一种EW420特厚海工钢板及其制造方法A kind of EW420 extra-thick marine steel plate and its manufacturing method
技术领域technical field
本发明涉及钢铁生产技术领域,特别是涉及一种EW420特厚海工钢板及其制造方法。The invention relates to the technical field of iron and steel production, in particular to an EW420 extra-thick marine steel plate and a manufacturing method thereof.
背景技术Background technique
我国开发海洋石油起步较晚,到了20世纪80年代才拥有自己的海洋石油平台,近10年来,国产的海洋平台钢板在我国海洋石油工程中才被广泛采用。我国目前对于EH36以下级别的海洋平台用钢基本实现国产化,占平台用钢量的90%,随着国家《中国制造2025》和《海洋工程装备制造业中长期发展规划》实施、国家南海战略的逐步实施,海洋工程装备和高技术船舶领域将大力发展深海探测、资源开发利用、海上作业保障装备及其关键系统和专用设备;推动深海空间站、大型浮式结构物的开发和工程化,必然对海洋平台用钢的需求量及要求也不断扩大,逐渐向高强度、厚规格方向发展。The development of offshore oil in my country started relatively late, and it was only in the 1980s that it had its own offshore oil platform. In the past 10 years, domestic offshore platform steel plates have only been widely used in my country's offshore oil projects. At present, my country has basically achieved localization of steel used for offshore platforms below EH36 level, accounting for 90% of the steel used for platforms. With the gradual implementation of the project, the field of marine engineering equipment and high-tech ships will vigorously develop deep-sea exploration, resource development and utilization, marine operation support equipment and its key systems and special equipment; to promote the development and engineering of deep-sea space stations and large floating structures, it is inevitable The demand and requirements for steel for offshore platforms are also expanding, gradually developing towards high strength and thick specifications.
海工传统企业对于420MPa级海工钢的性能均匀性、性能波动值要求非常高,一般要求调质态交货,但调质态钢板普遍焊接性能不好,需要高温预热,且焊接使用较小线能量焊接。随着海工装备行业的高质量发展,对钢板的焊接性能要求越来越高,且随着钢铁企业轧制设备的智能化和大型化,TMCP态易焊接的海工钢逐步被下游客户所接受。Traditional offshore enterprises have very high requirements on the performance uniformity and performance fluctuation value of 420MPa grade offshore steel, and generally require delivery in quenched and tempered state. Small line energy welding. With the high-quality development of the offshore equipment industry, the requirements for the welding performance of steel plates are getting higher and higher, and with the intelligent and large-scale rolling equipment of iron and steel enterprises, the TMCP-state easy-to-weld offshore steel is gradually favored by downstream customers. accept.
CN 104674117 A号发明专利提供了一种420MPa级海洋工程用钢板及其制造方法,未对夹杂元素As,Sn,Sb,Pb,Bi,B进行有效控制,且冶炼工艺一带而过,不具备实操性,实际最大厚度只能到80mm。同样,CN 104357742 A号发明专利提供了一种420MPa级海洋工程用大厚度热轧钢板及其生产方法,未对夹杂元素As,Sn,Sb,Pb,Bi,B进行有效控制,实际厚度为70mm,且其采用电炉工艺生产。两件专利在成分上没有明确为了提高焊接性能控制Cr、Cu、C、Si、Mn等元素的含量。The invention patent No. CN 104674117 A provides a 420MPa grade marine engineering steel plate and its manufacturing method. The inclusion elements As, Sn, Sb, Pb, Bi, and B are not effectively controlled, and the smelting process is passed by, and there is no practical For maneuverability, the actual maximum thickness can only be up to 80mm. Similarly, the invention patent No. CN 104357742 A provides a large-thickness hot-rolled steel sheet for marine engineering with a level of 420MPa and a production method thereof. The inclusion elements As, Sn, Sb, Pb, Bi, and B are not effectively controlled, and the actual thickness is 70mm. , and it is produced by the electric furnace process. The two patents do not specify the content of Cr, Cu, C, Si, Mn and other elements in order to improve the welding performance.
