JPH0456728A - Production of low relaxation pc steel material - Google Patents
Production of low relaxation pc steel materialInfo
- Publication number
- JPH0456728A JPH0456728A JP16684390A JP16684390A JPH0456728A JP H0456728 A JPH0456728 A JP H0456728A JP 16684390 A JP16684390 A JP 16684390A JP 16684390 A JP16684390 A JP 16684390A JP H0456728 A JPH0456728 A JP H0456728A
- Authority
- JP
- Japan
- Prior art keywords
- steel material
- tempering
- temp
- temperature
- steel
- 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.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 38
- 239000010959 steel Substances 0.000 title claims abstract description 38
- 239000000463 material Substances 0.000 title claims abstract description 31
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 238000005496 tempering Methods 0.000 claims abstract description 32
- 238000001816 cooling Methods 0.000 claims abstract description 11
- 238000010438 heat treatment Methods 0.000 claims abstract description 4
- 230000009466 transformation Effects 0.000 claims abstract description 3
- 238000000034 method Methods 0.000 abstract description 8
- 229910052799 carbon Inorganic materials 0.000 abstract description 4
- 239000000203 mixture Substances 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 238000011282 treatment Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 206010023204 Joint dislocation Diseases 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000005491 wire drawing Methods 0.000 description 2
- 235000017166 Bambusa arundinacea Nutrition 0.000 description 1
- 235000017491 Bambusa tulda Nutrition 0.000 description 1
- 241001330002 Bambuseae Species 0.000 description 1
- 235000015334 Phyllostachys viridis Nutrition 0.000 description 1
- 239000011425 bamboo Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 239000011513 prestressed concrete Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は低リラクセーションＰＣ鋼材の製造方法に関す
る。ここでＰＣ鋼材とはＰＣ鋼棒、ＰＣワイヤ、ＰＣス
トランドを包含するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a low relaxation PC steel material. Here, the term "PC steel material" includes PC steel bars, PC wires, and PC strands.
〔従来の技術１
プレストレストコンクリートに用いられるＰＣ鋼材は、
導入したプレストレスが時間の経過と共に減少するいわ
ゆるリラクセーションの問題がある。リラクセーション
が大きいと、設計応力の安全率を大きくとる必要があり
、リラクセーションの低いＰＣ鋼材が望ましい。[Conventional technology 1 PC steel materials used in prestressed concrete are:
There is a so-called relaxation problem in which the introduced prestress decreases over time. If the relaxation is large, it is necessary to take a large safety factor for the design stress, and a PC steel material with a low relaxation is desirable.
またＰＣパイルの製造工程において、ＰＣ鋼材緊張後蒸
気養生、高温高圧養生するため、リラクセーションロス
の少ないＰＣ鋼材が要求される。In addition, in the manufacturing process of PC piles, the PC steel material is steam-cured and high-temperature and high-pressure cured after tensioning, so a PC steel material with low relaxation loss is required.
低リラクセーションＰＣ鋼材の製造方法については、特
公昭４７−１３２９７号公報に０．６５〜０．９０重量
％の炭素を含有する鋼材を冷間伸線し、１５０〜３５０
℃の温度範囲で１０〜３０％の温間伸線を行う方法が開
示されている。Regarding the manufacturing method of low-relaxation PC steel materials, Japanese Patent Publication No. 13297/1983 describes that steel materials containing 0.65 to 0.90% by weight of carbon are cold drawn, and
A method of performing warm wire drawing of 10 to 30% in the temperature range of .degree. C. is disclosed.
また特開昭４８−２７９５６号公報には焼戻し炉の入側
と出側にキヤプスタンを設けて引張荷重の６０％以上の
応力をかけつつ焼戻すことが示されている。Further, JP-A-48-27956 discloses that capstans are provided on the entry and exit sides of a tempering furnace, and tempering is performed while applying a stress of 60% or more of the tensile load.
また、特公平１−２４８４８号公報には焼戻しの過程で
歪Ｎ３〜９０％の塑性加工または矯正加工の１間加工を
施すことが有効であると開示されている。Furthermore, Japanese Patent Publication No. 1-24848 discloses that it is effective to perform one-time plastic working or straightening working with a strain of N3 to 90% during the tempering process.
