Recently, approved by the People’s Government of Beijing Municipality, the winners of the 2020 Beijing Science and Technology Awards were officially announced. The project “Integration and Innovation of Key Technologies in Manufacturing and Application of High-Safety Automobile Steel” led by the Shougang Group won the first prize of the Beijing Science and Technology Progress Awards.

In 2009, China’s automobile output ranked first in the world, but its development and application of automobile steel lagged far behind the international advanced level. The maximum strength of domestic automobile steel used in batches was only 800 MPa, with an import ratio as high as 50%. Meanwhile, ultra-high strength steel of 1,000 MPa and above had been applied abroad, but the related standards in China were still blank. In recent years, with the development and promotion of 1,200 MPa grade cold-formed steel and 1,800 MPa grade hot-formed steel by foreign advanced iron and steel enterprises, automobile lightweight technology has increasingly become the focus of the industry. However, there remain several industrial difficulties that have not been effectively solved, such as the uneven size and performance of ultra-high strength steel parts, insufficient elongation of steel plates and poor surface quality, which are the main obstacles to its application. To comply with the lightweight trend and improve the production capacity and technical level of ultra-high strength steel in China, the Shougang Group joined forces with the BAIC Group, USTB, etc., to establish the “Industry-University-Research-Application” Joint Research Team. With the support of NSFC and the Beijing Science and Technology Program, the series of 600–1,200 MPa cold-formed steel and 1,500–1,800 MPa hot-formed steel were successfully developed after ten years, solving common difficulties in the development and application of ultra-high strength steel, and realizing innovative breakthroughs and technological leadership.

This project pioneered the high-precision prediction model of hot-formed parts, which solved the difficulties of the inaccurate control of the microstructures and properties of hot-formed parts, and the springback of cold-formed parts. The prediction accuracy of hot-formed parts has exceeded 95%, and the springback of cold-formed parts has been controlled within ± 0.5 mm. A method for evaluating the edge crack sensitivity of cold-formed high-strength steel and extreme cold-bending crack sensitivity of hot-formed steel was developed, and the influence law of material physical properties on these two kinds of crack sensitivity was revealed. As a result, the edge crack rate of cold-formed high-strength steel dropped below 2%, the extreme cold-bending angle of hot-formed steel increased by more than 10 degrees, and the cracking difficulty of high-strength steel changed from “post-analysis improvement” to “pre-prediction adjustment”, which greatly improved the production efficiency of automobile enterprises and reduced their cost loss. A series of 590–980 MPa enhanced formability dual-phase steel products was launched in China for the first time, solving the difficulties of insufficient formability, high punching cracking rate and poor plating ability of traditional dual-phase steel. The elongation of the first series of products was higher than that of traditional dual-phase steel by more than 32%, a new idea for structural control was put forward, and a series of 780–1,180 MPa multiphase steel products was developed. The qualified rate of the spatial dimensions of automobile parts made from such steel increased to over 96%, realizing the exclusive supply of some parts of high-end automobile enterprises such as Beijing Benz, and solving the “bottleneck”. With the above R&D achievements, this project obtained 23 patents, formulated one ISO international standard and filled in three gaps in the national standards.

By the end of the project, the domestic market share of Shougang’s enhanced formability dual-phase steel series products had reached 100%, and this automobile sheet took first place at the BAIC Group. The successful development of Shougang’s high-safety automobile steel strongly supports the lightweight trend of new energy automobile bodies, realizes the substitution of imported products and greatly contributes to promoting the localization of high-end materials.