发明内容SUMMARY OF THE INVENTION
为了解决以上技术问题,本发明提供一种EW420特厚海工钢板,其化学成分及质量百分比如下:C:0.04%~0.07%,Si:0.15%~0.25%,Mn:1.30%~1.60%,P≤0.013%,S≤0.003%,Nb:0.010%~050%,V:0.020%~0.040%,Ti:0.005%~0.020%,Cr:0.10%~0.20%,Ni:0.10%~0.70%,Cu:0.20%~0.30%,Cr+Cu≤0.50%,C+Si/30+Mn/20≤0.15%,Al:0.0250%~0.050%,不含Mo,O≤12ppm,N≤35ppm,H≤1.5ppm,杂质元素As≤0.012%,Sn≤0.010%,Sb≤0.010%,Pb≤0.010%,Bi≤0.010%,B≤0.003%,余量为Fe及不可避免的杂质。In order to solve the above technical problems, the present invention provides an EW420 extra-thick marine steel plate, whose chemical composition and mass percentage are as follows: C: 0.04%-0.07%, Si: 0.15%-0.25%, Mn: 1.30%-1.60%, P≤0.013%, S≤0.003%, Nb: 0.010%~050%, V: 0.020%~0.040%, Ti: 0.005%~0.020%, Cr: 0.10%~0.20%, Ni: 0.10%~0.70%, Cu: 0.20%~0.30%, Cr+Cu≤0.50%, C+Si/30+Mn/20≤0.15%, Al: 0.0250%~0.050%, Mo free, O≤12ppm, N≤35ppm, H≤ 1.5ppm, impurity elements As≤0.012%, Sn≤0.010%, Sb≤0.010%, Pb≤0.010%, Bi≤0.010%, B≤0.003%, the balance is Fe and inevitable impurities.
技术效果:本发明在GB712和十大船级社标准的化学成分范围之内,开发出易焊接81-100mm厚EW420特厚海工钢,生产工艺稳定,机械性能优良。对轧机负荷要求不是太高,一般的宽厚板轧机均可生产,因此,适用性广,适合国内大多数宽厚板厂生产。Technical effect: The invention develops EW420 extra-thick marine steel with a thickness of 81-100mm which is easy to weld, within the chemical composition range of GB712 and the ten major classification societies standards, with stable production process and excellent mechanical properties. The load requirement of the rolling mill is not too high, and the general wide and heavy plate rolling mill can be produced. Therefore, it has wide applicability and is suitable for the production of most wide and heavy plate factories in China.
本发明进一步限定的技术方案是:The technical scheme that the present invention is further limited is:
前所述的一种EW420特厚海工钢板,其化学成分及质量百分比如下:C:0.04%,Si:0.15%,Mn:1.60%,P:0.013%,S:0.0025%,Nb:0.010%,V:0.040%,Ti:0.020%,Cr:0.10%,Ni:0.10%,Cu:0.20%,Cr+Cu:0.30%,C+Si/30+Mn/20:0.125%,Al:0.050%,不含Mo,O:0.0012%,N:0.0035%,H:0.00015%,杂质元素As:0.003%,Sn:0.0003%,Sb:0.0003%,Pb:0.005%,Bi:0.002%,B:0.003%,余量为Fe及不可避免的杂质。The chemical composition and mass percentage of the aforementioned EW420 extra-thick marine steel sheet are as follows: C: 0.04%, Si: 0.15%, Mn: 1.60%, P: 0.013%, S: 0.0025%, Nb: 0.010% , V: 0.040%, Ti: 0.020%, Cr: 0.10%, Ni: 0.10%, Cu: 0.20%, Cr+Cu: 0.30%, C+Si/30+Mn/20: 0.125%, Al: 0.050% , without Mo, O: 0.0012%, N: 0.0035%, H: 0.00015%, impurity elements As: 0.003%, Sn: 0.0003%, Sb: 0.0003%, Pb: 0.005%, Bi: 0.002%, B: 0.003 %, and the balance is Fe and inevitable impurities.
