ROKOP连铸坯横裂纹的研究
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摘要
高效连铸是国外二十世纪与连铸坯热送热装工艺匹配而发展起来的冶金新技术,是以高作业率、高拉速、高质量为核心。ROKOP连铸机是在此背景下产生的机型。该机型由于不设二冷拉矫辊,处理漏钢事故方便迅速,作业率明显提高,得到国内外钢铁企业广泛的应用。我国方坯连铸机占总钢产量的60%以上,主要应用的为该机型;另一方面,也正是由于ROKOP连铸机无二冷拉矫辊,在生产过程中铸坯无导向辊,故而有一定的振颤,使铸坯横裂纹的缺陷明显表现出来;再者,我国转炉正处于由冶炼普碳钢向冶炼品种钢转型时期,钢中合金元素的增加,增加了钢的裂纹敏感性和钢的凝固收缩复杂性。连铸技术需要新的理论和新的基础数据支持。我国正处于经济高速发展时期,结构用钢占主导地位,同时品种钢的需求也大量增加,20MnSi钢种为现行主导产品之一。用ROKOP连铸机生产以该钢种为主的结构钢出现了广泛的横裂纹缺陷,严重时无法进行生产,严重影响了炼钢生产的技术经济指标。而本研究正是为解决炼钢由普碳钢连铸坯向品种钢连铸坯生产过渡出现的质量问题而提出的。
本课题以我国目前广泛采用的ROKOP连铸机生产的方坯和矩形坯为研究对象,建立符合现场实际工况条件的连铸坯凝固传热模型,求出合理的铸坯冷却强度和凝固收缩量,以优化铸坯冷却工艺,设计制造出符合铸坯收缩规律的抛物线结晶器,并优化振动参数,同时分析钢液成分对铸坯横裂纹的影响,以达到提出解决铸坯横裂纹的技术措施,解决铸坯横裂纹质量问题。
本研究在理论分析和现场操作的基础上,对影响铸坯表面质量的诸多因素进行研究,提出了有效的改善措施。对铸坯表面横裂纹的产生机理进行了研究,提出了控制矫直温度在脆化温度范围之外,从而优化结晶器与二冷配水制度。为了防止铸坯在振痕处表面质量恶化,研究了结晶器振动机构,提出及时对振动机构进行检修、清洁,并采用高振频、小振幅振动以减少负滑动时间来控制铸坯振痕深度,改善铸坯表面质量。通过对钢液化学成分的分析研究,提出了合适的合金元素含量以及杂质含量。使得铸坯由于横裂纹引起的废、次品基本消除。
In the metaphase and anaphase of 20 century,foreign high efficient continuous casting which is a new metallurgical technology had developed with the technology of hot charging and hot carrying of continuous slab. High efficiency,high pulling and high quality are the cores of it. ROKOP caster is generated in this background. This kind of caster deals with the accident of the leak quickly and improves the efficiency. Because it doesn’t have secondary cooling straightening roll. It is widely used in the world. In our country, square billet caster products more than 60% steel. On the other hand,without secondary cooling straightening roll in ROKOP caster and guide roll in operation,it has definite vibration,which makes the flaw of transverse crack appear clearly. Further more,our country’s converter is in the transition from smelting plain carbon steel to smelting specific steel. The sensitivity of steel crack and the complexity of solidifying contraction are increased by increasing the alloy elements augment. Casting technology needs the support of new theory and new basic data. In the time of economical rapid development,structural steel dominates the market. Meanwhile,the demand of specific steel is increased quickly. Particularly, 20MnSi steel is an actual main kind of products. Using ROKOP caster producing this kind of structural steel, transverse cracks appeared. The work doesn’t go on when it is severe. The technical and economical index of steel-making is affected severely. The aim of the study is to solve the quality problems which caused by the transition from plain carbon steel slab to specific steel slab.
