中厚板气体保护焊不清根熔透焊技术研究_刘小龙.pdf

摘要：在常规桥梁钢结构制作焊接中，为达到设计及规范要求，在主要受力构件的焊接中确保焊缝熔透，保证焊接质量，需要对焊缝根部进行气刨清根去除有害物质。然而，采用此焊接工艺时，焊接时间长，焊接材料消耗量大，且对作业空间的要求较大，效率也低。通过对常规的焊接清根焊工艺进行优化及改进，以达到节约焊接材料、提高工作效率，以及减少因焊接空间的因素导致无法满足设计及规范要求的目的。关键词：桥梁钢结构；熔透；气体保护焊；不清根中图分类号：U445.58+3文献标志码：B文章编号：1009-7716（2023）01-0268-03中厚板气体保护焊不清根熔透焊技术研究收稿日期：2021-12-28作者简介：刘小龙（1985），男，本科，工程师，从事钢结构桥梁制作工作。刘小龙，胡元峰，隗会军（海波重型工程科技股份有限公司，湖北 武汉 430207）DOI:10.16799/ki.csdqyfh.2023.01.0650引言在常规桥梁钢结构焊接施工中，对中厚板（t25 mm）的对接及熔透角接通常采用的开坡口正面打底填充焊盖面焊，反面碳弧气刨清根，去除焊缝根部有害物质后再进行填充盖面焊，以达到熔透的效果。常规的 CO2气体保护焊焊接工艺要达到焊缝熔透，必须对构件开坡口进行处理。在焊接时，要避免焊穿，控制装配精度要留 12 mm 钝边。常规的焊接弧长在焊接时不能完全熔化钝边，焊接时产生夹渣等有害物质，因此需要熔透就要采用碳弧清根清除焊缝钝边根部的有害物质。大面积使用碳棒进行清根，噪声大，产生有害气体多，焊材使用量也会增加，特别是在狭小空间中的熔透角接，如桥梁钢结构支座处，设备无法满足清根的要求等。在有限的条件下，且满足焊缝熔透，达到设计及规范要求的情况下，避免大量清根焊及节约成本，将是迫切需要解决的难题。现如今行业内采用气体保护焊配合埋弧焊来实现不清根达到熔透的工艺技术已经非常成熟，但在狭小空间内只能使用气体保护焊时，此工艺难以满足此要求。本文结合深熔弧模式优化焊接工艺，采用大量的工艺试验及钢结构生产的实际情况改进中厚板的对接及熔透角接焊接工艺，减少反面清根的环节，达到狭小空间不清根焊及节约成本的目的。1试验过程1.1试验基本情况（1）焊接设备。采用 D-Arc 焊机的深熔弧模式，较传统焊接设备，焊接电流更大、焊丝潜入母材坡口深入产生电弧，加热母材深处，实现深的熔深，大的电流增加电焊弧长，使坡口内钝边更易熔化，填埋式弧焊也不易引起缺陷的产生，如气孔、夹渣等。同时也减少焊缝飞溅，焊缝表面更易清理。（2）试验材料。试验用的母材采用 Q345qD 桥梁用结 构 钢，板 厚 为 36 mm。试 验 用 的 焊 材 采 用G49A2C1S6（直径 1.2 mm）实芯焊丝，气体采用 CO2气体保护。（3）试验项目。项目一共分为两组，一组为“X”型坡口对接，另外一组为“K”型坡口角接，均要求熔透焊接，具体见表 1。1.2试验过程（1）试验前调试好焊机、准备码板、引熄弧板、电焊手套、面罩、打磨机、敲渣锤、焊材等。URBAN ROADS BRIDGES&FLOOD CONTROL第 1 期（总第 285 期）2023 年 1 月表 1试验项目编号焊接材料母材材质接头形式备注S-1G49A2C1S6（1.2 mm）Q345qD不清根焊接S-2G49A2C1S6（1.2 mm）Q345qD不清根焊接相关专业268（2）试板装配。清除坡口两侧范围内 50 mm 的铁锈、底漆、氧化皮等。打磨出金属光泽后进行组装，不留装配间隙。然后用码板进行固定，试板两头安装引熄弧板。（3）焊前准备。采用烘枪对试板进行焊前预热，预热温度控制在 60120，并采用红外线测温仪在坡口两侧 50 mm 及坡口中心测量温度。预热过程中产生的水汽及浮锈，应及时进行清理。（4）焊接。预热温度达到后开始焊接，采用 D-Arc焊机焊接，采用推焊法（见图 1）焊枪与试件保持4045。对接试板焊接顺序及焊接工艺见表 2。1 层采用 D-Arc 深熔模式 CO2气体保护焊焊接打底，23 层填充，后翻身背面采用 D-Arc 深熔模式 CO2气体保护焊焊接打底填充，盖面。打底时电流控制在 450500A；再次翻身焊接 68 层盖面层。焊接工艺参数见表 3。角接熔透试板焊接顺序及焊接工艺见表 4。第 1、2 层采用 D-Arc 深熔模式 CO2气体保护焊焊接打底填充，后焊接背面 3、4 层，采用 D-Arc 深熔模式 CO2气体保护焊焊接打底填充，盖面。打底时电流控制在 450500A。再次翻身焊接 58 层填充层及 911 盖面层。焊接工艺参数见表 5。1.3试验结果（1）焊缝无损检测。焊缝 24 h 后进行无损检测，结果表明均达到熔透，满足规范1-3要求。（2）试板力学检测。对试板进行破坏性试验，试验项目有接头拉伸、焊缝冲击、弯曲、延伸率、维氏硬度及金相试验。试验结果见表 6，均满足规范要求。金相试验结果见表 7。刘小龙，等：中厚板气体保护焊不清根熔透焊技术研究图 1推焊法表 2对接试验项目（S-1）不清根项目焊接顺序图S-1表 3焊接工艺参数（S-1）不清根表 4熔透角接试验项目（S-2）不清根序号焊接材料电流/A电压/V送丝速度/（mmin-1）备注1G49A2C1S6（1.2 mm）50042.515.9打底23G49A2C1S6（1.2 mm）50042.515.9填充4G49A2C1S6（1.2 mm）50042.515.9打底5G49A2C1S6（1.2 mm）44039.513盖面68G49A2C1S6（1.2 mm）44039.513盖面项目焊接顺序图S-1表 5焊接工艺参数（S-2）不清根序号焊接材料电流/A电压/V送丝速度/（mmin-1）备注1G49A2C1S6（1.2 mm）50042.515.9打底2G49A2C1S6（1.2 mm）50042.515.9填充3G49A2C1S6（1.2 mm）50042.515.9打底4G49A2C1S6（1.2 mm）44039.513盖面58G49A2C1S6（1.2 mm）44039.513填充911G49A2C1S6（1.2 mm）44039.513盖面表 6破坏性试验结果试验项目抗拉强度 Rm/（Nmm-2）屈服强度 ReL/（Nmm-2）延伸率 A/%规范值49034520S-1 实验值55441036S-2 实验值61951826试验项目冲击值 KV2/J弯曲 180硬度/HV规范值-20，KV234Jd=3 a380HV10S-1 实验值56,75,98合格162，160，165S-2 实验值88,69,97合格163，166，1742023 年第 1 期269表 7破坏性试验结果刘小龙，等：中厚板气体保护焊不清根熔透焊技术研究金相试验结果表明，焊缝内部无气孔、夹渣、未融合等缺陷，满足规范要求。