JPH0565567B2 - - Google Patents
Info
- Publication number
- JPH0565567B2 JPH0565567B2 JP58118260A JP11826083A JPH0565567B2 JP H0565567 B2 JPH0565567 B2 JP H0565567B2 JP 58118260 A JP58118260 A JP 58118260A JP 11826083 A JP11826083 A JP 11826083A JP H0565567 B2 JPH0565567 B2 JP H0565567B2
- Authority
- JP
- Japan
- Prior art keywords
- weight
- steel
- hot
- strength
- 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 - Lifetime
Links
- 229910000831 Steel Inorganic materials 0.000 claims description 47
- 239000010959 steel Substances 0.000 claims description 47
- 238000010438 heat treatment Methods 0.000 claims description 30
- 238000012545 processing Methods 0.000 claims description 29
- 238000005496 tempering Methods 0.000 claims description 16
- 230000000171 quenching effect Effects 0.000 claims description 11
- 238000010791 quenching Methods 0.000 claims description 10
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 238000005098 hot rolling Methods 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- 230000015572 biosynthetic process Effects 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 239000000463 material Substances 0.000 description 12
- 238000012360 testing method Methods 0.000 description 9
- 238000003466 welding Methods 0.000 description 5
- 230000003247 decreasing effect Effects 0.000 description 4
- 230000006866 deterioration Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910052752 metalloid Inorganic materials 0.000 description 1
- 150000002738 metalloids Chemical class 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 238000010998 test method Methods 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
- C21D8/08—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires for concrete reinforcement
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (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 Strip Materials And Filament Materials (AREA)
- Heat Treatment Of Steel (AREA)
Description
（産業上の利用分野）
PC鋼棒の代表例とする高張力鋼棒材は、一般
に熱間圧延を経て調質熱処理すなわち焼入れおよ
び焼戻し処理を施し、その後に上記PC鋼棒によ
るコンクリート構造物に対するプレストレス導入
の便宜を与えるための、ヘツデイングを典型例と
する亜熱間加工に行つて使用に供されることが多
い。
このような亜熱間加工のための加熱には通常高
周波誘導加熱の如き急熱が行われる。
それ故かような亜熱間加工部材における棒材性
能の劣化を来すうれいがあり、その有効な回避に
関連して以下のべる技術内容は、高張力鋼棒材の
成分調整の下での調質組織の改善を目指し、一般
にPC鋼棒を代表例とする高張力鋼棒材の製造方
法が属する技術の分野に位置する。
（従来の技術）
一般にこの種鋼棒材としてC0.35重量％（以下
単に％で示す）、Mn0.8％程度を含み、焼入れ焼
