-13 |
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