JPS5871354A - Unnormalized structural steel and its manufacture - Google Patents
Unnormalized structural steel and its manufactureInfo
- Publication number
- JPS5871354A JPS5871354A JP16775081A JP16775081A JPS5871354A JP S5871354 A JPS5871354 A JP S5871354A JP 16775081 A JP16775081 A JP 16775081A JP 16775081 A JP16775081 A JP 16775081A JP S5871354 A JPS5871354 A JP S5871354A
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- steel
- structural steel
- toughness
- unnormalized
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Abstract
Description
【発明の詳細な説明】
本発明は、非調質、すなわち熱間加工の捷ま焼入れ・焼
戻しなどの調質処理を行なわなくても、すぐれた靭性を
有する構造用鋼に関し、その製造方法をも包含する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structural steel that has excellent toughness even without thermal refining, that is, without thermal refining treatment such as cold working, quenching, and tempering, and a method for producing the same. Also includes.
一般に構造用鋼からの製品の製造は、熱間加工ののち調
質をしてから切削加工を施すことによって行なわれてい
るが、調質を行なわないで済めばコストの低下がはかれ
るとともに、省エネルギーの要請にこたえることもでき
る〇
そこでこのような鋼の研究がさかんに試みられており、
とくに、■やNbなどを添加した鋼を熱間加工後に冷却
する過程でこれらの炭化物・窒化物がフェライト+パー
ライト組織中に町田することを利用して強化する鋼が開
発され、一部実用化されている。 熱間加工として圧延
を行なった場合は、圧延のままで強化した鋼材をそのま
ま、あるいは冷間または温間で塑性加工してから切削し
て最終製品とする。 また、鍛造を行なう場合は、圧延
した鋼材を型打鍛造し、硬化した粗材を切削して製品と
する。Generally, products made from structural steel are manufactured by hot working, tempering, and cutting, but if tempering is not required, costs can be reduced and energy can be saved. Therefore, research on such steels is actively being attempted.
In particular, steels that are strengthened by utilizing the fact that these carbides and nitrides form in the ferrite + pearlite structure during the cooling process after hot working of steels with additions such as ■ and Nb have been developed, and some of them have been put into practical use. has been done. When rolling is performed as hot working, the steel material is strengthened as it is or is cold or warm plastic worked and then cut into the final product. In addition, when forging is performed, the rolled steel material is die-forged, and the hardened rough material is cut into a product.
しかしこのようにして得た製品は、通常の調質処理をへ
たものにくらべて、その靭性が低いという弱点がある。However, the product obtained in this way has a disadvantage in that its toughness is lower than that of products that undergo ordinary heat treatment.
本発明は、この弱点を克服して、調質鋼にくらべてそん
色のない非調質構造用鋼を提供する。The present invention overcomes this weakness and provides a non-tempered structural steel that is comparable to tempered steel.
熱間加工のままですぐれた靭性を有する本発明の非調質
構造用鋼は、C: 0.30〜0.60%、si:0.
10〜2.0 % 、Mn ’ 0.20〜2.5%、
Al : 0.005〜0.10%およびN : 0.
005〜0.30チ、ならびに、V:0.5%以下およ
びNb : 0.5%以下のいずれか1種または2種を
含有し、残余が実質的にFeか争なる鋼合金を熱間加工
してなり、常温まで冷却した後の組織が、平均結晶粒度
番号5以上の旧オーステナイト結晶粒を有することを特
徴とする。The non-tempered structural steel of the present invention, which has excellent toughness even after hot working, has C: 0.30 to 0.60%, Si: 0.
10-2.0%, Mn' 0.20-2.5%,
Al: 0.005-0.10% and N: 0.
0.005 to 0.30%, and any one or two of V: 0.5% or less and Nb: 0.5% or less, with the remainder being substantially Fe or hot-processed. The structure after processing and cooling to room temperature is characterized by having prior austenite crystal grains with an average grain size number of 5 or more.
本発明で採用した合金組成における各成分の役割゛と、
その限定の理由を述べる。The role of each component in the alloy composition adopted in the present invention,
The reason for this limitation will be explained.