2结论以上结果显示，中厚板（t25 mm）采用深熔弧模式结合设备可以满足 CO2气体保护焊不清根熔透的要求，检测结果均满足规范的相应要求，可达到在有限的空间下，节约焊材及提高工装效率的目的。参考文献：1 Q/CR 92112015，铁路钢桥制造规范S.2 JTG/T 36502020，公路桥涵施工技术规范S.3 GB/T 506612011，钢结构焊接规范S.试验项目金相试验照片S-1S-2城市道桥与防洪 杂志是您合作的伙伴，为您提供平台，携手共同发展!欢迎新老读者订阅期刊 欢迎新老客户刊登广告投稿网站：http:/电话：[phone]联系邮箱：2023 年第 1 期270Abstract:Taking TBM tunnelling through the buildings in Qingdao Metro Line 2 as the background,thedeformation rules of buildings and ground surface under the influence of TBM tunnel construction arefurther studied by numerical simulation.The results show that during TBM tunnelling through twoadjacent brick-concrete structural buildings,the maximum settlement of the surface and the building doesnot appear at the centre line of the two tunnels.The maximum surface settlement will shift toward thelocation of the larger buildings.The maximum settlement of the building appears at the adjacent positionsof the two buildings.For the buildings with the irregular concave and convex,the maximum settlementvalue will shift to the superposition direction of the convex part and the adjacent buildings.When TBMtunnelling through the frame structural building,there will be the peak settlement at the independentfoundation in the ground surface.The closer to the tunnel is,the larger the peak is.The strip foundationused for the brick-concrete structure does not have this effect on the surface settlement.There will be theuplift phenomenon far from one side of tunnel,more than a certain distance from the tunnel.The buildinguplift will tend to a fixed value.Keywords:tunnel engineering;numerical simulation;tunnelling through buildings;surface settlement;building settlementDesign of Large-span and Small Clear Distance Tunnel Group of Mine Tunneling Method in Qinzhou,GuangxiXIAO Min(260)Abstract:There are four tunnels in the Beibu Gulf Project of Qinzhou,Guangxi Province,which are B1,B2,B3 and B4 tunnels.B2 and B3 tunnels are the double-way eight-lane tunnels,and B1 and B4 are thepedestrian and non-motored vehicle lane tunnels.The mutual clear distance is only 4.55 m.In order toensure the integral safety of tunnel during the construction,the interlaid rock reinforcement is adopted,the construction procedures are strictly controlled,the advance support and initial support arestrengthened,and the secondary lining construction time is adjusted according to the monitoring andmeasuring results,which finally ensure the smooth construction of the tunnel in the project.Keywords:tunnel group of mine tunneling method;large span;small clear distanceCalculation of Bearing Capacity and Settlement Observation of Hill-pile Engineering Foundation in Sandy SoilAreaLIN Min(264)Abstract:The artificial hill-pile project has the characteristics of large volume