JP7497447B2 - Steel for mining chains and its manufacturing method - Google Patents

Steel for mining chains and its manufacturing method Download PDF

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JP7497447B2
JP7497447B2 JP2022550659A JP2022550659A JP7497447B2 JP 7497447 B2 JP7497447 B2 JP 7497447B2 JP 2022550659 A JP2022550659 A JP 2022550659A JP 2022550659 A JP2022550659 A JP 2022550659A JP 7497447 B2 JP7497447 B2 JP 7497447B2
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steel
billet
tempering
mining
temperature
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JP2023515115A (en
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ガオ、ジアチアン
チャオ、スーシン
ワン、ウェイ
チャン、ジュン
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バオシャン アイアン アンド スティール カンパニー リミテッド
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21CMANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21JFORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J9/00Forging presses
    • B21J9/02Special design or construction
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21LMAKING METAL CHAINS
    • B21L11/00Making chains or chain links of special shape
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10Supplying or treating molten metal
    • B22D11/11Treating the molten metal
    • B22D11/113Treating the molten metal by vacuum treating
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    • C21D1/00General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18Hardening; Quenching with or without subsequent tempering
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    • C21D1/00General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18Hardening; Quenching with or without subsequent tempering
    • C21D1/25Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten")
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    • C21D1/00General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/56General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
    • C21D1/60Aqueous agents
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    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
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    • C21D9/0087Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for chains, for chain links
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Description

技術分野
本発明は、高強度を有する鋼、および特に高強度および高靭性を有する採掘チェーン用鋼、ならびにその製造方法に関する。
TECHNICAL FIELD The present invention relates to steels having high strength, and in particular steels for mining chains having high strength and high toughness, and to a method for producing same.

背景
高強度および高靭性を有する棒鋼は、通常高い安全性の機械および構造用部品に用いられる。例えば、鉱山用の円形のリンクチェーンは、鉱山機械の重要な摩耗部品である。従って、それらは高強度、高靭性、高耐摩耗性、高耐腐食性および高耐疲労性などを有すべきである。
Background Steel bars with high strength and high toughness are usually used in high safety machinery and structural parts. For example, circular link chains for mining are important wear parts of mining machinery. Therefore, they should have high strength, high toughness, high wear resistance, high corrosion resistance and high fatigue resistance, etc.

高強度および高靭性を有する鋼に対する多くの国内および外国の研究がある。通常、これらの鋼は、適切な化学組成および制御圧延および冷却過程または焼き入れおよび焼き戻し過程などの製造方法を採用することによって製造される。制御圧延および冷却過程を用いて高強度鋼が製造される場合、圧延および冷却過程は制御するのが困難であるので、鋼の機械特性の全体的な均一性が影響を受ける。焼き入れおよび焼き戻し過程を用いて高強度鋼が製造される場合、鋼の焼入性は、合金元素および炭素の含有量を最適化することによって改善され得、その結果、鋼は冷却過程の間にマルテンサイトを形成し得る。マルテンサイト-ベースの高強度鋼は高転位密度を有し、劣った衝撃靭性を生じる。微小クラックなどの小さな欠陥が延伸過程の間に現れる場合、これらの鋼はすぐに砕け、比較的低い破壊靭性を示す。 There are many domestic and foreign researches on steels with high strength and high toughness. Usually, these steels are produced by adopting suitable chemical composition and production methods such as controlled rolling and cooling process or quenching and tempering process. When high strength steels are produced using controlled rolling and cooling process, the rolling and cooling process is difficult to control, so the overall uniformity of the mechanical properties of the steel is affected. When high strength steels are produced using quenching and tempering process, the hardenability of the steel can be improved by optimizing the content of alloying elements and carbon, so that the steel can form martensite during the cooling process. Martensite-based high strength steels have high dislocation density, resulting in poor impact toughness. If small defects such as microcracks appear during the drawing process, these steels will fracture quickly and show relatively low fracture toughness.

Mn-Cr-Ni-Mo合金鋼は、それらの良好な強度および靭性のために、建設機械、自動車、橋梁、および船用機器などの分野において広く用いられる。一般に、これらの鋼の安全使用のための強度レベルは、900~1000MPaである。より高い強度を有する鋼の使用は、機器をより軽くし得るだけでなく、資源を節約し得る。従って、高強度を有する合金鋼は、将来の発展の必然的な傾向である。しかし、鋼の強度レベルが増加すると、製造の困難性が増加し、そして水素脆化に対するそれらの感受性は必ず増加する。高強度鋼の水素誘導遅れ破壊に対する感受性は、微細構造の微細化、微細合金化、粒界の強化および合金元素の添加によって大いに下げられ得る。 Mn-Cr-Ni-Mo alloy steels are widely used in fields such as construction machinery, automobiles, bridges, and marine equipment due to their good strength and toughness. Generally, the strength level for safe use of these steels is 900-1000 MPa. The use of steels with higher strength can not only make the equipment lighter, but also save resources. Therefore, alloy steels with high strength are an inevitable trend of future development. However, as the strength level of steels increases, the difficulty of manufacturing increases, and their susceptibility to hydrogen embrittlement necessarily increases. The susceptibility of high-strength steels to hydrogen-induced delayed fracture can be greatly reduced by microstructural refinement, fine alloying, grain boundary strengthening, and the addition of alloying elements.

最新の国家規格GB/T 10560-2017(「鉱山用の溶接した円形のリンクチェーン用の鋼」)に開示された低いケイ素含有量を有するMn-Cr-Ni-Mo系において、鉱山用の円形のリンクチェーンのための鋼の最高強度レベルは、1180MPaである。焼き入れおよび焼き戻し(880℃で焼き入れおよび430℃で焼き戻し)後のチェーン鋼の機械特性は以下の通りである:降伏強度ReL≧1060MPa、引張強度R≧1180MPa、伸び率A≧10%、断面収縮率Z≧50%、およびシャルピー衝撃エネルギーAkV≧60J。中国の鉱山機械において用いられる焼き入れおよび焼き戻し(880℃で焼き入れおよび400℃で焼き戻し)後の最高強度グレードを有するチェーン鋼の機械特性は以下の通りである:降伏強度ReL≧980MPa、引張強度R≧1180MPa、伸び率A≧10%、断面収縮率Z≧50%、およびシャルピー衝撃エネルギーAkU≧40J。 In the Mn-Cr-Ni-Mo system with low silicon content disclosed in the latest national standard GB/T 10560-2017 ("Steel for welded circular link chains for mining"), the highest strength level of steel for circular link chains for mining is 1180 MPa. The mechanical properties of the chain steel after quenching and tempering (quenching at 880°C and tempering at 430°C) are as follows: yield strength R eL ≧1060 MPa, tensile strength R m ≧1180 MPa, elongation A ≧10%, reduction in area Z ≧50%, and Charpy impact energy A kV ≧60 J. The mechanical properties of chain steel with the highest strength grade after quenching and tempering (quenching at 880°C and tempering at 400°C) used in Chinese mining machinery are as follows: yield strength R eL ≥ 980 MPa, tensile strength R m ≥ 1180 MPa, elongation A ≥ 10%, reduction in area Z ≥ 50%, and Charpy impact energy A kU ≥ 40 J.

湿った鉱山において、Mn-Cr-Ni-Mo合金鋼チェーンは、大きな負荷および動力学的衝撃に供され、そして応力腐食を受ける傾向にある。いくつかの厳しい場合において、これらのチェーンは非常に脆くなり、そして容易に砕け、このことは、膨大な経済的損失および安全事故でさえも引き起こしかねない。 In wet mines, Mn-Cr-Ni-Mo alloy steel chains are subjected to large loads and dynamic shocks and are prone to stress corrosion. In some severe cases, these chains become very brittle and easily break, which may cause huge economic losses and even safety accidents.

要約
本発明の目的は、採掘チェーン用鋼およびその製造方法を提供することである。チェーン鋼は、良好な衝撃靭性、良好な伸び率および断面収縮率を有する。鋼は、応力腐食割れに抵抗し得、そして良好な耐候性、良好な耐摩耗性および耐疲労性を有し得る。従って、鋼は、建設機械および船舶工学などの高強度および高靭性を有する鋼が要求される状況において用いられ得る。
SUMMARY The object of the present invention is to provide a steel for mining chains and a method for manufacturing the same. The chain steel has good impact toughness, good elongation and reduction in area. The steel can resist stress corrosion cracking and have good weathering resistance, good wear resistance and fatigue resistance. Thus, the steel can be used in situations where steel with high strength and high toughness is required, such as construction machinery and marine engineering.

