WO2020259715A1 - 一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板及其制造方法 - Google Patents

一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板及其制造方法 Download PDF

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WO2020259715A1
WO2020259715A1 PCT/CN2020/104008 CN2020104008W WO2020259715A1 WO 2020259715 A1 WO2020259715 A1 WO 2020259715A1 CN 2020104008 W CN2020104008 W CN 2020104008W WO 2020259715 A1 WO2020259715 A1 WO 2020259715A1
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temperature
cooling
low
steel plate
rolling
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French (fr)
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蒋昌林
李国忠
许晓红
苗丕峰
白云
诸建阳
徐国庆
徐伟明
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江阴兴澄特种钢铁有限公司
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    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/04—Making ferrous alloys by melting
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur

Definitions

  • the invention belongs to the technical field of metallurgy, and relates to a steel plate for extra-thick X80 pipelines and a manufacturing method thereof, and in particular to a low-temperature high-toughness X80 steel pipeline steel plate with a low carbon equivalent thickness of over 40 mm and a manufacturing method thereof.
  • This patent is an extension of the thickness based on the technical solution disclosed in the patent number CN201510153571.3, that is, the thickness specification is extended from the current 30-38.1 thick specification to a thickness greater than 40mm, and the carbon equivalent is correspondingly reduced.
  • the technical problem to be solved by the present invention is to provide a low-carbon equivalent thickness of over 40mm, low temperature and high toughness X80 steel grade pipeline steel plate and its manufacturing method for the above-mentioned prior art, and obtain super-thick specifications, excellent low temperature toughness and DWTT drop weight performance, and the composition relates to The process is relatively simple and has a high yield rate.
  • the technical solution adopted by the present invention to solve the above problems is: a low-carbon equivalent thickness of over 40mm, low-temperature high-toughness X80 steel grade pipeline steel plate, the chemical composition of the steel plate is C: ⁇ 0.07%, Mn: 1.6-1.9 in terms of mass percentage %, Si: ⁇ 0.35%, S: ⁇ 0.0006%, P: ⁇ 0.0070%, Nb: 0.045 ⁇ 0.08%, Ti: ⁇ 0.012%, V: ⁇ 0.008%, Alt: ⁇ 0.06%, N: ⁇ 0.0040% , O: ⁇ 0.004%, Mo: ⁇ 0.19%, Pb ⁇ 0.0015%, Zn ⁇ 0.003%, Sb ⁇ 0.0015%, Sn ⁇ 0.0015%, Cu: ⁇ 0.30%, Ni: 0.20-1.5%, Cr: 0.12- 0.19%, Mo+Cu+Ni+Cr ⁇ 2.0%, Ca: ⁇ 0.015%, Ceq ⁇ 0.41%, Pcm ⁇ 0.17%, the balance is Fe and inevitable impurity elements; the thickness of the steel plate is 40
  • the thickness of the steel plate is 40-50mm, and the grain size is not less than 10; the yield strength of the steel plate is ⁇ 570Mpa; the tensile strength is ⁇ 645Mpa, the yield ratio is ⁇ 0.86, and the round bar-like elongation is ⁇ 25 %, -25°C impact energy ⁇ 350J, -40°C impact energy ⁇ 320J, -60°C impact energy ⁇ 300 J, -10°C drop weight shear area ⁇ 85%, -20°C drop weight shear area ⁇ 75% ( Falling weight performance of full wall thickness specimens, thinned specimens: -20°C falling weight shearing area ⁇ 88%, -25°C falling weight shearing area ⁇ 85%, -30°C falling weight shearing area ⁇ 80%) .
  • composition design of the present invention is to use appropriate amounts of C and Mn, by adding microalloying elements such as Nb, V, Ti, etc., and a small amount of Mo, Cu, Ni and other elements, combined with a specific TMCP process, so as to ensure the ultimate thickness of X80 With low temperature and high toughness, especially excellent DWTT drop weight performance, its main basic elements are as follows:
  • C is the most economical and basic strengthening element in steel. Solid solution strengthening and precipitation strengthening can significantly increase the strength of steel, but it has an adverse effect on the toughness, ductility and welding performance of steel. Therefore, the development trend of pipeline steel It is to continuously reduce the C content. Considering the matching relationship between strength and toughness, the C content is controlled at 0.03 to 0.07%.
