低温罐施工技术措施

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1、5.施工技术措施 5.1 LNG储罐施工5.1.1 LNG储罐罐体施工程序（construction sequence）LNG储罐罐体主要施工程序见 “图5.1-1 LNG罐罐体施工流程图”。5.1.2 罐顶及钢结构预制5.1.3 罐顶临时支撑安装 罐顶板安装5.1.5 临时支撑拆除5.1.6 铝吊顶安装（1）、铝吊顶预制边缘圈梁的预制 边缘圈梁按每8-10m为一段进行预制。边缘圈梁的环板和立板运用等离子切割机进行下料，下料时留出5mm的加工裕量，下料完毕后，运用坡口加工机或刨边机加工边缘；立板运用滚床进行滚弧，滚弧时应留意将滚床辊子表面的毛刺、麻点等杂物清理干净并在辊子表面匀整的缠裹2-3层

2、白胶布，防止划伤铝板表面。 圈梁的立板和环板加工完毕后，组对成“T”型，并进行焊接。 最终在立板上号线、打孔。 圈梁预制时应留意：圈梁的立板与环板间的焊缝应错开250300mm（如下图）。 铝板安装前，将钻好孔的铝肋板安装焊接在铝板上。铝板在预制时应留意爱惜防止变形及划伤，铝吊顶的预制必需在上铺橡胶板的平台上进行；预制成型的构件必需放置在橡胶板或木板上。（2）、吊杆安装 用倒链将吊杆吊起后安装在罐顶的钢梁上，并调整吊杆基本垂直，检查吊杆安装是否坚实，并检查下端是否基本处以同一水平面。（3）、边缘圈梁安装 吊杆安装完毕后，将圈梁逐段安装到吊杆上，调整圈梁环板基本处于同一水平面，并组对圈梁间的焊缝

3、，（4）、铝板安装 铝板在安装完肋板后从中心向四周进行安装，安装时运用导链和滑轮组将铝板吊起，用螺栓连接肋板与吊柱；安装完部分铝板后组对铝板间的焊缝并进行焊接。铝吊顶周边与圈梁相连接的边缘铝板待铝板安装到周边后，按实际尺寸进行下料、预制并进行安装。（5）、铝吊顶的焊接 铝板焊接前必需进行化学清洗或机械清理后再进行焊接，化学清理的方法如下： 先运用丙酮将坡口四周的油污清理干净，运用10%的NaOH（40-60）清洗4小时，再运用30%的HNO3中和1-3小时，最终用清水清洗后，风干。 铝吊顶的焊缝，基本上运用MIG焊进行焊接，对于一些小型构件，运用TIG焊进行焊接。5.1.7 压缩环预制安装 压

4、缩环在预制场按8-10一段分段预制成型后，在罐吹顶前安装到混凝土上。安装时留意防止压缩环翘曲变形。 5.1.8罐顶气举顶升（1）、吹顶前的准备工作 吹顶前必需完成的施工项目罐顶包括罐顶附件必需全部安装焊接完毕，并检查合格；铝吊顶必需全部安装、焊接完毕并检查合格；混凝土墙必需施工完毕，并经过养护期，基本达到设计强度。罐顶部压缩环安装焊接在混凝土墙的钢预埋件上安装罐顶的中心柱及临时支柱已拆除。压缩环与罐顶板间的组装卡具准备完毕。 吹顶的工装、设备准备a平衡装置的安装罐吹顶前必需安装用钢丝绳和滑轮组成的平衡装置（如下图），罐顶平衡装置共26套沿径向均布。 平衡装置的钢丝绳顶部固定在混凝土墙上，下端固

