JPH01234528A - Production of shape steel for fork lift mast having excellent wear resistance and deformation resistance - Google Patents
Production of shape steel for fork lift mast having excellent wear resistance and deformation resistanceInfo
- Publication number
- JPH01234528A JPH01234528A JP5989588A JP5989588A JPH01234528A JP H01234528 A JPH01234528 A JP H01234528A JP 5989588 A JP5989588 A JP 5989588A JP 5989588 A JP5989588 A JP 5989588A JP H01234528 A JPH01234528 A JP H01234528A
- Authority
- JP
- Japan
- Prior art keywords
- hot rolling
- section steel
- shape steels
- wear resistance
- resistance
- 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.)
- Pending
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 52
- 239000010959 steel Substances 0.000 title claims abstract description 52
- 238000004519 manufacturing process Methods 0.000 title claims description 5
- 230000009466 transformation Effects 0.000 claims abstract description 33
- 229910000734 martensite Inorganic materials 0.000 claims abstract description 19
- 238000001816 cooling Methods 0.000 claims abstract description 17
- 238000010438 heat treatment Methods 0.000 claims abstract description 17
- 229910001562 pearlite Inorganic materials 0.000 claims abstract description 16
- 238000005098 hot rolling Methods 0.000 claims abstract description 14
- 239000003507 refrigerant Substances 0.000 claims abstract description 8
- 239000007788 liquid Substances 0.000 claims abstract description 7
- 238000000034 method Methods 0.000 claims description 9
- 238000005299 abrasion Methods 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 9
- 230000000717 retained effect Effects 0.000 abstract description 2
- 239000000463 material Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000005275 alloying Methods 0.000 description 4
- 230000006698 induction Effects 0.000 description 4
- 238000005496 tempering Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 238000010791 quenching Methods 0.000 description 3
- 238000005336 cracking Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910001566 austenite Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000029052 metamorphosis Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
- B21B45/0203—Cooling
- B21B45/0209—Cooling devices, e.g. using gaseous coolants
- B21B45/0215—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/08—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling structural sections, i.e. work of special cross-section, e.g. angle steel
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は耐摩耗性および耐変形抵抗性の優れたフォーク
リフトマスト用形鋼の製造法に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a section steel for forklift masts having excellent wear resistance and deformation resistance.
［従来の技術及び発明が解決しようとする課題］産業運
搬機器の分野において重要な役割を占めるフォークリフ
トは、近年より大型化・高性能化が指向されている。そ
れに伴って、重荷重を受けるフォークリフトマスト用形
鋼には摩耗や変形などに起因する以下の問題点が発生し
ていた。すなわち、
■ ローラーと接触するマスト用形鋼の部分で、摩耗剥
離片が発生して運転者の目に入る。[Prior Art and Problems to be Solved by the Invention] Forklifts, which play an important role in the field of industrial transportation equipment, have recently become larger and more sophisticated. As a result, the following problems have arisen in steel sections for forklift masts, which are subject to heavy loads, due to wear and deformation. Namely, (1) Abrasion flakes are generated in the section of the mast section steel that comes into contact with the rollers and come into contact with the driver's eyes.
■ 摩耗によるマスト用形鋼の板厚減少や、重荷重によ
ってマスト用形鋼が第１図図中の破線のように変形する
ことにより、ローラーとマスト用形鋼の間のすき間が大
きくなり、積荷の上げ・下げ時に騒音が発生したり、ま
た衝撃荷重の発生でマストビン溶接部から疲労き裂が発
生する。■ The gap between the roller and the mast section increases as the thickness of the mast section steel decreases due to wear and the mast section deforms as shown by the broken line in Figure 1 due to heavy loads. Noise is generated when lifting and lowering loads, and fatigue cracks occur at mast bin welds due to impact loads.
