热变形及调质工艺对石油储罐用钢组织和力学性能的影响
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摘要
战略石油储备建设,关系到国家经济安全。建造储存容积在10万m3以上的大型浮顶油罐所需的石油储罐用钢板应具有强度高、韧性好和焊接性能良好等特点。迄今为止,我国石油储罐所用的高强度钢板90%以上都依赖进口,其价格昂贵而又不能保证供货时间。为了国家和企业利益,国家发改委力主石油储罐用钢板的国产化,一方面满足国内市场需求,为国家石油战略储备提供保障；另一方面,完善国内宽厚板生产技术及其理论,提高企业技术水平。大型储罐在进行纵焊缝焊接过程中,当板厚为21mm时采用V型坡口气电立焊一次焊接成型时,线能量为90～100kJ/cm。因此开发大型储罐用大线能量焊接用钢的许多工艺技术尚待开发研究。本文结合东北大学-首秦金属材料有限公司4300mm宽厚板研发中心对石油储罐用钢板的研究开发,对实验钢的热变形及调质工艺进行研究。论文的主要工作如下：
(1)采用热模拟实验,测定了实验钢的临界点温度；绘制了实验钢的静、动态CCT曲线,研究了冷却速度、形变对奥氏体连续冷却转变的影响。结果表明,随着冷速的增加,实验钢的相变开始温度逐渐降低；变形提高了实验钢的相变开始温度。
(2)研究未再结晶区总压下量对实验钢组织和力学性能的影响。结果表明未再结晶区总压下量在60%左右时,实验钢具有最佳的综合力学性能。
(3)研究热轧后离线调质处理和在线淬火+离线回火热处理对实验钢组织和力学性能的影响。结果显示,实验钢离线950℃+40min淬火、650℃+50min回火与在线835℃淬火、离线650℃+50min回火两种工艺,力学性能相差不大,且均能满足国标要求。
(4)研究了不同的线淬火温度对实验钢组织和力学性能性能的影响,结果表明,淬火温度在910℃、880℃、850℃时,实验钢的各种力学性能基本保持不变,实验钢最合适的淬火温度区间为850℃-910℃。
(5)对SG610D钢板进行工业试制,研究钢板轧态及调质态的组织和力学性能。并与日本同类钢板的力学性能进行对比。结果表明,试制钢板调质后力学性能与轧态相比有很大提高；对比实验显示,试制调质钢的力学性能基本达到日本同类产品水平,可用于国内建造大型石油储罐。
The building of strategic oil reserves is very important to the national economic security. The construction of large floating roof oil storage tanks with volume more than 100,000 m3 requires steels with high strength, good toughness and favorable welding properties. However, more than 90% high-strength oil storage tank steels depend on imports; it's expensive and can not ensure date of delivery. For profit of business and our country, the National Development and Reform Commission urges to manufacture domestic oil storage tank steels in China, on one hand to meet the needs of the domestic market, build strategic oil reserve for the country's security; On the other hand, to improve domestic production technologies and theories of the heavy plate and elevate the technical level of enterprises. Considering the welding process of large-scale tank's, when the plate thickness is 21mm was used V-groove and Gas-electric welding, and the input energy is 90～100kJ/cm. Therefore many technologies of large-scale input energy storage tank steels needed to research and developed. In this paper, combine Northeastern University with 4300mm heavy plate R&D center of ShouQin Metal Materials Co.,Ltd, to research oil storage tank steel plate, and systematic study on thermal deformation of tested steel. The main thesis is as follows:
(1) Using thermal simulation experiment to determine the critical temperatures of tested steel; drawing static and dynamic CCT curves and researching the cooling rate, holding temperature and deformation on the impact of continuous cooling transformation. The results showed that the beginning transformation temperatures decrease with the increasing of cooling rates; deformation increases the beginning transformation temperatures.
(2) Studying on the relationship between total reduction in non-recrystallization zone and mechanical properties and microstructure of tested steels. The results showed that the tested steel with total reduction about 60% in non-crystallization zone has the best mechanical properties.
(3) Studying on the influence of reheat quenching or direct quenching on mechanical properties and microstructure of tested steel; It showed that the steels with tow processes:the offline quenching and tempering(950℃+40min,650℃+50min) and online quenching, offline tempering(835℃,650℃+50min), have similar mechanical properties.
(4) The different online quenching temperatures on the influence of microstructure and mechanical properties of tested steel have been studied. The results show that with the quenching temperatures at 910℃,880℃and 850℃, the mechanical properties of steel remains basically unchanged, the most appropriate quenching temperatures of tested steel is between 850℃and910℃.
(5) Carrying out industrial trial of SG610D steel, studying on the microstructure and mechanical properties of the steels with rolled state and quenched and tempered state. Comparing with rolled state, the mechanical properties of tested steel with quenched and tempered has greatly improved; Comparative experiment showed that the mechanical properties of SG610D steel with quenched and tempered achieve the requirement of similar products of Japan. SG610D steel can be used for domestic construction of large oil storage tank.
