Progress of the Chinese shipbuilding industry and welding technology

The China state shipbuilding corporation (CSSC), a leading shipbuilding enterprise of the Chinese shipbuilding industry, has made rapid progress during recent years. The welding technology, considered as the crucial factor in the development of the industry, plays a significant role. This paper presents the growth of shipbuilding technology, the associated welding processes and the prospects for the shipbuilding industry.

Achievements and developing trend of welding technology in Chinese shipbuilding

China's shipbuilding welding industry has passed a history of 40 years,and the rapid progresses in high efficient and automatic welding technology taken place in the recent 10 years, have made significant contribution to the development of national shipbuilding industry as well as to the state key projects, which promotes the welding consumables and equipment industry in China.This article presents the new welding technologices used in Chinese shipbuilding industry,particularly in recent decade,including new welding consumables and equipment,and economical benfit, caused by these new technologies,and predicts foe welding technology developing trend for Chinese shipbuilding industry in authors'opinion.

Progress of welding technology in aviation industry

Welding in aviation industry has become one of the dominate processing technologies for manufacturing flying apparatus.The percentage of welded structures in designs of new flying apparatus has been continuously growing up.Welding technology provides a freedom and guarantee to new structure design and new material application. Technical and economic benefits have been obtaining in application of newly developed welding technologies and achievements in research, such as, SPF/DB,electron beam welding, breezing,low stress nondistortion welding etc.

EFFECT OF Fe_2O_3 ON WELDING TECHNOLOGY AND MECHANICAL PROPERTIES OF WELD METAL DEPOSITED BY SELF-SHIELDED FLUX CORED WIRE

Five experimental self-shielded flux cored wires are fabricated withdifferent amount of Fe_2O_3 in the flux. The effect of Fe_2O_3 on welding technology and mechanicalproperties of weld metals deposited by these wires are studied. The results show that with theincrease of Fe_2O_3 in the mix, the melting point of the pretreated mix is increased. LiBaF_3 andBaFe_(12)O_(19), which are very low in inherent moisture, are formed after the pretreatment. Themechanical properties are evaluated to the weld metals. The low temperature notch toughness of theweld metals is increased linearly with the Fe_2O_3 content in the flux due to the balance betweenFe_2O_3 and residual Al in the weld metal. The optimum Fe_2O_3 content in flux is 2.5 percent approx3.5 percent.

Welding technology in oil-field construction in China

This paper introduces the application and development of welding technology in the oil-field construction in China. It focuses on introducing,by statistics,the growth of working capacity in the welding engineering of oil well heads,long-distance oil transmission lines,large-scale storage tanks, various kinds of oil station and stores, and the applications of welding technology in the typical construction of oil field. Finally, it presents suggestions on the future development of welding technology in oil-field construction for discussion.

Development of welding technology of hydroelectric power equipment

Hydroelectric power equipment consists of a hydro-turbine and a hydrogenerator whose weldments have the features of complicated construction and large bulk as well as some parts operating under water. With the increase of unit rating of the hydroelectric power equipment, the application field of high strength steel and dissimilar steel has been enlarged. What to be introduced in this paper is the development of the welding technology of large hydroelectric generating equipment in China since the 1970s, and the development orientation of its welding construction and procedure in the future.

Current status and prospects of welding technology in China

In this paper the history of welding technology and the current status in China was reviewed, and based on the situation the developmental trend was prospected.

Simulating molten pool features of shipbuilding steel subjected to submerged arc welding

Submerged arc welding process has been simulated to investigate the molten pool features of EH36 shipbuilding steel.One case only involved the surface tension model,and another one involved both the surface tension model and the interface tension model.The role of interface tension during welding is revealed,and the evolution of molten pool morphology is understood by comparing the surface temperature distribution,surface tension and interface tension distribution,and the streamline of the molten pool for the two cases.When the interface tension model is disregarded,a flow conducive to the outward expansion is formed in the surface area of the molten pool,resulting in a small weld depth-to-width ratio.After applying the interface tension model,the expanding outward flow is restrained,which leads to a deep penetration morphology with a large weld depth-to-width ratio due to the inward flow governed by the Marangoni forces.The simulation results involving the interface tension model have been verified with satisfactory predictability.

