Our company is the production roll forming machine.
1. Early:
1. Salt-bath furnace (but environmental pollution, and can only be applied to small and medium-sized parts, and the slow start (2-3 hours), only applies to high-volume continuous production.
2. Box-type furnace: spare parts buried in pig iron at the end of temperature (950 degrees Celsius), parts of stainless steel skin package. Packing method: (high temperature), more than 950 degrees Celsius
II. The use of paint (bearing industry is still widely used)
III. The protection of the atmosphere (which in recent years the use of)
1. Exothermic-type atmosphere: CH4, C3H8 + air ----( generated) H2 + N2 + H2O + CO + CO2 ----- (dehydration generated) N2-based and H2 (per 1 -- 20), such an atmosphere of carbon steel suitable for low-light handling, and low cost.
2. Endothermic-type atmosphere: RX atmosphere (40CO + per cent per 40N2 + per 20H2)
High and low temperature cracking of methanol CH3OH ---- 2H2 + CO (carburizing furnace to use more)
Ammonia decomposition: 2NH3 ---- N2 +3 H2 (furnace with the use of high-Wimbledon more)
3. Nitrogen-based atmosphere: (the use of the more common abroad, but higher costs)
(1) more than 99% of N2, plus a small amount of CO, H2
(2) The ratio of type: N2 + CH3OH ---- H2 + CO
4. Super Carburizing: acetone plus air, mixed-use instruments, a high carbon potential to improve the content of acetone, as the contrary.
Temperature choice: the depth of the high permeability of the workpiece from high temperature, depth of seepage from low temperature
Advantages: a large quantity of loaded furnace, soaking a long time.
Depth and carburizing carburizing time exponential relationship:
Carburizing the workpiece depth :0.8-1 .2 mm 3.5 hours
2.1-2.7mm 17 hours MechNet