  • Mn Improve the strength of steel through solid solution strengthening. It is the most important element in pipeline steel to compensate for the strength loss caused by the decrease in C content. Mn is also an element that expands the ⁇ phase region and can reduce the ⁇ transformation temperature of steel. , Helps to obtain fine phase transformation products, can improve the toughness of steel, reduce the ductile brittle transition temperature, Mn is also an element to improve the hardenability of steel. Considering that Mn segregation is found to have an adverse effect on the drop weight performance during the inspection process, and taking into account the strength requirements, the Mn content in the present invention is designed to be in the range of 1.80 to 2.0%. In order to alleviate the central segregation caused by higher Mn, continuous casting When using light pressure.
  • Nb It is one of the most important microalloying elements in modern microalloyed steel, especially pipeline steel, and has a very obvious effect on grain refinement. Through the solid solution drag of Nb and the Nb(C, N) strain-induced precipitation during the hot rolling process, it can hinder the recovery and recrystallization of deformed austenite. The deformed austenite rolled in the non-recrystallized zone is transformed by TMCP. In order to make the steel have high strength and high toughness, the present invention mainly determines the range of Nb content through the relationship between C and Nb content.
  • V It has high precipitation strengthening and weaker grain refinement effect. When used in combination in the three microalloying elements of Nb, V, and Ti, V mainly plays a role of precipitation strengthening.
  • Ti is a strong N-fixing element.
  • the stoichiometric ratio of Ti/N is 3.42.
  • the use of about 0.02% Ti can fix the N in steel below 60ppm, and the TiN precipitate phase can be formed during the slab continuous casting process.
  • This kind of fine precipitates can effectively prevent the growth of austenite grains in the slab during the heating process, help increase the solid solubility of Nb in austenite, and improve the impact toughness of the welding heat affected zone.
  • An indispensable element in pipeline steel, but too high Ti will form large TiN particles and affect drop weight performance. Therefore, the patent application controls Ti within 0.008-0.015%.
  • Mo It can delay the formation of the ferrite phase that precipitates first during the ⁇ phase transformation, and is the main element that promotes the formation of acicular ferrite. It plays an important role in controlling the phase transformation and is also an element to improve the hardenability of steel. At a certain cooling rate and final cooling temperature, an obvious acicular ferrite or bainite structure can be obtained by adding a certain amount of Mo.
  • the strength of steel can be improved by solid solution strengthening.
  • the addition of Ni can increase the toughness of steel, and at the same time improve the hot brittleness that Cu can easily cause in steel.
  • Preparation process Proportioning material preparation ⁇ converter or electric furnace smelting ⁇ refining outside the furnace ⁇ continuous casting ⁇ slab reheating ⁇ specific TMCP process + pile cooling after cooling ⁇ straightening.
  • the smelting raw materials are subjected to KR hot metal pretreatment, converter smelting, LF refining, RH vacuum refining and continuous casting in sequence to produce continuous casting billets that meet the chemical composition requirements and have a thickness of not less than 350mm;
  • the continuous casting slab is reheated to not higher than 1180°C, and the specific TMCP process + water cooling + stack cooling + straightening is performed.
  • the specific TMCP process includes two-stage rolling and intermediate billet cooling: the first stage is rolling in the recrystallization zone, the final rolling temperature is controlled not higher than 1150°C, and the rolling in the recrystallization zone is controlled for two to three consecutive passes.
  • the secondary reduction rate is not less than 20%;
  • the intermediate billet cooling is to moderately cool the intermediate billet to the second-stage non-recrystallization zone opening temperature through the Mild cooling cooling system.
  • the cooling method is to cool back and forth in the mild cooling box, and the cooling speed is 6-12. °C/s, to ensure that the austenite grains no longer grow after rolling and deformation in the recrystallization zone, and the temperature difference between the surface and the core of the intermediate billet is small;
  • the second stage is rolling in the non-recrystallization zone, the start-rolling temperature is not higher than 850°C, and the final rolling temperature is controlled at the critical temperature of phase transformation.
  • the steel plate After rolling, the steel plate is cooled by water cooling. After rolling, the steel plate is quickly cooled to the critical phase transition temperature with DQ, and then the cooling is stopped. After the steel plate is self-tempered, it is cooled to not higher than 520°C by ACC, and the post-stack is cooled to room temperature.
  • the use of this cooling process is mainly to alleviate the problem of the large difference in the cooling rate of different parts along the thickness direction, thereby obtaining a more uniform structure along the thickness direction and obtaining a very fine structure.
