JP2004027258A

JP2004027258A - Cutting-finished bar steel having excellent shear cuttability and method of producing the bar steel

Info

Publication number: JP2004027258A
Application number: JP2002182227A
Authority: JP
Inventors: Hiroaki Nakazato; 中里　弘昭; Shoichi Kajimoto; 梶本　昭一
Original assignee: Sanyo Special Steel Co Ltd
Current assignee: Sanyo Special Steel Co Ltd
Priority date: 2002-06-21
Filing date: 2002-06-21
Publication date: 2004-01-29
Anticipated expiration: 2022-06-21
Also published as: JP3860079B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of realizing satisfactory shear cutting operability, dimensional precision and severe weight control in bar steel subjected to a cutting finish for the removal of a scale skin formed after heat treatment such as a hot rolling finish and annealing after hot rolling, the future proof of surface flaws and the future proof of decarburizing by properly controlling the roughness of the surface of the bar steel and the viscosity of rust prevention oil applied after that and to provide bar steel by the method. <P>SOLUTION: When the scale skin of bar steel such as carbon steel for machine structural use, alloy steel for machine structural use and high carbon chromium bearing steel is subjected to a cutting finish, the cutting finish is performed so as to be a surface roughness Rz of 2.9 to 8.8 μm, and thereafter, rust prevention oil having a viscosity of 5 to 14 (Poise) is applied to the surface of the bar steel. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
シャー切断性に優れた機械構造用炭素鋼、機械構造用合金鋼や高炭素クロム軸受用鋼などの熱延あるいは熱処理などにより発生した黒皮肌の除去、表面キズ保証、脱炭保証あるいは寸法精度保証のために切削仕上げした棒鋼に関するものである。
【０００２】
【従来の技術】
熱間、温間あるいは冷間による鍛造用の棒鋼は、ユーザーにて切断し、その後所定の処理をして鍛造される場合が多い。この切断方法としては、シャー切断あるいは鋸切断が主として採用されている。ところで、例えばφ９０以上の特に太いサイズの棒鋼を除けば、シャー切断されるのが通常である。従来、棒鋼は熱間圧延仕上げ、あるいは熱間圧延後に焼きなましなどの熱処理を施した黒皮肌の棒鋼が使用されており、特に表面キズ保証、脱炭保証あるいは寸法精度保証の厳しい用途に対してはバーターニング（ピーリング、ターニング）等の切削による皮むき仕上げした棒鋼が使用されていた。
【０００３】
このような従来の技術において、最近は、鍛造歩留りの向上や、鍛造仕上げ寸法精度の向上等のニーズが強くなってきている。それに伴い素材である棒鋼に対しては、シャー切断後の棒鋼の重量管理のシビアー化に対応するため、みがき棒鋼並の寸法精度が求められてきており、また、シャー切断後のＴＰのダレ防止等の寸法精度向上のために切断機ガイドのクリアランスが小さくなってきている。さらに、鍛造仕上げ寸法精度向上に伴い、鍛造品の表面欠陥は極端に嫌われるようになり、それの原因となる素材の表面欠陥もあってはならず、たとえ錆び的なものでも嫌われる。従って、素材の防錆処理も重要となってきている。
【０００４】
棒鋼のシャー切断に関する従来の技術としては、切断方法に関するものとして特開昭５７−６１４１２号公報、特開昭５９−１６６４０８号公報、特開昭６３−３４０１３号公報など、良好な切断を実現するための材料の組織制御、硬さ制御等に関するものとして特開平１０−６０５９４号公報、特開平１０−６０５９５号公報、特開平１１−１９９９２７号公報など、切断装置に関するものとして特開平３−２９４１０４号公報、特開平７−３１４２３８号公報などが開示されているが、いずれもシャー切断用棒鋼の表面粗さ、防錆油の粘度には言及していない。