戻し処理を施したものが広く用いられて来たが、
点溶接後の伸びのほか、とくにヘツダー加工部に
充分な強度を実現するためのヘツダー加工加熱温
度の範囲が狭いことなどの点い問題が残されてい
る。
（発明が解決しようとする課題）
この種の鋼棒材はすでに触れたように、たとえ
ばPC鋼棒としてPCパイルなどの製造に利用さ
れ、通常引張り強さ145Kg／mm2以上のものが多く
使用される。
しかるにPCパイルの製造にあたつてPC鋼棒は
予め補助鉄筋など組合わせて点検接などによつて
鉄筋かごに編まれるが、それに先立つて鋼棒の端
部いしばしばヘツデイング加工を施し、多数の
PC鋼棒の端環と固定する便宜に供される。
このようしてつくられたヘツド部がもしも鋼棒
のプレストレス導入のための荷重下に破断する
と、鋼棒ヘツド部の破片が飛び散つて重大災害を
引きおこすおそれがあり、この故にヘツダー加工
を適用した鋼棒の端部における強度を十分ならし
めることが要求される一方で、作業上このヘツデ
イング加工つまり亜熱間加工の条件とくに加熱の
温度範囲が広く許容され、しかも安定な強度持続
が期待され得る必要がある。
鋼棒材の端部は亜熱間でヘツダー加工する場合
の加熱手段には通常高周波による短時間加熱が用
いられ、高周波出力と加熱時間を調節する。
ここに形成されるヘツド部の強度と、その破断
形態は加熱条件に大きく左右される。
そのため従来鋼棒材のロツトによつて、また場
合によつて同一ロツトにおいてもヘツダー自体の
変動などから、十分なヘツド部強度をもたらすた
めに高周波出力、加熱時間の設定をかえる必要を
伴う不利があつた。
それ故ヘツダー加工条件すなわち加熱条件が広
い範囲で選び得て、ここに充分なヘツド部強度が
達成されることによる利益は技術的にきわめて大
きい。
さてヘツド部における破断試験（第１図）の結
果によれば、破断形態は第２図のような五種類に
大別される。
(a)はヘツダー加工の影響をうけないところで破
断を生じるものでこの場合ヘツダー加工による強
度低下を生じていない。
(b)、(c)はヘツダー加工時の加熱によつて、ヘツ
ド部またはヘツド下部の軟化が大きいかつたもの
と考えられ、強度は低下することが多い。
(d)、(e)は、ヘツダー加工によりヘツド内部また
はヘツド下部が脆化しあるいはそこにクラツクが
入つたものと考えられ、強度は大きく低下する場
合がある。
かかる問題に対処する方法として、さきに亜熱
間における加工性を良好にし、しかも焼戻し軟化
抵抗を大きくする手段につき、特公昭55−11726
号公報をもつて提案をした。
しかるにその開示に従い破断形態(b)、(c)すなわ
ちヘツダー加工時のヘツド下部の軟化を防止する
ことでは有効であるが、ヘツダー加工時の加熱時
間が短い側および長い側に振れたような場合に
は、しばしばヘツド内部またはヘツド下部の脆化
による破断形態(d)、(e)を生じ、これを完全に抑え
ることができなかつた。
発明者らはかかる脆化の原因を種々検討し、そ
の原因が素材成分のうちSiおよびMnのミクロ編
析にもとづき縞状組織に起因することをつきと
め、Si含有量とMn含有量の比（以下単に
〔Si〕／〔Mn〕であらわす）の値を制御すること
により縞状組織の解消を果たし、PC鋼棒のヘツ
ド下部の脆化を完全に防止することができた。
上記知見に基き、熱間圧延を経て調質熱処理を
施し、その後に亜熱間でのヘツデイング加工を行
つて使用に供される高張力鋼棒材の、該亜熱間加
工に由来する棒材性能の劣化を回避することが、
この発明の目的である。
（課題を解決するための手段）
上記の目的は次の事項にて有効に達成される。
鋼片を熱間圧延したのち、焼入れ温度まで加熱
後、噴射水流ノズルにより急冷して焼入れし、つ
いで280℃以上の温度で焼戻しをする調質熱処理
を施して、亜熱間でのヘツデイング加工を行つて
使用に供する高張力鋼棒材を製造するにあたつ
て、鋼片が
Ｃ：0.20〜0.50重量％、Si：0.50〜2.0重量％、
Mn：0.9〜2.0重量％およびCr：0.10〜0.60重量％
を基本成分として、0.005重量％以下のＢを含有
する溶鋼、
又は上記基本成分に加えて、0.005重量％以下
のＢならびに0.010〜0.100重量％のAl及びTiのう
ちの１種又は２種を含有させた溶鋼について、
それぞれ上記Si含有量とMn含有量との比の値
を0.5〜1.2の範囲に成分調整することにより、こ
れらの溶鋼から造つた鋼片の縞状組織の生成をあ
らかじめ防止したものであることを特徴とし、使
用に際しての亜熱間ヘツダー加工中にSi、Mnの
ミクロ偏析に基づくような、縞状組織を含まず、
かくして亜熱間ヘツデイング加工性の向上に著し
く寄与することができる、点溶接性、リラクセー
シヨン値の良好なPCパイル用等のPC鋼棒に有利
に適用しえるヘツデイング加工性に優れる高張力
鋼棒材の製造方法である。
上記成分調整を行つた溶鋼については常法に従
う造塊又は連続鋳造のあと熱間圧延を加えて棒材
とし、その後加熱してオーステナイト領域より急
冷する焼れ入れ、ついで280℃以上の温度にて焼
戻しする調質熱処理を施すことにより爾後のたと
えばPC鋼棒としての使用に当つて亜熱間で施さ
れるヘツダー加工の加熱条件や、その温度変動に
拘らずヘツド部の強度が阻害されずして、しかも
ヘツド下部の脆化は完全に防止されるのであり、
加えて棒材に要求される点溶接材やリラクセーシ