  • the principle is to use the higher temperature of the core to carry out the steel plate. Self-tempering to obtain a finer and more uniform structure along the thickness direction, thereby obtaining ideal mechanical properties.
  • the improved TMCP process of this invention seems to increase the number of processes, which helps to reduce alloy costs and increase the yield rate.
  • the intermediate billet is rapidly cooled by the mild cooling cooling system to ensure that the austenite grains no longer grow after the deformation of the recrystallization zone in the first stage, reduce the temperature difference between the surface of the intermediate billet and the core, and improve the ultra-thick pipeline steel sheet Productivity.
  • the cooling process of water cooling + stack cooling is mainly to slow down the large difference in cooling rate of different parts along the thickness direction, so as to obtain a more uniform structure along the thickness direction and a very fine structure.
  • Figure 1 is the metallographic structure at the 1/4 thickness of the X80 pipeline steel used in this application;
  • Figure 2 is the metallographic structure at 1/2 thickness of the X80 pipeline steel used in this application;
  • the structure of the pipeline steel of the present application is very fine and small amount of ferrite + fine acicular ferrite + small amount of fine grained bainite, and also contains very fine Maru-Oshima (MA).
  • the manufacturing process of thick gauge X80 pipeline steel plate with excellent ultra-low temperature drop weight performance is: proportioning material preparation ⁇ converter or electric furnace smelting ⁇ furnace refining ⁇ continuous casting ⁇ slab reheating ⁇ specific TMCP process (to control the heating temperature and implement cooling The general term for technology) + pile cooling after cooling ⁇ straightening.
  • the specific process steps are as follows: the smelting raw materials are sequentially subjected to KR hot metal pretreatment, converter smelting, LF refining, RH vacuum refining and continuous casting.
  • the P content must not exceed 0.007%.
  • the light reduction process is used during continuous casting to improve the Mn Core segregation caused by higher content.
  • the specific TMCP process includes two-stage rolling and intermediate billet cooling: the first stage is rolling in the recrystallization zone, the final rolling temperature is controlled not higher than 1150°C, and the rolling in the recrystallization zone is controlled for two to three consecutive passes.
  • the secondary reduction rate is not less than 20%;
  • the intermediate billet cooling is to quickly cool the intermediate billet to the second stage of the non-recrystallization zone opening temperature through the Mild cooling cooling system.
  • the cooling method is to use the back and forth swing type cooling in the mild cooling box, and the cooling speed is 6-12 °C/s, to ensure that the austenite grains no longer grow after rolling and deformation in the recrystallization zone, and the temperature difference between the surface and the core of the intermediate billet is small;
  • the second stage is rolling in the non-recrystallization zone, the start rolling temperature is not higher than 900°C, and the final rolling temperature is controlled near the critical temperature of phase transformation Ar3.
  • the steel plate After rolling, the steel plate is cooled by water cooling. After rolling, the steel plate is quickly cooled to a certain temperature with DQ, and then the cooling is stopped. Based on the surface temperature, the phase transition temperature is 150-200°C below, and the steel plate is returned to a certain temperature after self-tempering. It is cooled to no higher than 520°C by ACC, and the rear stack is cooled to room temperature.
  • the present invention also includes other implementation modes, and all technical solutions formed by equivalent transformations or equivalent substitutions shall fall within the protection scope of the claims of the present invention.