上述目的を達成するため、本発明は以下の技術的解決法を提供する。 To achieve the above objectives, the present invention provides the following technical solutions:

重量%で:C:0.20~0.28%、Si:0.01~0.40%、Mn:0.50~1.50%、P≦0.015%、S≦0.005%、Cr:0.30~2.00%、Ni:0.50~2.00%、Mo:0.10~0.80%、Cu:0.01~0.30%、Al:0.01~0.05%、Nb:0.001~0.10%、V:0.001~0.10%、H≦0.00018%、N≦0.0150%、O≦0.0020%、および残部がFeおよび不可避的不純物である;を含み、かつ
1.0~9.9の範囲のマイクロ合金化元素の係数rM/N、ここで
in weight percent: C: 0.20-0.28%, Si: 0.01-0.40%, Mn: 0.50-1.50%, P≦0.015%, S≦0.005%, Cr: 0.30-2.00%, Ni: 0.50-2.00%, Mo: 0.10-0.80%, Cu: 0.01-0.30%, Al: 0.01-0.05%, Nb: 0.001-0.10%, V: 0.001-0.10%, H≦0.00018%, N≦0.0150%, O≦0.0020%, and the balance being Fe and unavoidable impurities; and a coefficient r M/N of the micro-alloying elements in the range of 1.0 to 9.9, where

を有し、
以下の通りの微量元素:As≦0.05%、Pb≦0.05%、Sn≦0.02%、Sb≦0.01%、Bi≦0.01%を有し、かつ≦500である有害性元素の係数J、ここで
having
the coefficient J H of harmful elements being ≦500, with the following trace elements: As≦0.05%, Pb≦0.05%, Sn≦0.02%, Sb≦0.01%, Bi≦0.01%,

を有する、採掘チェーン用鋼。 Steel for mining chains.

本発明における式中の[Al]、[Nb]、[V]、[N]などは、鋼中の対応する元素の重量パーセントを表すことに留意すべきである。式中の[Al]、[Nb]、[V]、[N]などは、計算を行う場合、パーセントの記号の前の値で置き換える。例えば、実施例1におけるAlの含有量は0.020%であり、次に式中の[Al]を0.00020の代わりに0.020で置き換える。他の元素の置き換えも同様である。 It should be noted that [Al], [Nb], [V], [N], etc. in the formulas in this invention represent the weight percentage of the corresponding element in the steel. [Al], [Nb], [V], [N], etc. in the formulas are replaced with the value before the percentage sign when performing calculations. For example, the content of Al in Example 1 is 0.020%, then [Al] in the formula is replaced with 0.020 instead of 0.00020. The replacement of other elements is similar.

好ましくは、当該不可避的不純物において、B≦0.0010%、Ti≦0.003%、Ca≦0.005%。 Preferably, the unavoidable impurities are B≦0.0010%, Ti≦0.003%, and Ca≦0.005%.

本発明における採掘チェーン用鋼の微細構造は、焼き戻しマルテンサイト、ベイナイト、および残留オーステナイトであり、ここでベイナイトの体積パーセントは10%以下である。 The microstructure of the steel for mining chains in this invention is tempered martensite, bainite, and retained austenite, where the volume percentage of bainite is less than 10%.

本発明における採掘チェーン用鋼は、降伏強度Rp0.2≧1000MPa、引張強度R≧1200MPa、伸び率A≧12%、断面収縮率Z≧50%、シャルピー衝撃エネルギーAkv≧60J、および水素脆化の係数η(Z)≦15%を有する。 The steel for mining chains according to the invention has a yield strength R p0.2 ≧1000 MPa, a tensile strength R m ≧1200 MPa, an elongation A ≧12%, a reduction in area Z ≧50%, a Charpy impact energy A kv ≧60 J and a coefficient of hydrogen embrittlement η(Z) ≦15%.

本発明における当該チェーン鋼の組成設計において:
Cは鋼の焼入性を改善し得、その結果、高硬度を有する相変態構造が焼き入れおよび冷却の過程において鋼中に形成され得る。C含有量が増加すると硬質相の割合が増加し、そしてそれ故鋼の硬度は増加するが、靭性の低下につながる。C含有量が低すぎる場合、マルテンサイトおよびベイナイトなどの相変態構造の含有量は低く、そして高い引張強度を有する鋼は得ることができない。本発明において、C含有量は0.20~0.28%に設定される。
In the composition design of the chain steel of the present invention:
C can improve the hardenability of steel, so that a phase transformation structure with high hardness can be formed in the steel in the process of quenching and cooling. As the C content increases, the proportion of hard phase increases, and therefore the hardness of the steel increases, but leads to a decrease in toughness. If the C content is too low, the content of phase transformation structures such as martensite and bainite is low, and steel with high tensile strength cannot be obtained. In the present invention, the C content is set to 0.20-0.28%.

Siは鋼の強度強化に有益である。適切な量のSiは、焼き戻しの間の粗い炭化物の形成を回避し得る。しかし、高いSi含有量は鋼の衝撃靭性を低下させる。低いSiの組成系が本発明において採用され、そしてSi含有量は0.01~0.40%に設定される。 Si is beneficial for strengthening the strength of steel. An appropriate amount of Si can avoid the formation of coarse carbides during tempering. However, a high Si content reduces the impact toughness of the steel. A low Si composition system is adopted in the present invention, and the Si content is set to 0.01-0.40%.

Mnは主として、鋼中に固溶体の形態で存在する。それは、鋼の焼入性を改善し得、そして焼き入れの間に高強度を有する低温相変態構造を形成し得る。従って、良好な耐摩耗性を有する鋼を得ることができる。Mn含有量が高すぎる場合、多量の残留オーステナイトが形成され、鋼の降伏強度の低下につながり、そして鋼中に中心偏析を容易に生じる。本発明において、Mn含有量は0.50~1.50%に設定される。 Mn mainly exists in the form of solid solution in steel. It can improve the hardenability of steel and form a low-temperature phase transformation structure with high strength during quenching. Therefore, steel with good wear resistance can be obtained. If the Mn content is too high, a large amount of retained austenite will be formed, which will lead to a decrease in the yield strength of the steel and easily cause center segregation in the steel. In the present invention, the Mn content is set to 0.50-1.50%.

鋼中の粒界でのPの偏析は、粒界結合エネルギーを低下させ、そして鋼の衝撃靭性を劣化させる。本発明において、P含有量は0.015%以下に設定される。Sは鋼中に偏析し、そして多くの硫化物介在物を形成し、耐衝撃性の低下につながる。本発明において、S含有量は0.005%以下に設定される。 Segregation of P at grain boundaries in steel reduces grain boundary bond energy and deteriorates the impact toughness of the steel. In the present invention, the P content is set to 0.015% or less. S segregates in steel and forms many sulfide inclusions, leading to a decrease in impact resistance. In the present invention, the S content is set to 0.005% or less.

Crは鋼の焼入性を改善し得る。それはまた、硬質マルテンサイト構造を形成し得、鋼の強度の改善につながる。Cr含有量が高すぎる場合、粗い炭化物が形成され、そして衝撃性能が低下する。本発明において、Cr含有量は0.30~2.00%に設定される。 Cr can improve the hardenability of steel. It can also form a hard martensite structure, leading to improved strength of steel. If the Cr content is too high, coarse carbides will be formed and the impact performance will decrease. In the present invention, the Cr content is set to 0.30-2.00%.

Niは鋼中に固溶体の形態で存在し、これは鋼の低温衝撃性能を改善し得る。しかし、過度に高いNi含有量は、鋼中の残留オーステナイトの過度に高い含有量につながり、それによって鋼の強度が低下する。本発明において、Ni含有量は0.50~2.00%に設定される。 Ni exists in the form of solid solution in steel, which can improve the low-temperature impact performance of the steel. However, an excessively high Ni content leads to an excessively high content of retained austenite in the steel, thereby reducing the strength of the steel. In the present invention, the Ni content is set to 0.50-2.00%.

Moは鋼中に固溶体の形態で溶解し得、そして鋼の焼入性および強度を改善するのに役立ち得る。Moは、鋼が高温で焼き戻しされる場合、微細な炭化物を形成し、これは鋼の強度をさらに増加させ得る。貴金属Moのコストを考慮して、本発明において、Mo含有量は0.10~0.80%に設定される。 Mo can dissolve in steel in the form of solid solution and can help improve the hardenability and strength of steel. Mo forms fine carbides when steel is tempered at high temperature, which can further increase the strength of steel. Considering the cost of the precious metal Mo, in this invention, the Mo content is set to 0.10-0.80%.