しかし、これらの方法は、リラクセーション特性が未だ
十分ではな（、また、−様伸び性及び真直性に劣る等の
問題がある。However, these methods still have problems such as insufficient relaxation properties (and poor -like elongation and straightness).
［発明が解決しようとする課題］
本発明者らは、上記従来技術が、歪加工にのみ江目して
いるが故に、−様伸びや真直性に問題があり、高温リラ
クセーションも改善が不十分となるのではないかとの疑
念を抱き、ＰＣ鋼材の熱履歴とりラクセーションの関係
について、多数の実験を行った。その結果、−次テンパ
ーと二次テンパーによる熱履歴を施すことが決定的であ
ることを知見し、本発明を完成した。[Problems to be Solved by the Invention] The present inventors believe that because the above-mentioned conventional technology focuses only on strain processing, there are problems with -like elongation and straightness, and there is insufficient improvement in high-temperature relaxation. Having a suspicion that this might be the case, we conducted numerous experiments on the relationship between the thermal history and luxation of PC steel materials. As a result, they discovered that it is crucial to apply a thermal history through -second tempering and second tempering, and completed the present invention.
本発明はこのような方法を提供するものである。The present invention provides such a method.
［課題を解決するための手段Ｊ
本発明は、
Ｃ二０．４重量％以下
Ｓｉ：１．０〜２．０重量％
を含む鋼材をＡ３変態点以上の温度から臨界冷却速度以
上の冷却速度でＭＳ点以下まで急速冷却し、次いで、３
５０℃以上４３０℃以下に加熱して一次テンバーを行う
と共にこの鋼材に歪を付与し、次いで４３０℃以上４８
０°Ｃ以下で、かつ一次テンパー温度より２０℃以上高
温に昇温し二次テンパーを行うことを特徴とする低すラ
クセションＰＣ鋼材の製造方法である。[Means for Solving the Problems J] The present invention provides a method for cooling a steel material containing 0.4% by weight or less of C2 and 1.0 to 2.0% by weight of Si from a temperature above the A3 transformation point to a cooling rate above the critical cooling rate. Rapid cooling to below the MS point, then 3
The steel is heated to a temperature of 50°C or higher and 430°C or lower to undergo primary tensile treatment and strain is applied to the steel, and then heated to a temperature of 430°C or higher and 48°C or higher.
This is a method for producing a low relaxation PC steel material, which is characterized by performing secondary tempering at a temperature of 0° C. or lower and at a temperature higher than the primary tempering temperature by 20° C. or more.
［作用１
本発明は、ＰＣ鋼材のテンパー履歴によるリラクセーシ
ョン特性と一様伸び、真直性との関連を開発したもので
ある。[Effect 1] The present invention has developed the relationship between the relaxation characteristics of PC steel materials based on their tempering history, uniform elongation, and straightness.
本発明に使用するＰＣ鋼材は炭素含有量が０．４重量％
以下である。０．４重量％を越えると、溶接性が劣るの
で適切なＰＣ鋼材として用いられない。下限は規定しな
いが、通常使用されているＰＣ鋼材は引張強さの観点か
６０，２重量％以上が好ましい。The carbon content of the PC steel used in the present invention is 0.4% by weight.
It is as follows. If it exceeds 0.4% by weight, weldability is poor and it cannot be used as a suitable PC steel material. Although no lower limit is specified, it is preferably 60.2% by weight or more for commonly used PC steel materials from the viewpoint of tensile strength.
Ｓｉ含有量は、１．０重量％未満ではリラクセションロ
スが太き（２，０重量％を越えると材質的に劣化するの
で１．０〜２．０重量％とするが、さらに好適には１．
４〜１．７重量％である。If the Si content is less than 1.0% by weight, relaxation loss will be large (if it exceeds 2.0% by weight, the material will deteriorate, so the Si content should be 1.0 to 2.0% by weight, but more preferably 1.
It is 4 to 1.7% by weight.