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Abstract

一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板，化学成分按质量百分比计为C：≤0.07％、Mn：1.6-1.9％，Si：≤0.35％，S：≤0.0006％，P：≤0.010％，Nb：0.045～0.08％、Ti：≤0.012％、V：≤0.008％，Alt：≤0.06％，N:≤0.0040％，O：≤0.004％，Mo：≤0.3％，Pb≤0.0015％，Zn≤0.003％，Sb≤0.0015％，Sn≤0.0015％，Cu：≤0.30％、Ni：0.20-2.0％，Cr：0.12-0.19％，Mo+Cu+Ni+Cr≤1.8％，Ca：≤0.015％，Ceq0.35-0.41％，Pcm≤0.17％余量为Fe及不可避免的杂质元素；所述钢板的厚度为40mm及以上。其制造流程如下：配比备料→进行转炉或电炉冶炼→炉外精炼→连铸→板坯再加热→特定TMCP工艺+热矫+冷却后堆冷→成品。本申请采用合适的成分，生产40mm以上厚规格X80，并与后续特定TMCP工艺相结合，获得优异的低温韧性。

Description

一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板及其制造方法 技术领域
本发明属于冶金技术领域，涉及一种特厚X80管线用钢板及其制造方法，具体涉及一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板及其制造方法。
背景技术
目前世界需求的能源中化石能源还占能源结构中的主体地位，近年来世界经济的急速增长极大带动了化石能源需求的急速增长，这也极大地促进了长距离输送管线的发展，为提高输送效率，降低投资，长距离石油天然气输送管线用钢的发展趋势是向高强度或超高钢级发展。目前世界各国使用的管线钢最高钢级为X80钢级，为推动管线钢技术发展及从降低建设成本及提到运营效率考虑，降低运营成本，提高输送效率的途径主要包括扩大管径、提高钢级和增加壁厚。
实际上，高强度钢级厚规格管线钢的低温韧性及落锤性能是世界公认的难题，国内外的研究表明，落锤性能除了钢中的组织及环境温度等因素以外，还与钢板的厚度有密切的关系，且随厚度增加，对厚度越敏感！这称之为厚度效应！为解决超厚规格下的厚度效应，需要从组织上进行设计，即控制组织类型和细化晶粒上进行控制，同时还要考虑到其他影响落锤影响因素如应力等。
X80管线钢国内外专利授权或申请专利，目前较多，但是涉及厚度达到40mm厚规格且为低碳当量的专利还没有相关报到。
本专利是在申请专利号为CN201510153571.3所公开技术方案的基础上进行的在厚度方面的延伸，即将厚度规格从目前30-38.1厚规格以上向40mm厚以上延伸，同时碳当量相应减少。
发明内容
本发明所要解决的技术问题是针对上述现有技术提供一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板及其制造方法，获得超厚规格优异低温韧性及DWTT落锤性能，成分涉及该工艺相对比较简练，成材率较高。
本发明解决上述问题所采用的技术方案为：一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板，该钢板的化学成分按质量百分比计为C：≤0.07％、Mn：1.6-1.9％， Si：≤0.35％，S：≤0.0006％，P：≤0.0070％，Nb：0.045～0.08％、Ti：≤0.012％、V：≤0.008％，Alt：≤0.06％，N:≤0.0040％，O：≤0.004％，Mo：≤0.19％，Pb≤0.0015％，Zn≤0.003％，Sb≤0.0015％，Sn≤0.0015％，Cu：≤0.30％、Ni：0.20-1.5％，Cr：0.12-0.19％，Mo+Cu+Ni+Cr≤2.0％，Ca：≤0.015％，Ceq≤0.41％，Pcm≤0.17％，余量为Fe及不可避免的杂质元素；所述钢板的厚度为40mm及以上。
进一步地，所述钢板的厚度为40-50mm，晶粒度不低于10级；所述钢板的屈服强度≥570Mpa；抗拉强度≥645Mpa，屈强比≤0.86，圆棒样延伸率≥25％，-25℃冲击功≥350J，-40℃冲击功≥320J，-60℃冲击功≥300J，-10℃落锤剪切面积≥85％，-20℃落锤剪切面积≥75％(全壁厚试样落锤性能，减薄试样：-20℃落锤剪切面积≥88％，-25℃落锤剪切面积≥85％，-30℃落锤剪切面积≥80％)。