【０００５】
以上の従来技術において、上記した黒皮肌の棒鋼では、その寸法精度向上のニーズには応えきれていないため、シャー切断棒鋼のシビアーな重量管理が実現できていない。さらに、切断機ガイドでのクリアランスが良好に保てないため、ガイドでの詰まりが生じ、また、切断棒鋼のダレなどのため、良好な寸法精度が確保できていない。また、従来の切削によるピーリング仕上げ棒鋼は表面が平滑であって、かつ、防錆油が塗布されているため、シャー切断時に滑りを起こし、このため切断棒鋼の切断面が斜め（いわゆる「倒れ」）になり、これがその後の鍛造でキズの原因になる。さらに、切断時に滑るため、切断棒鋼のシビアーな重量管理も実現できていない、などの種々の問題点がある。
【０００６】
【発明が解決しようとする課題】
本発明が解決しようとする課題は、熱延仕上げや熱延後の焼きなましなどの熱処理後に発生した黒皮肌の除去、表面キズ保証および脱炭保証のための切削仕上げした棒鋼において、棒鋼表面の粗さと、その後に塗布される防錆油の粘度を適正に制御することにより、切断用母材（鋼材）の寸法精度を、通常幅で、例えば０．１〜０．２ｍｍとするが、ユーザーのニーズに応じた仕様に確保して、良好なシャー切断作業性、切断棒鋼の寸法精度およびシビアーな重量管理を実現する方法を提供するものである。
【０００７】
【課題を解決するための手段】
上記の課題を解決するための本発明の手段は、請求項１の発明では、機械構造用炭素鋼、機械構造用合金鋼あるいは高炭素クロム軸受鋼などの鋼種からなる棒鋼の黒皮肌の表面粗さＲｚを２．９〜８．８μｍとして切削仕上げした棒鋼表面に粘度５〜１４（Ｐｏｉｓｅ）の防錆油を防錆および鋼材同士の擦れキズ防止のため塗布したことを特徴とするシャー切断性に優れた切削仕上げ棒鋼である。
【０００８】
請求項２の発明では、機械構造用炭素鋼、機械構造用合金鋼あるいは高炭素クロム軸受鋼などの鋼種からなる棒鋼の黒皮肌の切削仕上げにおいて、表面粗さ：Ｒｚを２．９〜８．８μｍとして切削仕上げを行い、この切削仕上げした棒鋼の表面に粘度５〜１４（Ｐｏｉｓｅ）の防錆油を防錆および鋼材同士の擦れキズ防止のため塗布することを特徴とするシャー切断性に優れた切削仕上げ棒鋼の製造方法である。
【０００９】
【発明の実施の形態】
本発明の実施の形態を以下に示す実施例の発明例と比較例および従来例を通じて説明する。先ず、説明に先立って、本発明の作用および本発明の手段の限定理由を述べると、本発明は良好なシャー切断作業性と切断棒鋼の寸法精度、シビアーな重量管理を実現できるもので、その手段の限定理由を説明すると以下のとおりである。
【００１０】
本発明における鋼種は機械構造用炭素鋼、機械構造用合金鋼あるいは高炭素クロム軸受鋼などのφ９０以下の例えばφ２２．５〜４４．５の棒鋼であって、切削仕上げ棒鋼の表面粗さＲｚを２．９〜８．８μｍとする理由は、表面粗さＲｚが小さいと、シャー切断時にホルダーとの「噛み合い」が弱いため棒鋼が滑るので、この滑りを防止するためにＲｚ２．９μｍ以上が必要である。表面粗さＲｚが大きすぎるとシャー切断時に切断部近傍でクラックが生じ易くなり、その後の鍛造でキズの原因になる可能性が高くなるので、このクラックの発生を防止するためにＲｚの上限を８．８μｍとする必要がある。そこで、切削仕上げ棒鋼の表面粗さＲｚを２．９〜８．８μｍとする。
【００１１】
防錆油の粘度：５〜１４（Ｐｏｉｓｅ）とする理由は、防錆油の粘度が小さすぎると、鋼材搬送中に鋼材同士の擦れキズが発生し、また防錆効果も小さくなるために粘度の下限を５（Ｐｏｉｓｅ）とする。防錆油の粘度が大きすぎると、シャー切断時に鋼材とシャー切断ホルダーの間に防錆油が残留し易くなり、そのため鋼材とシャー切断ホルダーとの「噛み合い」が弱くなり滑るので、粘度の上限を１４（Ｐｏｉｓｅ）とする。そこで、防錆油の粘度を５〜１４（Ｐｏｉｓｅ）とする。
【００１２】
【実施例】
熱間圧延仕上げして得られた黒皮肌を有するφ２４〜φ４６の機械構造用合金鋼からなる棒鋼をピーリング機により黒皮を除去する切削仕上げし、防錆油を塗布し、それらの棒鋼の９種を得た。それらをシャー切断してその切断性で評価した。表１に示すように、これら９種は、それぞれ切削仕上げ棒鋼の表面粗さＲｚ、防錆油の粘度が本発明の範囲にあるものを本発明例として４種と、一つでも本発明の範囲外のものを比較例の３種と従来例の２種として、それぞれシャー切断性は、切断作業能率および切断棒鋼の寸法精度で判断し、シャー切断性の良好なものを○、切断できたが問題のあるものを△、切断不良のものを×で評価した。なお、寸法精度については、切断面の形状が良好なもの、すなわち切断面が斜めにならず、いわゆる「倒れ」が発生せず、かつ、切断部近傍でクラックが発生しないものを○とした。
【００１３】
【表１】

【００１４】
表１に見られるように、表面粗さＲｚおよび防錆油の粘度が共に本発明の範囲にあるものはいずれもシャー切断性は良好で問題はなかった。これに対し比較例のＮｏ．５のものは表面粗さＲｚが本発明の上限を超えており、この場合は鍛造品にシャー切断部近傍で発生したクラックが起因の鍛造キズの発生が見られた。比較例のＮｏ．６のものは表面粗さＲｚは本発明の範囲にあるが、防錆油の粘度が本発明の下限未満であり、この場合は素材擦れキズの発生が見られた。さらに、比較例のＮｏ．７のものは表面粗さＲｚは本発明の範囲を満足するが、防錆油の粘度が本発明の上限を超えるものであり、この場合は滑りが発生して切断が不良で×であった。従来例のＮｏ．８のものは、黒皮品であり、鋼材（切断用母材）の寸法公差、真円度などの寸法精度保証ができておらず、そのため詰まりを発生して満足にシャー切断出来なかった。さらに、従来例のＮｏ．９のものは表面粗さＲｚが本発明の下限値に満たなかったもので、防錆油は本発明の範囲に入る粘度のものであったが、滑りが発生して満足にシャー切断出来なかった。