ヨン値において、優れいることが確かめられた。
（作用）
鋼中成分の限定理由は次のとおりである。
Ｃ：0.2〜0.5％
Ｃは焼戻しのあとでの引張り強さに関係し0.2
％未満では280℃以上の焼戻しにより所要の引張
強さとすることが困難となり、また0.5％を超え
ると充分な溶接強度を与える溶接条件のもとでの
伸びの劣化が著しくなるため0.2〜0.5％の範囲を
規定する。
ここに溶接後の伸びの劣化に対しても上記
〔Si〕／〔Mn〕の値の制御が有効であつて、それ
による脆化の防止により、上掲特公昭55−11726
号公報にあつてはＣの上限が0.3％に規制されて
いたのを0.5％まで拡大し得る。
Si：0.5〜2.0％
Siについては、ヘツデインク加工時におけるヘ
ツド下部の脆下を抑止するのに不可欠な〔Si〕／
〔Mn〕の値を0.50〜1.20の範囲内とする条件を満
たすため最低値は、0.45％となるのが若干の余裕
をみこんで下限を0.5％とする。またSiは半金属
としての性格を有すため、添加量を増すと材料の
靱性を損なう傾向があるため上限値は2.0％とし
た。
Mn：0.9〜2.0％
Mnは通常の脱酸および焼入れ効果のほかに、
点溶接性の改善に役立ち、それに有効な0.9〜2.0
％において従来の通常鋼材よりも高目に設定し
た。
Cr：0.1〜0.6％
Crは亜熱間でのヘツダー加工における加工性
改善と広範な加熱条件の下で、ヘツド部の強度を
安定に維持するのに有効な成分であり、0.1％に
満たないとヘツダー加工の加熱条件の範囲を拡げ
る効果に乏しく、また0.6％を超えて含有させて
も効果の増強が期待されず、経済性も劣ることか
ら0.1〜0.6％の範囲に限定した。
焼入れ性を改善する目的でＢを0.0050％以下で
添加し、また必要により有効Ｂを確保するために
0.010〜0.100％のTi及び／又はAlを添加する。
なお調質熱処理のための焼戻し温度は、280℃
より低いときには、良好なリラクセーシヨン値が
得られ難く、それ故280℃以上を必要とする。
（実施例）
従来品種として低Si、低Mn材(A)、(B)、高Si低
Mn(C)、(D)および(E)ならびに低Si、高Mn材(F)，
(G)および(H)を、比較例として、これに対しこの発
明に従う実施例(I)，(J)，(K)および(L)について行つ
たヘツド部の破断試験結果を以下に示す。
表１に供試材の成分を掲げ、これらに高周波出
力を一定にして加熱時間を変えてヘツダー加工を
行つた鋼棒ヘツド部の破断試験結果を第３図に示
した。
(Industrial Application Field) High-strength steel bars, which are a typical example of PC steel bars, are generally hot-rolled and then subjected to tempering heat treatment, that is, quenching and tempering, and then used for concrete structures using the above-mentioned PC steel bars. In order to facilitate the introduction of prestress, the material is often subjected to sub-hot processing, typically hedding. For heating for such sub-hot processing, rapid heating such as high frequency induction heating is usually performed. Therefore, there is a good chance that such deterioration of bar performance in sub-hot processed parts may occur, and the following technical contents related to effective avoidance are based on investigation under composition adjustment of high-strength steel bars. It is located in the field of technology that generally includes methods for manufacturing high-strength steel bars, of which PC steel bars are a typical example, with the aim of improving quality and structure. (Prior art) In general, steel bars of this type containing about 0.35% by weight of C (hereinafter simply expressed as %) and about 0.8% of Mn and subjected to quenching and tempering treatment have been widely used.