焼入処理はこの種鋼材についての常套手段であるが、こ
こで冷却後の温度は常温まで冷却する必要はなく、マル
テンサイト化するＭｓ点以下まで冷却し、この温度に保
持し１次いで一次テンバー温度まで加熱すると、熱エネ
ルギーの経済、処理工程の簡易化等の利点があり、一方
５このあとの一次テンパー、二次テンパー処理の結果に
影響を及ぼさない。もちろん、常温まで冷却することを
排除するものではない。Quenching treatment is a common method for this type of steel, but the temperature after cooling does not need to be cooled to room temperature, but it is cooled to below the Ms point at which it becomes martensitic, and maintained at this temperature, and then subjected to primary tempering. Heating to this temperature has advantages such as economy of thermal energy and simplification of processing steps, while it does not affect the results of the subsequent primary tempering and secondary tempering treatments. Of course, cooling to room temperature is not excluded.
一次テンバー温度は３５０℃以上４３０℃以下とし、Ｃ
，Ｓｉ量の高い材料はど、この範囲の高温側とする。こ
のテンパー温度は、従来の通常のテンパー温度より低い
温度である。この温度は。The primary temperature is 350°C or more and 430°C or less, and C
, materials with a high Si content are on the high temperature side of this range. This tempering temperature is lower than the conventional normal tempering temperature. This temperature is.
３５０℃未満では加工ラインのローラの摩耗が大きくな
るので適当でない、また４３０℃を越えると、このあと
の二次テンパーの効果が減殺されるので上限は４３０℃
以下に定められる。If it is less than 350°C, it is not suitable because the wear of the rollers on the processing line will increase, and if it exceeds 430°C, the effect of the subsequent secondary tempering will be diminished, so the upper limit is 430°C.
Defined below.
この一次テンパー温度において、公知の歪付与がなされ
る。At this primary tempering temperature, known distortion is applied.
次テンパーは４３０℃以上４８０℃以下でかつ、−次テ
ンパー温度より２０℃以上高くする。The next tempering temperature is 430°C or more and 480°C or less, and is 20°C or more higher than the -second tempering temperature.
二次テンパー温度もＣ，Ｓｉｌが高くなると高くする。The secondary tempering temperature is also increased as C and Sil become higher.
４３０″Ｃ未満では引張強さが高すぎるので適当でなく
、４８０℃を越えると逆に引張強さが低下し、所要の機
械的特性を得ることができない。また、一次テンパー温
度より２０’Ｃ以上高めるのは、２０℃未満では可動転
化が残存し、十分な転位の不動化を図ることができない
からである。If it is less than 430"C, the tensile strength is too high and is not suitable. If it exceeds 480"C, the tensile strength will decrease, making it impossible to obtain the required mechanical properties. The reason why the temperature is increased above 20° C. is that mobile conversion remains at temperatures below 20° C., and sufficient immobilization of dislocations cannot be achieved.
〔実施例Ｉ
Ｃ：０．２９重鳳％、Ｓｌ：１．５５重量％を含も直径
９．２ ｍ ｍφのＰＣ鋼材を伸線加工後９２０℃に加
熱し、水冷却焼入を施して２００℃まで降召し１次いで
本発明方法のテンパー処理により製造した。−次テンパ
ー温度を３３０℃〜４３０℃に変化させ、二次テンパー
を温度差３０〜１３０℃で４３０〜４８０℃の範囲に設
定した。[Example I A PC steel material containing C: 0.29% by weight and Sl: 1.55% by weight and having a diameter of 9.2 mmφ was heated to 920°C after wire drawing and water-cooled and quenched. Produced by tempering to 200°C and then tempering according to the method of the invention. - The secondary tempering temperature was changed from 330°C to 430°C, and the secondary tempering was set in the range of 430°C to 480°C with a temperature difference of 30°C to 130°C.
第１表に実施例及び比較例のテンパー処理条件と、その
結果得られた引張強さ、−様伸び、破断後伸び、リラク
セーション植、真直性のデータを示した。Table 1 shows the tempering conditions of Examples and Comparative Examples and the resulting data on tensile strength, -like elongation, elongation after break, relaxation set, and straightness.
一様伸びは引張試験において試験片の平竹部かほぼ一様
均一に変形する永久伸びの限界値でｉ）る。破断後伸び
は破断時の伸びを言い、−様伸びと局部伸びの合計伸び
である。Uniform elongation is the limit value of permanent elongation at which the flat bamboo part of the test piece deforms almost uniformly in a tensile test i). Elongation after break refers to elongation at break, and is the total elongation of -like elongation and local elongation.