Automation Technology in Welding Seam Welding Machining Design

With the continuous development of society,the gradual improvement of mechanical automation technology has been introduced into the production of many enterprises in China,which has had a great impact on the increase of China′s gross national product.Applying mechanical automation technology greatly saves labor cost,improves working efficiency and the production level of enterprises,effectively promotes the development of enterprises,and increases the enterprise′s income.In addition,mechanical automation technology is closely related to product production⁃related technology and plays a very important role in the innovation of enterprise products.This article will briefly introduce the design and application of automation technology in welding seam welding design,and understand the development background,research status,current application and simulation design.

Discussion on Construction Technology and Welding Deformation of High-Rise Steel Frame Structure

Because of urbanization,land resources in China’s cities has become increasingly scarce.Therefore,modern buildings are becoming taller,making high-rise steel frame structures the new favorite of the construction industry.However,the construction of high-rise steel frame structures requires advanced technology.If the construction technology is effectively implemented and the welding techniques of the construction personnel align with the requirements for high-rise steel frame structures,it can help mitigate deformations in the steel structure,thus preserving the overall construction quality of high-rise steel frame structures.To enhance the applicability of steel frame structures in high-rise buildings,this paper focuses on analyzing the optimization path for the construction process of high-rise steel frame structures.It introduces a tailored approach to control welding-induced deformations in steel frame structures,aiming to make a valuable contribution to the advancement of China’s construction industry.

Heterogeneous Microstructure-Induced Mechanical Responses in Various Sub-Zones of EH420 Shipbuilding Steel Welded Joint Under High Heat Input Electro-Gas Welding

Heterogeneous microstructure-induced mechanical responses in EH420 shipbuilding steel welded joint by electro-gas welding processed have been systematically studied by scanning electron microscopy,electron backscatter diffraction and mechanical testing.Comparing with the coarse-grained heat-affected zone(CGHAZ),the weld metal presents higher toughness(129.3 J vs.37.3 J)as it contains a large number of acicular ferrites with high-angle grain boundaries(frequency 79.2%)and special grain boundary∑3(frequency 55.3%).Moreover,coarse austenite grains in CGHAZ and slender martensite–austenite constituents between bainite laths may likely facilitate crack propagation.Polygonal ferrites and tempered pearlites formed at the junction of the fine-grained heat-affected zone and the intercritical heat-affected zone induced a softened zone with an average hardness of 185 HV0.5,which is the main reason for the occurrence of tensile fracture.

Application and prospect of computer technology in welding materials field

This paper summarizes the application status of computer technology in welding materials field from three aspects: the CAD of welding materials, the date base system for welding materials and the expert system for welding materials .Besides, this paper explores and discusses the existing problems and the developing trend in the future.

高温合金熔化焊的研究现状及发展趋势

综述了高温合金熔化焊的研究进展.对电弧焊、电子束焊和激光焊等常见高温合金熔化焊工艺技术的优势和应用范围进行了阐述;介绍了常见的焊接裂纹类型,并对凝固裂纹、晶界液化裂纹、应变时效裂纹和失塑裂纹的形成机理及影响因素进行了概括总结;此外,从热输入、材料的成分和微观结构以及焊接残余应力等方面探讨了提高熔化焊焊接性的主要技术方法.由于母材合金成分和组织结构与焊接性能密切相关,在未来的发展中,应加强对新兴高温合金和传统不可焊高温合金等的成分设计,此外,也应关注焊接工艺技术的完善以及焊前和焊后处理方法的改进,协同提高高温合金的焊接性能,促进高温合金熔化焊的广泛应用.