本发明成分设计原理是采用适量的C、Mn，通过加入微量Nb、V、Ti等微合金化元素，同时加入少量Mo、Cu、Ni等元素，结合特定TMCP工艺，以便最终保证特厚规格X80具有低温高韧性，尤其是优异的DWTT落锤性能，其主要的基本元素作用如下：
C：C是钢中最经济、最基本的强化元素，通过固溶强化和析出强化可明显提高钢的强度，但对钢的韧性及延性以及焊接性能带来不利影响，因此管线钢的发展趋势是不断降低C含量，考虑到强度及韧性的匹配关系，将C含量控制在0.03～0.07％。
Mn：通过固溶强化提高钢的强度，是管线钢中弥补因C含量降低而引起强度损失的最主要的元素，Mn同时还是扩大γ相区的元素，可降低钢的γ→α相变温度，有助于获得细小的相变产物，可提高钢的韧性，降低韧脆性转变温度，Mn也是提高钢的淬透性元素。考虑到检验过程中发现Mn偏析对落锤性能产生不利影响，同时兼顾到强度要求，本发明中Mn含量设计在1.80～2.0％范围,为缓解因Mn较高所带来的中心偏析，连铸时采用轻压下。
Nb：是现代微合金化钢特别是管线钢中最主要的微合金化元素之一，对晶粒细化的作用非常明显。通过Nb的固溶拖曳及热轧过程中的Nb(C，N)应变诱导析出可阻碍形变奥氏体的回复、再结晶，经TMCP使未再结晶区轧制的形变奥氏体在相变时转变为细小相变产物，以使钢具有高强度和高韧性，本发明主要是通过C与Nb含量的关系来确定Nb含量范围,
V：具有较高的析出强化和较弱的晶粒细化作用，在Nb、V、Ti三种微合金化元素中复合使用时，V主要起析出强化作用。
Ti：是强的固N元素，Ti/N的化学计量比为3.42，利用0.02％左右的Ti就可固定钢中60ppm以下的N，在板坯连铸过程中即可形成TiN析出相，这种细小的析出相可有效阻止板坯在加热过程中奥氏体晶粒的长大，有助于提高Nb在奥氏体中的固溶度，同时可改善焊接热影响区的冲击韧性，是管线钢中不可缺少的元素，但过高的Ti会形成大的TiN质点，影响落锤性能，因此本申请专利将Ti控制在0.008-0.015％之间。
Mo：可推迟γ→α相变时先析出铁素体相的形成，促进针状铁素体形成的主要元素，对控制相变起到重要作用，同时也是提高钢的淬透性元素。在一定的冷却速度和终冷温度下通过添加一定Mo即可获得明显的针状铁素体或贝氏体组织。
S、P：是管线钢中不可避免的杂质元素，希望越低越好，通过超低硫及Ca处理改变硫化物形态可使管线钢具有很高的冲击韧性。
Cu、Ni：可通过固溶强化提高钢的强度，Ni的加入一方面可提高钢的韧性，同时改善Cu在钢中易引起的热脆性。
Cr：Cr的加入可提高钢的淬透性，且相对经济。
Pb,Zn,Sb,Sn,，这些残余元素很容易在晶界聚集，弱化晶界间的结合力，从而影响落锤性能，因此需要控制Pb≤0.0015％，Zn≤0.003％，Sb≤0.0015％，Sn≤0.0015％。
上述厚规格优异低温韧性X100管线钢板方法如下，
制备流程：配比备料→进行转炉或电炉冶炼→炉外精炼→连铸→板坯再加热→特定TMCP工艺+冷却后堆冷→矫直。
具体工艺步骤如下：首先将冶炼原料依次经KR铁水预处理、转炉冶炼、LF精炼、RH真空精炼和连铸，制造出满足化学成分要求、厚度为不小于350mm的连铸坯；
冶炼时控制P含量不高于0.007％
连铸时采用轻压下以便改善因Mn较高造成的芯部偏析。
将连铸坯再加热至不高于1180℃，进行特定TMCP工艺+水冷+堆冷+矫直。
特定TMCP工艺包括两阶段轧制和中间坯冷却：第一阶段为再结晶区轧制，终轧温度控制在不高于1150℃，再结晶区轧制时控制连续两至三道次的单道次压下率不低于20％；
中间坯冷却是通过Mild cooling冷却系统对中间坯适度冷却至第二阶段的非再结晶区开轧温度，冷却方式为是在mild cooling箱体内采用来回摆动式进行冷却，冷速速度为6-12℃/s，保证再结晶区轧制变形后奥氏体晶粒不再长大，中间坯表面与心部温差较小；
第二阶段为非再结晶区轧制，开轧温度不高于850℃，终轧温度控制在相变临界温度轧制。
轧后以水冷方式冷却钢板，轧后用DQ迅速将钢板冷却到临界相变温度后停止冷却，后钢板通过自回火后再通过ACC冷却到不高于520℃，后堆冷到室温。采用此种冷却工艺主要是减缓沿厚度方向不同部位冷却速率相差较大的问题，从而获得沿厚度方向较均匀的组织，并获得非常细小的组织，其原理就是利用芯部较高的温度进行钢板自回火，从而获得沿厚度方向细小且较均匀的组织，从而获得理想的力学性能。
与现有技术相比，本发明的优点在于：
1)采用低碳当量的成分，生产40mm以上厚规格X80，并与后续特定TMCP工艺， 获得优异的低温韧性。
