Recently, the scientific research achievement of ‘Development and Application of High-strength Easily Welded Thick Plates and Supporting Welding Materials and Welding Technology Used for Large Hydropower Stations’ led by the Shougang Institute of Technology and Qinhuangdao Shouqin Metal Materials Co., Ltd., in which such units as the University of Science & Technology Beijing, Sinohydro Bureau 7 Co., Ltd. and Tianjin Bridge Welding Materials Group Co., Ltd. also jointly participated, passed the achievement appraisal of the Chinese Society for Metals. The overall technology of the project has reached the international advanced level, of which the steel utilization manufacturing and supporting welding integrated technology of high head large power stations has reached the international leading level.

About 70% of the electric power structure of our country is thermal power, but with the promotion of requirements for environmental protection, it has become a national strategy to develop clean energy. Hydropower proves to be first and foremost a kind of clean energy as it accounts for over 60% of the total clean energy of our country. In order to improve the generating efficiency of hydropower stations, the design of water heads and installed capacity have constantly been improved both at home and abroad. The pressure pipelines are the aorta of hydropower stations, so their steel utilization has been developed in the direction of extreme thickness, high strength, high durability and easy welding. For a long period of time, China has been dependent on import for the extra-thick steel plates of 120-150 mm used for branch pipes and 800 MPa-level welding materials, and such problems as high preheating temperatures and narrow welding windows have also existed, thus making it hard to satisfy the requirements for field welding and complex service conditions, as well as severely limiting the upgrading and updating of large power stations.

The Shougang Group has taken the lead in starting with the requirements of the hydropower industry of our country, made joint efforts with the Power Construction Corporation of China and China Energy Engineering Corporation Limited, and after 8 years of tackling key problems, made breakthroughs in such difficulties as the design and manufacturing of easily welded high-strength and ultra-thick hydropower steel of 600 to 800 MPa under many restrictive conditions, including the realization of low preheating, low quenching tendency, adaptation to great heat input and low strain aging sensitivity with low alloy addition amount; adopted original quenching and tempering technology to realize the refinement of the heart of bainite structures; broken through the technical bottleneck in the 150 mm ultra-thick plates used for branch pipes with low a compression ratio, as well as the continuous casting process for the production of the heart part performance, thus getting out of the situation of long-term dependence on import; developed integrated welding joint metal fine structure control technology and the low-hydrogen high-fluidity welding rod coating design scheme, and was the first to develop 800 MPa-level supporting ultra-low hydrogen welding materials that are suitable for 50 kJ/cm large heat input welding, filling both the domestic and international gaps in this field. On the basis of solving a series of technical bottlenecks concerning the manufacturing and application of high-strength and ultra-thick hydropower steel, the Group has for the first time put forward an integrated solution concerning easily welded and high-strength hydropower steel plates, welding materials and supporting welding process that can satisfy the construction and service of pressure pipelines of high head large hydropower stations.

Thanks to the joint efforts of generations of technicians, the 600-800 MPa high-strength hydropower products of the Shougang Group were first applied in Guandi Hydropower Station, full supply of the whole power station has been realized in Murum Hydropower Station of Malaysia, and XPXN Power Station in Laos has provided users with an integrated solution concerning products and welding. In this process, the hydropower products of the Shougang Group have undergone a development history of growing out of nothing and changing from weak to strong. Currently, such products have also been applied in many large hydropower stations both at home and abroad, including Tarbela Power Station in Pakistan, Gibb III Power Station in Ethiopia and Xianju Power Station. As of 2016, hydropower products have created an accumulative economic benefit of more than RMB 20 million for the Shougang Group, and over 10 core technology patents have been authorized in this field. The implementation of this project has not only provided strong support for the technology upgrading of the hydropower industry of our country, but also increased the influence of China’s hydropower industry on countries along the route of ‘One Belt and One Road’, which is of great significance for promoting the export of the dominant manufacturing capacity of our country.