of earthwork,wide loaddistribution and long consolidation time.At the same time,due to the high requirements for the hill-pileengineering foundation,it is easy to cause the major engineering accidents such as the insufficient bearingcapacity of foundation or insufficient shear strength of soil.Combined with the artificial hill-pile projectin Zilang Park in the Central Innovation Zone of Nantong,through the analysis of geological conditions,the calculation of foundation bearing capacity and the observation of periphery surface settlement,thefeasibility of using the natural foundation treatment scheme for the hill-pile project is studied.Theanalysis on the long-term observation data shows that the periphery surface settlement is all in the rangeof allowed settlement.Therefore,the natural foundation can be used to build the mountain more than 20meters for the hill-pile project in the sandy soil area,which provides some suggestions for the foundationtreatment of the similar hill-pile projects in the sandy soil area.Keywords:sandy soil;hill-pile project;bearing capacity of foundation;settlement observationStudy on Technology of Gas-shielded Unclean Root Penetration Welding for Medium PlateLIU Xiaolong,HU Yuanfeng,WEI Huijun(268)Abstract:In the conventional fabrication and welding of steel bridge structure,in order to meet therequirements of design and specification,the penetration of weld seam is ensured and the welding qualityUrban Roads,Bridges&Flood ControlMonthlyNumber 1,2023(Total Number 285)Publication on January 15th,2023Start Publication in 1984Issuance Scope:Domestic and International IssuanceExcellent Journal of the Ministry of Housing and Urban-Rural Development,PRCGoverning Body:Ministry of Housing and Urban-Rural Development,PRCSponsor:Shanghai Municipal Engineering Design Institute(Group)Co.,Ltd.Edition and Publication:Editorial Office of Urban Roads,Bridges&Flood ControlEditor-in-chief:LUO YanniAddress:901 Zhongshan Bei Er Road,Shanghai,ChinaP.C.:200092Tel.:[phone]Fax:[phone]Website:http:/E-mail:Domestic Price:RMB 25 YuanISSN 1009-7716CN 31-1602/UChina Standard Serial Numbering:is guaranteed in the welding of main stressed components,and it is necessary to remove the harmfulsubstances from the root of weld seam by carbon arc gouging.But when using this welding process,thewelding time is long,the welding material consumption is large,and the requirements for working spaceare large,and the efficiency is low.The conventional welding root cleaning welding process is optimizedand improved to achieve the purpose of saving the welding materials,improving the work efficiency andreducing the factors that cannot meet the design and specification requirements due to welding space.Keywords:steel bridge structure;penetration;gas-shielded welding;unclean root