In addition to elongation after spot welding, other problems remain, such as the narrow range of heating temperature for header processing to achieve sufficient strength in the header processing section. (Problem to be solved by the invention) As mentioned above, this type of steel bar material is used, for example, as a prestressed steel bar in the manufacture of prestressed piles, etc., and usually has a tensile strength of 145 kg/mm 2 or more. be done. However, when manufacturing PC piles, the PC steel bars are combined with auxiliary reinforcing bars and woven into reinforcing bar cages through inspection and inspection. of
Provides convenience for fixing with the end ring of the PC steel bar. If the head section created in this way breaks under the load applied to introduce prestress into the steel bar, there is a risk that fragments of the steel bar head section will fly out and cause a serious accident.For this reason, header processing is applied. While it is required to have sufficient strength at the end of the steel bar, it is expected that the conditions of this hedging process, that is, sub-hot working, in particular, the heating temperature range, are permissible over a wide range, and that stable strength is maintained. need to get it. When the end of a steel bar is subjected to sub-hot header processing, short-time heating using high frequency is usually used as a heating means, and the high frequency output and heating time are adjusted. The strength of the head portion formed here and its fracture form are greatly influenced by the heating conditions. Therefore, conventionally, due to variations in the header itself depending on the lot of steel bars, and in some cases even within the same lot, there is a disadvantage in that it is necessary to change the settings of the high frequency output and heating time in order to provide sufficient head strength. It was hot. Therefore, the header processing conditions, that is, the heating conditions, can be selected within a wide range, and the advantages of achieving sufficient head strength are technically extremely large. Now, according to the results of the fracture test (FIG. 1) on the head portion, the fracture forms can be roughly divided into five types as shown in FIG. In (a), the fracture occurs in a place that is not affected by header processing, and in this case, there is no decrease in strength due to header processing. In cases (b) and (c), it is thought that the head portion or the lower part of the head was greatly softened due to heating during header processing, and the strength often decreased. In cases (d) and (e), it is thought that the inside of the head or the lower part of the head became brittle or cracked due to the header processing, and the strength may be significantly reduced. As a way to deal with this problem, we first proposed a method to improve the workability in sub-heating and to increase the resistance to softening during tempering.
We made a proposal with the publication number. However, according to the disclosure, fracture modes (b) and (c) are effective in preventing softening of the lower part of the head during header processing, but in cases where the heating time during header processing deviates to the shorter and longer sides. In this case, fracture patterns (d) and (e) often occur due to embrittlement inside the head or under the head, and this cannot be completely suppressed. The inventors investigated various causes of such embrittlement and found that the cause was due to a striped structure based on the microstructure of Si and Mn among the material components, and the ratio of Si content to Mn content ( By controlling the value of [Si]/[Mn] (hereinafter simply expressed as [Si]/[Mn]), we were able to eliminate the striped structure and completely prevent the embrittlement of the lower part of the head of the PC steel bar. Based on the above knowledge, the bar material derived from the sub-hot processing of high-strength steel bars that are subjected to hot rolling, temper heat treatment, and then subjected to sub-hot hedging processing for use. Avoiding performance deterioration is
This is the object of this invention. (Means for solving the problem) The above purpose will be effectively achieved by the following items. After hot-rolling a steel billet, it is heated to the quenching temperature, then rapidly cooled and quenched using a water jet nozzle, and then tempered at a temperature of 280°C or higher, which allows for sub-hot hedging processing. In producing high-tensile steel bars for use in the field, the steel pieces contain C: 0.20 to 0.50% by weight, Si: 0.50 to 2.0% by weight,
Mn: 0.9-2.0 wt% and Cr: 0.10-0.60 wt%
Molten steel containing 0.005% by weight or less of B as a basic component, or containing 0.005% by weight or less of B and 0.010 to 0.100% by weight of one or two of Al and Ti in addition to the above basic components. By adjusting the ratio of Si content to Mn content within the range of 0.5 to 1.2 for each molten steel, we prevented the formation of striped structures in slabs made from these molten steels. It is characterized by the fact that it does not contain striped structures such as those caused by micro-segregation of Si and Mn during sub-hot header processing during use,
This is a high-strength steel with excellent hedging workability that can be advantageously applied to PC steel bars for PC piles, etc., which can significantly contribute to improving sub-hot hedging workability and has good spot weldability and relaxation values. This is a method for manufacturing bars. The molten steel with the above-mentioned composition adjustment is made into a bar by hot rolling after ingot formation or continuous casting according to the conventional method, followed by quenching, which rapidly cools from the austenite region by heating, and then by quenching at a temperature of 280℃ or higher. By applying tempering heat treatment, the strength of the head part will not be impaired regardless of the heating conditions of sub-hot header processing or temperature fluctuations when used as a prestressing steel bar. Moreover, embrittlement of the lower part of the head is completely prevented.
In addition, it has been confirmed that it is excellent in spot welding material and relaxation value required for bars. (Function) The reasons for limiting the components in the steel are as follows. C: 0.2~0.5% C is related to the tensile strength after tempering and is 0.2
If it is less than 0.2%, it will be difficult to achieve the required tensile strength by tempering at 280°C or higher, and if it exceeds 0.5%, the elongation will deteriorate significantly under welding conditions that provide sufficient welding strength, so 0.2 to 0.5%. Define the scope of Controlling the above-mentioned [Si]/[Mn] values is also effective against deterioration of elongation after welding, and by preventing embrittlement, the
The upper limit of C, which was regulated at 0.3% in Publication No. 3, can be expanded to 0.5%. Si: 0.5-2.0% Si is essential for preventing brittleness of the lower part of the head during head ink processing.