以上の問題点を解決するために、従来は硬質化合金元素
を微量添加して材料強度を向上したり、あるいはローラ
ーと接触するマスト用形鋼部分を局部的に硬質化するな
どの対策がとられてきた。しかし、合金元素の微量添加
による材料強度の向上は必すしも耐摩耗性の改善にはつ
ながらず、またローラーと接触するマスト用形鋼部分の
局部的硬質化も、耐摩耗性はかなり改善てきるものの、
第１図中破線で示すような変形に対しては効果がないこ
とかわかった。そこで、マスト用形鋼の変形発生原因に
ついて検討するために、実機フォークリフトを用いてマ
スト形鋼各部分にひずみケージを貼付し、２ｔｆの積荷
を乗せ、上・下繰返し試験中に発生するひずみ測定を行
った。その結果、変形の主原因は積荷の上げ・下げ時の
動的荷重によって、マスト用形鋼のフランジとウェブの
付根コーナ一部（第１図中のＡ、Ｂおよび０部）が繰返
し塑性変形しているためであることがわかった。したが
って、変形を防止しさらにローラーと接触するマスト用
形鋼部分の耐摩耗性を改善するためには、マスト用形鋼
全体を硬質化することが最善であることがわかった。そ
の硬質化の方法としてはマスト用形鋼全体を焼もどしマ
ルテンサイト組織にすることか最も有効と考えられる。In order to solve the above problems, conventional measures have been taken such as adding a small amount of hardening alloying elements to improve the material strength, or locally hardening the section of the mast section that comes into contact with the rollers. I've been exposed to it. However, improving material strength by adding small amounts of alloying elements does not necessarily lead to improvement in wear resistance, and localized hardening of the section of the mast section that comes into contact with the rollers does not significantly improve wear resistance. Although
It was found that this method had no effect on deformations as shown by the broken line in FIG. Therefore, in order to investigate the cause of deformation of the mast section steel, we attached strain cages to each part of the mast section using an actual forklift, loaded it with a 2 tf load, and measured the strain that occurred during the top and bottom cyclic tests. I did it. As a result, the main cause of deformation was the repeated plastic deformation of the flange of the mast section steel and part of the root corner of the web (sections A, B, and 0 in Figure 1) due to dynamic loads during lifting and lowering of the load. It turns out that this is because of the fact that Therefore, it has been found that in order to prevent deformation and further improve the wear resistance of the mast section steel portion that comes into contact with the rollers, it is best to harden the entire mast section steel. The most effective method of hardening is to temper the entire mast section steel so that it has a martensitic structure.
しかし、マスト用形鋼の部位によっては従来形鋼よりは
耐摩耗性および耐疲労変形性は改善が必要であるが、よ
り低コストてこれを達成出来れはとの要望もある。そこ
で本発明者らはマスト用形鋼全体を焼きもどしマルテン
サイト組織にして硬質化する方法とマスト用形鋼全体を
微細パーライト組織として硬質化する方法を実験から知
見した。なお、フェライト・パーライト組織では、前記
のように合金元素の微量添加による機械的性質の向上に
よっては耐摩耗性の改善はほとんど期待できなかった。However, depending on the part of the mast shaped steel, it is necessary to improve the wear resistance and fatigue deformation resistance compared to conventional shaped steel, and there is a desire to achieve this at a lower cost. Therefore, the present inventors discovered through experiments a method of hardening the entire mast section steel by tempering it into a martensitic structure, and a method of hardening the entire mast section steel with a fine pearlite structure. In addition, in a ferrite-pearlite structure, almost no improvement in wear resistance could be expected by improving mechanical properties by adding a small amount of alloying elements as described above.
これは合金元素の微量添加による材質強化が主にフェラ
イトの固溶効果や微細析出物の析出強化によったもので
あることを究明し、フェライト・パーライト組織でもパ
ーライト組織の微細化により材質が硬質化すると同時に
耐摩耗性も改善できることを明らかにした。It was discovered that the strengthening of the material due to the addition of small amounts of alloying elements was mainly due to the solid solution effect of ferrite and the precipitation strengthening of fine precipitates. It was revealed that the wear resistance can be improved at the same time.