前所述的一种EW420特厚海工钢板,其化学成分及质量百分比如下:C:0.06%,Si:0.20%,Mn:1.50%,P:0.012%,S:0.0030%,Nb:0.025%,V:0.030%,Ti:0.005%,Cr:0.18%,Ni:0.45%,Cu:0.25%,Cr+Cu:0.43%,C+Si/30+Mn/20:0.142%,Al:0.040%,不含Mo,O:0.0011%,N:0.0033%,H:0.00014%,杂质元素As:0.002%,Sn:0.0003%,Sb:0.0003%,Pb:0.003%,Bi:0.001%,B:0.002%,余量为Fe及不可避免的杂质。The chemical composition and mass percentage of the aforementioned EW420 extra-thick marine steel sheet are as follows: C: 0.06%, Si: 0.20%, Mn: 1.50%, P: 0.012%, S: 0.0030%, Nb: 0.025% , V: 0.030%, Ti: 0.005%, Cr: 0.18%, Ni: 0.45%, Cu: 0.25%, Cr+Cu: 0.43%, C+Si/30+Mn/20: 0.142%, Al: 0.040% , without Mo, O: 0.0011%, N: 0.0033%, H: 0.00014%, impurity elements As: 0.002%, Sn: 0.0003%, Sb: 0.0003%, Pb: 0.003%, Bi: 0.001%, B: 0.002 %, and the balance is Fe and inevitable impurities.
前所述的一种EW420特厚海工钢板,其化学成分及质量百分比如下:C:0.07%,Si:0.25%,Mn:1.30%,P:0.011%,S:0.0015%,Nb:0.050%,V:0.020%,Ti:0.015%,Cr:0.20%,Ni:0.70%,Cu:0.30%,Cr+Cu:0.50%,C+Si/30+Mn/20:0.143%,Al:0.025%,不含Mo,O:0.0010%,N:0.0030%,H:0.00011%,杂质元素As:0.002%,Sn:0.0002%,Sb:0.0002%,Pb:0.003%,Bi:0.001%,B:0.0015%,余量为Fe及不可避免的杂质。The chemical composition and mass percentage of the aforementioned EW420 extra-thick marine steel sheet are as follows: C: 0.07%, Si: 0.25%, Mn: 1.30%, P: 0.011%, S: 0.0015%, Nb: 0.050% , V: 0.020%, Ti: 0.015%, Cr: 0.20%, Ni: 0.70%, Cu: 0.30%, Cr+Cu: 0.50%, C+Si/30+Mn/20: 0.143%, Al: 0.025% , without Mo, O: 0.0010%, N: 0.0030%, H: 0.00011%, impurity elements As: 0.002%, Sn: 0.0002%, Sb: 0.0002%, Pb: 0.003%, Bi: 0.001%, B: 0.0015 %, and the balance is Fe and inevitable impurities.
前所述的一种EW420特厚海工钢板,钢板厚度81-100mm。The aforementioned EW420 extra-thick marine steel plate has a thickness of 81-100mm.
本发明的另一目的在于提供一种EW420特厚海工钢板的制造方法,Another object of the present invention is to provide a manufacturing method of EW420 extra-thick marine steel plate,
炼钢及连铸工艺:铁水脱硫后目标S≤0.002%;转炉冶炼采用高吹低拉法脱磷,下水口干净无缺损,转炉出钢挡渣;精炼采用白渣操作,白渣保持时间≥15分钟,目标碱度5~7;真空处理保持时间≥25分钟;真空处理后进行无缝钙线处理;连铸使用五孔水口,中包目标温度为液相线温度+(5~15)℃,拉速稳定;Steelmaking and continuous casting process: target S≤0.002% after molten iron desulfurization; high blowing and low pulling method is used for dephosphorization in converter smelting, the drain is clean and free of defects, and the converter taps slag; white slag is used for refining, and the retention time of white slag is ≥ 15 minutes, target alkalinity 5~7; vacuum treatment holding time ≥ 25 minutes; seamless calcium wire treatment after vacuum treatment; continuous casting uses five-hole nozzle, and the target temperature of the middle bag is liquidus temperature + (5~15) ℃, the pulling speed is stable;
轧制工艺:采用控轧控冷工艺,为两阶段轧制;采用控轧控冷工艺,轧前加热温度1130~1200℃,粗轧温度960~1060℃,精轧开轧温度780~840℃;轧后层流冷却,终冷温度300~450℃,冷却速率7~12℃/s;随后空冷。Rolling process: The controlled rolling and controlled cooling process is adopted, which is a two-stage rolling process; the controlled rolling and controlled cooling process is adopted. ; Laminar cooling after rolling, the final cooling temperature is 300-450°C, and the cooling rate is 7-12°C/s; then air cooling.