In order to satisfy the condition that the value of [Mn] be within the range of 0.50 to 1.20, the minimum value is 0.45%, but the lower limit is set to 0.5%, allowing for some margin. Furthermore, since Si has characteristics as a metalloid, increasing the amount added tends to impair the toughness of the material, so the upper limit was set at 2.0%. Mn: 0.9~2.0% In addition to the normal deoxidizing and quenching effects, Mn also has
0.9 to 2.0 useful for improving spot weldability and effective for that purpose
% is set higher than conventional ordinary steel materials. Cr: 0.1-0.6% Cr is an effective component for improving workability in sub-hot header processing and stably maintaining the strength of the head under a wide range of heating conditions, and is less than 0.1%. The content was limited to 0.1 to 0.6% because it was not effective in expanding the range of heating conditions for header processing, and even if it was added in excess of 0.6%, no enhancement of the effect was expected, and it was also less economical. B is added at 0.0050% or less for the purpose of improving hardenability, and if necessary to ensure effective B.
Add 0.010-0.100% Ti and/or Al. The tempering temperature for tempering heat treatment is 280℃.
At lower temperatures, it is difficult to obtain good relaxation values, thus requiring temperatures above 280°C. (Example) Conventional products include low Si, low Mn materials (A), (B), high Si and low
Mn (C), (D) and (E) and low Si, high Mn material (F),
(G) and (H) are used as comparative examples, and the results of head part fracture tests conducted on Examples (I), (J), (K), and (L) according to the present invention are shown below. Table 1 lists the components of the test materials, and FIG. 3 shows the results of a fracture test on the head of a steel bar, which was subjected to header processing while keeping the high frequency output constant and changing the heating time.
【表】
比較例では加熱時間６秒を超えると破断強度は
低下しているのに対し、実施例は強度の低下がほ
とんどなかつた。
次に形態(a)のみの破断とそれ以外の破断形態を
含むものを記号を分けて、〔Si〕／〔Mn〕の値と
破断強度の関係をヘツダー加工時の熱負荷の最も
大きい加熱時間7.5秒について示すと第４図のと
おりである。
図から明らかなように、7.5秒加熱後の破断強
度は〔Si〕／〔Mn〕の値0.85前後を最良値とし、
該比が0.5よりも小さい場合もまた1.2より大きい
場合も著しく破断強度が低下する。
また破断形態についても〔Si〕／〔Mn〕の値
が0.5未満および1.2超えて形態ａ以外の破断を示
す。
従つて〔Si〕／〔Mn〕の値の範囲としては
0.50〜1.20の間に調整すべき必要が明らかであ
る。
これは縞状組織を解消するための炭素溶解度に
対する溶質原子量の適当なバランスがあり、
〔Si〕／〔Mn〕の値0.85はこのバランス量比の最
適値を示している。
次にPCパイルなどをオートクレープ養生する
場合の高温でのリラクセーシヨン値を示す。
ここに、高温リラクセーシヨン値は、調温室温
（20℃）で試験片を適当な間隔でつかみ、約１分
間で試験片の規格破断荷重に70％を乗じた値の荷
重をかけ、つかみ間隔をそのままに保持しなが
ら、１時間で180℃の温度に昇温してその温度に
３時間保持したのち、自然空冷し、荷重をかけて
から23時間の経過中に減少する荷重の測定をつづ
け、試験の終期減少荷重の初期荷重に対する百分
率で算出する。
表２に高温リラクセーシヨン値を示した。[Table] In the comparative examples, the breaking strength decreased when the heating time exceeded 6 seconds, whereas in the examples there was almost no decrease in strength. Next, we separate the symbols for fractures that include only mode (a) and those that include other fracture modes, and calculate the relationship between the value of [Si]/[Mn] and fracture strength at the heating time when the heat load is greatest during header processing. The diagram for 7.5 seconds is shown in Figure 4. As is clear from the figure, the best value for the breaking strength after heating for 7.5 seconds is a value of [Si]/[Mn] of around 0.85.
