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Amid the global trend toward energy transition, hydrogen energy is gradually becoming a focal point in the energy sector thanks to its significant advantages of being clean, efficient, and sustainable. **Strong support for the hydrogen energy industry has provided significant impetus for its development, and it has also placed the welding technology associated with it at a new historical milestone, making its importance even more evident. On December 30, 2024, three ministries and commissions including the Ministry of Industry and Information Technology jointly issued the \"Implementation Plan to Accelerate the Use of Clean and Low-Carbon Hydrogen in the Industrial Sector.\" The plan specifies that by 2027, positive progress should be made in the development of equipment and technologies related to the use of clean and low-carbon hydrogen in the industrial sector. Clean and low-carbon hydrogen should be used on a large scale in industries such as metallurgy, ammonia synthesis, methanol production, and petrochemical processing, and it should also be utilized in pilot projects in areas such as industrial green microgrids, ships, aviation, and rail transport. A number of commercial application models for hydrogen in transportation, power generation, and energy storage should be established. The introduction of this policy signifies that the hydrogen energy industry is poised for rapid development. A large number of projects related to the manufacturing of hydrogen energy equipment are set to be launched. As a crucial step in equipment manufacturing, welding plays a vital role; the quality and safety of the equipment depend on the proficiency of welding techniques. This, in turn, affects the overall development trajectory of the hydrogen energy industry. “ Prevention of hydrogen embrittlement: Dual breakthroughs in process innovation and material development. In the manufacturing of hydrogen energy equipment, hydrogen embrittlement represents a long-standing technical challenge that poses a serious threat to the quality and safety of welded joints. During the thermal cycling involved in welding, hydrogen atoms readily diffuse into the metal lattice, resulting in a sharp decrease in the material’s toughness and strength; this can even lead to catastrophic consequences. With the rapid development of the hydrogen energy industry, especially driven by the \"dual carbon\" goals, solving the problem of hydrogen embrittlement has become a key technical challenge that the industry urgently needs to overcome. Process innovation: Controlling the source of hydrogen at the source is key. By optimizing the purity of the welding gas and reducing the inclusion of moisture and impurities, the introduction of hydrogen atoms can be significantly reduced. For example, by using ultra-high-purity argon gas (with a purity of ≥99.999%) as the shielding gas, along with a drying system whose dew point temperature is below -60°C, the concentration of diffused hydrogen in the weld can be kept below 2 ml/100g, which represents a reduction of over 60% compared to traditional processes. Furthermore, precisely controlling the parameters of the welding heat cycle (such as peak temperature and cooling rate) and reducing the high-temperature dwell time can effectively decrease the diffusion rate of hydrogen atoms into the metal lattice. Materials research and development: Developing new welding materials with special alloy compositions and microstructural characteristics is another important direction. For example, adding trace amounts of hydrogen-trapping elements such as Ti and Nb can form stable hydrides at grain boundaries, preventing the aggregation and diffusion of hydrogen atoms. Japan’s JIS Z3118 standard specifies that the hydrogen content in the welds of hydrogen-related equipment must be below 5 ml/100g, providing clear technical specifications for material development. High-precision welding: Process innovations in hydrogen fuel cell manufacturing. In the production of hydrogen fuel cells, key components such as electrodes and flow channels require extremely high standards regarding dimensional accuracy and welding quality. Even the slightest dimensional deviations or welding defects can lead to a significant decline in battery performance, severely affecting its service life and energy conversion efficiency. Laser welding and electron beam welding: Advanced laser welding and electron beam welding technologies have become key to solving this problem. The industrialization breakthrough of domestically produced 500W-class blue laser lasers has increased the absorption rate of copper materials by short-wavelength 450nm lasers by more than 3 times, allowing the welding deformation to be kept within ±5μm. With a six-axis robot system equipped with visual guidance, domestic companies have achieved ultra-high-speed precision welding at 12 solder joints per second, achieving a yield rate of 99.98%. Process optimization: By optimizing welding parameters such as power, frequency, and focusing position, defects like pores and cracks can be effectively reduced, thereby significantly improving the performance and lifespan of hydrogen fuel cells. Material compatibility: Welding techniques for gradient functional materials and dissimilar materials. The manufacturing of hydrogen energy equipment involves various special materials, such as high-strength alloy steels, aluminum alloys, and various composite materials. These materials each possess unique physical and chemical properties, and during welding, complex chemical reactions can easily occur between different materials, resulting in the formation of brittle intermetallic compounds that significantly affect the strength and corrosion resistance of the welded joint. Applications of gradient functional materials: For welding dissimilar materials such as titanium/aluminum composite structures, gradient functional materials exhibit great potential. By pre-depositing a nanosstructured Ni-Ti interlayer at the welding interface, the formation of the brittle TiAl3 phase can be effectively suppressed, raising the joint strength to over 85% of that of the base material. The Ministry of Industry and Information Technology’s \"Guidance Catalogue for the Pilot Application of Key New Materials in Their First Batch\" includes such materials within the scope of subsidies, and it is expected that the market size for these materials will exceed 2 billion yuan by 2025. Customized welding processes: Customized welding processes need to be developed based on the welding properties of different materials. For example, for welding aluminum alloys and steel, friction stir welding (FSW) or laser-arc hybrid welding can be employed; by precisely controlling the heat input and interfacial reactions, weld joints with high strength and excellent corrosion resistance can be achieved. Intelligent detection: A multi-physics-field integrated quality control system. The safety of hydrogen energy equipment is of paramount importance, as any potential welding defects can lead to serious safety accidents. Traditional welding quality inspection methods, such as visual inspection and ultrasonic testing, have certain limitations in terms of inspection accuracy and the ability to detect minor defects, making it difficult to meet the stringent requirements for welding quality in hydrogen energy equipment. AI-based non-destructive testing technology: The \"acoustic-optical-thermal\" multi-sensor integrated testing device developed by Hainan University of Technology can, by collecting plasma spectrum data, acoustic emission signals, and infrared thermal imaging data from the welding process and utilizing deep learning algorithms, detect micro-cracks as small as 0.05 mm in real time. This technology has been included in the \"Guidelines for the Development of Standards in the Hydrogen Energy Industry,\" and it is expected to reduce testing costs by 40% and increase testing efficiency by 300%. Digital twin technology: By creating a digital twin model of the welding process, real-time monitoring and prediction of welding quality are possible, thereby providing a solid guarantee for the safe operation of hydrogen energy equipment. Conclusion: The rise of the hydrogen energy industry has brought unprecedented challenges and opportunities to welding technology. Through coordinated breakthroughs in multiple dimensions—such as process innovation, material research and development, and intelligent inspection—welding technology will provide robust support for the high-quality development of the hydrogen energy industry. Driven by both policy support and technological innovation, China is poised to take a leading role in the global hydrogen energy revolution, offering Chinese wisdom and solutions to the global energy transition. What are your views and expectations for the future development of the hydrogen energy industry and welding technology? 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