Cuは鋼の強度および耐腐食性を改善し得る。Cu含有量が高すぎる場合、Cuは加熱の間に粒界に堆積し、粒界の弱化および次いで鋼の割れを生じる。本発明において、Cu含有量は0.01~0.30%に設定される。 Cu can improve the strength and corrosion resistance of steel. If the Cu content is too high, Cu will deposit at the grain boundaries during heating, resulting in weakening of the grain boundaries and then cracking of the steel. In the present invention, the Cu content is set to 0.01-0.30%.

Alは鋼中に微細なAlN粒子を形成し、これはオーステナイト粒子の成長を阻害し得る。Al含有量が高すぎる場合、粗いAl酸化物が形成され、これらの粗くて硬い介在物は、鋼の衝撃靭性および疲労特性の低下を生じる。本発明において、Al含有量は0.01~0.05%に設定される。 Al forms fine AlN particles in steel, which can inhibit the growth of austenite grains. If the Al content is too high, coarse Al oxides are formed, and these coarse and hard inclusions cause a decrease in the impact toughness and fatigue properties of the steel. In the present invention, the Al content is set to 0.01-0.05%.

Nbは鋼に添加され、微細な沈殿物を形成し、これは鋼の再結晶を阻害し得、そして粒子を微細化する。Nb含有量が高すぎる場合、粗いNbC粒子が精錬の間に形成され、これは鋼の衝撃靭性を低下させる。粒子の微細化は、鋼の機械特性、特に強度および靭性の改善に重要な役割を果たす。その一方で、粒子の微細化はまた、鋼の水素脆化感受性を低下させるのに役立つ。本発明において、Nb含有量は0.001~0.10%に設定される。 Nb is added to steel to form fine precipitates, which can inhibit the recrystallization of steel, and refine the grains. If the Nb content is too high, coarse NbC particles will be formed during refining, which will reduce the impact toughness of the steel. Grain refinement plays an important role in improving the mechanical properties of steel, especially the strength and toughness. Meanwhile, grain refinement also helps to reduce the hydrogen embrittlement susceptibility of steel. In the present invention, the Nb content is set to 0.001-0.10%.

Vは、鋼中でCまたはNと沈殿物を形成して鋼の強度を改善し得る。CおよびVの含有量が高すぎる場合、粗いVC粒子が形成される。本発明において、V含有量は0.001~0.10%に設定される。 V can form precipitates with C or N in steel to improve the strength of the steel. If the C and V contents are too high, coarse VC particles are formed. In the present invention, the V content is set to 0.001-0.10%.

Tiが鋼に添加される場合、微細な沈殿物が形成され得る。しかしTi含有量が高すぎる場合、縁および角を有する粗いTiN粒子が精錬の間に形成され、それによって鋼の衝撃靭性が低下する。本発明において、Ti含有量は0.003%以下に設定される。 When Ti is added to steel, fine precipitates may be formed. However, if the Ti content is too high, coarse TiN particles with edges and corners will be formed during refining, thereby reducing the impact toughness of the steel. In the present invention, the Ti content is set to 0.003% or less.

B元素は偏析しやすいので、B含有量は0.0010%以下に制限される。 Because B element is prone to segregation, the B content is limited to 0.0010% or less.

鋼へのCa元素の添加は、硫化物介在物のサイズおよび形態を改善し得、そして衝撃靭性の劣化を回避し得る。しかし、Ca元素は、介在物を形成しそして最終製品の疲労性能に影響を与えやすい。Ca含有量は0.005%以下に制御される。 The addition of Ca element to steel can improve the size and morphology of sulfide inclusions and avoid the deterioration of impact toughness. However, Ca element is prone to form inclusions and affect the fatigue performance of the final product. The Ca content is controlled to less than 0.005%.

Nは、格子間原子のタイプであり、そしてまたMX-型沈殿物を形成するための元素である。鋼中のN元素の濃縮を回避するため、本発明において、N含有量は0.015%以下に設定される。マイクロ合金化元素Al、NbおよびVの含有量のNの含有量に対する比は、制御されなければならず、そしてそれ故マイクロ合金化元素の係数はrM/Nとして定義され、ここでrM/Nは1.0~9.9であり、そして N is a type of interstitial atom and also an element for forming MX-type precipitates. In order to avoid enrichment of N element in steel, in the present invention, the N content is set to be less than or equal to 0.015%. The ratio of the content of micro-alloying elements Al, Nb and V to the content of N must be controlled, and therefore the coefficient of micro-alloying elements is defined as r M/N , where r M/N is 1.0-9.9; and

マイクロ合金化元素の係数は、ナノスケールの沈殿物に関連する。マイクロ合金化元素の高い係数は、鋼中の粗い沈殿物の存在につながり、これは沈殿の強化の効果を達成することができない。さらに、マイクロ合金化元素の高い係数は、介在物と類似の悪影響につながり、疲労強度の低下を生じる。マイクロ合金化元素の低い係数は、少量の沈殿物につながり、これは分散の強化の効果を達成することができない。好ましくは、マイクロ合金化元素の係数rM/Nは1.0~6.0である。 The coefficient of micro-alloying elements is related to nano-scale precipitates. A high coefficient of micro-alloying elements leads to the presence of coarse precipitates in the steel, which cannot achieve the strengthening effect of precipitation. Furthermore, a high coefficient of micro-alloying elements leads to a negative effect similar to that of inclusions, resulting in a decrease in fatigue strength. A low coefficient of micro-alloying elements leads to a small amount of precipitates, which cannot achieve the strengthening effect of dispersion. Preferably, the coefficient of micro-alloying elements r M/N is between 1.0 and 6.0.

Sn、Sb、As、Bi、およびPbなどの微量元素は、焼き戻し温度で粒界に偏析し、粒間結合力の弱化につながる。MnおよびSiは、これらの有害性元素の偏析を促進し得、そしてそれ故鋼の脆化を増加させ得る。さらに、Sn、Sb、As、Bi、およびPbは、環境に対して有害であり、本発明において、これらの元素の含有量は以下の通り設定される:As≦0.05%、Pb≦0.05%、Sn≦0.02%、Sb≦0.01%、およびBi≦0.01%。Pの効果を考慮して、有害性元素の係数Jは≦500であり、そして Trace elements such as Sn, Sb, As, Bi, and Pb will segregate to grain boundaries at the tempering temperature, leading to the weakening of intergranular bonding strength. Mn and Si can promote the segregation of these harmful elements and therefore increase the embrittlement of steel. In addition, Sn, Sb, As, Bi, and Pb are harmful to the environment, and in the present invention, the contents of these elements are set as follows: As≦0.05%, Pb≦0.05%, Sn≦0.02%, Sb≦0.01%, and Bi≦0.01%. Considering the effect of P, the coefficient JH of harmful elements is ≦500, and

Hは鋼中の欠陥で堆積する。1000MPaよりも大きい引張強度を有する鋼において、水素誘導遅れ破壊が起こるかもしれない。本発明において、引張強度は1200MPaを超え、そしてH含有量は0.00018%以下に制御されなければならない。Nは鋼中に窒化物または炭窒化物を形成し、これはオーステナイト粒子の微細化の役割を果たす。しかし高いN含有量は粗い粒子の形成につながり、これは粒子を微細化するのに役立たない。さらに、Nは格子間原子であり、そして粒界に堆積し、衝撃靭性の低下を生じる。本発明において、N含有量は0.0150%以下に制御される。鋼中のOおよびAlは、酸化物および複合酸化物などを形成する。鋼構造の均一性、ならびに鋼の低温衝撃エネルギーおよび疲労性能を確保するため、本発明において、Oの含有量は0.0020%以下に制御される。 H accumulates at defects in steel. In steels with tensile strengths greater than 1000 MPa, hydrogen-induced delayed fracture may occur. In the present invention, the tensile strength exceeds 1200 MPa, and the H content must be controlled to 0.00018% or less. N forms nitrides or carbonitrides in steel, which plays a role in refining austenite grains. But high N content leads to the formation of coarse grains, which is not conducive to refining grains. In addition, N is an interstitial atom, and accumulates at grain boundaries, resulting in a decrease in impact toughness. In the present invention, the N content is controlled to 0.0150% or less. O and Al in steel form oxides and composite oxides, etc. In order to ensure the uniformity of the steel structure, as well as the low-temperature impact energy and fatigue performance of the steel, in the present invention, the content of O is controlled to 0.0020% or less.