［課題を解決するための手段］
本発明は上記知見に基づいてなされたもので、その主旨
とするところは、熱間圧延時の保有熱または外部からの
加熱によりＡ１変態点を越え１３００℃以下の温度にあ
るマスト用形鋼全体を急速冷却してマルテンサイト変態
を起こさせ、その後３００℃以上Ａ１変態点を越えない
温度に加熱後、急速冷却して硬質化する方法、または熱
間圧延時の保有熱あるいは外部からの加熱によりＡ、変
態点を越え１３００℃以下の温度にあるマスト用形鋼全
体を、微細パーライト組織を呈する速さでパーライト変
態が終了するまで冷却し、その後、急速冷却して硬質化
する方法であり、これらの方法により、ローラーと接触
するマスト用形鋼部分の耐摩耗性が改善し、マスト用形
鋼全体が硬質化するためフランジとウェブの付根コーナ
一部の変形抵抗も増して、耐摩耗性および耐変形抵抗性
の優れたフォークリフトマスト形鋼を提供できるもので
ある。[Means for Solving the Problems] The present invention has been made based on the above findings, and its gist is that the A1 transformation point is exceeded and the temperature is below 1300°C by heat retained during hot rolling or by external heating. A method in which the entire mast section steel at a temperature of A. The entire mast section steel, which is at a temperature exceeding the transformation point and below 1300℃, is cooled at a speed at which it exhibits a fine pearlite structure until the pearlite transformation is completed, and then rapidly cooled. These methods improve the wear resistance of the mast section steel parts that come into contact with the rollers, and harden the entire mast section steel, so some of the root corners of the flanges and webs are hardened. It is possible to provide a forklift mast section steel with increased deformation resistance and excellent wear resistance and deformation resistance.
以下に本発明について詳細に説明する。The present invention will be explained in detail below.
耐摩耗性および耐変形抵抗性を抜本的に改善する製造法
として熱間圧延で製造されたフォークリフトマスト用形
鋼をＡ１変態点を越え１３００℃以下の温度に加熱した
もの、または熱間圧延を終え、Ａ１変態点を越え１３０
０℃以下の温度にあるフォークリフトマスト用形鋼全体
を、水またはソリプル液または油などの冷媒液で急速冷
却してマルテンサイト変態させ、その後３００℃以上Ａ
、変態点を越えない範囲に加熱後、急速ン令却する。As a manufacturing method that dramatically improves wear resistance and deformation resistance, forklift mast sections manufactured by hot rolling are heated to a temperature exceeding the A1 transformation point and below 1300°C, or hot rolling is used. Finished, passed the A1 metamorphosis point, 130
The entire section steel for forklift masts at a temperature of 0°C or lower is rapidly cooled with water or a refrigerant liquid such as Solipul liquid or oil to transform it into martensitic material, and then heated to a temperature of 300°C or higher.
After heating to a temperature that does not exceed the transformation point, it is rapidly turned off.
まず、加熱温度範囲をＡ１変態点を越え１３００℃以下
の温度に設定する理由について述べる。First, the reason why the heating temperature range is set to a temperature exceeding the A1 transformation point and below 1300°C will be described.
加熱温度かＡ１変態点を越えなければならない理由は、
オーステナイト化せしめて、それにつづく急速冷却によ
りマルテンサイト変態させて高強度化するためである。The reason why the heating temperature must exceed the A1 transformation point is
This is to make the steel austenitic and then transform it into martensitic material by rapid cooling, thereby increasing the strength.
加熱温度を１３００℃以下に設定する理由は１３００℃
を越える温度に加熱すると結晶粒か粗大化して延性か低
下し、また焼割れが発生しやすくなるためである。なお
、この温度範囲に加熱するには高周波誘導あるいはガス
等の火焔あるいは電気炉などを使用することかできる。The reason why the heating temperature is set below 1300℃ is 1300℃
This is because, if heated to a temperature exceeding 1,000 yen, the crystal grains will become coarse, ductility will decrease, and quench cracking will occur more easily. Note that high frequency induction, gas flame, electric furnace, etc. can be used to heat to this temperature range.
水またはソリプル液あるいは油などの冷媒液で急速冷却
するのは、これらの冷媒で冷却することによってマルテ
ンサイト変態を起こさせ、マルテンサイト組織を得るた
めである。これらの冷媒液により冷却速度の遅い圧縮空
気のような冷媒を用いると、マルテンサイト変態が起こ
らず、フェライト・バーライ］・組織となり、目的とす
る高強度か得られない。The reason for rapid cooling with a refrigerant liquid such as water, Solipul liquid, or oil is to cause martensitic transformation and obtain a martensitic structure by cooling with these refrigerants. If a refrigerant such as compressed air, which has a slow cooling rate due to these refrigerant liquids, is used, martensitic transformation does not occur, resulting in a ferrite/burry structure, and the desired high strength cannot be obtained.
