annealing furnace
annealing furnace 2
annealing
Full Annealing
Full annealing is the process of slowly raising the temperature about 50 ºC (122 ºF) above the Austenitic temperature line A3 or line ACM in the case of Hypoeutectoid steels (steels with < 0.77% Carbon) and 50 ºC (122 ºF) into the Austenite-Cementite region in the case of Hypereutectoid steels (steels with > 0.77% Carbon).
It is held at this temperature for sufficient time for all the material to transform into Austenite or Austenite-Cementite as the case may be. It is then slowly cooled at the rate of about 20 ºC/hr (36 ºF/hr) in a furnace to about 50 ºC (122 ºF) into the Ferrite-Cementite range. At this point, it can be cooled in room temperature air with natural convection.
The grain structure has coarse Pearlite with ferrite or Cementite (depending on whether hypo or hyper eutectoid). The steel becomes soft and ductile.
Process Annealing
Process Annealing is used to treat work-hardened parts made out of low-Carbon steels (< 0.25% Carbon). This allows the parts to be soft enough to undergo further cold working without fracturing. Process annealing is done by raising the temperature to just below the Ferrite-Austenite region, line A1on the diagram. This temperature is about 727 ºC (1341 ºF) so heating it to about 700 ºC (1292 ºF) should suffice. This is held long enough to allow recrystallization of the ferrite phase, and then cooled in still air. Since the material stays in the same phase through out the process, the only change that occurs is the size, shape and distribution of the grain structure. This process is cheaper than either full annealing or normalizing since the material is not heated to a very high temperature or cooled in a furnace.
Stress Relief Annealing
Stress Relief Annealing is used to reduce residual stresses in large castings, welded parts and cold-formed parts. Such parts tend to have stresses due to thermal cycling or work hardening. Parts are heated to temperatures of up to 600 – 650 ºC (1112 – 1202 ºF), and held for an extended time (about 1 hour or more) and then slowly cooled in still air.
We can supply follows heat treatment services:
Normalizing, Annealing, Quenching, Tempering, Carburizing, Nitriding, High-frequency surface hardening and other processing services.
And we can strictly enforce the national standards.
And we have follows heating equipment:
Pit furnace: Dia1300mm max, Length9500mm max.
Salt bath furnace: Length1900mm max, Width1600mm max, Height900mm max.
Trolley furnace: Legth15000mm max, Width6000mm max, Height6000mm max.
Tunnel type continuous reheating furnace：dia30mm-dia250mm
Induction quenching line: dia15mm-dia120mm
Normalizing cooling fan can be used in combination of wind capacity air-cooled systems.