さらに、採掘チェーン用鋼の溶接要件を満足するため、鋼の炭素当量Ceqは0.80以下に制御されなければならず、ここで Furthermore, to meet the welding requirements of steel for mining chains, the carbon equivalent Ceq of the steel must be controlled to 0.80 or less, where

さらに採掘チェーン用鋼の耐候性を確保し、かつ応力腐食割れへの耐性を改善するため、耐大気腐食性の指標Iは7.0以上であり、ここで Furthermore, in order to ensure the weather resistance of the steel for mining chains and improve its resistance to stress corrosion cracking, the atmospheric corrosion resistance index I is 7.0 or more, where

本発明における採掘チェーン用鋼の微細構造は、焼き戻しマルテンサイト、ベイナイト、および残留オーステナイトである。 The microstructure of the steel for mining chains in this invention is tempered martensite, bainite, and retained austenite.

一般に、異なる微細構造の水素脆化に対する感受性は、高い順に:元のマルテンサイト>焼き戻しマルテンサイト(低温で焼き戻し)>元のマルテンサイト配向を有する焼き戻しマルテンサイト>ベイナイト>焼き戻しマルテンサイト(高温で焼き戻し)であると考えられる。チェーン鋼は、先行技術において低温焼き戻しマルテンサイト構造を有する。しかし、本発明によって設計された化学組成の採用ならびに合金元素およびマイクロ合金化元素の相変態および微細構造に対する影響の完全な利用によって、焼き戻しマルテンサイト、少量のベイナイト、および残留オーステナイトの複合微細構造が、焼き入れおよび焼き戻し熱処理後に形成される。その一方で、C、P、S、N、O、およびHの含有量は、鋼の強度、衝撃靭性、伸び率および塑性を確保するよう制御されなければならない。従って、適合した超高強度および超高靭性ならびに高塑性を有する採掘チェーン用鋼を製造することができる。これらのチェーン鋼は、良好な耐候性、良好な耐摩耗性、良好な耐応力腐食性および良好な耐疲労性を有する。 In general, the susceptibility of different microstructures to hydrogen embrittlement is considered to be in the following order: original martensite > tempered martensite (tempered at low temperature) > tempered martensite with original martensite orientation > bainite > tempered martensite (tempered at high temperature). Chain steels have a low-temperature tempered martensite structure in the prior art. However, by adopting the chemical composition designed by the present invention and fully utilizing the effects of alloying elements and micro-alloying elements on phase transformation and microstructure, a composite microstructure of tempered martensite, a small amount of bainite, and retained austenite is formed after quenching and tempering heat treatment. Meanwhile, the contents of C, P, S, N, O, and H must be controlled to ensure the strength, impact toughness, elongation and plasticity of the steel. Therefore, steels for mining chains with adapted ultra-high strength and ultra-high toughness as well as high plasticity can be produced. These chain steels have good weather resistance, good wear resistance, good stress corrosion resistance and good fatigue resistance.

精錬、鋳造、加熱、鍛造または圧延、焼き入れ熱処理および焼き戻し熱処理過程の工程を含む、本発明における採掘チェーン用鋼の製造方法;ここで該加熱過程において、加熱温度は1050~1250℃であり、保持時間は3~24hrであり;該鍛造または圧延過程において、最終鍛造温度または最終圧延温度は≧800℃であり;該焼き入れ熱処理において、加熱温度は850~1000℃であり、保持時間は60~240minであり、そして水焼き入れはオーステナイト化後に実施され;該焼き戻し熱処理において、焼き戻し温度は350~550℃であり、保持時間は60~240minであり、そして焼き戻し後、鋼ビレットは空冷または水冷される。 The manufacturing method of the steel for mining chains in the present invention includes the steps of refining, casting, heating, forging or rolling, quenching heat treatment and tempering heat treatment; in the heating process, the heating temperature is 1050-1250°C and the holding time is 3-24hr; in the forging or rolling process, the final forging temperature or final rolling temperature is ≧800°C; in the quenching heat treatment, the heating temperature is 850-1000°C, the holding time is 60-240min, and water quenching is performed after austenitization; in the tempering heat treatment, the tempering temperature is 350-550°C, the holding time is 60-240min, and after tempering, the steel billet is air-cooled or water-cooled.

好ましくは、該精錬は電気炉中での精錬または転炉中での精錬であり得、そして次いで溶融鋼は微細化および真空処理に供される。 Preferably, the refining may be in an electric furnace or in a converter, and the molten steel is then subjected to refinement and vacuum treatment.

好ましくは、該鋳造はダイカストまたは連続鋳造である。 Preferably, the casting is die casting or continuous casting.

好ましくは、該鍛造過程において、鋼ビレットは最終製品のサイズに直接鍛造され;該圧延過程において、鋼ビレットは最終製品のサイズに直接圧延され、または鋼ビレットは特定の中間ビレットサイズに圧延され、そして次いで加熱されそして最終製品のサイズに圧延され、ここで中間ビレットの加熱温度は1050~1250℃であり、そして保持時間は3~24hrである。 Preferably, in the forging process, the steel billet is directly forged to the size of the final product; in the rolling process, the steel billet is directly rolled to the size of the final product, or the steel billet is rolled to a specific intermediate billet size and then heated and rolled to the size of the final product, where the heating temperature of the intermediate billet is 1050-1250°C and the holding time is 3-24 hrs.

好ましくは、該圧延過程において、鋼ビレットは、加熱炉の外に出されると高圧水のスケール除去に供され、そして次いで圧延され、そして圧延後、鋼ビレットは空冷または徐冷される。 Preferably, in the rolling process, the steel billet is subjected to high-pressure water descaling when it leaves the heating furnace, and then rolled, and after rolling, the steel billet is air-cooled or slowly cooled.

本発明における採掘チェーン用鋼は、降伏強度Rp0.2≧1000MPa、引張強度R≧1200MPa、伸び率A≧12%、断面収縮率Z≧50%、シャルピー衝撃エネルギーAkv≧60J、および水素脆化の係数η(Z)≦15%を有する。この種の鋼は、良好な強度、良好な塑性、良好な靭性、ならびに良好な耐候性および耐応力腐食性を有する。 The steel for mining chains according to the invention has a yield strength R p0.2 ≥ 1000 MPa, a tensile strength R m ≥ 1200 MPa, an elongation A ≥ 12%, a reduction in area Z ≥ 50%, a Charpy impact energy A kv ≥ 60 J, and a coefficient of hydrogen embrittlement η(Z) ≤ 15%. This type of steel has good strength, good plasticity, good toughness, as well as good weathering resistance and stress corrosion resistance.

本発明における採掘チェーン用鋼は、高強度棒鋼が要求される状況において用いられ得、ここで棒鋼のサイズおよびゲージ範囲Φは50~170mmである。 The mining chain steel of the present invention can be used in situations where high strength steel bars are required, where the size and gauge range Φ of the steel bars is 50-170mm.

本発明における高強度および高靭性を有する採掘チェーン用鋼は、1050~1250℃で加熱されて完全にオーステナイト化される。加熱の間、Al、Nb、Vの炭化物、窒化物および炭窒化物ならびにCrおよびMoの炭化物は、オーステナイト中に部分的にまたは完全に溶解され得る。続く圧延/鍛造および冷却過程の間、Al、NbおよびVは微細な沈殿物を形成する。オーステナイト中に溶解したMn、CrおよびMoは、鋼の焼入性を改善し得、それによってマルテンサイトの硬度および強度を増加させる。最終圧延または最終鍛造の温度が≧800℃である場合、微細化マルテンサイト、少量のベイナイト、および残留オーステナイトの複合マトリクス構造が形成され、そしてその上微細で分散した沈殿物が形成される。 The high strength and high toughness steel for mining chains in the present invention is heated at 1050-1250°C to be fully austenitized. During heating, the carbides, nitrides and carbonitrides of Al, Nb, V and the carbides of Cr and Mo can be partially or completely dissolved in the austenite. During the subsequent rolling/forging and cooling process, Al, Nb and V form fine precipitates. The Mn, Cr and Mo dissolved in the austenite can improve the hardenability of the steel, thereby increasing the hardness and strength of the martensite. When the temperature of the final rolling or final forging is ≧800°C, a composite matrix structure of refined martensite, a small amount of bainite and retained austenite is formed, and fine and dispersed precipitates are formed as well.