マルテンサイト変態終了後３００℃以上Ａ１変態点を越
えない範囲に加熱するのはマルテンサイト組織は非常に
高強度ではあるが脆いため、これを改善して延性のある
焼もどしマルテンサイト組織を得るためである。焼もど
し温度を３００℃以上とする理由は十分にマルテンサイ
ト組織を焼もどすためである。３００℃未満の温度では
マルテンサイト組織が十分に焼もどしされずに不均質な
焼もどしマルテンサイト組織となり、良好な強靭化が得
られないためである。The reason for heating to a temperature above 300°C and not exceeding the A1 transformation point after the completion of martensitic transformation is to improve this and obtain a ductile tempered martensitic structure, since martensitic structure has very high strength but is brittle. It is. The reason why the tempering temperature is set to 300° C. or higher is to sufficiently temper the martensitic structure. This is because at a temperature lower than 300° C., the martensite structure is not sufficiently tempered, resulting in a heterogeneous tempered martensite structure, and good toughening cannot be obtained.
Ａ１変態点を越えない温度に設定する理由は、Ａ１変態
点を越える温度に加熱すると、オーステナイト化してし
まい、せっかく前記焼入れ処理によって得られた高強度
マルテンサイト組織が消滅してしまうためである。焼も
どし後急速冷却するのは、出来るたけ大きい圧縮残留応
力を得るためである。残留応力は平均応力として作用す
るので、疲労強度に大きく影響を及ぼずことが知られて
いる。すなわち、引張残留応力は悪影響を及ぼし、圧縮
残留応力は効果的に疲労強度に作用する。本発明ではこ
の圧縮残留応力の効果もねらったものである。The reason why the temperature is set not to exceed the A1 transformation point is that heating to a temperature exceeding the A1 transformation point causes austenite formation, and the high-strength martensitic structure obtained by the quenching process disappears. The reason for rapid cooling after tempering is to obtain as large a compressive residual stress as possible. It is known that residual stress does not significantly affect fatigue strength because it acts as an average stress. That is, tensile residual stress has a negative effect, while compressive residual stress effectively affects fatigue strength. The present invention also aims at the effect of this compressive residual stress.
さらに、本発明はより低コストで耐摩耗性および耐変形
抵抗性の改善をねらったものであるが、耐摩耗性や耐変
形抵抗性は前記発明より劣る。前記発明と基本的に異な
る点は本発明では微細パーライト組織を得て耐摩耗性お
よび耐変形抵抗性の改善を図ったものである。すなわち
、本発明は熱間圧延を終えＡ、変態点を越え１３００℃
以下の温度にあるフォークリフトマスト用形鋼または熱
間圧延で製造されたフォークリフトマスト用形鋼をＡ、
変態点を越え、１３００℃以下の温度に加熱したものを
圧縮空気あるいは圧縮含水空気によってパーライト変態
が終了するまで冷却し、その後急速冷却する。Furthermore, although the present invention aims to improve wear resistance and deformation resistance at lower cost, the abrasion resistance and deformation resistance are inferior to those of the above-mentioned inventions. The basic difference from the above invention is that the present invention obtains a fine pearlite structure to improve wear resistance and deformation resistance. That is, in the present invention, after hot rolling A, the temperature exceeds the transformation point and reaches 1300°C.
Forklift mast section steel at the following temperatures or forklift mast section steel manufactured by hot rolling is A,
The material heated to a temperature exceeding the transformation point and below 1300° C. is cooled with compressed air or compressed water-containing air until the pearlite transformation is completed, and then rapidly cooled.
冷却開始温度のＡ１変態点を越え１３００℃以下の加熱
温度範囲は微細パーライト組織を得て高強度化を図り、
耐摩耗性、耐変形抵抗性および疲労強度を向上せしめる
ための温度範囲であって、１３００℃を越える高い温度
では結晶粒か粗大化して焼割れが起り易く、かつ延性が
低下し、Ａ１変態点より低い温度ではパーライト変態が
起こらず微細なパーライト組織を得ることが出来ない。The heating temperature range is above the A1 transformation point of the cooling start temperature and below 1300℃ to obtain a fine pearlite structure and increase the strength.