The subject studies the square billet and rectangular billet made by ROKOP caster,which widely used in our country. Solidifying and heat transferring model according to the actual conditions and extracts reasonable cooling strength and solidifying contraction for optimizing the cooling process of slab and making parabola crystallizer according to contractive rule are established. The vibrating parameters are optimized and the effect of the steel content on transverse crack are analyzed for bringing technical measures to solve transverse crack and the quality problems.
On the base of academic analysis and actual operation,the factors which affect casting slab surface quality have been studied and effective measures to improve them have been brought out. The mechanism of transverse crack has been studied and controlling straightening temperature out of the range of brittle temperature has also been brought out. The crystallizer and the secondary cooling system have been optimized. In order to prevent slab surface quality at vibrating trace from deteriorating , the vibrated system of crystallizer has been studied. The vibrated system has been checked and cleaned. The depth of trace is controlled by high frequency and amplitude of vibration which can decrease negative slipping time. The surface quality of slab has been improved. By analyzing the chemical components of steel, moderate alloy element content and impurity content have been studied. The waste and degraded products caused by transverse crack are eliminated.
本课题以我国目前广泛采用的ROKOP连铸机生产的方坯和矩形坯为研究对象,建立符合现场实际工况条件的连铸坯凝固传热模型,求出合理的铸坯冷却强度和凝固收缩量,以优化铸坯冷却工艺,设计制造出符合铸坯收缩规律的抛物线结晶器,并优化振动参数,同时分析钢液成分对铸坯横裂纹的影响,以达到提出解决铸坯横裂纹的技术措施,解决铸坯横裂纹质量问题。
本研究在理论分析和现场操作的基础上,对影响铸坯表面质量的诸多因素进行研究,提出了有效的改善措施。对铸坯表面横裂纹的产生机理进行了研究,提出了控制矫直温度在脆化温度范围之外,从而优化结晶器与二冷配水制度。为了防止铸坯在振痕处表面质量恶化,研究了结晶器振动机构,提出及时对振动机构进行检修、清洁,并采用高振频、小振幅振动以减少负滑动时间来控制铸坯振痕深度,改善铸坯表面质量。通过对钢液化学成分的分析研究,提出了合适的合金元素含量以及杂质含量。使得铸坯由于横裂纹引起的废、次品基本消除。
In the metaphase and anaphase of 20 century,foreign high efficient continuous casting which is a new metallurgical technology had developed with the technology of hot charging and hot carrying of continuous slab. High efficiency,high pulling and high quality are the cores of it. ROKOP caster is generated in this background. This kind of caster deals with the accident of the leak quickly and improves the efficiency. Because it doesn’t have secondary cooling straightening roll. It is widely used in the world. In our country, square billet caster products more than 60% steel. On the other hand,without secondary cooling straightening roll in ROKOP caster and guide roll in operation,it has definite vibration,which makes the flaw of transverse crack appear clearly. Further more,our country’s converter is in the transition from smelting plain carbon steel to smelting specific steel. The sensitivity of steel crack and the complexity of solidifying contraction are increased by increasing the alloy elements augment. Casting technology needs the support of new theory and new basic data. In the time of economical rapid development,structural steel dominates the market. Meanwhile,the demand of specific steel is increased quickly. Particularly, 20MnSi steel is an actual main kind of products. Using ROKOP caster producing this kind of structural steel, transverse cracks appeared. The work doesn’t go on when it is severe. The technical and economical index of steel-making is affected severely. The aim of the study is to solve the quality problems which caused by the transition from plain carbon steel slab to specific steel slab.
The subject studies the square billet and rectangular billet made by ROKOP caster,which widely used in our country. Solidifying and heat transferring model according to the actual conditions and extracts reasonable cooling strength and solidifying contraction for optimizing the cooling process of slab and making parabola crystallizer according to contractive rule are established. The vibrating parameters are optimized and the effect of the steel content on transverse crack are analyzed for bringing technical measures to solve transverse crack and the quality problems.
