Development of vacuum heat treatment furnace vacuum technology

Development of vacuum heat treatment furnace vacuum technology

Development of vacuum heat treatment process is inseparable from the development of equipment to improve the level of equipment and technology to adapt to the technological requirements, they often closely associated with the development of technology supporting parts.
Pump development
Before 1873 incandescent bulbs invention, is mainly obtained by a piston-type air pump vacuum, but only reached 0.25 Torr. Then a higher degree of vacuum tube manufacturing technology requirements, promoting the development of vacuum technology, which have appeared in a variety of pumps: rotary mercury pump (1905), oil seal rotary pump (1907), molecular pump (1913) and diffusion pump (1915). The invention of which the diffusion pump, the vacuum technology into the high vacuum (10-8 hair around) stage. With the development of modern science and technology, such as accelerators, thermonuclear reactor, large vacuum care, etc., are required to be able to establish the necessary degree of vacuum in the space of a large volume. Thus, by the early 1960s, the diffusion pump exhaust rate has reached capacity of tens of thousands liters / sec.
However, the required vacuum heat treatment, the general reach 1x10-2 ~ 1x10-4 Torr enough, only in exceptional circumstances, only with 1x10-5 ~ 1X10-6 Torr. So common vacuum pump vacuum heat treatment furnace, by a mechanical pump and an oil diffusion pump composed of evaporation.