JPH0147528B2 - - Google Patents
Info
- Publication number
- JPH0147528B2 JPH0147528B2 JP57083277A JP8327782A JPH0147528B2 JP H0147528 B2 JPH0147528 B2 JP H0147528B2 JP 57083277 A JP57083277 A JP 57083277A JP 8327782 A JP8327782 A JP 8327782A JP H0147528 B2 JPH0147528 B2 JP H0147528B2
- Authority
- JP
- Japan
- Prior art keywords
- steel
- heat treatment
- strength
- product
- toughness
- 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
Links
- 229910000831 Steel Inorganic materials 0.000 claims description 22
- 239000010959 steel Substances 0.000 claims description 22
- 238000010438 heat treatment Methods 0.000 claims description 13
- 239000002826 coolant Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 229910001566 austenite Inorganic materials 0.000 claims description 4
- 238000005098 hot rolling Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 description 9
- 238000001816 cooling Methods 0.000 description 8
- 239000000463 material Substances 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 239000003949 liquefied natural gas Substances 0.000 description 2
- 239000003915 liquefied petroleum gas Substances 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910000746 Structural steel Inorganic materials 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0068—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (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 Steel (AREA)
- Heat Treatments In General, Especially Conveying And Cooling (AREA)
Description
この発明は靭性にすぐれた高張力形鋼の製造方
法に関し、特に熱間圧延後に熱処理を行う製造方
法に関する。
近年、エネルギ危機以来、液化石油ガス
（LPG）および液化天然ガス（LNG）の運搬用、
貯蔵用容器として、さらに寒冷地における低温用
構造用鋼として、靭性にすぐれた高張力形鋼の需
要が増加する傾向にある。
一般に高靭性高張力の製品を得る方法として
は、コントロールドローリングによる方法と熱処
理による方法とが知られているが、形鋼の場合は
孔型圧延が主であるためロール強度等の制約から
厚鋼板にみられるようなコントロールドローリン
グによる方法の適用は困難である。一方、熱処理
については、形鋼の場合、通常バツチ炉による焼
ならし処理が採用され、厚さ25mm以下の所謂薄物
サイズの場合、靭性については良好な結果が得ら
れているが、反面強度（降伏点、引張強さ）低下
が大きく十分な効果が期待できない。また板厚25
mm以上の厚物サイズについては強度低下は更に著
しく靭性の向上も薄物ほど期待できない。
更に熱処理自体バツチ型が適用されていたた
め、形鋼製品のように製品単重（Kg／ｍ）が小さ
く長さが比較的長く、更に複雑な形状を有する場
合には製品長さが炉長に制約されることや積み重
ね処理を行つた場合、上段の製品と下段のものと
の機械的性質の変動が大きいという問題があつ
た。また昇温速度や冷却速度の制御が困難であり
製品の歪曲り制御が難しい等の問題があつた。し
たがつて形鋼の場合、より高い靭性、高い強度を
得るためには焼入性の高いＣ，Mn，Ni，Mo，
Cr，Ｖ等の合金元素を添加する必要があつた。
しかし、これら元素の添加は製造コストを上昇さ
せるだけでなく溶接性の優劣を示すパラメータで
ある炭素当量の値を上昇させるため溶接部の機械
的性質の劣化をもたらすという欠点がある。
本発明は上記した従来技術の欠点を改善するた
めになされたもので、通常の工程により熱間圧延
した後、熱処理炉として連続熱処理炉を採用し、
ここで被処理形鋼をオーステナイト域まで加熱
し、次いで加速冷却するようにしたものである。
この加速冷却においては形鋼の各部位に応じて冷
却媒体の量を調整しつつ形鋼全体を冷却する。
本発明において連続熱処理炉を用いることとし
たのは、連続熱処理炉では材料の送り速度が可変
であるため、製品寸法や厚みに応じて昇温速度が
コントロールでき、そのためバツチ炉に比較して
品質のバラツキが小さく安定した品質が得られる
からである。また昇温速度が大きいとオーステナ
イト結晶粒が小さくなるため、熱処理後のフエラ
イト粒が小さくなり、その結果、高靭性、高強度
が得られるためである。更に連続処理炉の採用に
より製品寸法の制限や、積み重ね処理による品質
のバラツキといつた問題も解決することができ
る。
オーステナイト域まで加熱後、本発明において
は加速冷却を行う。これは昇温の場合と同様に冷
却速度が適切な範囲で大きいと徴細なフエライト
粒が得られ、高靭性、高強度が得られるためであ
る。しかも本発明においては、この加速冷却を冷
却する個所に応じて冷却媒体の量を制御しつつ行
う。これにより非対称の形鋼であつても適切に歪
や曲がりを防止することができる。
第１図に本発明における加速冷却を実施するた
めの冷却装置の具体的一実施例を示す。この実施
例では被熱処理形鋼６の上下左右に冷却媒体用の
ヘツダ１，２，３，４を配置し、各ヘツダからの
冷却媒体の吐出量を個別に制御し得るように構成
している。このような装置により、被熱処理形鋼
６の厚肉部には冷却媒体を多量に吐出し、薄肉部
には少量を吐出する等して形鋼全体を均一に冷却
することができる。なお、図中５はテーブルロー
ラである。また冷却媒体としては製品の厚みによ
りエアー、水あるいは両者の混合（ミスト）を使
用すれば良い。
次に実施例を示す。
実施例
50Kg／mm2鋼（0.12％Ｃ−0.35％Si−1.43％Mn−
0.020％Nb）のＨ形鋼に本発明方法による熱処理
と従来法による焼ならしを施し、製品の機械的性
質を検査した。
その結果を下掲表に示す。
The present invention relates to a method for manufacturing high-strength steel sections with excellent toughness, and more particularly to a method for manufacturing high-strength steel sections in which heat treatment is performed after hot rolling. In recent years, since the energy crisis, for the transportation of liquefied petroleum gas (LPG) and liquefied natural gas (LNG),
There is an increasing demand for high-strength steel sections with excellent toughness, both as storage containers and as structural steel for low-temperature use in cold regions. Controlled rolling and heat treatment are generally known methods for obtaining products with high toughness and high tensile strength. However, in the case of section steel, groove rolling is the main method, so due to constraints such as roll strength, It is difficult to apply a method using controlled draw rolling as seen in steel plates. On the other hand, regarding heat treatment, in the case of section steel, normalizing treatment using a batch furnace is usually adopted, and in the case of so-called thin products with a thickness of 25 mm or less, good results have been obtained regarding toughness, but on the other hand, strength ( (yield point, tensile strength) are significantly reduced, and sufficient effects cannot be expected. Also plate thickness 25