If the ratio is smaller than 0.5 or larger than 1.2, the breaking strength is significantly reduced. Regarding the fracture mode, the values of [Si]/[Mn] are less than 0.5 and more than 1.2, indicating fracture other than mode a. Therefore, the range of [Si]/[Mn] values is
The need to adjust between 0.50 and 1.20 is obvious. This is because there is an appropriate balance between solute atomic weight and carbon solubility to eliminate the striped structure.
The value of [Si]/[Mn] of 0.85 indicates the optimum value of this balance amount ratio. Next, we will show the relaxation value at high temperatures when autoclaving PC piles, etc. Here, the high temperature relaxation value is determined by gripping the test piece at appropriate intervals in a controlled room temperature (20℃), applying a load equal to the standard breaking load of the test piece multiplied by 70% for about 1 minute, and then While maintaining the same interval, the temperature was raised to 180℃ in 1 hour, held at that temperature for 3 hours, then naturally air cooled, and the load decreased during the 23 hours after the load was applied. Next, calculate the final reduced load of the test as a percentage of the initial load. Table 2 shows the high temperature relaxation values.
【表】
この結果より実施例は、従来品に比べ高温リラ
クセーシヨン特性もとくにすぐれていることがわ
かつた。
第５図は、焼戻し温度と常温リラクセーシヨン
値の関係を求めたものである。
ここに、常温リラクセーシヨンは、常温で試験
片を適当な間隔でつかみ、約１分間で規格降伏点
荷重に80％を乗じた地の荷重104Kgｆ／mm2をかけ、
つかみ間隔をそのままに保持しながら、荷重をか
けてから10時間の経過中に減少する荷重の測定を
つづけ、試験の終期減少荷重の初期荷重に対する
百分率で算出する。
常温リラクセーシヨン値は焼戻し温度280℃未
満では急激に増加している。このことから焼戻し
温度は、280℃以上とすることがとくに有利であ
る。
（発明の効果）
この発明によれば熱間加工を経て焼入れ、焼戻
し処理を施した高張力鋼棒材につき、使用に際し
て亜熱間でのヘツデイング加工が加えられる場合
には、該加工にもとなう棒材特性の劣化を来たす
べき原因が適切な鋼材の成分調整によつて除去さ
れたので、この種の使途における該特性の信頼性
を高めその使途の増大に著しい寄与をもたらす。[Table] From the results, it was found that the example had particularly excellent high-temperature relaxation characteristics compared to the conventional product. FIG. 5 shows the relationship between tempering temperature and room temperature relaxation value. Here, room temperature relaxation involves gripping the test specimens at appropriate intervals at room temperature and applying a ground load of 104 kgf/mm 2 , which is the standard yield point load multiplied by 80%, for about 1 minute.
While maintaining the grip spacing as is, continue to measure the load that decreases over the course of 10 hours after applying the load, and calculate the decreased load at the end of the test as a percentage of the initial load. The room temperature relaxation value increases rapidly at tempering temperatures below 280°C. For this reason, it is particularly advantageous to set the tempering temperature to 280°C or higher. (Effects of the Invention) According to the present invention, when a high-tensile steel bar material that has been subjected to hot working, quenching, and tempering is subjected to subhot hedging processing during use, the Since the causes of the deterioration of the bar properties have been eliminated by appropriate composition adjustment of the steel material, the reliability of the properties in this type of use has been increased and this has made a significant contribution to increasing the number of uses thereof.
第１図はヘツド部の破断試験要領説明図、第２
図は破断形態模式図、第３図は亜熱間ヘツダー加
工加熱時間が破断強度に及ぼす影響を示すグラ
フ、第４図は〔Si〕／〔Mn〕についての同様な
グラフ、第５図は、焼戻し温度と常温リラクセー
シヨン関係グラフである。
Figure 1 is an explanatory diagram of the fracture test procedure for the head section, Figure 2
The figure is a schematic diagram of fracture morphology, Figure 3 is a graph showing the effect of sub-hot header processing heating time on fracture strength, Figure 4 is a similar graph for [Si]/[Mn], and Figure 5 is: It is a graph showing the relationship between tempering temperature and room temperature relaxation.