C:0゜30〜060%、
必要な強度を確保するため、0.30%以上の存在が必
須で菖る。 上限は靭性の観点がら定めた。C: 0°30-060%, in order to ensure the necessary strength, the presence of 0.30% or more is essential. The upper limit was determined from the viewpoint of toughness.
Si : 0.10〜2.0%、好ましくは0.15〜
1.0%Siは脱酸剤として必要な元素であり、0.1
0チ以上含有させるが、非調質構造用鋼は、熱間加工後
、轡械加工にょシ製品とするのがふううであシ、被削性
が良好であることが望まれる。 従2て、siは2.0
%以下、好ましくは1.0チまでに止めるべきである。Si: 0.10-2.0%, preferably 0.15-2.0%
1.0%Si is an element necessary as a deoxidizer, and 0.1%Si is a necessary element as a deoxidizing agent.
However, after hot working, it is preferable that non-tempered structural steel be made into a machined product, and it is desirable that the machinability is good. Therefore, si is 2.0
% or less, preferably 1.0% or less.
Mn 二〇、20〜2.5%、好ましくは0.5〜1.
8%いうまでもなくMnも脱酸剤として作用するが、非
調質鋼においては高い靭性を得る上で重要である。 本
発明においても、比較的重含有量、代表的には15チ内
外を採用する。Mn 20, 20-2.5%, preferably 0.5-1.
8% Needless to say, Mn also acts as a deoxidizing agent, which is important in obtaining high toughness in non-tempered steel. In the present invention, a relatively heavy content, typically around 15 inches, is used.
ただし被剛性の点からは、あまり多量に加えることは避
けたい。However, from the viewpoint of rigidity, it is desirable to avoid adding too much.
Al : 0.005〜0.10%、好ましくはQ、0
1〜0.05%脱酸作用もあるが、主な役割は結晶粒の
微細 “化である。 A1もまた被削性に関してはマイ
ナスにはたらくので、0.10%以下に限定するO
N : 0.005〜0.30%、好ましくは0.23
%までNの効果は、ひとつは結晶粒の微細化であり、込
まひとつはVまたはNbとの窒化物形成による析出強化
である。−これも多量にすぎると靭性を損う。Al: 0.005-0.10%, preferably Q, 0
1 to 0.05% It also has a deoxidizing effect, but its main role is to make the crystal grains finer. Since A1 also has a negative effect on machinability, it should be limited to 0.10% or less. 0.005-0.30%, preferably 0.23
One of the effects of N up to % is the refinement of crystal grains, and the other is precipitation strengthening due to the formation of nitrides with V or Nb. - Too much of this also impairs toughness.
V:0.5%以下、Nb:0.5%以下(−併用Ota
合は合計で0.5%以下)
どちらも窒化物を形成し、析出強化および結晶粒の微細
化に寄与する。 ただし、後に述べるように、鋼材の加
工条件に対しては、Nbの影響が大きく、高含有量の方
が適切な加工温度の上限が拡がる。 上限は熱間加工性
の −低下を理由に設けたが、VもNbも高価な材料
であるから、添加効果と経済性との調和において添加量
を定めればよい。V: 0.5% or less, Nb: 0.5% or less (-combined Ota
(0.5% or less in total) Both form nitrides and contribute to precipitation strengthening and grain refinement. However, as will be described later, the influence of Nb is large on the processing conditions of steel materials, and the higher the content, the wider the upper limit of the appropriate processing temperature. Although the upper limit was set on the basis of a decrease in hot workability, since both V and Nb are expensive materials, the amount added should be determined in harmony with the effect of addition and economical efficiency.