5、定在罐底的铆点上。b密封装置罐吹顶前将厚5mm宽1000mm的橡胶板作为密封装置用临时压板固定在罐顶下部周圈。安装完毕后，是否安装坚实。吹顶前一些大的管孔也要用盲板封死。c风压调整系统为便于视察罐内风压的大小，在罐底部和罐顶部设两套风压计，风压计用“U”型管制作，如下图：在风机进风管处安装调整风门和排风管，便于调整罐内风压。d进风系统 吹顶用风通过两台风量为86385m3/h，风压为1671Pa的混流风机供应，进罐的临时通道用=10mm的钢板临时封堵，风机通过管线连接在临时封板的开孔上。 吹顶时要准备两台75kw的沟通发电机作为备用电源。 吹顶前检查检查吹顶前，须要完成的施工项目是否已完成。检

6、查确认罐顶与临时支撑之间无点焊等各种形式的连接。确认吹顶的临时设施如平衡装置、密封装置等已正确地进行了安装。风机、发电机、电路、风路以及风力调整系统等在吹顶前必需经过试验，运转正常后方可投入运用。备用风机和备用发电机也必需经过试验。（2）、吹顶 吹顶前建立统一的指挥系统，明确指挥信号，编制详细的操作规程。 操作员接到送风的指令后，启动风机，观查风压并慢慢加大风量，直至罐顶缓慢浮起。调整风量保证罐顶匀速升。 不断视察风压，保证风压稳定。 吹顶期间指挥员与操作员不得擅自离岗。（3）、压缩环和罐顶的组装焊接 罐顶吹至顶部与压缩环靠紧时，在罐顶上每隔0.5m焊接一个龙门板，用扁楔子组装压缩环与罐顶焊缝

7、、点焊并进行焊接。组对形式如下图所示：（4）、停风和临时设施的拆除 罐顶板和压缩环焊接完毕后，停止送风，并拆除吹顶用的平衡装置、密封装置等临时设施；将点焊的焊点、疤痕等打磨干净； 拆除风机等送风设备及管线、拆除进罐的临时堵板。5.1.9 角部爱惜处的施工（1）、罐底与罐壁连接处施工程序罐底衬板施工（碳钢底板）混凝土墙内第一圈防潮衬板施工罐底混凝土层浇筑保温层施工其次层罐底的边缘板施工角部第一圈9%Ni钢爱惜板安装混凝土环梁施工内罐罐底边缘板施工（2）、罐底衬板与罐壁第一圈混凝土防潮衬板的施工 罐底衬板在罐底混凝土施工完毕后，铺设并进行焊接，焊接时要留意实行合理的焊接依次，防止焊接变形；罐底衬板

8、与罐比预埋件连接的边缘板依据实际尺寸进行下料。 罐壁第一圈防潮衬板待罐底板施工完毕后进行施工，防潮衬板运用倒链吊起紧贴在罐壁上，点焊后焊接在混凝土的预埋件上。（3）、其次层底板的边缘板先进行号出每块板的位置线，然后用吊车依次进行铺设并进行组对，组对时应留意保证坡口间隙为32mm,错边量不大于2.5mm; 边缘板进行焊接时，先用手工焊进行打底焊，焊接完毕后，打磨并进行着色检查，然后再进行填充焊接。（4）、其次层底板的边缘板焊接完毕后，进行真空试验，合格后号出第一圈9%Ni钢壁板的位置线，安装定位板后组对第一圈壁板。壁板安装后检查垂直度、椭圆度、焊缝间隙、纵缝错变量全部合格后，现焊接纵缝再焊接壁板

9、与底板的角焊缝。（5）、混凝土环梁施工完毕后，安装内罐罐底边缘板，安装方法基本与其次层底板边缘板相同。 罐壁施工（1）、混凝土墙内衬板安装 吹顶完毕后，先将角部爱惜区域内剩余部分的衬板安装完毕，再安装其它衬板。其它衬板安装前，先在罐内将混凝土墙内衬板预制成长条，然后用卷扬机吊起安装在混凝土墙内的预埋件上，安装时应留意尽量使钢板贴紧混凝土墙。（2）角部其次层护板及保温层的施工 角部爱惜部分的混凝土墙内衬板施工完毕后，安装角部其次层护板。安装前，先将环缝垫板安装好，再安装壁板，壁板安装前，立缝两侧各点焊三个方帽环缝点焊9-10个方帽。 组对时先运用圆楔子和背杠（用10#槽钢制作）固定环缝如下图：