Ｊラクセーションは高温リラクセーションによって評価
した。高温リラクセーション条件は４時間で１８０℃に
昇温し、３時間保持し、自然冷却（約１６時間）する条
件であり、高温リラクセーションの初期荷重はσｂ （
引張強さ）の７０％で行った。また真直性はＰＣ鋼材長
１．５ｍの弧の高さである。この真直性は、ユーザーに
おいてＰＣ鋼材を使用する際、定尺切断後の鋼材が作業
台を転がらないと作業に支障を米（ので品質項目として
特に定められたものである。真直性は１ｍｍ以下であれ
ば問題がない。J relaxation was evaluated by high temperature relaxation. The high-temperature relaxation conditions are such that the temperature is raised to 180°C in 4 hours, held for 3 hours, and naturally cooled (about 16 hours), and the initial load of high-temperature relaxation is σb (
tensile strength). Straightness is defined as the arc height of the PC steel material having a length of 1.5 m. This straightness has been specifically specified as a quality item because when using PC steel materials, users will have trouble working if the steel materials do not roll on the workbench after being cut to a specified length. If so, there is no problem.
第１表から本発明のテンパー条件で加重されたＰＣ鋼材
はりラクセーション値が低く、−様伸びも優れ、破断後
伸びも高く、真直性に優れ、好適であることが知られる
。From Table 1, it is known that the PC steel beam loaded under the tempering conditions of the present invention has a low luxation value, excellent -like elongation, high elongation after break, and excellent straightness, and is therefore suitable.
〔発明の効果１
本発明によれば、低リラクセーションＰＣ鋼材を得るこ
とができ、−様伸び、真直性にも優れたＰＣ鋼材を製造
することが可能となった。[Effect 1 of the Invention According to the present invention, it has become possible to obtain a low relaxation PC steel material and to produce a PC steel material that is excellent in -like elongation and straightness.
出 願 人 川鉄テクノワイヤ株式会社代 理 人Applicant: Kawatetsu Techno Wire Co., Ltd. Reason Man
Claims (1)
以上の冷却速度でＭｓ点以下まで急速冷却し、３５０℃
以上４３０℃以下に加熱して一次テンパーを行うと共に
該鋼材に歪を付与し、次いで４３０℃以上４８０℃以下
で、かつ一次テンパー温度より２０℃以上 高温に昇温し二次テンパーを行うことを特徴とする低リ
ラクセーションＰＣ鋼材の製造方法。[Claims] 1 A steel material containing C: 0.4% by weight or less and Si: 1.0 to 2.0% by weight is rapidly cooled from a temperature above the A_3 transformation point to below the Ms point at a cooling rate above the critical cooling rate. Cool to 350℃
Primary tempering is performed by heating the steel material to 430°C or lower and strain is applied to the steel material, and then secondary tempering is performed by heating the steel material to 430°C or higher and 480°C or higher and 20°C or higher higher than the primary tempering temperature. A method for producing a characteristically low relaxation PC steel material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2166843A JPH079038B2 (en) | 1990-06-27 | 1990-06-27 | Low relaxation PC steel manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2166843A JPH079038B2 (en) | 1990-06-27 | 1990-06-27 | Low relaxation PC steel manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0456728A true JPH0456728A (en) | 1992-02-24 |
| JPH079038B2 JPH079038B2 (en) | 1995-02-01 |
Family
ID=15838682
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2166843A Expired - Fee Related JPH079038B2 (en) | 1990-06-27 | 1990-06-27 | Low relaxation PC steel manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH079038B2 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57198211A (en) * | 1981-05-29 | 1982-12-04 | Sumitomo Electric Ind Ltd | Manufacture of heat treat pc steel rod |
| JPS63151720A (en) * | 1986-12-11 | 1988-06-24 | 川鉄テクノワイヤ株式会社 | High strength pc steel rod and high strength pile |
-
1990
- 1990-06-27 JP JP2166843A patent/JPH079038B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57198211A (en) * | 1981-05-29 | 1982-12-04 | Sumitomo Electric Ind Ltd | Manufacture of heat treat pc steel rod |
| JPS63151720A (en) * | 1986-12-11 | 1988-06-24 | 川鉄テクノワイヤ株式会社 | High strength pc steel rod and high strength pile |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH079038B2 (en) | 1995-02-01 |
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