圧延または鍛造後、鋼を850~1000℃に加熱し、そしてしばらくの間保持し、そして次いで焼き入れが実施される。十分なオーステナイト化が保持過程の間に達成される。加熱の間、Al、Nb、V、CrおよびMoなどの炭化物形成元素の沈殿物が部分的に溶解され、そして未溶解の沈殿物は、粒界を固定しそしてオーステナイトの粗大化を阻害し得る(オーステナイトの粒径は≧6グレードである)。焼き入れおよび冷却過程の間、オーステナイト中に溶解した合金元素は、鋼が高強度および良好な靭性を有するようにする。焼き入れした鋼は、350~550℃で焼き戻し熱処理に供される。Al、Nb、V、CrおよびMoは、CおよびNと微細な沈殿物を形成し、これは鋼強度および塑性靭性の整合を改善する。本発明における焼き入れおよび焼き戻しの温度範囲内で、鋼が良好な強度および塑性ならびに良好な靭性を有することが確保され得、これは棒鋼の加工および適用に有益である。例えば、鍛造または溶接により良好な性能を有する採掘チェーンを製造すること。 After rolling or forging, the steel is heated to 850-1000 ° C and held for a while, and then quenching is carried out. Sufficient austenitization is achieved during the holding process. During heating, the precipitates of carbide-forming elements such as Al, Nb, V, Cr and Mo are partially dissolved, and the undissolved precipitates can fix the grain boundaries and inhibit the coarsening of austenite (the grain size of austenite is ≧ 6 grades). During the quenching and cooling process, the alloying elements dissolved in the austenite make the steel have high strength and good toughness. The quenched steel is subjected to tempering heat treatment at 350-550 ° C. Al, Nb, V, Cr and Mo form fine precipitates with C and N, which improve the matching of steel strength and plastic toughness. Within the temperature range of quenching and tempering in the present invention, it can be ensured that the steel has good strength and plasticity as well as good toughness, which is beneficial for the processing and application of bar steel. For example, manufacturing mining chains with good performance by forging or welding.

本発明は、以下の通り先行技術と比較される:
US特許US006146583は、合金鋼の組成およびこのような合金鋼で製造されたチェーン製品を開示し、ここで鋼の成分は:C:0.15~0.28%、Cr:0.2~1.0%、Mo:0.1~1.0%、Ni:0.3~1.5%、V:0.05~0.2%、および残部はFeおよび不可避的不純物である。鋼の強度は800MPaグレードに達し得、そして鋼は耐応力腐食性を有する。高強度および高靭性を有するチェーンは、鍛造、溶接、および熱処理によって得ることができる。
The present invention is compared with the prior art as follows:
US Patent US006146583 discloses the composition of an alloy steel and a chain product made of such alloy steel, where the components of the steel are: C: 0.15-0.28%, Cr: 0.2-1.0%, Mo: 0.1-1.0%, Ni: 0.3-1.5%, V: 0.05-0.2%, and the balance is Fe and unavoidable impurities. The strength of the steel can reach 800 MPa grade, and the steel has stress corrosion resistance. Chains with high strength and high toughness can be obtained by forging, welding, and heat treatment.

そのUS特許と比較して、本発明は、組成において異なるCu含有量を採用し、そしてC、Nの含有量、およびMn、Cr、Ni、Moなどの合金元素の含有量、ならびにAl、V、およびNbなどのマイクロ合金化元素の含有量を最適化する。本発明は、C、NiおよびCu元素を含む組成設計を採用し、そしてMn、Cr、およびMoの含有量を最適化し、そしてそれ故焼き戻しマルテンサイト、少量のベイナイト、および残留オーステナイトの複合微細構造を形成することができる。さらに、本発明における鋼の機械特性は、US特許の鋼の機械特性よりも明らかに良好である。 Compared with that US patent, the present invention adopts different Cu content in the composition, and optimizes the contents of C, N, and the contents of alloying elements such as Mn, Cr, Ni, Mo, and the contents of micro-alloying elements such as Al, V, and Nb. The present invention adopts a composition design including C, Ni and Cu elements, and optimizes the contents of Mn, Cr, and Mo, and thus can form a composite microstructure of tempered martensite, a small amount of bainite, and retained austenite. Moreover, the mechanical properties of the steel in the present invention are obviously better than those of the steel in the US patent.

中国特許CN103276303Aは、採掘チェーン用高強度鋼およびその製造方法を開示する。チェーン鋼の成分は:C:0.21~0.25%、Mn:0.20~0.25%、Si:0.15~0.35%、Cr:0.40~0.65%、Ni:0.60~0.70%、Cu:0.07~0.15%、Alt:0.02~0.05%、N≦0.012%、S≦0.015%、P≦0.015%、および残部はFeである。製造方法は:電気炉または転炉における精錬過程、炉外微細化過程、ビレット連続鋳造過程、ならびに加熱および圧延過程を含み、20~50mmのゲージΦを有する直棒を得、そして焼鈍後に採掘チェーン用高強度鋼を得ることができる。 Chinese patent CN103276303A discloses high strength steel for mining chain and its manufacturing method. The composition of the chain steel is: C: 0.21-0.25%, Mn: 0.20-0.25%, Si: 0.15-0.35%, Cr: 0.40-0.65%, Ni: 0.60-0.70%, Cu: 0.07-0.15%, Alt: 0.02-0.05%, N≦0.012%, S≦0.015%, P≦0.015%, and the balance is Fe. The manufacturing method includes: a refining process in an electric furnace or converter, an out-of-furnace refinement process, a billet continuous casting process, and a heating and rolling process, to obtain a straight bar with a gauge Φ of 20-50 mm, and a high strength steel for mining chain can be obtained after annealing.

そのCN特許と比較して、本発明の鋼におけるCr、Mn、NiおよびMoの含有量は、完全に異なる。さらに、本発明は、C、Cu、Al、Nb、およびVの含有量を最適化し、そしてNおよびCaの含有量を制限する。本発明において記載した合金元素の含有量を採用することによって、焼き戻しマルテンサイトおよび残留オーステナイトの微細構造が形成され、そして鋼は高強度および高靭性の機械特性を示す。1000Mpaより大きい引張強度を有する高強度鋼について、それは環境中にHを吸着させ、それによって鋼の遅れ割れを引き起こす。重いゲージを有する高強度棒鋼は、水素に対してより感受性が高い。従って、鋼中のHの含有量は、本発明において制御されるが、中国特許出願においてそのような要件はない。従って、本発明における鋼の耐応力腐食性および耐遅れ割れは、中国特許出願における鋼のそれらよりも良好である。その特許は、Φ20~50mmの直棒を製造するために用いられ、一方、本発明は、Φ50~170mmの棒鋼を製造するために用いられ得、本発明の方法は、より広範な用途を有し、そしてより重いゲージを有する鋼を製造するために用いられ得る。本発明は、組成、組織および過程設計に関して技術経路が上記特許とは完全に異なる。本発明において、鋼は引張強度R≧1200MPa、降伏強度Rp0.2≧1000MPa、および衝撃エネルギーAkv≧60Jを有する。本発明における鋼の強度グレードは、上述の特許における鋼の強度グレードよりも大きい。本発明における鋼は、優れた衝撃靭性および耐応力腐食割れを有する。 Compared with that CN patent, the contents of Cr, Mn, Ni and Mo in the steel of the present invention are completely different. Moreover, the present invention optimizes the contents of C, Cu, Al, Nb and V, and limits the contents of N and Ca. By adopting the contents of alloying elements described in the present invention, the microstructure of tempered martensite and retained austenite is formed, and the steel shows high strength and high toughness mechanical properties. For high strength steel with tensile strength greater than 1000Mpa, it will adsorb H in the environment, thereby causing delayed cracking of the steel. High strength steel bars with heavy gauge are more sensitive to hydrogen. Therefore, the content of H in the steel is controlled in the present invention, but there is no such requirement in the Chinese patent application. Therefore, the stress corrosion resistance and delayed cracking resistance of the steel in the present invention are better than those of the steel in the Chinese patent application. The patent is used to produce straight bars with Φ20-50mm, while the present invention can be used to produce steel bars with Φ50-170mm, and the method of the present invention has a wider range of applications and can be used to produce steel with heavier gauge. The present invention has a completely different technological path from the above patent in terms of composition, structure and process design. In the present invention, the steel has a tensile strength R m ≧1200MPa, a yield strength R p0.2 ≧1000MPa, and an impact energy A kv ≧60J. The strength grade of the steel in the present invention is greater than that of the steel in the above patent. The steel in the present invention has excellent impact toughness and stress corrosion cracking resistance.