前所述的一种EW420特厚海工钢板的制造方法,精轧后三道累计压下率大于30%。In the aforementioned manufacturing method of EW420 extra-thick marine steel plate, the cumulative reduction ratio of three passes after finishing rolling is greater than 30%.
本发明的有益效果是:The beneficial effects of the present invention are:
(1)本发明中铁水预处理进行降硫,转炉采用高吹低拉法降磷和出钢挡渣防止回磷,保证白渣精炼时间和碱度,尽可能吸附夹杂物和减少钢中的S、O等元素含量;使用无缝钙线处理,改善夹杂物形态;长时间高真空度真空处理,使N≤35ppm,H≤1.5ppm,最终得到内部质量较优良的连铸坯;(1) in the present invention, molten iron pretreatment is carried out to reduce sulfur, and the converter adopts high blowing and low pulling method to reduce phosphorus and tap slag to prevent returning to phosphorus, to ensure the refining time and basicity of white slag, to absorb inclusions as much as possible and reduce the amount of S, O and other element content; use seamless calcium wire treatment to improve the shape of inclusions; long-term high-vacuum vacuum treatment, so that N≤35ppm, H≤1.5ppm, and finally obtain a continuous casting billet with better internal quality;
(2)本发明中轧前连铸坯加热温度1130℃~1200℃,保证微合金元素完全 固溶情况下,使原始奥氏体晶粒尽可能小;粗轧采用高温低速大压下来破碎柱状晶、焊合坯料内部缺陷、细化奥氏体晶粒;精轧后三道累计压下率大于30%,通过未在结晶区的低温大变形诱导铁素体机制以及高过冷度的情况下快速冷却,得到控制组织形态及晶粒大小的目的。(2) In the present invention, the heating temperature of the continuous casting billet before rolling is 1130°C to 1200°C, so as to ensure that the microalloying elements are completely dissolved, so that the original austenite grains are as small as possible; grains, internal defects of welded billets, and refined austenite grains; the cumulative reduction ratio of three passes after finishing rolling is greater than 30%, and the ferrite mechanism and high undercooling are induced by the large deformation at low temperature not in the crystallization zone. Under rapid cooling, the purpose of controlling the microstructure and grain size is obtained.
附图说明Description of drawings
图1为实施例1钢板在金相显微镜下典型的组织形貌图;Fig. 1 is the typical microstructure diagram of embodiment 1 steel plate under the metallographic microscope;
图2为实施例2钢板在金相显微镜下典型的组织形貌图;Fig. 2 is the typical microstructure diagram of embodiment 2 steel plate under the metallographic microscope;
图3为实施例3钢板在金相显微镜下典型的组织形貌图。3 is a typical microstructure diagram of the steel sheet of Example 3 under a metallographic microscope.