造船焊接工艺评定系统设计与实践

为提高焊接工艺评定效率,设计了造船生产的焊接工艺评定系统。在焊接工艺评定数据流自动导入设计的基础上,通过置入规范要求条款、将焊接工艺纳入船舶分段项目式管理、以及工艺的预测等,完成了具有船企特征和智能化特征的焊接工艺评定系统的设计。焊接工艺评定系统投入使用后,提升了焊接工艺评定效率,节省了焊接工艺评定成本,有效疏通了与上游生产设计和下游焊接生产管理的信息交互。

980MPa级先进高强钢的发展

选用轻量化汽车材料时应综合考虑材料的性能、质量和成本。目前,先进高强钢被广泛用于汽车工业。先进高强钢有双相钢、相变诱导塑性钢、马氏体钢、复相钢、淬火-配分钢、DH钢等。综述了980 MPa及以上高强钢的分类和主要钢种,汽车用高强钢的化学成分、显微组织、力学性能和使用性能,并结合实际零件的制造过程对这些高强钢的焊接和成形性能作了较深入的探讨,简述了其发展现状和研究进展。

探究汽车工业机器人中的机电一体化技术

研究探索机电一体化技术在汽车工业机器人中的应用,为了满足汽车焊接生产对安全性和效率的高要求,提出焊接机器人工作站设计,并使用蚁群算法对焊接机器人路径进行优化。实验结果表明,该路径规划与焊接机器人的实际工作情况吻合较好,设计的焊接机器人性能表现优越。

激光技术在塑料加工中的应用与案例

激光技术在工业中应用得到了很大的发展,尤其在塑料加工中应用逐步取代传统的加工方式,这对塑料加工质量和加工效率等都有较好地成效。本文就激光原理、特点与类型作些介绍,围绕了激光技术在塑料加工中应用作了描述,结合对3D打印、切割(打孔)、焊接、表面打标、表面处理、表面清洗等原理和应用案例进行详细分享,并对激光在塑料加工中应用趋势作些预料。

火炮摇架焊缝缺陷智能分类

针对火炮摇架结构复杂,焊缝内部缺陷检测效果不理想,选择对非平面物体和复杂结构体均适用的超声相控阵检测技术对摇架焊缝缺陷进行检测。将得到的超声相控阵图谱与ResNeXt网络模型相结合,实现焊缝缺陷的智能分类。将SK卷积单元引入ResNeXt网络模型,对摇架焊缝缺陷进行定性分析。改进后的网络模型比原ResNeXt网络的分类准确率提升5.5%,最终达到98.2%。

Study of microstructures and properties for girth weldingof domestic X70 pipeline steels

With the development of domestic pipeline steels, it is necessary to develop suitable welding technology which can improve the properties of the welded pipeline. In this paper, the microstructures and mechanical properties of domestic XTO pipeline steels and welded joints are discussed. The welding consumables of BOHLER E6010 and HOBART 81N1 are matched for girth welding. The following characteristics in heat-affected zone（ HAZ） are indicated that microstructures of intercritical HAZ（ ICHAZ） is finer and more uniform, the grain sizes of fine-grain HAZ （ FGHAZ） and subcritical HAZ （ SCHAZ） are smaller than that of coarse-grain HAZ（ CGHAZ）. The hardness, tensile strength and toughness of welded joints come up to the standard. The micrographs of impact specimens in welded joints are cleavage, quasi-cleavage and dimple which shows there is typical ductile rupture.

浮空器囊体材料用焊接胶对热合焊接工艺适应性分析

本文结合浮空器囊体加工过程中的工艺要求,围绕提高囊体材料热合焊接强度、热合焊接效率和热合焊接工艺可实现性等要求,基于开发的双组份囊体材料用焊接胶,从热合焊接参数的边界条件、焊接胶稳定性及适用期、热封层开放时间、施胶的胶量范围四个方面,对热合焊接工艺窗口进行分析,确认该型焊接胶对囊体材料加工工艺适应性,为其在工程应用提供工艺参考。