本発明の鋼の最大の特徴は、前記した旧オーステナイト
結晶粒の大きさが平均結晶粒度番号5以上であるという
特異な組織にある。 いうまでもなく、「旧オーステナ
イト」箱晶粒とは、熱間加工後常温まで冷却されて生成
したフエライトーバ−ライト系の組織のフェライト粒が
、高温の状態では存在していだオーステナイト結晶粒界
をくまどるように存在し、以前の結晶粒の大きさを示す
ものを意味する。 この測定は、JIS G 055]
に定める徐冷法に従って行なう。The greatest feature of the steel of the present invention is its unique structure in which the size of the prior austenite crystal grains is an average grain size number of 5 or more. Needless to say, "prior austenite" box grains are ferrite grains with a ferrite-to-barrite structure that are generated when cooled to room temperature after hot working, forming austenite grain boundaries that already exist at high temperatures. It means something that exists in circles and indicates the size of previous crystal grains. This measurement is based on JIS G 055]
Follow the slow cooling method specified in .
従来一般の非調質鋼の組織は、結晶粒度番号2〜3であ
ることを考慮すると、本発明でえらんだ組織は、きわめ
て特異なものである。Considering that the structure of conventional non-tempered steel has a grain size number of 2 to 3, the structure selected in the present invention is extremely unique.
調質非調質をとわす、鋼材には機械的特性に関する異方
性が、程良の差こそあれ免れ難い。 本発明の鋼におい
て、とくに靭性の方向性を低くしたい場合には、S:0
.40%以下およびTe:O,]0チ以下を、Te /
S : 0.04以上の割合で含有させることが推奨
される。 Sはもちろん被剛性の改善に役立つ元素であ
るが、ここではむしろ、適量のSとTeとの組み合わせ
により、鋼中の硫化物系介在物の形態をコントロールし
、靭性の異方性を軽減する効果が得られるのである。
SおよびTeの上限値は、主として熱間加工性にもとづ
いて定めた。Anisotropy in mechanical properties is inevitable in steel materials, even if it is not thermally refined. In the steel of the present invention, when the directionality of toughness is particularly desired to be lowered, S: 0
.. 40% or less and Te:O, ]0chi or less, Te /
S: It is recommended to contain it in a ratio of 0.04 or more. S is, of course, an element that helps improve stiffness, but here the combination of appropriate amounts of S and Te controls the morphology of sulfide inclusions in the steel and reduces the anisotropy of toughness. The effect can be obtained.
The upper limits of S and Te were determined mainly based on hot workability.
用途に応じて、さまざまな効果を期待して下記の諸元素
を特定の範囲内で添加し、または特定の限度まで低減す
るとよい。Depending on the application, the following elements may be added within a specific range or reduced to a specific limit in anticipation of various effects.
○結晶粒度をさらに微細化したいとき Ti:0.5チ
以下、Ta:0.5%以下、またはZr : 0.5%
以下
○耐候性を高めたいとき・・Cu : 2.0%以下○
被剛性の一層の向上を望むとき・・Pb:0.4%以下
、Bi二O,4%以下、Se:0.4%以下、Ca:0
.01チ以下
○抜力強度を改善したいとき・ 0 : 0.0030
%以下○強度の増大をはかるとき・・・Cr : 5%
以下、Ni : 5%以下、Mo : 3%以下、上述
のような、熱間加工のままで高い靭性を有する構造用鋼
を得るには、前記の組成の鋼合金を熱間加工して冷却す
る際の加工条件を、所定の結晶粒度番号になるようえら
ばなければならない。○When you want to further refine the grain size Ti: 0.5 inches or less, Ta: 0.5% or less, or Zr: 0.5%
Below ○ When you want to increase weather resistance...Cu: 2.0% or less ○
When further improvement in rigidity is desired...Pb: 0.4% or less, Bi2O, 4% or less, Se: 0.4% or less, Ca: 0
.. 01 inches or less ○ When you want to improve the pulling force strength・0: 0.0030
% or less ○ When increasing strength...Cr: 5%
Hereinafter, Ni: 5% or less, Mo: 3% or less. In order to obtain a structural steel having high toughness as hot-worked as described above, a steel alloy having the above composition is hot-worked and then cooled. Processing conditions must be selected to achieve a predetermined grain size number.
その条件は、えらんだ組成によって異なるが、最も支配
的な因子°はNおよびNbの含有量である。The conditions vary depending on the composition chosen, but the most dominant factors are the N and Nb contents.