(1)采用热模拟实验,测定了实验钢的临界点温度；绘制了实验钢的静、动态CCT曲线,研究了冷却速度、形变对奥氏体连续冷却转变的影响。结果表明,随着冷速的增加,实验钢的相变开始温度逐渐降低；变形提高了实验钢的相变开始温度。
(2)研究未再结晶区总压下量对实验钢组织和力学性能的影响。结果表明未再结晶区总压下量在60%左右时,实验钢具有最佳的综合力学性能。
(3)研究热轧后离线调质处理和在线淬火+离线回火热处理对实验钢组织和力学性能的影响。结果显示,实验钢离线950℃+40min淬火、650℃+50min回火与在线835℃淬火、离线650℃+50min回火两种工艺,力学性能相差不大,且均能满足国标要求。
(4)研究了不同的线淬火温度对实验钢组织和力学性能性能的影响,结果表明,淬火温度在910℃、880℃、850℃时,实验钢的各种力学性能基本保持不变,实验钢最合适的淬火温度区间为850℃-910℃。
(5)对SG610D钢板进行工业试制,研究钢板轧态及调质态的组织和力学性能。并与日本同类钢板的力学性能进行对比。结果表明,试制钢板调质后力学性能与轧态相比有很大提高；对比实验显示,试制调质钢的力学性能基本达到日本同类产品水平,可用于国内建造大型石油储罐。
The building of strategic oil reserves is very important to the national economic security. The construction of large floating roof oil storage tanks with volume more than 100,000 m3 requires steels with high strength, good toughness and favorable welding properties. However, more than 90% high-strength oil storage tank steels depend on imports; it's expensive and can not ensure date of delivery. For profit of business and our country, the National Development and Reform Commission urges to manufacture domestic oil storage tank steels in China, on one hand to meet the needs of the domestic market, build strategic oil reserve for the country's security; On the other hand, to improve domestic production technologies and theories of the heavy plate and elevate the technical level of enterprises. Considering the welding process of large-scale tank's, when the plate thickness is 21mm was used V-groove and Gas-electric welding, and the input energy is 90～100kJ/cm. Therefore many technologies of large-scale input energy storage tank steels needed to research and developed. In this paper, combine Northeastern University with 4300mm heavy plate R&D center of ShouQin Metal Materials Co.,Ltd, to research oil storage tank steel plate, and systematic study on thermal deformation of tested steel. The main thesis is as follows:
(1) Using thermal simulation experiment to determine the critical temperatures of tested steel; drawing static and dynamic CCT curves and researching the cooling rate, holding temperature and deformation on the impact of continuous cooling transformation. The results showed that the beginning transformation temperatures decrease with the increasing of cooling rates; deformation increases the beginning transformation temperatures.
(2) Studying on the relationship between total reduction in non-recrystallization zone and mechanical properties and microstructure of tested steels. The results showed that the tested steel with total reduction about 60% in non-crystallization zone has the best mechanical properties.
(3) Studying on the influence of reheat quenching or direct quenching on mechanical properties and microstructure of tested steel; It showed that the steels with tow processes:the offline quenching and tempering(950℃+40min,650℃+50min) and online quenching, offline tempering(835℃,650℃+50min), have similar mechanical properties.
(4) The different online quenching temperatures on the influence of microstructure and mechanical properties of tested steel have been studied. The results show that with the quenching temperatures at 910℃,880℃and 850℃, the mechanical properties of steel remains basically unchanged, the most appropriate quenching temperatures of tested steel is between 850℃and910℃.
(5) Carrying out industrial trial of SG610D steel, studying on the microstructure and mechanical properties of the steels with rolled state and quenched and tempered state. Comparing with rolled state, the mechanical properties of tested steel with quenched and tempered has greatly improved; Comparative experiment showed that the mechanical properties of SG610D steel with quenched and tempered achieve the requirement of similar products of Japan. SG610D steel can be used for domestic construction of large oil storage tank.
引文
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[3]李敏,郑香增.大线能量焊接用钢的研究概况[J],山东冶金,2008,30(3)：8-12.
[4]章小浒,王正东,涂善东.原油储罐用钢的开发与应用最新进展[J],压力容器,2006,23(6)：38-43.
[5]贺秀丽,关小军等.大型石油储罐用钢板的特征及开发现状[J],山东冶金,2006,28(3),61-63.
[6]陈学东,袁榕等.高强钢在石化企业压力容器和管道中的科学应用[J],压力容器,1998,(6)：12-20.
[7]季伟明.高效焊接技术在10万m3油罐施工中的综合应用[J],石油工程建设,2000,(6)：16-19.
[8]汪辉,郑云龙等12MnNiVR钢板焊接裂纹敏感性的试验研究[J],压力容器,2003,(6)：19-24.
[9]陈晓,王青,李经涛等.石油储备库建设技术研讨会论文集[C],北京,2004,6：167-182.
[10]章小浒,许强等.十万立方米原油储罐用钢板的国产化研究[J],石油化工设备技术,2001,22(5)：32-36.
[11]王蕾,陈晓,习天辉.大线能量低焊接裂纹敏感性钢的研究[J],材料导报,2002,(5)：24-26.
[12]郗祥远,钟桂香,樊永红等.大型原油储罐钢材国产化的探讨与分析[J],石油化工建设,2007,29(5)：23-24.
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[14]齐俊杰,黄运华,张跃.微合金化钢[M],北京：冶金工业出版社,2006,86-90.
[15]崔文芳,刘春明,吴江华.低碳钢超细晶铁素体的形成[J],材料研究学报,2006,20(3)：240-244.
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