On the base of academic analysis and actual operation,the factors which affect casting slab surface quality have been studied and effective measures to improve them have been brought out. The mechanism of transverse crack has been studied and controlling straightening temperature out of the range of brittle temperature has also been brought out. The crystallizer and the secondary cooling system have been optimized. In order to prevent slab surface quality at vibrating trace from deteriorating , the vibrated system of crystallizer has been studied. The vibrated system has been checked and cleaned. The depth of trace is controlled by high frequency and amplitude of vibration which can decrease negative slipping time. The surface quality of slab has been improved. By analyzing the chemical components of steel, moderate alloy element content and impurity content have been studied. The waste and degraded products caused by transverse crack are eliminated.
引文
[1] 蔡开科,程士富.连续铸钢原理与工艺.冶金工业出版社,1994.320
[2] 卢盛意.连铸坯质量.冶金工业出版社,1994.148
[3] 周国忠.连铸坯缺陷成因与防止措施.国外钢铁,1995.(6):35
[4] 连铸板坯裂纹的成因与防止措施.鞍钢技术,1997.(2):18
[5] 程常桂,邓康,任忠鸣.连铸坯振痕的形成机理及控制技术的发展.炼钢,2000.(5):55
[6] Edward S.Szekeres.Overview of mould oscillation in continuous casting.Iron and steel engineer.1996.(7):29～37
[7] E.Takeuchi and J.K.Brimacombe.The formation of oscillation marks in the continuous casting of steel slabs.Metallurgical transaction B.1984.15B.(3):493～509
[8] 张洪波.小方坯连铸结晶器的发展现状.河北冶金,1997.(5):12
[9] 杜会英.结晶器振动对连铸坯表面质量的影响.钢铁,2002.(3):66～67
[10] 杨春政.刘杰等。高效连铸结晶器的应用实践.河北理工学院学报,2000.(5):65
[11] 陈家祥.连续铸钢手册.冶金工业出版社,1991:161
[12] 朱立光等.现代连铸工艺与实践.河北科学技术出版社 2000:7～9
[13] Takeshi TaKawa,Tsutomu Takamoto,Hiroshi Tomon. Initial Solidification Analysis in the Vicinity of Meniscus Steelmaking conf.Proc,1991:73～77
[14] 张富强,王久彬.热量传输基础知识和连铸坯凝固传热特点.鞍钢技术,1998 (8):58～61
[15] M.S.Jekins. Steelmaking,1995:78
[16] Herbert L.Gilles. Steelmaking Conf,1993:76
[17] 陈雷.连续铸钢.北京:冶金工业出版社,1996:54
[18] 刘风云.传热数学模型在小方坯连铸上的应用.河北冶金,1984,(4):19～21
[19] 萨莫依洛维齐(苏).连续铸钢原理.北京:冶金工业出版社
[20] 周筠清.传热学.北京:冶金工业出版社,1989:10
[21] 史惠康.Visual Basic 6.0 中文版实用编程技术.中国水利水电出版社,1999
[22] RAUTARUUKKI.连铸机钢水位自动控制系统(内部资料).芬兰,1998
[23] 陈家祥.连续铸钢手册.冶金工业出版社,1991:455～466