Claims (1)
熱後、噴射水流ノズルにより急冷して焼入れし、
ついで280℃以上の温度で焼戻しをする調質熱処
理を施して、亜熱間でのヘツデイング加工を行つ
て使用に供する高張力鋼棒材を製造するにあたつ
て、鋼片が Ｃ：0.20〜0.50重量％ Si：0.50〜2.0重量％ Mn：0.9〜2.0重量％および Cr：0.10〜0.60重量％ を基本成分として、 0.005重量％以下のＢを含有する溶鋼について、 上記Si含有量とMn含有量との比の値を0.5〜
1.2の範囲に成分調整することにより、この溶鋼
から造つた鋼片の縞状組織の生成をあらかじめ防
止したものであることを特徴とするヘツデイング
加工法に優れる高張力鋼棒材の製造方法。 ２ 鋼片を熱間圧延したのち、焼入れ温度まで加
熱後、噴射水流ノズルにより急冷して焼入れし、
ついで280℃以上の温度で焼戻しをする調質熱処
理を施して、亜熱間でのヘツデイング加工を行つ
て使用に供する高張力鋼棒材を製造するにあたつ
て、鋼片が Ｃ：0.20〜0.50重量％ Si：0.50〜2.0重量％ Mn：0.9〜2.0重量％および Cr：0.10〜0.60重量％ を基本成分として、 0.005重量％以下のＢならびに0.010〜0.100重量
％のAl及びTiのうちから選んだ１種又は２種を
含有する溶鋼について、 上記Si含有量とMn含有量との比の値を0.5〜
1.2の範囲に成分調整することにより、この溶鋼
から造つた鋼片の縞状組織の生成をあらかじめ防
止したものであることを特徴とするヘツデイング
加工法に優れる高張力鋼棒材の製造方法。[Claims] 1. After hot rolling a steel billet, heating it to a quenching temperature, and then quenching it with a water jet nozzle and quenching it,
Then, when producing high-tensile steel bars for use by subjecting them to tempering heat treatment at a temperature of 280°C or higher, and performing sub-hot hedging processing, the steel billet has a C: 0.20~ For molten steel containing 0.005% by weight or less of B, with the basic components of 0.50% by weight Si: 0.50 to 2.0% by weight Mn: 0.9 to 2.0% by weight and Cr: 0.10 to 0.60% by weight, the above Si content and Mn content The value of the ratio between 0.5 and
1. A method for producing high-strength steel bars that is excellent in hedging processing, characterized in that the formation of striped structures in steel slabs made from this molten steel is prevented in advance by adjusting the composition within the range of 1.2. 2 After hot-rolling the steel billet, it is heated to the quenching temperature, then rapidly cooled and quenched using a water jet nozzle,
Then, when producing high-tensile steel bars for use by subjecting them to tempering heat treatment at a temperature of 280°C or higher, and performing sub-hot hedging processing, the steel billet has a C: 0.20~ 0.50% by weight Si: 0.50-2.0% by weight Mn: 0.9-2.0% by weight and Cr: 0.10-0.60% by weight as basic components, selected from B of 0.005% by weight or less and Al and Ti of 0.010-0.100% by weight. For molten steel containing Type 1 or Type 2, the ratio of the Si content to the Mn content is set to 0.5 to 0.5.
1. A method for producing high-strength steel bars that is excellent in hedging processing, characterized in that the formation of striped structures in steel slabs made from this molten steel is prevented in advance by adjusting the composition within the range of 1.2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11826083A JPS6013029A (en) | 1983-07-01 | 1983-07-01 | Production of high-tension steel bar material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11826083A JPS6013029A (en) | 1983-07-01 | 1983-07-01 | Production of high-tension steel bar material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6013029A JPS6013029A (en) | 1985-01-23 |
| JPH0565567B2 true JPH0565567B2 (en) | 1993-09-20 |
Family
ID=14732218
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11826083A Granted JPS6013029A (en) | 1983-07-01 | 1983-07-01 | Production of high-tension steel bar material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6013029A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| JPH06105246B2 (en) * | 1988-03-11 | 1994-12-21 | 株式会社日立製作所 | Liquid chromatograph |
| JP2698374B2 (en) * | 1988-05-26 | 1998-01-19 | 川崎製鉄株式会社 | Method of manufacturing high-strength PC steel rod |
| CN111041363B (en) * | 2019-12-13 | 2021-06-15 | 首钢集团有限公司 | 1420 Mpa-grade prestressed steel material and preparation method and application thereof |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55107734A (en) * | 1979-02-14 | 1980-08-19 | Sumitomo Metal Ind Ltd | Manufacture of high tensile steel wire rod |
| JPS5618052A (en) * | 1979-07-25 | 1981-02-20 | Mazda Motor Corp | Suction device for engine |