本発明の利点は以下を含む:
1.本発明は、化学成分の合理的な設計および最適化過程の組み合わせによって高強度および高靭性を有する鋼を開発する。圧延または鍛造後、焼き入れした棒鋼は焼き戻し熱処理に供され、焼き戻しマルテンサイト、少量のベイナイト、および残留オーステナイトの構造を形成する。その上微細で分散した沈殿物が形成される。
2.鋼の組成および製造過程は合理的であり、そしてプロセスウィンドウは広い。鋼は、棒鋼または高速ワイヤ製造ライン上で商業的に大量生産され得る。
3.本発明における鋼は、降伏強度Rp0.2≧1000MPa、引張強度R≧1200MPa、伸び率A≧12%、断面収縮率Z≧50%、およびシャルピー衝撃エネルギーAkv≧60Jを有する。
Advantages of the present invention include:
1. The present invention develops a steel with high strength and high toughness by combining the rational design and optimization process of chemical components. After rolling or forging, the quenched steel bar is subjected to tempering heat treatment to form a structure of tempered martensite, a small amount of bainite, and retained austenite. Moreover, fine and dispersed precipitates are formed.
2. The composition and manufacturing process of the steel are reasonable, and the process window is wide. The steel can be commercially mass-produced on bar or high-speed wire production lines.
3. The steel according to the invention has a yield strength R p0.2 ≧1000 MPa, a tensile strength R m ≧1200 MPa, an elongation A ≧12%, a reduction in area Z ≧50% and a Charpy impact energy A kv ≧60J.

工学分野において、環境条件下での伸び率の変化は、通常応力腐食の傾向を反映するために用いられる。本発明において、円形断面試験片が、水素脆化に対する感受性についてDNV(DET NORSKE VERITAS)の要件を参照し、そしてGB/T 2975-2018「鋼および鋼製品-機械試験のためのサンプルおよび試験片の配置および調製」に従って調製され、ここで試験片の直径は10mmである。引張試験は、国家規格GB/T 228.1に従って実施され、ひずみ速度は≦0.0003/sであり、そしてそれ故断面収縮率Zが得られる。水素脆化の係数η(Z)は、鋼の耐応力腐食性を評価するために定義される: In engineering, the change in elongation under environmental conditions is usually used to reflect the tendency of stress corrosion. In the present invention, circular cross-section test specimens are prepared according to the requirements of DNV (DET NORSKE VERITAS) for susceptibility to hydrogen embrittlement and according to GB/T 2975-2018 "Steels and steel products - Arrangement and preparation of samples and test specimens for mechanical tests", where the diameter of the test specimen is 10 mm. Tensile tests are carried out according to national standard GB/T 228.1, the strain rate is ≦0.0003/s, and thus the area reduction ratio Z is obtained. The coefficient of hydrogen embrittlement η(Z) is defined to evaluate the stress corrosion resistance of steels:

式中、Zは、250℃で2hの焼き付けの脱水素化後の引張試験での丸鋼の断面収縮率であり;
は、引張試験での丸鋼の断面収縮率である。
In the formula, Z 1 is the area reduction rate of the round steel in the tensile test after dehydrogenation at 250 ° C. for 2 h;
Z2 is the cross-sectional reduction rate of the round bar in the tensile test.

水素脆化の小さい係数η(Z)は、小さい応力腐食傾向を示す。本発明における鋼の水素脆化の係数η(Z)は15%以下であり、鋼が良好な耐応力腐食性を有することを示す。 A small hydrogen embrittlement coefficient η(Z) indicates a small stress corrosion tendency. The hydrogen embrittlement coefficient η(Z) of the steel of the present invention is 15% or less, indicating that the steel has good stress corrosion resistance.

図1は、本発明における実施例2の丸鋼の金属組織微細構造写真である(拡大は500倍である);FIG. 1 is a photograph of the metallographic microstructure of the round steel of Example 2 of the present invention (magnification: 500 times); 図2は、本発明における実施例2のリンクチェーンの金属組織微細構造写真である(拡大は500倍である)。FIG. 2 is a photograph of the metallographic microstructure of the link chain of Example 2 of the present invention (magnification: 500 times).

実施態様の詳細な説明
本発明は、添付の図面および実施態様を参照して以下にさらに記載される。実施態様は、本発明を説明するためにのみ用いられ、本発明を限定するために用いられない。
DETAILED DESCRIPTION OF EMBODIMENTS The present invention is further described below with reference to the accompanying drawings and embodiments. The embodiments are only used to explain the present invention, and are not used to limit the present invention.

本発明における実施例および比較例の丸鋼の化学成分は、表1に示される。本発明における実施例1~7の高強度および高靭性を有する鋼の成分の係数および比較例1~3の鋼の成分の係数は、表2に示される。本発明の実施例において、マイクロ合金化元素の係数rM/Nは1.0~9.9の範囲に及び、炭素当量Ceqは0.80以下であり、そして有害性元素の係数Jは500以下であることが分かり得る。ここでrM/Nは、マイクロ合金化元素Al、Nb、およびVの含有量のNの含有量に対する比である。 The chemical compositions of the round steels of the examples and comparative examples of the present invention are shown in Table 1. The coefficients of the components of the steels with high strength and high toughness of the examples 1-7 of the present invention and the coefficients of the components of the steels of the comparative examples 1-3 are shown in Table 2. It can be seen that in the examples of the present invention, the coefficients of the micro-alloying elements r M/N range from 1.0 to 9.9, the carbon equivalent Ceq is less than or equal to 0.80, and the coefficients of the harmful elements J H are less than or equal to 500, where r M/N is the ratio of the content of the micro-alloying elements Al, Nb, and V to the content of N.

本発明における実施例および比較例の鋼の製造方法は、表3に示される。機械試験のための試験片を調製し、本発明における実施例および比較例における鋼の試験結果は、表4に示される。 The manufacturing methods of the steels in the examples and comparative examples of the present invention are shown in Table 3. Test pieces were prepared for mechanical testing, and the test results of the steels in the examples and comparative examples of the present invention are shown in Table 4.

試験片は、GB/T 2975-2018「鋼および鋼製品-機械試験のためのサンプルおよび試験片の配置および調製」に従って調製される。機械試験は、GB/T 228.1-2010「金属材料-引張試験-第1部:室温での試験の方法」に従って実施される。室温での衝撃靭性は、GB/T 229-2007「金属材料-シャルピー振子式衝撃試験方法」に従って試験される。3つのサンプルが試験され、そして衝撃エネルギーの3つの値が得られた。 Test specimens are prepared according to GB/T 2975-2018 "Steels and steel products - Arrangement and preparation of samples and specimens for mechanical tests". Mechanical tests are carried out according to GB/T 228.1-2010 "Metallic materials - Tensile tests - Part 1: Methods for tests at room temperature". Impact toughness at room temperature is tested according to GB/T 229-2007 "Metallic materials - Charpy pendulum impact test method". Three samples were tested and three values of impact energy were obtained.

実施例1
表1に示す化学組成に従って、溶融した鋼を電気炉中で精錬し、そして次いで微細化および真空処理に供する。その後、溶融した鋼を連続鋳造ビレットに鋳造する。次いで、連続鋳造ビレットを1050℃に加熱し、保持時間は4hrである。鋼ビレットを加熱炉から外に出すと高圧水のスケール除去に供し、そして次いで中間ビレットに圧延する。最終圧延温度は850℃であり、そして中間ビレットサイズは200mm×200mmである。次いで中間ビレットを1050℃に加熱し、保持時間は24hrであり、中間ビレットを加熱炉から外に出すと高圧水のスケール除去に供し、そして次いで圧延し、最終圧延温度は800℃であり、そして完成した棒鋼のサイズΦは50mmである。鋼ビレットを圧延後に積み重ねて冷却する。焼き入れ加熱温度は850℃であり、加熱時間は60minであり、焼き戻し温度は390℃であり、そして焼き戻し時間は90minである。鋼ビレットを焼き戻し後に空冷する。
Example 1
According to the chemical composition shown in Table 1, the molten steel is refined in an electric furnace, and then subjected to refinement and vacuum treatment. The molten steel is then cast into a continuous casting billet. The continuous casting billet is then heated to 1050°C, and the holding time is 4hr. When the steel billet is taken out of the heating furnace, it is subjected to high-pressure water descaling, and then rolled into an intermediate billet. The final rolling temperature is 850°C, and the intermediate billet size is 200mm x 200mm. The intermediate billet is then heated to 1050°C, and the holding time is 24hr, when the intermediate billet is taken out of the heating furnace, it is subjected to high-pressure water descaling, and then rolled, the final rolling temperature is 800°C, and the size Φ of the finished steel bar is 50mm. The steel billet is stacked and cooled after rolling. The quenching heating temperature is 850°C, the heating time is 60min, the tempering temperature is 390°C, and the tempering time is 90min. The steel billet is air cooled after tempering.

