The outstanding performance of steel blocks in high-pressure applications primarily stems from their inherent material strength and designability. Take deep-sea exploration equipment as an example. The pressure-resistant cabin made of 4340 chromium-molybdenum alloy steel has a yield strength of up to 860 megapascals and can withstand a hydrostatic pressure of approximately 110 megapascals at a depth of 10,000 meters underwater, which is equivalent to the load of 1.1 family cars parked on an area of 1 square centimeter. The HY-100 special steel blocks used in the spherical shell of the manned submersible Arvin of the Woods Hole Oceanographic Institution in the United States have been precisely calculated. When the wall thickness is 120 millimeters, the blasting pressure exceeds 150 megapascals, and the safety factor is set at 1.5 to ensure that the deformation is less than 0.05% when working at a depth of 6,000 meters.
Through the collaborative design of heat treatment and structural optimization, the pressure-bearing capacity of steel blocks can be significantly enhanced. The P110 oil casing steel was subjected to quenching and tempering treatment (quenching + tempering at 580℃), and its resistance to crushing pressure increased from 55 megapascals in the conventional state to 85 megapascals, with an increase of 54%. More advanced technologies such as isostatic pressing processing enable large steel blocks to densify in an environment of 1200 degrees Celsius and 100 megapascals of argon gas, reducing the internal porosity from the initial 0.3% to 0.01%, thereby increasing the fatigue life to over 10^7 cycles. The reactor pressure vessel of China’s “Hualong One” nuclear power plant adopts SA-508Gr3Cl2 steel blocks. Through triple heat treatment process, the impact energy at -20℃ is maintained at more than 150 joules, and it can operate safely for 60 years under a working pressure of 17.5 megapascals.
In extreme dynamic pressure scenarios, the energy absorption characteristics of steel blocks are particularly crucial. Ballistic protection tests show that the AR500 wear-resistant steel block with a thickness of 200 millimeters can withstand the impact of armor-piercing projectiles with an initial speed of 950 meters per second. The peak deceleration of the projectile reaches 15,000 grams, and the height of the deformation and protrusion on the back of the steel plate is controlled within 3 millimeters. In contrast, Invar steel blocks (containing 36% nickel) used in the aerospace field have a thermal expansion coefficient of less than 1.5×10^(-6)/K within the temperature range of -196℃ to 200℃, ensuring that the dimensional stability error of liquid oxygen storage tanks does not exceed 0.1 mm under a working pressure of 21 megapascals.
From the perspective of full life cycle cost analysis, the selection of high-pressure steel blocks directly affects the reliability of the system. According to the 2023 report of Det Norske Veritas, the use of forged steel blocks with optimized design instead of cast steel parts to manufacture the valve bodies of subsea oil trees, although the initial cost increases by 25%, extends the maintenance cycle from 5 years to 15 years and reduces the failure probability from 3% to 0.5%. For instance, in the Brazilian subsalt oilfield project, the high-pressure steel block assembly used, through computer simulation, optimized the stress concentration coefficient from 2.8 to 1.3, reducing the annual unplanned downtime of the equipment under 70 megapascals by 85%, and saving approximately 1.2 million US dollars in operating costs annually for a single system.
Innovative materials engineering is continuously expanding the pressure tolerance boundaries of steel blocks. The latest gradient structure steel block developed by the Metal Composite Materials Laboratory has a surface hardness of HV600 while maintaining the toughness of HV250 in the core. In the variable-amplitude pressure test simulating shale gas extraction (with a pressure fluctuation range of 20-140 megapascals and a frequency of 0.5Hz), its crack growth rate is 60% lower than that of the homogeneous steel block. This technology has been applied to the constrained steel blocks of Tesla’s 4680 battery module. Under a stacking pressure of 200 tons, it still maintains a flatness of 0.01 millimeters, significantly increasing the energy density of the battery pack to 300Wh/kg while reducing the risk of thermal runaway by 40%.