10、纵缝运用球罐卡具固定如下图：（3）、内罐施工围第一圈壁板a、号壁板位置线在边缘板上号出壁板的安装位置。壁板内侧安装基准线R考虑到纵缝的焊缝收缩，R必需满足以下要求：R图纸要求的焊后壁板内径+（1.5第一圈壁板的焊缝数量）/2b、点焊壁板安装限位板 沿壁板内侧安装基准线点焊壁板内侧限位板，沿壁板外侧基准线（内侧基准线半径R+第一圈壁板板厚）点焊壁板外侧限位板。每隔1m点焊一限位板，内外交织，立缝两侧100mm处必需有限位板。（如下图） C、围第一圈壁板围第一圈壁板时，通常从0或90、180、270起先，先确定第一张壁板位置并安装第一张壁板。然后从该张壁板起先向两边同时围板。板与板间的纵缝先用两马

11、卡具进行固定，每条纵缝至少须要三套卡具。第一圈壁板围完后，每张板上安装两套丝杠用以调整壁板垂直度。围其它各圈壁板a其它各圈壁板围板的方法与第一圈板基本相同，但是围板前要做好以下准备工作：*在所要围的壁板上点焊用于悬挂三角架的蝴蝶板（每隔2500mm点焊一个）以及用于组对纵缝的方帽（每侧3个）。点焊位置如下图：* 在下一圈壁板上悬挂三角架，搭设跳板、护栏作为施工用脚手架。*在距下一圈壁板上口250-300mm处点焊龙门板，每隔1500mm点焊一个，每张壁板上点焊9个。b、围板时纵缝通过两马卡具进行固定；环缝运用1.2m的背杠进行固定（如下图）。 壁板找正a、第一圈壁板找正 第一圈壁板的几何尺寸是

12、否精确对于整个罐体几何尺寸有特殊重要的影响，因此必需细致对第一圈壁板进行找正。* 用两马卡具调整坡口的间隙及错边量：错边量1.5mm* 用加减丝杠调整壁板垂直度。 其允许偏差：3mm* 用千斤顶调整壁板上口水平度。相邻两板上口水平高差1mm；整个圆周上口水平高差6mm。在调整上口水平度时，在边缘板下加垫铁，使边缘板与壁板下口间的间隙保持为0。* 第一圈壁板的椭圆度主要通过限位板的精确度来保证。椭圆度20mm。局部椭圆度达不到要求时，可运用方楔子进行调整。找正时必需对椭圆度、垂直度、水平度同时进行调整，保证“三度”全部合格。找正完毕后，在壁板内侧每3米点焊一个支架对壁板进行固定。b、其它各圈壁板

13、找正 在施工中假如第一圈壁板的椭圆度和上口水平度严格限制在允许偏差之内，并且每张壁板的几何尺寸都符合规范要求的状况下，按正常的程序围板，当壁板垂直度和纵缝调整合格后，一般状况下，椭圆度和上口水平度也能达到规范要求。所以，其它各圈壁板的找正主要是对垂直度进行调整。每一圈板的垂直度都必需细致调整并做好记录。每一圈壁板的垂直度都将作为下一圈壁板找正的依据。垂直度的调整主要通过调整纵缝的间隙实现。减小纵缝上半部分的间隙使壁板内倾，增大纵缝上半部分的间隙使壁板外倾。当垂直度偏差太大难于调整时，可运用倒链进行调整。找正时每张壁板必需测量三点以上，除保证该张壁板垂直度符合要求外，还应对其下方壁板的垂直度偏差