【００１５】
【発明の効果】
以上説明したように、本発明は、熱間圧延仕上げや熱間圧延後焼きなましした黒皮肌の機械構造用炭素鋼、機械構造用合金鋼あるいは高炭素クロム軸受鋼などの棒鋼を、例えばピーリングなどにより切削仕上げ棒鋼とする際に、その切削仕上げ粗さおよび切削仕上げ後塗布する防錆油の粘度を最適化することにより、シャー切断の噛み合いが良好で、切断寸法精度が良好で有るなど極めて優れたシャー切断性を有する棒鋼に製造できる優れた効果を有するものである。[0001]
TECHNICAL FIELD OF THE INVENTION
Removal of black skin caused by hot rolling or heat treatment of carbon steel for machine structure, alloy steel for machine structure, steel for high carbon chromium bearing, etc. with excellent shearing property, surface flaw guarantee, decarburization guarantee or dimensional accuracy It is related to steel bars cut and finished for guarantee.
[0002]
[Prior art]
A steel bar for forging by hot, warm or cold is often cut by a user and then subjected to a predetermined treatment to be forged. As this cutting method, shear cutting or saw cutting is mainly employed. By the way, shearing is usually performed except for a bar having a particularly large size of, for example, φ90 or more. Conventionally, the steel bars used are black-rolled steel bars that have been subjected to heat treatment, such as hot rolling finish or hot rolling, followed by annealing, especially for applications where surface scratches, decarburization or dimensional accuracy are strictly guaranteed. For the steel bar, bar steel peeled by cutting such as bar turning (peeling, turning) was used.
[0003]
In such conventional techniques, recently, needs for improving forging yield and forging finished dimensional accuracy have been increasing. As a result, the bar material, which is the material, is required to have the same dimensional accuracy as that of a polished bar in order to respond to the severe weight management of the bar after cutting the shear, and to prevent TP from dripping after cutting the shear. In order to improve the dimensional accuracy, the clearance of the cutting machine guide has been reduced. Furthermore, with the improvement of the forging finish dimensional accuracy, the surface defects of the forged product are extremely disliked, and there must be no surface defects of the material that causes it, and even the rust-like ones are disliked. Therefore, rust prevention treatment of the material is also becoming important.