This is a temperature range for improving wear resistance, deformation resistance, and fatigue strength. At temperatures higher than 1,300°C, crystal grains become coarse and quench cracking tends to occur, and ductility decreases, leading to the A1 transformation point. At lower temperatures, pearlite transformation does not occur and a fine pearlite structure cannot be obtained.
また、この場合の冷媒に使用する高圧の気体または含水
気体は冷却中に生成するパーライトの粗大化を阻止し、
かつ圧縮残留応力を付与せしめて耐疲労性をも向上させ
るためである。水または油などによる冷却では冷却速度
が早すぎて、パーライト変態は起こらず前記発明の場合
のようにマルテンサイト変態が起こり、目的とする微細
パーライト組織を得ることかできない。In addition, the high-pressure gas or water-containing gas used as the refrigerant in this case prevents the coarsening of pearlite generated during cooling.
This is also to improve fatigue resistance by imparting compressive residual stress. When cooling with water or oil, the cooling rate is too fast and pearlite transformation does not occur, but martensitic transformation occurs as in the case of the invention, making it impossible to obtain the desired fine pearlite structure.
［実施例及び発明の効果］ 次に本発明の実施例について述べる。[Examples and effects of the invention] Next, examples of the present invention will be described.
実施例−１
熱間圧延により製造されたインナーマスト用形鋼につい
て速度約１０ｍｍ／秒で連続的に移動させながら高周波
誘導加熱コイルにより形鋼全体を９５０℃に加熱し、加
熱コイルを出た直後水によりマルテンサイト変態が終了
するまで急速冷却を行った。その後再び高周波誘導コイ
ルにより形鋼全体を４５０℃に加熱して焼もどしを行い
、加熱コイルを出た直後、水により室温まて急速冷却を
行った。その結果、第１表中に示すように、本発明形鋼
は表面および内部ともに非常に硬質化し、またフランジ
部表面には約３０ｋｇｆ／ｍｍ２の圧縮残留応力が発生
している。本発明形鋼について実機テスト（荷重＋２ｔ
ｆ、荷重上・下繰返し数・ｌＯ万回）の結果、耐摩耗性
および耐変形抵抗性は従来形鋼と比較して極めて優れて
いる。Example-1 A section steel for an inner mast manufactured by hot rolling was heated to 950°C by a high-frequency induction heating coil while continuously moving at a speed of about 10 mm/sec, and immediately after leaving the heating coil. Rapid cooling was performed with water until martensitic transformation was completed. Thereafter, the entire shaped steel was heated again to 450° C. using a high-frequency induction coil for tempering, and immediately after leaving the heating coil, it was rapidly cooled to room temperature with water. As a result, as shown in Table 1, the steel section of the present invention became extremely hard both on the surface and inside, and compressive residual stress of about 30 kgf/mm2 was generated on the flange surface. Actual machine test for the shaped steel of the present invention (load + 2t
f, the number of load up/down cycles/10,000 times), the wear resistance and deformation resistance are extremely superior compared to conventional shaped steel.
実施例−２
熱間圧延により製造されたインナーマスト用形鋼につい
て、速度約１０ｍｍ／秒で連続的に穆動させなから高周
波誘導加熱コイルにより形鋼全体を９５０℃に加熱し、
加熱コイルを出た直後、形鋼全体の上・下に配置したノ
ズルにより圧縮空気を噴出させてパーライト変態が終了
する５５０℃位まで冷却し、その復水を噴出させて室温
まで急速冷却を行った。その結果、本発明形鋼は第１表
中に示すように、前記した実施例１の発明形鋼より硬質
化は劣るものの、従来形鋼よりはかなり硬質化し、実機
テストの結果においても耐摩耗性および耐変形抵抗性が
従来形鋼よりかなり改善している。Example 2 A section steel for an inner mast manufactured by hot rolling was heated to 950°C by a high frequency induction heating coil while being continuously rolled at a speed of about 10 mm/sec.