14、进行修正，保证罐整体垂直度符合要求。垂直度偏差：3/1000板宽；罐壁总体垂直度偏差50mm。 纵缝组对a纵缝组对从内侧进行。运用两马卡具，通过圆楔子、扁楔子调整纵缝间隙及错边量。组对间隙为4-6mm；错边量不大于1/10板厚，且不大于1.5mm。b纵缝组对完毕后，在内侧点焊4-5块防变形板，防止焊接过程中出现角变形。c因第1-4圈壁板纵缝为双面焊且焊接时先焊接外侧再焊接内侧，为防止焊接时出现角变形，组对时应实行反变形措施。如下图所示： 加强圈 加强圈安装前，先在罐外分段预制成型，分段长度约1012m，预制完毕后用弧型样板检查其内弧偏差，间隙不大于4mm；检查弦高偏差不大于10mm。加强圈所在

15、罐壁安装焊接完毕后安装加强圈，安装时先将加强圈支架安装在罐壁上，再分段进行安装。临时通道处的壁板 内罐中的全部施工项目（包括罐底板）施工完毕后，将罐内工装、卡具及施工废料等清理干净、检查确认后安装临时通道处的内罐壁板，安装时运用电动葫芦和倒链进行就位，用球罐卡具和背杠进行组对。 焊接内罐的纵缝的焊接全部接受手工焊，电源极性尽量接受沟通；环缝接受埋弧自动焊；通道处壁板全部接受手工焊进行焊接。焊接时要留意限制焊接线能量，焊接的同时做好施焊记录。（4）、内罐安装时的脚手架搭设方法、将挂壁三角架安装在焊接于罐壁板上的蝴蝶板上,约每2.5米安装一个三角架；、在三角架上并排铺设三排钢跳板并用铁丝绑扎坚实；

16、安装时留出小平台的安装位置；、安装栏杆。先安装立杆，再安装横杆；、将小平台安装于焊在壁板上的蝴蝶板上并安装小斜梯；、将竹编板铺在跳板上并用竹编板封闭栏杆；、检查各部位是否坚实稳妥。内脚手架简图：5.1.11 罐底施工（1）、罐底边缘部分施工要在储罐升顶前完成。（2）、其它部分的施工基本与内罐罐壁同时施工，在进罐通道未封闭前完成施工，基本施工程序如下：其次层底板中幅板（9%Ni）施工铺50mm的干砂绝热层施工加强混凝土层施工碳钢衬板施工基础检查、验收检查验收上层底板中幅板施工铺50mm的干砂绝热层施工加强混凝土层施工（3）、钢衬板和它上部的混凝土层全部施工完毕后，其它部分从进罐通道对面按上述程序

17、慢慢向外施工如下图：（4）、罐底施工前要对罐基础进行验收。验收的主要内容有：罐底的标高、罐底平整度以及基础表面质量。基础表面不得有蜂窝、裂纹等缺陷。（5）、上层及中间层罐底板的铺设上层及中间层罐底板均为条状排板，铺设时从内向外先号线再铺板。铺板时先铺设条状大板，再铺设周边小板；每铺三排板作为一个单元，铺设完毕后进行焊接并进行焊接检验，然后进行下一层的施工，最上层底板焊接完毕后接着下一个单元的施工。铺板时为防止板变形，吊板应运用特地的吊装梁如下图：（6）、焊接依次 中间层底板和最上层底板焊接时应实行合理的焊接依次：焊接时先焊接短焊缝，再焊接长焊缝，每条焊缝焊接时实行分段跳焊的方法，削减焊接变形。

18、基本焊接依次如下图所示：（7）、中间层底板和最上层底板均为搭接结构，铺设时要保证搭接宽度不小于40mm。（8）、三层板重叠搭接的部位焊时要留意：先将最上面一层板的角部撬起，将起覆盖的位置焊好再焊接其它部位，如下图：（9）、底板焊接完毕后应进行真空试漏。如下图所示：（10）、底板焊接完毕后检查其凹凸变形及焊缝是否符合规范要求。5.1.12储罐内部管道、下降管等安装5.1.13罐体试验（1）、罐底板和罐顶板以及罐壁衬板组件焊接完毕后，按BS7777的要求进行真空试验。（2）、内罐罐壁焊接完毕后按BS7777 进行X射线探伤检查。（3）、内罐安装焊接完毕后，进行充水试验，充水前编制详细的充水方案。充