For thicker materials of mm or more, the strength decreases more significantly and toughness cannot be expected to improve as much as for thinner materials. Furthermore, since the batch type heat treatment itself was applied, when the product unit weight (Kg/m) is small and the length is relatively long, such as a shaped steel product, and the product has a complicated shape, the product length may not match the furnace length. There were problems in that there were restrictions and when stacking was performed, there was a large variation in mechanical properties between the products in the upper row and the products in the lower row. Further, there were problems such as difficulty in controlling the heating rate and cooling rate, making it difficult to control product distortion. Therefore, in the case of section steel, in order to obtain higher toughness and strength, C, Mn, Ni, Mo,
It was necessary to add alloying elements such as Cr and V.
However, the addition of these elements not only increases manufacturing costs, but also increases the value of carbon equivalent, which is a parameter indicating the superiority or inferiority of weldability, resulting in deterioration of the mechanical properties of the welded part. The present invention has been made to improve the drawbacks of the prior art described above, and after hot rolling in a normal process, a continuous heat treatment furnace is adopted as the heat treatment furnace,
Here, the shaped steel to be treated is heated to the austenite region and then acceleratedly cooled.
In this accelerated cooling, the entire shaped steel is cooled while adjusting the amount of cooling medium depending on each part of the shaped steel. The reason why we chose to use a continuous heat treatment furnace in the present invention is that in a continuous heat treatment furnace, the feed rate of the material is variable, so the temperature increase rate can be controlled according to the product dimensions and thickness, and as a result, the quality is higher than that in a batch furnace. This is because the variation in quality is small and stable quality can be obtained. Furthermore, if the temperature increase rate is high, the austenite crystal grains become smaller, so the ferrite grains after heat treatment become smaller, and as a result, high toughness and high strength are obtained. Furthermore, by adopting a continuous processing furnace, it is possible to solve problems such as limitations on product size and variations in quality due to stacking processing. After heating to the austenite region, accelerated cooling is performed in the present invention. This is because, as in the case of temperature elevation, if the cooling rate is high within an appropriate range, fine ferrite grains can be obtained, resulting in high toughness and high strength. Moreover, in the present invention, this accelerated cooling is performed while controlling the amount of cooling medium depending on the location to be cooled. As a result, even if the steel section is asymmetrical, distortion and bending can be appropriately prevented. FIG. 1 shows a specific embodiment of a cooling device for performing accelerated cooling according to the present invention. In this embodiment, headers 1, 2, 3, and 4 for cooling medium are arranged on the upper, lower, left, and right sides of the heat-treated section steel 6, and the configuration is such that the discharge amount of the cooling medium from each header can be controlled individually. . With such a device, it is possible to uniformly cool the entire shaped steel by discharging a large amount of cooling medium to the thick portion of the heat-treated shaped steel 6 and discharging a small amount to the thin walled portion. Note that 5 in the figure is a table roller. As the cooling medium, air, water, or a mixture of both (mist) may be used depending on the thickness of the product. Next, examples will be shown. Example 50Kg/mm 2 steel (0.12%C-0.35%Si-1.43%Mn-
H-beam steel (0.020%Nb) was heat treated by the method of the present invention and normalized by the conventional method, and the mechanical properties of the product were examined. The results are shown in the table below.
