In 1795, the British inventor J. Bramah applied Pascal's principle to invent the hydraulic press, initially using it for applications such as baling and extracting vegetable oil. By the mid-19th century, Britain began employing hydraulic presses for forging, leading to their gradual replacement of massive steam forging hammers. By the end of the 19th century, the United States had constructed a 126,000 kN free-forging hydraulic press. Subsequently, more than twenty free-forging hydraulic presses in the 100,000 kN class were built worldwide, two of which were manufactured in China (see color plate). With the advent and refinement of electric high-pressure pumps, the development of forging hydraulic presses also expanded to include lower-tonnage models.
Small, high-speed forging hydraulic presses emerged after the 1950s, capable of performing work equivalent to that of 30–50 kN forging hammers. In the 1940s, Germany built a massive 180,000 kN die-forging hydraulic press; since then, eighteen die-forging hydraulic presses with capacities exceeding 180,000 kN have been built globally, including one manufactured in China with a capacity of 300,000 kN.