19、水试验的流程如下图：充水按充水曲线进行，充水后检查罐壁、罐底等有无泄漏现象，罐壁有无异样变形，并定期测量罐基础沉降状况。 充水试验合格后，进行排水。排水时先用大泵将水基本排出罐外，再用自吸泵将大泵抽不到的水排出罐外，最终用人工将罐内的水清理干净。 排水完毕后，用干燥的空气将罐内吹干。（4）、充N2 储罐全部施工完毕后，利用液氮罐车对内充N2，试验完毕后，往罐内吹压缩空气。5.1.16 罐脱水、干燥及设备安装5.1.17 罐绝热施工5.1.18 罐外部工艺系统试运转5.1.19 罐吹除、钝化、冷却与移交5.1.20 储罐焊接5.1.20.1Welding management and Weldi

20、ng Procedures(1)Welding shall be in accordance with BS 7777. All vertical and horizontal seams of the inner tank shell shall be welded by the following methods: manually, semiautomatic, or by machine.(2)All welding procedure specifications and procedure qualification records to be used for the const

21、ruction of the tanks, including those for prefabrication, repair, tack and attachment welds, shall be accepted by Purchaser/Main Contractor prior to the work being performed. Where new WPS/PQR is required, it shall be on contract materials and shall follow impact testing requirement as follows,The p

22、ositions of Charpy impact test at 196 deg.C shall be:Weld metal center lineFusion lineFusion line + 2mmFusion line + 5mm(3)The welding procedures used for all welds and the radiographic inspection procedure shall clearly be indicated in construction documents. (4)No welding is permitted on the inner

23、 tank after completion of the hydrotest.(5)Welding Consumables*Filler metal for 9% nickel welding shall conform to ASME/AWS SFA5.11 and/or SFA5.14. Filler metals and fluxes shall be selected by Tank Contractor based on providing strength, ductility, soundness and successful LNG tank experience.*Each

24、 lot or heat of the austenitic stainless steel welding (filler) materials shall meet the requirements of Section VIII, Div 1 UHA-51(e) and (f). All welding procedures shall be qualified in accordance with BS 7777 or ASME Code Section IX.*Tank Contractor shall implement a rigorous system to control t

25、he segregation and storage of welding consumables.(6)Welding Qualification and Identification*Qualified welders tested in accordance with the requirements of BS 7777 or ASME Code Section IX shall carry out all welding. The welders shall be newly qualified irrespective of any previous qualifications.

26、 Tank Contractor shall issue an individual certificate with photograph to each qualified welder. Welders who are not in possession of the required certification and identification shall not be allowed to do any welding. Tank Contractor shall also implement an identification badge system to clearly s

27、how which welders are qualified for which materials.(7)Inspection*Radiographic Inspection a)The radiographic extent, techniques and acceptance criteria for the inner tank shall be in accordance with BS 7777.b)All vertical and horizontal butt welds of inner tank shell, annular plate butt welds, inner

28、 tank stiffeners and internal piping shall be inspected by radiography. c)Lead screens shall be used, salt screens shall not be permitted. Radiographic inspection shall follow as soon as possible after welding, and the inspections shall be co-ordinated with the Purchasers/Main Contractors inspector.

29、 d)Radiography for 9% nickel welds shall be by X-ray methods with a maximum focal spot 2.5 x 2.5 mm. All personnel performing Code evaluations shall meet ASME Section V, SNT-TC-1A, Level II or equivalent qualifications. The film to be used for radiography shall be ultra fine, high contrast type e.g.