いま、これらの含有量の大小に応じて、良好な結果を与
える熱間加工の加熱温度および仕上げ温度の上限界を示
せば、次のとおりである。Now, depending on the magnitude of these contents, the upper limits of the heating temperature and finishing temperature for hot working that give good results are as follows.
0 0.005〜0.015 1000 9
00Q O,015〜0.30 1100
1000(0,10,005〜0.015 12
00 1100<0.1 0.015〜0.3
0 1300 12000.1〜0.5 0.
005〜0.30 1300 1300明らか
に、Nb含有量の増大につれて限界が似大している。
これは好ましいことではあるが、Nbは高価であるから
、添加量の増大に庄う利益とコスト増とのバランスにお
いて、実際の添加シを定めるのがよい。 なお、実際の
操業条件は、上記限界内で、高いはと塑性加工に対する
抵抗が低いが、得られる鋼材の靭性に関する限りは比較
的低温が好ましい。 これもまた、回者のバランスをは
かつてそれぞれの場合・に応じて選択すべきことになる
。0 0.005~0.015 1000 9
00Q O,015~0.30 1100
1000 (0,10,005~0.015 12
00 1100<0.1 0.015~0.3
0 1300 12000.1~0.5 0.
005-0.30 1300 1300 Obviously, the limit becomes larger as the Nb content increases.
Although this is preferable, since Nb is expensive, it is better to decide on the actual amount of Nb to be added, taking into consideration the balance between the benefit of increasing the amount added and the increase in cost. Note that the actual operating conditions are within the above limits, with high resistance to plastic working being low, but relatively low temperatures are preferred as far as the toughness of the obtained steel material is concerned. Again, the balance of players should be chosen depending on each case.
本発明によれば、産業機械や自動車などの製造に広く使
われている構造用鋼において、熱間加工のままで高い強
度と靭性をもった鋼が得られる。According to the present invention, it is possible to obtain structural steel that has high strength and toughness even after hot working, which is widely used in the manufacture of industrial machinery, automobiles, and the like.
従って、これまで焼入れ、焼戻しの調質処理を必要とし
ていた各種機械部品、たとえばクランクシャフト、コネ
クティングロッド、アクスルシャフト、スピンドル、ス
テアリングラックなどの製造に当って、熱処理工程を省
略することができ、生産性は大いに高まる。 この利益
は大量生産品において一層顕著である。Therefore, the heat treatment process can be omitted when manufacturing various mechanical parts, such as crankshafts, connecting rods, axle shafts, spindles, and steering racks, which previously required heat treatment such as quenching and tempering. sex will greatly increase. This benefit is even more pronounced for mass-produced products.
実施例
第1表に示す合金組成の鋼を2 tonアーク炉で溶解
し鋳造した。(A V[’は比較鋼)インゴットを圧延
して1pOmm角のビレットをつくり、加熱温度と仕上
は温度とを下に示す条件に設定して鍛造し、断面20m
mX60mmの素材とした。 比較拐は、鍛造後さらに
、850℃・油冷−600℃・空冷の条件で焼入れ一焼
戻し処理をした。EXAMPLE Steel having the alloy composition shown in Table 1 was melted and cast in a 2 ton arc furnace. (A V [' is comparative steel) An ingot was rolled to make a 1 pOmm square billet, and the heating temperature and finishing temperature were set to the conditions shown below, and the billet was forged to a cross section of 20 m.
The material was m x 60 mm. After forging, the comparative steel was further quenched and tempered under the conditions of 850°C, oil cooling - 600°C, and air cooling.
処理条件 加熱温度 仕上温度 冷却内A l3
00℃ 1300℃ 空冷B 130
0 1100C10001000
D 1000 800E
焼入れ(850℃、水冷)
十−焼戻しく600℃)
上記のようにして得た素材について、種々試験した結果
を第2表に示す。 表中、番号にX印を付したものは比
較例、無印が本発明の実施例である。 1−一」は未測
定を慧味する。Processing conditions Heating temperature Finishing temperature Cooling inside A l3
00℃ 1300℃ Air cooling B 130
0 1100C10001000 D 1000 800E
Table 2 shows the results of various tests performed on the materials obtained as described above. In the table, the numbers with an X mark are comparative examples, and the numbers without a mark are examples of the present invention. 1-1” takes advantage of unmeasured results.