実施例2
製造方法を実施例1と同じ方法で実施し、ここで加熱温度は1080℃であり、保持時間は3hrであり、最終圧延温度は880℃であり、そして中間ビレットサイズは220mm×220mmである。中間ビレットを1120℃に加熱し、保持時間は3hであり、最終圧延温度は850℃であり、そして完成した棒鋼のサイズΦは75mmである。鋼ビレットを圧延後に空冷する。焼き入れ加熱温度は870℃であり、加熱時間は100minであり、焼き戻し温度は550℃であり、そして焼き戻し時間は60minである。鋼ビレットを焼き戻し後に水冷する。
Example 2
The manufacturing method is carried out in the same manner as in Example 1, where the heating temperature is 1080 ° C, the holding time is 3 hr, the final rolling temperature is 880 ° C, and the intermediate billet size is 220 mm × 220 mm. The intermediate billet is heated to 1120 ° C, the holding time is 3 h, the final rolling temperature is 850 ° C, and the finished steel bar size Φ is 75 mm. The steel billet is air-cooled after rolling. The quenching heating temperature is 870 ° C, the heating time is 100 min, the tempering temperature is 550 ° C, and the tempering time is 60 min. The steel billet is water-cooled after tempering.

実施例3
製造方法を実施例1と同じ方法で実施し、ここで加熱温度は1120℃であり、保持時間は8hrであり、最終圧延温度は940℃であり、そして中間ビレットサイズは260mm×260mmである。中間ビレットを1200℃に加熱し、保持時間は5hrであり、最終圧延温度は880℃であり、そして完成した棒鋼のサイズΦは100mmである。鋼ビレットを圧延後に空冷する。焼き入れ加熱温度は890℃であり、加熱時間は150minであり、焼き戻し温度は430℃であり、そして焼き戻し時間は100minである。鋼ビレットを焼き戻し後に空冷する。
Example 3
The manufacturing method is carried out in the same manner as in Example 1, where the heating temperature is 1120°C, the holding time is 8hr, the final rolling temperature is 940°C, and the intermediate billet size is 260mm x 260mm. The intermediate billet is heated to 1200°C, the holding time is 5hr, the final rolling temperature is 880°C, and the size Φ of the finished steel bar is 100mm. The steel billet is air-cooled after rolling. The quenching heating temperature is 890°C, the heating time is 150min, the tempering temperature is 430°C, and the tempering time is 100min. The steel billet is air-cooled after tempering.

実施例4
製造方法を実施例1と同じ方法で実施し、ここで加熱温度は1250℃であり、保持時間は14hrであり、そして鋼ビレットを熱間連続圧延によって形成する。ここで最終圧延温度は900℃であり、完成した棒鋼のサイズΦは150mmである。鋼ビレットを圧延後に空冷する。焼き入れ加熱温度は990℃であり、加熱時間は210minであり、焼き戻し温度は350℃であり、そして焼き戻し時間は180minである。鋼ビレットを焼き戻し後に水冷する。
Example 4
The manufacturing method is carried out in the same manner as in Example 1, where the heating temperature is 1250°C, the holding time is 14hr, and the steel billet is formed by hot continuous rolling. Here, the final rolling temperature is 900°C, and the size Φ of the finished steel bar is 150mm. The steel billet is air-cooled after rolling. The quenching heating temperature is 990°C, the heating time is 210min, the tempering temperature is 350°C, and the tempering time is 180min. The steel billet is water-cooled after tempering.

実施例5
表1に示す化学組成に従って、溶融した鋼を転炉中で精錬し、そして次いで微細化および真空処理に供する。次いで溶融した鋼を鋼塊に鋳造する。加熱温度は1180℃であり、保持時間は3.5hrであり、最終圧延温度は980℃であり、そして中間ビレットサイズは280mm×280mmである。中間ビレットを1250℃に加熱し、保持時間は12hrであり、最終圧延温度は950℃であり、そして完成した棒鋼のサイズΦは160mmである。鋼ビレットを圧延後に徐冷する。焼き入れ加熱温度は900℃であり、加熱時間は210minであり、焼き戻し温度は450℃であり、そして焼き戻し時間は190minである。鋼ビレットを焼き戻し後に水冷する。
Example 5
According to the chemical composition shown in Table 1, the molten steel is refined in a converter and then subjected to refinement and vacuum treatment. The molten steel is then cast into a steel ingot. The heating temperature is 1180°C, the holding time is 3.5hr, the final rolling temperature is 980°C, and the intermediate billet size is 280mm x 280mm. The intermediate billet is heated to 1250°C, the holding time is 12hr, the final rolling temperature is 950°C, and the finished steel bar size Φ is 160mm. The steel billet is slowly cooled after rolling. The quenching heating temperature is 900°C, the heating time is 210min, the tempering temperature is 450°C, and the tempering time is 190min. The steel billet is water-cooled after tempering.

実施例6
製造方法を実施例5と同じ方法で実施し、ここで加熱温度は1220℃であり;保持時間は24hrである。鋼ビレットを鍛造によって形成し、最終鍛造温度は920℃であり、そして完成した棒鋼のサイズΦは170mmである。鋼ビレットを鍛造後に空冷する。焼き入れ加熱温度は920℃であり、加熱時間は40minであり、焼き戻し温度は420℃であり、そして焼き戻し時間は240minである。鋼ビレットを焼き戻し後に空冷する。
Example 6
The manufacturing method is carried out in the same manner as in Example 5, where the heating temperature is 1220°C; the holding time is 24hr. The steel billet is formed by forging, the final forging temperature is 920°C, and the size Φ of the finished steel bar is 170mm. The steel billet is air-cooled after forging. The quenching heating temperature is 920°C, the heating time is 40min, the tempering temperature is 420°C, and the tempering time is 240min. The steel billet is air-cooled after tempering.

実施例7
製造方法を実施例2と同じ方法で実施し、ここで加熱温度は1080℃であり、保持時間は3hrであり、最終圧延温度は880℃であり、そして中間ビレットサイズは220mm×220mmである。次いで中間ビレットを1100℃に加熱し、保持時間は3hrであり、最終圧延温度は850℃であり、完成した棒鋼のサイズΦは65mmである。鋼ビレットを圧延後に空冷する。焼き入れ加熱温度は880℃であり、加熱時間は150minであり、焼き戻し温度は400℃であり、そして焼き戻し時間は100minである。鋼ビレットを焼き戻し後に水冷する。
Example 7
The manufacturing method is carried out in the same manner as in Example 2, where the heating temperature is 1080 ° C, the holding time is 3 hr, the final rolling temperature is 880 ° C, and the intermediate billet size is 220 mm × 220 mm. The intermediate billet is then heated to 1100 ° C, the holding time is 3 hr, the final rolling temperature is 850 ° C, and the finished steel bar size Φ is 65 mm. The steel billet is air-cooled after rolling. The quenching heating temperature is 880 ° C, the heating time is 150 min, the tempering temperature is 400 ° C, and the tempering time is 100 min. The steel billet is water-cooled after tempering.

比較例1~3は、異なる製造業者からの市販材料であり、熱処理過程は供給業者の推奨パラメーターを参照する。表3を参照。 Comparative Examples 1-3 are commercial materials from different manufacturers, and the heat treatment process refers to the supplier's recommended parameters. See Table 3.

表4において、比較例1が高いNb含有量および10.1の微細合金化係数を有することが分かり得る。それは、乏しい沈殿強化効果、低い強度、低い衝撃靭性、および短い疲労寿命を示す。比較例2は、高いP含有量、有害性元素の係数678、および耐大気腐食性の指標5.3を有する。それは、乏しい衝撃靭性および耐応力腐食割れ、ならびに水素脆化の高い係数を示す。比較例3は、高いS含有量を有し、乏しい衝撃靭性を生じる。 In Table 4, it can be seen that Comparative Example 1 has a high Nb content and a fine alloying coefficient of 10.1. It shows poor precipitation strengthening effect, low strength, low impact toughness, and short fatigue life. Comparative Example 2 has a high P content, a coefficient of harmful elements of 678, and an index of atmospheric corrosion resistance of 5.3. It shows poor impact toughness and stress corrosion cracking resistance, as well as a high coefficient of hydrogen embrittlement. Comparative Example 3 has a high S content, resulting in poor impact toughness.