30、 Kodak AA or Agfa D7.*Liquid Penetrant Examination a)Liquid penetrant examination for the inner tank shall be carried out according to BS 7777. The Secondary Bottom Annular Plates shall have the same Liquid Penetrant Examination Requirements as the Inner Bottom Annular Plates. TCP welds shall have t

31、he root pass and the final weld examined by Liquid Penetrant. The weld between the Secondary Bottom and the TCP shall have the root pass and the final weld examined by Liquid Penetrant.*Solution Film Testinga)Vacuum box testing shall be carried out in accordance with BS 7777. All welds of the roof l

32、iner plates shall be vacuum box tested before concrete placement on the roof. Vacuum box testing of the bottom and sidewall vapor barrier welds shall be completed before commencing any operations that cover up the plates. Welds between liner components (e.g. wall liner to bottom liner) shall be vacu

33、um box tested.c)All secondary bottom and TCP welds shall be vacuum box tested.d)Inner tank bottom plate welds shall be vacuum box tested before and after hydrostatic testing.e)The inner tank shell-to-bottom Tee joint shall be pressure tested for leakage using a solution film in accordance with BS 77

34、77, Part 2, para.11.13.3.3.5.1.20.2底板 焊接Bottom Plate（1） 最外层底板材质为ASTM A516 Gr60 厚度=5mm，主要运用CO2气体爱惜焊进行焊接，点焊、局部短缝运用手工焊进行焊接。The material used for the bottom plats of outmost layer is ASTM A516 Gr60 with their thickness of 5mm, apply CO2 gas shielded welding method to them and apply manual welding method

35、 to spot welding and parts of short weld joint.（2） 中间层底板材质为ASTM A533 Type 1厚度=5mm，运用手工焊进行焊接；中间层边缘板材质为ASTM A533 Type 1厚度=10mm，运用手工焊进行焊接。The material of bottom plates of inner layer is ASTM A533 Type 1 with their thickness of 5mm, apply manual welding to them. The material of rim plates of inner layer

36、 is ASTM A533 Type 1 with their thickness of 5mm, apply manual welding to them（3） 上层底板材质为ASTM A533 Type 1厚度=6mm，运用手工焊进行焊接；上层边缘板材质为ASTM A533 Type 1厚度=25mm，运用手工焊进行焊接。The material of bottom plates of upper layer is ASTM A533 Type 1 with their thickness of 5mm, apply manual welding to them. The material

37、 of rim plates of upper layer is ASTM A533 Type 1 with their thickness of 5mm, apply manual welding to them5.1.20.3罐壁焊接 Shell Plate（1） 罐壁板9%Ni（ASTM A533 Tpye1）部分： 除最终一道环缝外其余环缝均接受埋弧自动焊进行焊接；纵缝、最终一道环缝以及进罐通道最终两张板的焊缝运用手工焊进行焊接。For the shell plates with their material of 9% (ASTM A533 Tpye1): except the la

38、st circumferential weld, apply automatic submerged ace welding to the rest of them; for the longitudinal weld, the last circumferential weld and the weld of the last two plates used for walkway for entering the tank, apply manual welding to them.（2）与混凝土墙相贴的碳钢板的焊接接受手工电弧焊。For the carbon steel plates a

39、butting upon the concrete wall, apply manual welding to them.5.1.20.4 拱顶 焊接Dome Roof（1） 拱顶结构的预制焊接依据焊缝的详细状况分别接受手工焊、CO2气体爱惜焊或埋弧焊。For the fabrication of dome roof, apply manual welding and CO2 gas-shielded arc welding or submerged arc welding.（2） 拱顶结构的安装接受手工焊进行焊接。Apply manual welding to the erection of

40、 dome roof structure.（3） 拱顶瓜皮板的焊接主要接受CO2气体爱惜焊进行焊接。Apply CO2 gas-shielded arc welding to the roof plates of dome roof.（4） 铝吊顶的焊接接受熔化极气体爱惜焊（用氩气进行爱惜）。Apply metal gas welding to the aluminium suspension decks( argon gas).（5） 拱顶上的螺柱接受提升式螺柱焊。Apply lifting stud welding to the studs of the dome roof.5.1.20.

