During the "12th Five-Year Plan" period, R&D and production of high-performance, low-cost weathering and corrosion-resistant steel will be one of the main tasks for optimizing the variety structure in the steel industry. Besides the traditional industries such as containers, railway locomotives and vehicles, and bridge construction that use weathering and corrosion-resistant steel, some new fields have also started adopting weathering and corrosion-resistant steel, such as the shipbuilding industry.
For special requirement engineering machinery plates, apart from the general requirements of strength, stiffness, and weldability, they should also possess wear resistance, impact resistance, fatigue resistance, low-temperature toughness, and corrosion resistance. Special requirement engineering machinery plates are key varieties for future development.
New requirements for steel production and use in building steel structures. From the perspective of safety and performance analysis, high toughness and low yield-to-strength ratio are required. To improve processability, carbon equivalent and crack sensitivity coefficient need to be reduced, while also having a certain ability to resist layered tearing. Considering durability and safety, corrosion resistance, weather resistance, fire resistance, and earthquake resistance are required.
Green environmental protection for ships imposes new requirements on steel. Nippon Steel and Japan ___ Shipping Co., Ltd. cooperated to develop and practically apply high corrosion-resistant thick steel plates for the bottom surface of oil tanker oil tanks, which was the first in the world. This steel plate was developed to prevent the corrosion of the bottom surface of oil tanks caused by oil leakage accidents, thus enhancing the safety of ships and protecting the global environment. The corrosion resistance of this steel plate is about five times that of ordinary thick steel plates, and no anti-corrosion coating is needed, so there's no need to use paint and organic solvents, making ships environmentally friendly.
New requirements for steel under harsh geological conditions and new processes in the petroleum industry. Key advanced products include X80 grade welded pipes with better performance, X90 and higher grade welded pipes, high-strength steel pipes meeting -45°C low-temperature toughness requirements, anti-large deformation pipeline steel and welded pipes, deep-sea oil and gas pipeline steel pipes, and acid service steel pipes.
High-performance steel for bridges. Compared to previous ones, further improvements in the strength, fracture toughness, weldability, corrosion resistance, and machinability of bridge steel are required. These materials bring all properties to their optimal range, which is called "high-performance steel BHS."
Requirements for steel due to mechanical product upgrades. In traditional equipment manufacturing, engineering machinery steel develops towards high strength, high wear resistance, and special performance steel; wind power equipment needs to increase the life of bearing steel, which requires improving the purity of bearing steel (reducing inclusions); heavy machinery forgings need to solve machining capability and heat treatment levels; general machinery steel needs to develop into easy-cutting steel, non-tempered steel, bright steel, etc.
The proportion of high-strength steel plates used in automobiles will further increase. Currently, the strength of automobile steel plates has been improved from 200~300MPa level to 500~1000MPa level, significantly enhancing the strength level of automobile steel. In the future, the proportion of ultra-high-strength steel exceeding 590MPa level will further increase, gradually aligning with international standards.
Container steel tends to become lightweight and thinner, reducing weight while expanding the effective volume rate of containers. The proportion of thin container plates will increase significantly. Moreover, to meet the needs of transporting different types of goods, specialized containers such as insulated containers, tank containers, pallet containers, and animal containers have emerged and developed rapidly. These changes in demand have raised higher requirements for the material quality and corrosion resistance of steel, increasing the demand for duplex stainless steel and low-alloy structural steel resistant to low temperatures (-60°C).
Trend of steel reduction. As the strength of steel increases and its thickness decreases, the market trend downstream is towards steel reduction. Under "low-carbon" pressure, steel usage standards will be improved, and "steel reduction" will become a trend. Industries using steel such as construction, automobiles, home appliances, containers, and engineering machinery have proposed "12th Five-Year Plan" requirements for saving steel usage through high strength, corrosion resistance, light weight, long life, and recyclability, which will affect the increase in the quantity of steel and influence the improvement in steel quality.
Reinforced concrete buildings require higher strength grades of steel. Among the 130 million tons of construction reinforcement bars, 60% are Grade I and Grade II steel bars with yield strength less than 335 MPa. Promoting hot-rolled steel bars with more than 400 MPa can reduce the consumption of steel bars by about 10 million tons. Starting from July 1, 2011, the GB50010-2010 "Code for Design of Concrete Structures" was implemented, requiring priority use of 400 MPa grade steel bars, actively promoting 500 MPa grade steel bars, replacing HPB235 smooth round steel bars with HPB300 smooth round steel bars, gradually reducing the use of 335 MPa grade steel bars, and eventually eliminating this variety.
New features of steel for home appliances include tendencies towards light weight, aesthetics, and energy savings. With the upgrading and replacement of home appliances, the proportion of coated steel plates, stainless steel plates, aluminum-zinc-coated plates, wide-width plates, and other plates with high surface requirements in home appliances has increased, as well as the demand for new functional steel plates such as antibacterial and heat dissipation properties. The demand for high-grade electrical steel, high-strength steel plates, hot-rolled pickled plates, and environmentally friendly post-treatment steel plates is rapidly increasing.
Comprehensive performance requirements for steel include wear resistance, impact resistance, fatigue resistance, low-temperature toughness, and corrosion resistance. Corrosion-resistant and weather-resistant steel will be more widely applied. Compared to ordinary carbon steel, the corrosion resistance of corrosion-resistant and weather-resistant steel has improved 2 to 8 times, thus having advantages such as long life, resource saving, and reduced energy consumption, widely applied in industries such as containers, railway locomotives and vehicles, bridge construction, marine engineering, and petrochemical equipment. Currently, the development of tall buildings and steel structures, the construction of cross-sea bridges, offshore oil platforms, and the development of supercritical and ultra-supercritical thermal power units, as well as the industrial upgrading of the petrochemical industry, have continuously raised requirements for the corrosion resistance of weather-resistant and corrosion-resistant steel. Cone Crusher