シャルピー衝撃値はJIS 3号試験片を用い、室温で
測定したものである。 また旧オーステナイト結晶粒度
は、JIS 00551に定める徐冷法による粒度測定
方法を採用して測定した〇第2表のデータから、本発明
に従う合金組成および加工処理条件の組み合わせが所定
の大きさの旧オーステナイト結晶粒度をもたらすこと、
そしてその条件をみたした鋼材が、硬さ、靭性および靭
性の方向性に関して、調質を行なった在来品にそん色の
ない値を示すことがわかり、さらに、適量のSおよびT
eを含有する場合には靭性の方向性が著しく改善される
ことが裏付けられる0特許出願人 大同特殊鋼株式会社The Charpy impact value was measured at room temperature using a JIS No. 3 test piece. In addition, the prior austenite crystal grain size was measured by adopting the grain size measurement method using the slow cooling method specified in JIS 00551. From the data in Table 2, it is found that the combination of the alloy composition and processing conditions according to the present invention results in prior austenite crystals of a predetermined size. providing granularity;
It was found that steel materials that met these conditions exhibited hardness, toughness, and directionality of toughness that were comparable to conventional products that had undergone thermal refining.
It is confirmed that the directionality of toughness is significantly improved when containing e0 Patent applicant Daido Steel Co., Ltd.
Claims (3)
0.10〜2.0チ、Mn : 0.20〜2.5%、
AI : 0.005〜0.10 %およびN:0.0
05〜0.30チ、ならびに、V二0.5%以下および
Nb : 0.5%以下のいずれか1種または2種を含
有し、残余が実質的にFeからなる鋼合金を熱間加工し
てなシ、常温まで冷却した後の組織が、平均結晶粒度番
号5以上の旧オーステナイト結晶粒を有することを特徴
とする非調質構造用鋼。(1) C: 0.30~. 0.60%, Si:
0.10~2.0chi, Mn: 0.20~2.5%,
AI: 0.005-0.10% and N: 0.0
Hot working a steel alloy containing one or both of the following: 0.05 to 0.30%, V2: 0.5% or less, and Nb: 0.5% or less, with the remainder substantially consisting of Fe. A non-tempered structural steel characterized in that the structure after cooling to room temperature has prior austenite crystal grains with an average grain size number of 5 or more.
e : 0.10 %以下を、Te/S: 0.04以
上の割合で含有する特許請求の範囲第1項または第2項
の鋼。(2) The steel alloy further contains S: 0.40% or less and T
The steel according to claim 1 or 2, containing e: 0.10% or less and Te/S: 0.04 or more.