[24] Roberto Villoria Steel Making Conference Processding,196
[25] 周建安.结晶器锥度及其较好配合拉速的计算探讨炼钢.1992.(2):42～46
[26] 施延藻.铸钢实用手册.沈阳东工工学院出版社,1988.(2):12
[27] 曹广畴.现代板坯连铸.北京:冶金工业出版社,1989:10
[28] 祝菊生等.金属理论基础.宇航出版社,1992.(7):91
[29] 候增寿.金属原理.上海科技科学技术出版社,1989:90～93
[30] (苏)李夫舍茨著,王润等译.金属与合金的物理性能.中国工业出版社,1978.(4):334～335
[31] 张洪波.方坯连铸连续锥度结晶器的设计与选择.炼钢,1992.(2)42～45
[32] 张富强等.二冷区的凝固传热.鞍钢技术,1998.(11):60～61
[33] 张富强等.连铸二冷冷却的优化和控制.鞍钢技术,1999.(1):54～55
[34] 李佐军.结晶器液压振动系统及其控制方法.孝感学院学报,2001.(6):25～26
[35] 王硕明,朱立光等。崇利制钢厂连铸坯横裂纹的成因.铸造,2000.(1):46
[2] 卢盛意.连铸坯质量.冶金工业出版社,1994.148
[3] 周国忠.连铸坯缺陷成因与防止措施.国外钢铁,1995.(6):35
[4] 连铸板坯裂纹的成因与防止措施.鞍钢技术,1997.(2):18
[5] 程常桂,邓康,任忠鸣.连铸坯振痕的形成机理及控制技术的发展.炼钢,2000.(5):55
[6] Edward S.Szekeres.Overview of mould oscillation in continuous casting.Iron and steel engineer.1996.(7):29～37
[7] E.Takeuchi and J.K.Brimacombe.The formation of oscillation marks in the continuous casting of steel slabs.Metallurgical transaction B.1984.15B.(3):493～509
[8] 张洪波.小方坯连铸结晶器的发展现状.河北冶金,1997.(5):12
[9] 杜会英.结晶器振动对连铸坯表面质量的影响.钢铁,2002.(3):66～67
[10] 杨春政.刘杰等。高效连铸结晶器的应用实践.河北理工学院学报,2000.(5):65
[11] 陈家祥.连续铸钢手册.冶金工业出版社,1991:161
[12] 朱立光等.现代连铸工艺与实践.河北科学技术出版社 2000:7～9
[13] Takeshi TaKawa,Tsutomu Takamoto,Hiroshi Tomon. Initial Solidification Analysis in the Vicinity of Meniscus Steelmaking conf.Proc,1991:73～77
[14] 张富强,王久彬.热量传输基础知识和连铸坯凝固传热特点.鞍钢技术,1998 (8):58～61
[15] M.S.Jekins. Steelmaking,1995:78
[16] Herbert L.Gilles. Steelmaking Conf,1993:76
[17] 陈雷.连续铸钢.北京:冶金工业出版社,1996:54
[18] 刘风云.传热数学模型在小方坯连铸上的应用.河北冶金,1984,(4):19～21
[19] 萨莫依洛维齐(苏).连续铸钢原理.北京:冶金工业出版社
[20] 周筠清.传热学.北京:冶金工业出版社,1989:10
[21] 史惠康.Visual Basic 6.0 中文版实用编程技术.中国水利水电出版社,1999
[22] RAUTARUUKKI.连铸机钢水位自动控制系统(内部资料).芬兰,1998
[23] 陈家祥.连续铸钢手册.冶金工业出版社,1991:455～466
[24] Roberto Villoria Steel Making Conference Processding,196
[25] 周建安.结晶器锥度及其较好配合拉速的计算探讨炼钢.1992.(2):42～46
[26] 施延藻.铸钢实用手册.沈阳东工工学院出版社,1988.(2):12
[27] 曹广畴.现代板坯连铸.北京:冶金工业出版社,1989:10
[28] 祝菊生等.金属理论基础.宇航出版社,1992.(7):91
[29] 候增寿.金属原理.上海科技科学技术出版社,1989:90～93
[30] (苏)李夫舍茨著,王润等译.金属与合金的物理性能.中国工业出版社,1978.(4):334～335
[31] 张洪波.方坯连铸连续锥度结晶器的设计与选择.炼钢,1992.(2)42～45
[32] 张富强等.二冷区的凝固传热.鞍钢技术,1998.(11):60～61
[33] 张富强等.连铸二冷冷却的优化和控制.鞍钢技术,1999.(1):54～55
[34] 李佐军.结晶器液压振动系统及其控制方法.孝感学院学报,2001.(6):25～26
[35] 王硕明,朱立光等。崇利制钢厂连铸坯横裂纹的成因.铸造,2000.(1):46