When evaluating critical components used to withstand extreme pressures above 100 megapascals, forged steel becomes the preferred material due to its unparalleled mechanical properties. According to a study in the Journal of Pressure Vessel Engineering in 2023, under the same pressure load, the failure probability of forged steel components is 75% lower than that of cast steel, and the median tensile strength can reach 860 megapascals, which is much higher than the 550 megapascals of cast materials. For instance, in the oil drilling platform in the North Sea, BP’s oil tree valve body made of forged steel successfully withstood wellhead pressure exceeding 80 megapascals, extending the equipment’s service life from 15 years to 30 years and reducing maintenance costs by 40%. This reliability stems from its dense grain structure, with grain size controllable below 20 microns and an internal defect rate of less than 0.02%, which makes its safety factor under high pressure reach 4.0, far exceeding the industry standard of 2.5.
From the perspective of materials science, the forging process, by applying a pressure of over 8,000 tons and operating at a temperature of 1200°C, aligns the grain flow direction of the billet with the stress direction, thereby increasing the fatigue life to more than 10^7 cycles. The ASME BPVC Section VIII code of the American Society of Mechanical Engineers stipulates that forged steel used for high-pressure vessels must undergo 100% ultrasonic testing to ensure that the defect size is less than 1.5 mm and the testing accuracy reaches 99.9%. A typical case is that in the aerospace field, SpaceX’s Raptor rocket engine uses forged steel propellant delivery pipelines, which can operate stably at a pressure of 300 bar and an extremely low temperature of -180°C, keeping the fuel flow error within ±0.5%, a level of precision that cannot be achieved with cast or welded structures.
Although the initial cost is about 15% to 20% higher than that of cast components, the total life cycle cost of forged steel in high-pressure applications is actually 30% lower, thanks to its outstanding durability and almost zero risk of unexpected downtime. A cost-benefit analysis of the chemical industry shows that for a high-pressure reactor project with a budget of 5 million US dollars, although the initial investment increased by 600,000 US dollars by choosing forged steel inner tanks, the net income increased by approximately 2 million US dollars during the 10-year operation period due to the reduction of two unplanned outages and one replacement, and the return on investment increased by 25%. This long-term economic benefit, coupled with its stability of withstanding peak pressure fluctuations of no more than 5% of the rated value, makes it an inevitable choice for chemical giants like BASF when building new high-pressure polymerization facilities.
Of course, material selection also needs to be balanced. For instance, in non-load-bearing components with a pressure lower than 50 megapascals and extremely complex shapes, casting or additive manufacturing may be more cost-effective, and the deviation range can be relaxed to ±10%. However, looking at energy, aerospace and heavy industry, from hydrogen storage tanks that withstand 70 megapascals of pressure to hydraulic machine spindles with peak loads of up to 500 tons, forged steel, with its well-tempered integrity, has built the cornerstone of modern high-pressure engineering. As pointed out in the 2022 International Energy Agency report, in the transition to clean energy, the demand for high-voltage technology is growing at an annual rate of 8%, and the reliability of forged steel will be a core element in ensuring the security of global energy infrastructure.