【表】
この表より本発明方法によれば、すぐれた特性
を得られることがわかる。[Table] From this table, it can be seen that excellent properties can be obtained according to the method of the present invention.
第１図は本発明方法を実施するための冷却装置
の一実施例を示す概略図である。
図中、１，２，３，４…はヘツダ、５はテーブ
ルローラ、６は形鋼である。
FIG. 1 is a schematic diagram showing an embodiment of a cooling device for carrying out the method of the present invention. In the figure, 1, 2, 3, 4... are headers, 5 is a table roller, and 6 is a section steel.
Claims (1)
張力形鋼の製造方法において、連続熱処理炉によ
りオーステナイト域に加熱後形鋼の各部位に応じ
て冷却媒体の量を調整しつつ均一に加速冷却する
ことを特徴とする靭性にすぐれた高張力形鋼の製
造方法。1. In a method for producing high-strength steel sections with excellent toughness, in which heat treatment is performed after hot rolling, the steel section is heated to the austenite region in a continuous heat treatment furnace and then uniformly accelerated cooled while adjusting the amount of cooling medium according to each part of the section steel. A method for producing high-strength steel sections with excellent toughness.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8327782A JPS58199817A (en) | 1982-05-19 | 1982-05-19 | Production of high tensile shape steel having excellent toughness |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8327782A JPS58199817A (en) | 1982-05-19 | 1982-05-19 | Production of high tensile shape steel having excellent toughness |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58199817A JPS58199817A (en) | 1983-11-21 |
| JPH0147528B2 true JPH0147528B2 (en) | 1989-10-16 |
Family
ID=13797861
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8327782A Granted JPS58199817A (en) | 1982-05-19 | 1982-05-19 | Production of high tensile shape steel having excellent toughness |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58199817A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0243322A (en) * | 1988-08-01 | 1990-02-13 | Rozai Kogyo Kaisha Ltd | Cooler for stainless shape steel |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5249920A (en) * | 1975-10-21 | 1977-04-21 | Nippon Kokan Kk <Nkk> | Equipment for water cooling of steel sections |
| JPS5295514A (en) * | 1976-02-09 | 1977-08-11 | Nippon Steel Corp | Cooling for reducing camber of u-shaped sheet piling |
| JPS52104450A (en) * | 1976-02-28 | 1977-09-01 | Nippon Steel Corp | Device for cooling hhshaped steel |
| JPS52142013A (en) * | 1976-05-19 | 1977-11-26 | Standard Oil Co | Use of coated catalyst for production of maleic anhydride |
| JPS5355404A (en) * | 1976-10-29 | 1978-05-19 | Nippon Steel Corp | Preventing method for bending of long-sized steel |
| JPS5448629A (en) * | 1977-09-26 | 1979-04-17 | Nippon Steel Corp | Manufacture of h type steel having high low-temperature toughness of root portion with web |
-
1982
- 1982-05-19 JP JP8327782A patent/JPS58199817A/en active Granted
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5249920A (en) * | 1975-10-21 | 1977-04-21 | Nippon Kokan Kk <Nkk> | Equipment for water cooling of steel sections |
| JPS5295514A (en) * | 1976-02-09 | 1977-08-11 | Nippon Steel Corp | Cooling for reducing camber of u-shaped sheet piling |
| JPS52104450A (en) * | 1976-02-28 | 1977-09-01 | Nippon Steel Corp | Device for cooling hhshaped steel |
| JPS52142013A (en) * | 1976-05-19 | 1977-11-26 | Standard Oil Co | Use of coated catalyst for production of maleic anhydride |
| JPS5355404A (en) * | 1976-10-29 | 1978-05-19 | Nippon Steel Corp | Preventing method for bending of long-sized steel |
| JPS5448629A (en) * | 1977-09-26 | 1979-04-17 | Nippon Steel Corp | Manufacture of h type steel having high low-temperature toughness of root portion with web |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58199817A (en) | 1983-11-21 |
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