2)该发明改良的TMCP工艺(含采用mild cooling冷却系统进行中间坯冷却)，看似增加了工序，有助于降低合金成本，提高成材率高。在TMCP工艺过程通过mild cooling冷却系统对中间坯快速冷却，保证第一阶段再结晶区变形后奥氏体晶粒不再长大，减小中间坯表面与心部温差，提高超厚规格管线钢板生产效率。
3)钢板轧后采用水冷+堆冷的冷却工艺主要是减缓沿厚度方向不同部位冷却速率相差较大的问题，从而获得沿厚度方向较均匀的组织，并获得非常细小的组织。
附图说明
图1为本申请X80管线用钢1/4厚度处的金相组织；
图2为本申请X80管线用钢1/2厚度处的金相组织；
图中可以看出本申请的管线钢的组织为极细少量铁素体+细针状铁素体+少量细粒状贝氏体，同时含有极细马－奥岛(M－A)。
具体实施方式
以下结合附图实施例对本发明作进一步详细描述。
超低温落锤性能优异的厚规格X80管线用钢板的制造流程为：配比备料→进行转炉或电炉冶炼→炉外精炼→连铸→板坯再加热→特定TMCP工艺(是控制加热温度并实施冷却的技术总称)+冷却后堆冷→矫直。
具体工艺步骤如下：将冶炼原料依次经KR铁水预处理、转炉冶炼、LF精炼、RH真空精炼和连铸，P含量不得高于0.007％，连铸时采用轻压下工艺，目的在于改善因Mn含量较高造成的芯部偏析。制造出满足化学成分要求、厚度350mm的连铸坯；将连铸坯再加热不高于1180℃，进行特定TMCP工艺+水冷+堆冷+矫直。
特定TMCP工艺包括两阶段轧制和中间坯冷却：第一阶段为再结晶区轧制，终轧温度控制在不高于1150℃，再结晶区轧制时控制连续两至三道次的单道次压下率不低于20％；
中间坯冷却是通过Mild cooling冷却系统对中间坯快速冷却至第二阶段的非再结晶区开轧温度，冷却方式为是在mild cooling箱体内采用来回摆动式进行冷却，冷速速度为6-12℃/s，保证再结晶区轧制变形后奥氏体晶粒不再长大，中间坯表面与心部温差较小；
第二阶段为非再结晶区轧制，开轧温度不高于900℃，终轧温度控制在相变临界温度Ar3附近。
轧后以水冷方式冷却钢板，轧后用DQ迅速将钢板冷却到一定温度后停止冷却，以 表面温度算，相变温度以下150－200℃，后钢板通过自回火后回升到一定温度后再通过ACC冷却到不高于520℃，后堆冷到室温。
各实施例所涉及钢板的具体化学成分见表1，具体TMCP工艺参数见表2，主要力学性能见表3。
表1
Figure PCTCN2020104008-appb-000001
表2
Figure PCTCN2020104008-appb-000002
表3
Figure PCTCN2020104008-appb-000003
Figure PCTCN2020104008-appb-000004
除上述实施例外，本发明还包括有其他实施方式，凡采用等同变换或者等效替换方式形成的技术方案，均应落入本发明权利要求的保护范围之内。

Claims (8)

  1. 一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板，其特征在于：该钢板的化学成分按质量百分比计为C：≤0.07％、Mn：1.6-1.9％，Si：≤0.35％，S：≤0.0006％，P：≤0.0070％，Nb：0.045～0.08％、Ti：≤0.012％、V：≤0.008％，Alt：≤0.06％，N:≤0.0040％，O：≤0.004％，Mo：≤0.3％，Pb≤0.0015％，Zn≤0.003％，Sb≤0.0015％，Sn≤0.0015％，Cu：≤0.30％、Ni：0.20-1.5％，Cr：0.12-0.19％，Mo+Cu+Ni+Cr≤2.0％，Ca：≤0.015％，Ceq≤0.41％，Pcm≤0.17％余量为Fe及不可避免的杂质元素；所述钢板的厚度为40mm及以上。
  2. 根据权利要求1所述的一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板，其特征在于：所述钢板的屈服强度≥570Mpa；抗拉强度≥645Mpa，屈强比≤0.86，圆棒样延伸率≥25％，-25℃冲击功≥350J，-40℃冲击功≥320J，-60℃冲击功≥300J，-10℃落锤剪切面积≥85％，-20℃落锤剪切面积≥75％。
  3. 根据权利要求2所述的一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板，其特征在于：全壁厚试样落锤性能，减薄试样：-20℃落锤剪切面积≥88％，-25℃落锤剪切面积≥85％，-30℃落锤剪切面积≥80％。
  4. 一种如权利要求1所述的低碳当量厚度超40mm低温高韧性X80钢级管线钢板的制造方法，其特征在于：所述方法包括首先将冶炼原料依次经KR铁水预处理、转炉冶炼、LF精炼、RH真空精炼和连铸，制造出满足化学成分要求、厚度为不小于350mm的连铸坯；将连铸坯再加热至≤1180℃，进行特定TMCP工艺+水冷+堆冷+矫直。