本発明における実施例1-7の高強度鋼は、降伏強度Rp0.2≧1000MPa、引張強度R≧1200MPa、伸び率A≧12%、断面収縮率Z≧50%、シャルピー衝撃エネルギーAkv≧60J、および水素脆化の係数η(Z)≦15%を有する。実施例6の鋼は、1回限りの加熱および圧延過程ならびに大きい棒サイズのせいで比較的乏しい構造濃密性を示す。その強度および衝撃特性は、他の実施例の鋼と比較してわずかに劣化している。実施例7の鋼は、低い耐大気腐食性指標のせいで劣化した衝撃靭性、水素脆化の係数、および耐腐食割れを示し、そして他の実施例の鋼と比較して乏しい性能を有する。 The high strength steels of Examples 1-7 in the present invention have a yield strength R p0.2 ≧1000 MPa, a tensile strength R m ≧1200 MPa, an elongation A ≧12%, a reduction in area Z ≧50%, a Charpy impact energy A kv ≧60 J, and a coefficient of hydrogen embrittlement η(Z) ≦15%. The steel of Example 6 shows relatively poor structural compactness due to the one-time heating and rolling process and the large bar size. Its strength and impact properties are slightly deteriorated compared with the steels of the other Examples. The steel of Example 7 shows deteriorated impact toughness, coefficient of hydrogen embrittlement, and corrosion cracking resistance due to the low atmospheric corrosion resistance index, and has poor performance compared with the steels of the other Examples.

実施例2の丸鋼の微細構造および実施例2の鋼を用いて調製した採掘チェーンを研究し、そして光学顕微鏡写真を図1および2に示す。図から、丸鋼の微細構造は焼き戻しマルテンサイト、少量のベイナイト、および残留オーステナイトであり、一方、実施例2の丸鋼を用いてさらに調製した採掘チェーンの微細構造は微細化焼き戻しマルテンサイトおよび少量のベイナイトであることが分かり得る。 The microstructure of the round steel of Example 2 and the mining chain prepared with the steel of Example 2 were studied and the optical micrographs are shown in Figures 1 and 2. From the figures it can be seen that the microstructure of the round steel is tempered martensite, a small amount of bainite, and retained austenite, while the microstructure of the mining chain further prepared with the round steel of Example 2 is refined tempered martensite and a small amount of bainite.

Claims (9)

重量%で:C:0.20~0.28%、Si:0.01~0.40%、Mn:0.50~1.50%、P≦0.015%、S≦0.005%、Cr:0.30~2.00%、Ni:0.50~2.00%、Mo:0.10~0.80%、Cu:0.01~0.30%、Al:0.01~0.05%、Nb:0.001~0.10%、V:0.001~0.10%、H≦0.00018%、N≦0.0150%、O≦0.0020%、および残部がFeおよび不可避的不純物である;からなり
該不可避的不純物において、B≦0.0010%、Ti≦0.003%、Ca≦0.005%であり、かつ
1.0~9.9の範囲のマイクロ合金化元素の係数rM/N、ここで

を有し、
以下の通りの微量元素:As≦0.05%、Pb≦0.05%、Sn≦0.02%、Sb≦0.01%、Bi≦0.01%を有し、かつ≦500である有害性元素の係数J、ここで

を有する、採掘チェーン用鋼。
in weight percent: C: 0.20-0.28%, Si: 0.01-0.40%, Mn: 0.50-1.50%, P≦0.015%, S≦0.005%, Cr: 0.30-2.00%, Ni: 0.50-2.00%, Mo: 0.10-0.80%, Cu: 0.01-0.30%, Al: 0.01-0.05%, Nb: 0.001-0.10%, V: 0.001-0.10%, H≦0.00018%, N≦0.0150%, O≦0.0020 % , and the balance being Fe and unavoidable impurities;
In the unavoidable impurities, B≦0.0010%, Ti≦0.003%, Ca≦0.005%, and the coefficient r M / N of the micro-alloying elements is in the range of 1.0 to 9.9, where

having
the coefficient J H of harmful elements being ≦500, with the following trace elements: As≦0.05%, Pb≦0.05%, Sn≦0.02%, Sb≦0.01%, Bi≦0.01%,

Steel for mining chains having
Ceq≦0.8を有し、ここで

である請求項1の採掘チェーン用鋼。
Ceq≦0.8, where

2. The steel for mining chains according to claim 1,
≧7.0である耐大気腐食性の指標Iを有し、ここで

である請求項1の採掘チェーン用鋼。
7.0、 5.0%、 6.0%、 7.0%、 8.0%、 9.0%、 10.0%、 11.0%、 12.0%、 13.0%、 14.0%、 15.0%、 16.0%、 17.0%、 18.0%、 19.0%

2. The steel for mining chains according to claim 1,
焼き戻しマルテンサイト、ベイナイト、および残留オーステナイトの微細構造を有する請求項1~3のいずれかの採掘チェーン用鋼。 A steel for mining chains according to any one of claims 1 to 3, having a microstructure of tempered martensite, bainite, and retained austenite. 降伏強度Rp0.2≧1000MPa、引張強度R≧1200MPa、伸び率A≧12%、断面収縮率Z≧50%、シャルピー衝撃エネルギーAkv≧60J、および水素脆化の係数η(Z)≦15%を有する請求項1~3のいずれかの採掘チェーン用鋼。 4. A steel for mining chains according to any of claims 1 to 3, having a yield strength R p0.2 ≥ 1000 MPa, a tensile strength R m ≥ 1200 MPa, an elongation A ≥ 12%, a reduction in area Z ≥ 50%, a Charpy impact energy A kv ≥ 60 J and a coefficient of hydrogen embrittlement η(Z) ≤ 15%. 請求項1~5のいずれかの採掘チェーン用鋼の製造方法であって、精錬、鋳造、加熱、鍛造または圧延、焼き入れ熱処理、および焼き戻し熱処理過程の工程を含み、ここで
該加熱過程において、加熱温度が1050~1250℃であり、保持時間が3~24hrであり;
該鍛造または圧延過程において、最終鍛造温度または最終圧延温度が≧800℃であり;
該焼き入れ熱処理において、加熱温度が850~1000℃であり、保持時間が60~240minであり、そして水焼き入れがオーステナイト化後に実施され;
該焼き戻し熱処理において、焼き戻し温度が350~550℃であり、保持時間が60~240minであり、そして空冷または水冷が焼き戻し後に実施される、
製造方法。
A method for producing steel for mining chains according to any one of claims 1 to 5, comprising the steps of refining, casting, heating, forging or rolling, quenching heat treatment, and tempering heat treatment, wherein in the heating step, the heating temperature is 1050 to 1250°C and the holding time is 3 to 24 hours;
In the forging or rolling process, the final forging temperature or final rolling temperature is ≧800° C.;
In the quenching heat treatment, the heating temperature is 850-1000°C, the holding time is 60-240min, and water quenching is carried out after austenitization;
In the tempering heat treatment, the tempering temperature is 350-550°C, the holding time is 60-240min, and air cooling or water cooling is carried out after tempering;
Production method.
精錬が、電気炉中での精錬または転炉中での精錬、ならびに微細化および真空処理を含み;鋳造がダイカストまたは連続鋳造である請求項6の採掘チェーン用鋼の製造方法。 The method for producing steel for mining chains according to claim 6, wherein the refining includes refining in an electric furnace or in a converter, as well as refining and vacuum treatment; and the casting is die casting or continuous casting. 鍛造過程において、鋼ビレットが最終製品のサイズに直接鍛造され;圧延過程において、鋼ビレットが最終製品のサイズに直接圧延され;または鋼ビレットが特定の中間ビレットサイズに圧延され、そして次いで加熱されそして最終製品のサイズに圧延され、ここで中間ビレットの加熱温度が1050~1250℃であり、そして保持時間が3~24hrである請求項6の採掘チェーン用鋼の製造方法。 The method for producing steel for mining chains according to claim 6, wherein in the forging process, the steel billet is directly forged to the size of the final product; in the rolling process, the steel billet is directly rolled to the size of the final product; or the steel billet is rolled to a specific intermediate billet size and then heated and rolled to the size of the final product, wherein the heating temperature of the intermediate billet is 1050-1250°C and the holding time is 3-24 hrs. 圧延過程において、鋼ビレットが加熱炉から外に出されると高圧水のスケール除去に供され、そして次いで圧延され、そして圧延後、鋼ビレットが空冷または徐冷される請求項6または8の採掘チェーン用鋼の製造方法。 The method for manufacturing steel for mining chains according to claim 6 or 8, wherein in the rolling process, when the steel billet is taken out of the heating furnace, it is subjected to high-pressure water descaling and then rolled, and after rolling, the steel billet is air-cooled or slowly cooled.
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