0〜2.0%、Mn : 0.20〜2.5%、Al
: 0.005〜0.10 %およびN : 0.00
5〜0.30 g6、ならびにV:0.5チ以下および
Nb:0.5%以下のいずれか1種または2種を含有し
残余が実質的にFeからなる鋼合金を、NおよびNbの
含有量に応じてつぎの限度以下の加熱温度および仕上げ
温度において熱間加工を行なうことを特徴とする非調質
構造用鋼の製造方法。 0 0.005〜0.015 1000 9
000 0.015〜0.30 1100
1000(0,10,005〜0.015 120
0 1100(0,1’ 0.015〜0.30
1300 12000.1〜0.5 0.0
05〜0.30 1300 1300(3) C: 0.30-0.60%, Si: 051
0-2.0%, Mn: 0.20-2.5%, Al
: 0.005-0.10% and N: 0.00
5 to 0.30 g6, and a steel alloy containing one or both of V: 0.5% or less and Nb: 0.5% or less, with the remainder substantially consisting of Fe, is A method for producing non-tempered structural steel, characterized in that hot working is performed at a heating temperature and finishing temperature below the following limits depending on the content. 0 0.005~0.015 1000 9
000 0.015~0.30 1100
1000 (0,10,005~0.015 120
0 1100 (0,1' 0.015~0.30
1300 12000.1~0.5 0.0
05~0.30 1300 1300
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16775081A JPS5871354A (en) | 1981-10-20 | 1981-10-20 | Unnormalized structural steel and its manufacture |
JP15112386A JPS6296653A (en) | 1981-10-20 | 1986-06-27 | Nonrefined structural steel |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16775081A JPS5871354A (en) | 1981-10-20 | 1981-10-20 | Unnormalized structural steel and its manufacture |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP15112386A Division JPS6296653A (en) | 1981-10-20 | 1986-06-27 | Nonrefined structural steel |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5871354A true JPS5871354A (en) | 1983-04-28 |
JPH0140901B1 JPH0140901B1 (en) | 1989-09-01 |
Family
ID=15855402
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP16775081A Pending JPS5871354A (en) | 1981-10-20 | 1981-10-20 | Unnormalized structural steel and its manufacture |
JP15112386A Granted JPS6296653A (en) | 1981-10-20 | 1986-06-27 | Nonrefined structural steel |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP15112386A Granted JPS6296653A (en) | 1981-10-20 | 1986-06-27 | Nonrefined structural steel |
Country Status (1)
Country | Link |
---|---|
JP (2) | JPS5871354A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4895700A (en) * | 1988-03-10 | 1990-01-23 | Dana Corporation | Low grade material axle shaft |
CN1039835C (en) * | 1995-07-20 | 1998-09-16 | 张玉田 | Non-hardened and non-tempered alloy structure steel and making process thereof |
JP2016538417A (en) * | 2013-09-26 | 2016-12-08 | ペキン ユニバーシティ ファウンダー グループ カンパニー,リミティド | Non-tempered steel and manufacturing method thereof |
JP2019085615A (en) * | 2017-11-07 | 2019-06-06 | 日産自動車株式会社 | Axle shaft |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01290751A (en) * | 1988-05-19 | 1989-11-22 | Topy Ind Ltd | High-strength non-heattreated steel bar |
JPH0796695B2 (en) * | 1988-08-10 | 1995-10-18 | 新日本製鐵株式会社 | Medium carbon tough steel |
JP2669178B2 (en) * | 1991-05-08 | 1997-10-27 | 住友金属工業株式会社 | High toughness and high strength seamless steel pipe |
JP5233848B2 (en) * | 2009-06-08 | 2013-07-10 | 新日鐵住金株式会社 | Non-tempered steel bar for direct cutting |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4923124A (en) * | 1972-06-23 | 1974-03-01 | ||
JPS5921369B2 (en) * | 1976-10-25 | 1984-05-19 | 新日本製鐵株式会社 | Manufacturing method for high-tensile, high-carbon steel wire with excellent wire drawability |
JPS5853708B2 (en) * | 1979-03-15 | 1983-11-30 | 住友金属工業株式会社 | Welded steel pipe with excellent butt toughness |
-
1981
- 1981-10-20 JP JP16775081A patent/JPS5871354A/en active Pending
-
1986
- 1986-06-27 JP JP15112386A patent/JPS6296653A/en active Granted
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4895700A (en) * | 1988-03-10 | 1990-01-23 | Dana Corporation | Low grade material axle shaft |
CN1039835C (en) * | 1995-07-20 | 1998-09-16 | 张玉田 | Non-hardened and non-tempered alloy structure steel and making process thereof |
JP2016538417A (en) * | 2013-09-26 | 2016-12-08 | ペキン ユニバーシティ ファウンダー グループ カンパニー,リミティド | Non-tempered steel and manufacturing method thereof |
JP2019085615A (en) * | 2017-11-07 | 2019-06-06 | 日産自動車株式会社 | Axle shaft |
Also Published As
Publication number | Publication date |
---|---|
JPH0557351B2 (en) | 1993-08-23 |
JPH0140901B1 (en) | 1989-09-01 |
JPS6296653A (en) | 1987-05-06 |
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