[0004]
As a conventional technique relating to shear cutting of a steel bar, as to a cutting method, good cutting such as disclosed in JP-A-57-61412, JP-A-59-166408, and JP-A-63-34013 is realized. Japanese Patent Application Laid-Open Nos. 10-60594, 10-60595, 11-199927, and the like, related to the control of the structure and hardness of the material, and the like, to JP-A-3-294104 related to the cutting device. Japanese Patent Application Laid-Open No. 7-314238 and the like, but none of them mention the surface roughness of a steel bar for shearing and the viscosity of rust preventive oil.
[0005]
In the prior art described above, the bar steel with the above-mentioned black skin does not meet the needs of improving the dimensional accuracy, and thus severe weight management of the shear-cut steel bar cannot be realized. Further, the clearance in the guide of the cutting machine cannot be maintained well, so that the guide is clogged, and good dimensional accuracy cannot be secured due to sagging of the cut steel bar. In addition, since the surface of a peeled steel bar obtained by conventional cutting has a smooth surface and is coated with rust-preventive oil, slip occurs at the time of shear cutting, so that the cut surface of the cut steel bar is oblique (so-called “falling”). ), Which causes scratches in subsequent forging. Furthermore, there are various problems such as severe weight control of the cut steel bars cannot be realized due to slippage during cutting.
[0006]
[Problems to be solved by the invention]
The problem to be solved by the present invention is to remove black scale skin generated after heat treatment such as hot rolling and annealing after hot rolling, and to cut and finish the bar for surface flaw guarantee and decarburization guarantee. By properly controlling the roughness and the viscosity of the rust-preventive oil applied thereafter, the dimensional accuracy of the cutting base material (steel material) is set to a normal width, for example, 0.1 to 0.2 mm. It is intended to provide a method for ensuring good shearing workability, dimensional accuracy of cut steel bars, and severe weight management by securing specifications according to the needs of (1).
[0007]
[Means for Solving the Problems]
Means of the present invention for solving the above-mentioned problems are, in the invention of claim 1, a surface of a black skin of a steel bar made of a steel type such as carbon steel for machine structure, alloy steel for machine structure or high carbon chromium bearing steel. A shear cutting characterized in that a rust-preventive oil having a viscosity of 5 to 14 (Poise) is applied to the surface of a steel bar cut and finished with a roughness Rz of 2.9 to 8.8 μm to prevent rust and prevent scratches between steel materials. This is a finished steel bar with excellent properties.
[0008]
According to the second aspect of the present invention, the surface roughness: Rz is 2.9 to 8 in the black-finished skin of a steel bar made of a steel type such as carbon steel for machine structure, alloy steel for machine structure, or high carbon chromium bearing steel. .8 μm, and the surface of the cut bar is coated with a rust-preventive oil having a viscosity of 5 to 14 (Poise) to prevent rust and to prevent scratches between steel materials. This is a method for producing excellent cut and finished steel bars.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described with reference to the following examples, comparative examples, and conventional examples. First, prior to the description, the operation of the present invention and the reasons for limiting the means of the present invention will be described.The present invention can realize good shear cutting workability, dimensional accuracy of a cut steel bar, and severe weight management. The reasons for limiting the means will be described below.
[0010]
The steel type in the present invention is a bar steel of φ90 or less, for example, φ22.5 to 44.5, such as carbon steel for mechanical structure, alloy steel for mechanical structure, or high carbon chromium bearing steel, and has a surface roughness Rz of the cut and finished steel bar. The reason for setting the thickness to 2.9 to 8.8 μm is that if the surface roughness Rz is small, the bar is slipped because the “meshing” with the holder is weak at the time of cutting the shear, so Rz 2.9 μm or more is required to prevent this slippage. It is. If the surface roughness Rz is too large, cracks are likely to occur near the cut portion during shear cutting, and the possibility of causing scratches in subsequent forging increases, so the upper limit of Rz is set to prevent the occurrence of cracks. It needs to be 8.8 μm. Therefore, the surface roughness Rz of the cut steel bar is set to 2.9 to 8.8 μm.