41、5焊接材料Welding Materials 本工程中涉及到的母材及对应的焊材如下表： Base metal and corresponding welding materials involved in this project are as follows:序号No.母 材Base Metal焊接方法Welding Method焊材型号及规格Type and Specification of Welding material1ASTM A533 TYPE 1 (9%Ni)手工焊(SMAW)ENiCrMo-4 2.53.24.0埋弧焊(SMW)ERNiCrMo-4 2.6 and assor

42、ted flux2ASTM A516 Gr60&Gr70ASTM A36(低碳钢)(low carbon steel)手工焊(SMAW)E7018 2.53.24.0CO气体爱惜焊(GMAW)E71T-9 1.2埋弧焊(SMW)A5.17 F6A4-EL83ASTM B209-ALLOY 5083-0(铝合金)(Aluminium Alloy)气体爱惜焊(GMAW)ER5183 1.24ASTM A312 TP 304(不锈钢)(SS)手工焊(SMAW)E308L 2.53.24.0Filler metal for 9% nickel welding shall conform to ASME

43、/AWS SFA5.11 and/or SFA5.14. Filler metals and fluxes shall be selected by Tank Contractor based on providing strength, ductility, soundness and successful LNG tank experience.Each lot or heat of the austenitic stainless steel welding (filler) materials shall meet the requirements of Section VIII, D

44、iv 1 UHA-51(e) and (f). All welding procedures shall be qualified in accordance with BS 7777 or ASME Code Section IX.5.1.20.6工程施工中 9Ni%钢（ASTM A533 Tpye1）焊接的工艺参数及留意事项Welding Parameter and Precautions for Welding of 9% Ni Steel（ASTM A533 Tpye1） during Construction（1）手工焊 Manual Welding 平焊 Flat Position

45、 Welding主要坡口形式：Main groove types are as follows:焊接材料 welding material：ENiCrMo-43.2/4.0 烘干温度 drying temperature:200-250 烘干时间 drying period:0.5-1h焊接电源特性 characteristics of welding source: 沟通(A.C)焊接参数 welding parameter:焊接层次Weld Layer焊材型号Type of Welding Material电 流Current(A)电 压Voltage(V)焊接速度Welding Spee

46、d (cm/min)打底焊道Back RunENiCrMo-4/3.270-9020-2513-16填充焊道Filler PassENiCrMo-4/3.270-11020-2513-16填充焊道Filler PassENiCrMo-4/4.095-14020-2513-16 立焊横焊 Vertical Welding/Horizontal Welding 主要坡口形式： Main groove types are as follows:焊接方法welding method：手工焊（SMAW）焊接材料welding material：ENiCrMo-43.2/4.0 烘干温度drying te

47、mperature:200-250 烘干时间drying period:0.5-1h焊接电源特性characteristics of welding source: 沟通(A.C)焊接参数welding parameter: 焊接层次Weld Layer焊材型号Type of Welding Material电 流Current(A)电 压Voltage(V)焊接速度Welding Speed(cm/min)打底焊道Back RunENiCrMo-4/3.265-9020-2513-16填充焊道Filler PassENiCrMo-4/3.265-10020-2513-16填充焊道Filler

48、 PassENiCrMo-4/4.085-13020-2513-16 手工焊时的留意事项：Precautions during the course of manual arc welding are as follows: 焊接前不须要预热，但是焊接层间温度必需限制在150 以下；焊接时尽量接受多层多道焊，为减小焊接线能量，每一焊道焊接时尽量接受快速不摇摆的操作方法，在横、立仰焊必需摇摆焊条时，实行快速的“Z”字摇摆；禁止在母材上引弧，引弧时应在坡口内引弧，收弧时要填满弧坑。Preheat is not necessary prior to welding, but the inter-pa