Immediately after exiting the heating coil, compressed air is jetted out through nozzles placed above and below the entire shaped steel to cool it to around 550°C, where pearlite transformation is completed, and the condensate is jetted out to rapidly cool it to room temperature. Ta. As a result, as shown in Table 1, although the hardness of the shaped steel of the present invention is inferior to that of the invented shaped steel of Example 1 described above, it is considerably harder than the conventional shaped steel, and the results of the actual machine test show that it has good wear resistance. The strength and deformation resistance of this steel are considerably improved compared to conventional shaped steel.
以上のように、本発明形鋼は耐摩耗性および耐変形抵抗
性が非常に優れたものである。As described above, the shaped steel of the present invention has extremely excellent wear resistance and deformation resistance.
第１図はインナーマスト用形鋼の変形状況を示す図であ
る。
Ａ・・・フランジ付根コーナ一部
Ｂ、Ｃ・・・ウェブ付根コーナ一部
Ａ、フランミ
Ｂ、Ｃ：つｊ
ン付根コーナ一部
【ブ付根コーナ一部FIG. 1 is a diagram showing the state of deformation of the inner mast section steel. A... Part of the flange root corner B, C... Part of the web root corner A, Flange B, C: Part of the flange root corner [Part of the web root corner
Claims (1)
度に加熱したフォークリフトマスト用形鋼を、または熱
間圧延を終えＡ＿１変態点を越え１３００℃以下の温度
にあるフォークリフトマスト用形鋼を、冷媒液で急速冷
却してマルテンサイト変態させ、その後、３００℃以上
Ａ＿１変態点を越えない範囲に加熱後、急速冷却するこ
とを特徴とする耐摩耗性および耐変形抵抗性の優れたフ
ォークリフトマスト用形鋼の製造法。 ２ 熱間圧延後Ａ＿１変態点を越え１３００℃以下の温
度に加熱したフォークリフトマスト用形鋼を、または熱
間圧延を終えＡ＿１変態点を越え１３００℃以下の温度
にあるフォークリフトマスト用形鋼を、圧縮空気あるい
は圧縮含水空気によってパーライトが変態するまで冷却
し、その後急速冷却することを特徴とする耐摩耗性およ
び耐変形抵抗性の優れたフォークリフトマスト用形鋼の
製造法。[Scope of Claims] 1. Forklift mast section steel heated to a temperature exceeding the A_1 transformation point and 1300°C or less after hot rolling, or a forklift that has been heated to a temperature exceeding the A_1 transformation point and 1300°C or less after hot rolling. Abrasion resistance and deformation resistance characterized by rapidly cooling the mast section steel with a refrigerant liquid to transform it into martensite, then heating it to a range of 300°C or higher but not exceeding the A_1 transformation point, and then rapidly cooling it. ’s superior manufacturing method for section steel for forklift masts. 2 Forklift mast section steel heated to a temperature exceeding A_1 transformation point and below 1300°C after hot rolling, or forklift mast section steel heated to a temperature exceeding A_1 transformation point and below 1300°C after hot rolling, A method for manufacturing a section steel for forklift masts with excellent wear resistance and deformation resistance, which is characterized by cooling pearlite with compressed air or compressed hydrous air until it transforms, and then rapidly cooling it.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5989588A JPH01234528A (en) | 1988-03-14 | 1988-03-14 | Production of shape steel for fork lift mast having excellent wear resistance and deformation resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5989588A JPH01234528A (en) | 1988-03-14 | 1988-03-14 | Production of shape steel for fork lift mast having excellent wear resistance and deformation resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01234528A true JPH01234528A (en) | 1989-09-19 |
Family
ID=13126307
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5989588A Pending JPH01234528A (en) | 1988-03-14 | 1988-03-14 | Production of shape steel for fork lift mast having excellent wear resistance and deformation resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01234528A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103817177A (en) * | 2012-11-19 | 2014-05-28 | 爱信精机株式会社 | Roll forming method and roll forming apparatus |
-
1988
- 1988-03-14 JP JP5989588A patent/JPH01234528A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103817177A (en) * | 2012-11-19 | 2014-05-28 | 爱信精机株式会社 | Roll forming method and roll forming apparatus |
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