  5. 根据权利要求4所述的一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板的制造方法，其特征在于：连铸时控制好过热度，并采用轻压下，控制好坯料质量，确保铸坯中心偏低不高于C1。
  6. 根据权利要求4所述的一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板的制造方法，其特征在于：特定TMCP工艺包括两阶段轧制和中间坯冷却：第一阶段为再结晶区轧制，终轧温度控制在≤1150℃，再结晶区轧制时控制连续两至三道次的单道次压下率不低于20％；第二阶段为非再结晶区轧制，开轧温度不高于850℃，终轧温度控制在相变临界温度。
  7. 根据权利要求6所述的一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板的制造方法，其特征在于：在完成第一阶段的再结晶区轧制后进行中间坯冷却，中间坯冷却是通过Mild cooling冷却系统对中间坯快速冷却至第二阶段的非再结晶区开轧温度，冷却方式为是在mild cooling箱体内采用来回摆动式进行冷却，冷速速度为6-12℃/s。
  8. 根据权利要求4所述的一种低碳当量厚度超40mm低温高韧性X80钢级管线钢 板的制造方法，其特征在于：轧后以水冷方式冷却钢板，轧后用DQ迅速将钢板冷却到一定温度后停止冷却，以表面温度算，相变温度以下150－200℃，后钢板通过自回火后再通过ACC冷却到不高于520℃，后堆冷到室温。
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003013138A (ja) * 2001-06-26 2003-01-15 Nkk Corp 高強度ラインパイプ用鋼板の製造方法
JP2006183127A (ja) * 2004-12-28 2006-07-13 Jfe Steel Kk 高強度溶接鋼管の製造方法
CN104805375A (zh) * 2015-04-02 2015-07-29 江阴兴澄特种钢铁有限公司 一种超厚规格高韧性x80管线用钢板及其制造方法
CN105950973A (zh) * 2016-05-13 2016-09-21 江阴兴澄特种钢铁有限公司 超低温落锤性能优异的厚规格x80管线用钢板及其制造方法
CN107604249A (zh) * 2017-08-11 2018-01-19 江阴兴澄特种钢铁有限公司 一种经济型抗hic及抗ssccx80ms管线钢及其制造方法
WO2018216638A1 (ja) * 2017-05-22 2018-11-29 新日鐵住金株式会社 ベンド鋼管およびその製造方法
CN110331347A (zh) * 2019-06-22 2019-10-15 江阴兴澄特种钢铁有限公司 一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板及其制造方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003013138A (ja) * 2001-06-26 2003-01-15 Nkk Corp 高強度ラインパイプ用鋼板の製造方法
JP2006183127A (ja) * 2004-12-28 2006-07-13 Jfe Steel Kk 高強度溶接鋼管の製造方法
CN104805375A (zh) * 2015-04-02 2015-07-29 江阴兴澄特种钢铁有限公司 一种超厚规格高韧性x80管线用钢板及其制造方法
CN105950973A (zh) * 2016-05-13 2016-09-21 江阴兴澄特种钢铁有限公司 超低温落锤性能优异的厚规格x80管线用钢板及其制造方法
WO2018216638A1 (ja) * 2017-05-22 2018-11-29 新日鐵住金株式会社 ベンド鋼管およびその製造方法
CN107604249A (zh) * 2017-08-11 2018-01-19 江阴兴澄特种钢铁有限公司 一种经济型抗hic及抗ssccx80ms管线钢及其制造方法
CN110331347A (zh) * 2019-06-22 2019-10-15 江阴兴澄特种钢铁有限公司 一种低碳当量厚度超40mm低温高韧性X80钢级管线钢板及其制造方法

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