49、ss temperature must be controlled below 150 . Apply multi-pass welding as much as possible. In order to reduce weld heat input, apply welding at high speed and with no weaving to each of pass. When it is necessary to apply welding with weaving to horizontal and vertical welding, adopt Z-type weaving

50、 at high speed; it is strictly prohibited to strike the arc on the base metal, start the arc within the groove and fill in the crater while finishing the arc.（2）埋弧焊 Submerged Arc Welding焊接位置：横焊Welding position: horizontal welding坡口形式type of groove：焊接材料 welding material：ERNiCrMo-42.6 &A5.14 焊剂烘干 flux

51、 drying:200-300, 烘干时间 drying period:1h焊接电源的特性characteristic of welding source：方波沟通（Square Wave . A.C）焊接参数 welding parameter:焊接层次Weld Layer焊材型号Type of Welding Material电 流Current(A)电 压Voltage(V)焊接速度Welding Speed(cm/min)打底焊道Back RunERNiCrMo-4/2.6290-32026-2830-55填充焊道Filler PassERNiCrMo-4/2.6300-36026-2

52、830-55留意事项:焊接层间温度不大于150；焊接线能量限制在35-40KJ/cm以下；封底焊时背面填加焊剂帮助成型，焊接完一侧后，背面进行清根并进行PT检查，合格后在进行焊接。Precautions are as follows:Interlayer temperature is not above150；weld heat input is controlled below 35-40KJ/cm. While performing back welding, fill the flux on the back side to assist to form, complete weldin

53、g one side, carry out back gouging and PT, if qualified, go on to carry out welding.5.2 Piping installationThe afflicted piping inside of the LNG tank is of stainless steel. All shall be prefabricated in workshop. Cut by power saw and welded by argon-electric weld. Clean the two sides of the weld wi

54、th steel brush and special grinder. Apply X-ray detection for butted weld.Simultaneously, prefabricate and erect the pipe support and its afflicted structure.After erection, execute pressure test, blow and tightness test according to the specification. LNG medium piping system should be blowed and k

55、ept dry.5.3 LNG pumps installationBefore installation, carefully check the pumps as per the product manual, and then execute installation under the instruction of representative of manufacturer.LNG pump installation should be executed after the qualified erection of its support, and strictly avoid t

56、he water immerge.After qualified installation, execute test run as per the product manual supplied by manufacturer.5.4 Electrical and Instrument WorkThe installation of electrical and instrument equipment and cable will be executed synchronously as condition possessing, and the loop testing shall be

57、 undertaken timely.5.4.1 Electrical Construction Technical PlanElectrical work of this project mainly includes grounding system, lighting system, heating tracing system and all relevant works in regards of tank bodies in tank farm, such as steel conduit installation, cable laying and wiring, assembl

58、e of electrical equipments and testing etc. Construction of Lighting and Grounding- During the construction of electrical work the electrical discipline shall make good coordination with the civil discipline; the construction personnel shall make clear know of the ground level and drawings. The cons

59、truction shall be executed strictly according to the drawing to avoid the omitting embedding of earth bar.- Before grounding, test the soil receptivity and corrosiveness and the resistance of the existing grounding net. Add earth bar in case the resistance is above 2ohms.- The embedded depth of the

60、grounding cable shall no less short than 700.- All connection between the grounding conductor shall be connected by thermoweld according to the drawings. A detailed plan concerned about the overlap length and overlap type and welding requirement shall be prepared before construction and submit to re

61、levant department for approval. The welder shall be qualified with certain certificate. - The cable extend length over the tank coffer shall be no small than 2m. All the metal without electricity shall be grounded. - Each no longer than 100m of pipeline in central tank farm pipe and each no longer than 20m of pipeline in steam cracking tank farm shall provide grounding point which connecte