[0011]
The reason for setting the viscosity of the rust preventive oil to 5 to 14 (Poise) is that if the viscosity of the rust preventive oil is too low, scratches occur between the steel materials during the transfer of the steel materials, and the rust preventive effect is also reduced. Is set to 5 (Poise). If the viscosity of the rust-preventive oil is too high, the rust-preventive oil tends to remain between the steel material and the shear cutting holder when cutting the shear, thereby weakening the "meshing" between the steel material and the shear cutting holder and slipping. Is set to 14 (Poise). Therefore, the viscosity of the rust preventive oil is set to 5 to 14 (Poise).
[0012]
【Example】
A steel bar made of alloy steel for machine structure of φ24 to φ46 having a black skin surface obtained by hot rolling finishing is subjected to a cutting finish to remove black scale by a peeling machine, coated with a rust-preventive oil, and subjected to Nine kinds were obtained. They were sheared and evaluated for their cutting properties. As shown in Table 1, these nine types are four types as examples of the present invention in which the surface roughness Rz of the cut steel bar and the viscosity of the rust-preventive oil are within the range of the present invention. Out of the ranges, three types of comparative examples and two types of conventional examples were used, and the shear cutting performance was judged based on the cutting work efficiency and the dimensional accuracy of the cut steel bar. Was evaluated as "A" when there was a problem, and as "X" when the cutting was poor. The dimensional accuracy was evaluated as good when the cut surface had a good shape, that is, when the cut surface did not become oblique, so-called "falling" did not occur, and cracks did not occur near the cut portion.
[0013]
[Table 1]

[0014]
As can be seen from Table 1, those having both the surface roughness Rz and the viscosity of the rust-preventive oil within the range of the present invention exhibited good shearing properties and no problem. On the other hand, in Comparative Example No. In the case of No. 5, the surface roughness Rz exceeded the upper limit of the present invention, and in this case, forging scratches were found in the forged product due to cracks generated near the shear cut portion. No. of the comparative example. In the case of No. 6, the surface roughness Rz was within the range of the present invention, but the viscosity of the rust-preventive oil was less than the lower limit of the present invention, and in this case, scratching of the material was observed. Further, in Comparative Example No. In the case of No. 7, the surface roughness Rz satisfies the range of the present invention, but the viscosity of the anticorrosive oil exceeds the upper limit of the present invention. . No. of the conventional example. No. 8 was a black-skinned product, and dimensional tolerances such as dimensional tolerance and roundness of steel material (base material for cutting) could not be guaranteed. Therefore, clogging occurred and shear cutting could not be performed satisfactorily. Further, the conventional example No. In the case of No. 9, the surface roughness Rz was less than the lower limit of the present invention, and the rust preventive oil had a viscosity falling within the range of the present invention. Was.
[0015]
【The invention's effect】
As described above, the present invention provides a steel bar for machine structure carbon steel, machine structure alloy steel or high-carbon chromium bearing steel having a hot-rolled finish or annealed after hot-rolling, for example, peeling, etc. By optimizing the cutting finish roughness and the viscosity of the rust preventive oil to be applied after the cutting finish, it is extremely excellent, such as good meshing of shear cutting and good cutting dimensional accuracy. It has an excellent effect that it can be manufactured into a steel bar having shear shearing property.

Claims

The surface roughness of the black scale skin of a steel bar made of a steel type such as carbon steel for machine structure, alloy steel for machine structure, or high carbon chromium bearing steel is set to Rz 2.9 to 8.8 μm, and the surface of the steel bar cut and finished has a viscosity of 5 to 14. (Poise) A cut-finished steel bar excellent in shear cutability, characterized by being applied with rust-preventive oil for rust prevention and preventing scratches between steel materials.

In the cutting finishing of the black skin of steel bars made of steel types such as carbon steel for machine structure, alloy steel for machine structure, and high carbon chromium bearing steel, the surface roughness: Rz is set to 2.9 to 8.8 μm. The manufacture of a cut-finished steel bar excellent in shear cutting characteristics, characterized in that a rust-preventive oil having a viscosity of 5 to 14 (Poise) is applied to the surface of the cut-finished steel bar to prevent rust and prevent scratches between steel materials. Method.