| JPS56119728A (en) * | 1980-02-25 | 1981-09-19 | Sumitomo Metal Ind Ltd | Manufacture of high tensile wire rod |
| JPS5745811A (en) * | 1980-08-30 | 1982-03-16 | Matsushita Electric Works Ltd | Mirror cabinet |
| JPS5782432A (en) * | 1980-11-08 | 1982-05-22 | Sumitomo Metal Ind Ltd | Production of high tensile wire rod |
| JPS57169020A (en) * | 1981-04-11 | 1982-10-18 | Sumitomo Metal Ind Ltd | Production of high tensile steel bar |
| JPS5839737A (en) * | 1981-09-02 | 1983-03-08 | Sumitomo Metal Ind Ltd | Manufacture of high tensile wire rod |
-
1983
- 1983-07-01 JP JP11826083A patent/JPS6013029A/en active Granted
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55107734A (en) * | 1979-02-14 | 1980-08-19 | Sumitomo Metal Ind Ltd | Manufacture of high tensile steel wire rod |
| JPS5618052A (en) * | 1979-07-25 | 1981-02-20 | Mazda Motor Corp | Suction device for engine |
| JPS56119728A (en) * | 1980-02-25 | 1981-09-19 | Sumitomo Metal Ind Ltd | Manufacture of high tensile wire rod |
| JPS5745811A (en) * | 1980-08-30 | 1982-03-16 | Matsushita Electric Works Ltd | Mirror cabinet |
| JPS5782432A (en) * | 1980-11-08 | 1982-05-22 | Sumitomo Metal Ind Ltd | Production of high tensile wire rod |
| JPS57169020A (en) * | 1981-04-11 | 1982-10-18 | Sumitomo Metal Ind Ltd | Production of high tensile steel bar |
| JPS5839737A (en) * | 1981-09-02 | 1983-03-08 | Sumitomo Metal Ind Ltd | Manufacture of high tensile wire rod |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6013029A (en) | 1985-01-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9394580B2 (en) | High-toughness cold-drawn non-heat-treated wire rod, and method for manufacturing same | |
| JPS61238917A (en) | Manufacture of low alloy tempered high tensile seamless steel pipe | |
| JP2731797B2 (en) | Manufacturing method of steel wire rod for non-heat treated bolts | |
| JP3267772B2 (en) | Manufacturing method of high strength, high ductility, high toughness rail | |
| JPH06299240A (en) | Manufacture of steel material for bearing having excellent spheroidizing characteristic | |
| JPH05171262A (en) | Manufacture of wire rod or bar steel for case hardened product | |
| JPH0565567B2 (en) | ||
| JPH06128631A (en) | Production of high manganese ultrahigh tensile strength steel excellent in low temperature toughness | |
| JP3999457B2 (en) | Wire rod and steel bar excellent in cold workability and manufacturing method thereof | |
| JP4976985B2 (en) | Manufacturing method of wire rod and steel bar with excellent low-temperature torsional characteristics | |
| JPH0693332A (en) | Production of high tensile strength and high toughness fine bainitic steel | |
| JPH03183739A (en) | Manufacture of high toughness non-heat treated steel for hot forging, its bar steel | |
| JPH0672258B2 (en) | Method for producing rolled steel bar with excellent homogeneity | |
| JPH0643605B2 (en) | Manufacturing method of non-heat treated steel for hot forging | |
| JP3243987B2 (en) | Manufacturing method of high strength and high corrosion resistance martensitic stainless steel | |
| JP5248222B2 (en) | Cold tool steel manufacturing method | |
| JPH0813028A (en) | Production of precipitation hardening steel material having high tensile strength and high toughness | |
| JPH05255738A (en) | Production of steel for machine structural use excellent in delayed fracture resistance | |
| JP2698374B2 (en) | Method of manufacturing high-strength PC steel rod | |
| JPH0229727B2 (en) | DORIRUKARAAYOBOKONOSEIZOHOHO | |
| JPH0688129A (en) | Production of high strength steel pipe as welded low in residual stress | |
| JPH10168518A (en) | Manufacture of high tensile strength steel plate with tapered thickness | |
| JPH03260010A (en) | Production of non-heattreated steel bar for hot forging and production of hot forged non-heattreated parts | |
| JPH0366383B2 (en) | ||
| JPS62253725A (en) | Production of high-toughness non-heattreated bar steel for hot forging |