具体实施方式detailed description
本实施例提供的一种EW420特厚海工钢板及其制造方法,化学成分如表1所示,A kind of EW420 extra-thick marine steel plate and its manufacturing method provided by this embodiment, the chemical composition is shown in Table 1,
表1 实施例1~3的EW420特厚海工钢板化学成分(wt,%)Table 1 Chemical composition (wt, %) of EW420 extra-thick marine steel sheets of Examples 1-3
实施例1的81mm厚EW420特厚海工钢板的生产方法,具体如下:The production method of the 81mm thick EW420 extra-thick marine steel plate of embodiment 1 is as follows:
炼钢及连铸工艺:铁水脱硫后目标硫0.002%;转炉冶炼采用高吹低拉法脱磷,下水口干净无缺损,转炉出钢挡渣;精炼采用白渣操作,白渣保持时间15分钟,目标碱度5;真空处理保持时间25分钟;真空处理后进行无缝钙线处理; 铸使用五孔水口,连铸中包目标温度为液相线温度+15℃,拉速稳定;Steelmaking and continuous casting process: target sulfur is 0.002% after molten iron desulfurization; converter smelting adopts high blowing and low pulling method to dephosphor , the target alkalinity is 5; the vacuum treatment holding time is 25 minutes; the seamless calcium wire treatment is carried out after the vacuum treatment; the five-hole nozzle is used for casting, and the target temperature of the continuous casting medium bag is the liquidus temperature + 15 ℃, and the pulling speed is stable;
轧制工艺:采用控轧控冷工艺,为两阶段轧制;轧前连铸坯加热温度1200℃;粗轧温度1060℃,高温低速大压下轧制,第一道道次压下量40mm;精轧开轧温度840℃,后三道累积压下率30%;轧后层流冷却,终冷温度450℃,冷却速率12℃/s;随后空冷。得到的81mm厚EW420特厚海工钢板。Rolling process: The controlled rolling and controlled cooling process is adopted, which is two-stage rolling; the heating temperature of the continuous casting slab before rolling is 1200 °C; ; The starting temperature of finishing rolling is 840°C, the cumulative reduction rate of the last three passes is 30%; the laminar flow cooling after rolling, the final cooling temperature is 450°C, and the cooling rate is 12°C/s; followed by air cooling. The obtained 81mm thick EW420 extra-thick marine steel plate.
实施例2的90mm厚EW420特厚海工钢板的生产方法,具体如下:The production method of the 90mm thick EW420 extra-thick marine steel plate of embodiment 2 is as follows:
炼钢及连铸工艺:铁水脱硫后目标硫0.0018%;转炉冶炼采用高吹低拉法脱磷,下水口干净无缺损,转炉出钢挡渣;精炼采用白渣操作,白渣保持时间18分钟,目标碱度6;真空处理保持时间30分钟;真空处理后进行无缝钙线处理;铸使用五孔水口,连铸中包目标温度为液相线温度+10℃,拉速稳定;Steelmaking and continuous casting process: the target sulfur is 0.0018% after the molten iron desulfurization; the converter smelting adopts the high blowing and low pulling method to dephosphor , the target alkalinity is 6; the vacuum treatment holding time is 30 minutes; the seamless calcium wire treatment is carried out after the vacuum treatment; the five-hole nozzle is used for casting, and the target temperature of the continuous casting medium bag is the liquidus temperature + 10 ℃, and the pulling speed is stable;
轧制工艺:采用控轧控冷工艺,为两阶段轧制;轧前连铸坯加热温度1150℃;粗轧温度980℃,高温低速大压下轧制,第一道道次压下量42mm;精轧开轧温度800℃,后三道累积压下率30%;轧后层流冷却,终冷温度350℃,冷却速率8℃/s;随后空冷。得到的90mm厚EW420特厚海工钢板。Rolling process: Controlled rolling and controlled cooling process is adopted, which is two-stage rolling; the heating temperature of the continuous casting slab before rolling is 1150 °C; ; The starting temperature of finishing rolling is 800°C, the cumulative reduction rate of the last three passes is 30%; the laminar flow cooling after rolling, the final cooling temperature is 350°C, and the cooling rate is 8°C/s; then air cooling. The obtained 90mm thick EW420 extra-thick marine steel plate.
实施例3的100mm厚EW420特厚海工钢板的生产方法,具体如下:The production method of the 100mm thick EW420 extra-thick marine steel plate of embodiment 3 is as follows:
炼钢及连铸工艺:铁水脱硫后目标硫0.0015%;转炉冶炼采用高吹低拉法脱磷,下水口干净无缺损,转炉出钢当渣;精炼采用白渣操作,白渣保持时间20分钟,目标碱度7;真空处理保持时间34分钟;真空处理后进行无缝钙线处理;铸使用五孔水口,连铸中包目标温度为液相线温度+5℃,拉速稳定;Steelmaking and continuous casting process: target sulfur is 0.0015% after molten iron desulfurization; converter smelting adopts high blowing and low pulling method for dephosphorization, the water outlet is clean and free of defects, and the converter taps steel as slag; white slag is used for refining, and the white slag retention time is 20 minutes , the target alkalinity is 7; the vacuum treatment holding time is 34 minutes; the seamless calcium wire treatment is carried out after the vacuum treatment; the five-hole nozzle is used for casting, and the target temperature of the continuous casting medium bag is the liquidus temperature +5 °C, and the pulling speed is stable;
轧制工艺:采用控轧控冷工艺,为两阶段轧制;轧前连铸坯加热温度1130℃;粗轧温度960℃,高温低速大压下轧制,第一道道次压下量45mm;精轧开轧温度780℃,后三道累积压下率30%;轧后层流冷却,终冷温度300℃,冷却速率7℃/s;随后空冷。得到的100mm厚EW420特厚海工钢板。Rolling process: The controlled rolling and controlled cooling process is adopted, which is two-stage rolling; the heating temperature of the continuous casting slab before rolling is 1130 °C; ; The starting temperature of finishing rolling is 780°C, the cumulative reduction rate of the last three passes is 30%; the laminar flow cooling after rolling, the final cooling temperature is 300°C, and the cooling rate is 7°C/s; then air cooling. The obtained 100mm thick EW420 extra-thick marine steel plate.
由图1-3可见,通过合理的成分设计以及精准的轧制工艺控制,得到细小 均匀贝氏体为主的组织,综合力学性能优良。It can be seen from Figure 1-3 that through reasonable composition design and precise rolling process control, a fine and uniform bainite-based microstructure is obtained, and the comprehensive mechanical properties are excellent.
冶炼+轧制处理后,实施例1~3的板厚1/4处和板厚1/2处的横向拉伸性能和横向冷弯性能如表2,横向冲击性能和Z向性能如表3,After smelting + rolling treatment, the transverse tensile properties and transverse cold bending properties at 1/4 of the plate thickness and 1/2 of the plate thickness of Examples 1 to 3 are shown in Table 2, and the transverse impact properties and Z-direction properties are shown in Table 3 ,
表2 实施例1~3的板厚1/4处和板厚1/2处的横向拉伸性能和横向冷弯性能Table 2 Transverse tensile properties and transverse cold bending properties at 1/4 of the plate thickness and 1/2 of the plate thickness of Examples 1 to 3
表3 实施例1~3的板厚1/4处和板厚1/2处的横向冲击性能和Z向性能Table 3 Transverse impact properties and Z-direction properties at 1/4 of the plate thickness and 1/2 of the plate thickness of Examples 1 to 3
其中,实施例3钢板在50kJ/cm的线能量的情况下焊接接头冲击性能如表4,Among them, the impact performance of the welded joint of the steel plate of Example 3 under the condition of 50kJ/cm line energy is shown in Table 4,
表4 实施例3钢板在50kJ/cm的线能量的情况下焊接接头冲击性能Table 4 The impact properties of welded joints of the steel plate of Example 3 under the condition of 50kJ/cm line energy
由表2和表3可以看出,实施例钢板力学性能满足各大船级社标准中对420级别E级超高强海工钢的性能要求,屈服强度≥439MPa,抗拉强度≥545MPa,延伸率≥23%,Z向截面收缩率≥66%。由表4可以看出,在50kJ/cm的线能量的情况下焊接接头冲击性能优良,满足EW420特厚海工钢板的要求。具有生产工艺稳定,机械性能优良特点。It can be seen from Table 2 and Table 3 that the mechanical properties of the steel plates of the examples meet the performance requirements of the 420-grade E-grade ultra-high-strength marine steel in the standards of major classification societies, the yield strength is ≥ 439 MPa, the tensile strength is ≥ 545 MPa, and the elongation is ≥ 545 MPa. ≥23%, Z-direction section shrinkage rate ≥66%. It can be seen from Table 4 that the impact performance of the welded joint is excellent under the condition of 50kJ/cm line energy, which meets the requirements of EW420 extra-thick marine steel plate. It has the characteristics of stable production process and excellent mechanical properties.
除上述实施例外,本发明还可以有其他实施方式。凡采用等同替换或等效变换形成的技术方案,均落在本发明要求的保护范围。In addition to the above-described embodiments, the present invention may also have other embodiments. All technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope of the present invention.