1. Incomplete annealing called incomplete crystallization annealing. The steel is heated to a temperature between track and Ac3 or Ac1 Ac1 and Acm, slowly cooled down after the heat, the steel tissue incomplete recrystallization.

2. Incomplete annealing the workpiece is heated to a semi austenitizing annealing and fully annealed workpiece is heated to a fully austenitic annealed.

3. Incomplete annealing generally used eutectoid steel, also available in sub-eutectoid steel, and fully annealed generally used only for the sub-eutectoid steel.

The fully annealed generally get flaky pearlite, not get fully annealed globular pearlite.

Two, three Thai SUNTHAI not fully annealed Applications

Incomplete annealing can be used for sub-eutectoid steel, it can also be used over a total steel. It characterized by annealing pearlite cementite into a ball, which finish annealing is also known as ball annealing.

For sub-eutectoid steel is not fully annealed often due to the following conditions:

(1) to improve the cutting performance, such annealing after forging mainly used in structural parts, especially high carbon content structures, due to the meticulous pearlite after forging, high hardness is difficult to cut.

(2) to improve the cold-deformation properties of the ball back, the need for this type of annealing of cold deformation hypoeutectoid steel.

The difference between three, three Thai SUNTHAI isothermal annealing in the ordinary annealed

And so there are some differences between process and cooling method with ordinary annealing temperature annealing, general annealing is generally holding the workpiece after slow cooling process is completed with the furnace, when the workpiece is cooled to 500 degrees Celsius can be cooled baked. The isothermal annealing after the workpiece heating or cooling at a faster rate cooled to a temperature of Ac1 or less certain to stay for some time, so that the isothermal decomposition of austenite to pearlite, and then cooled at a faster rate (air cooling) to room temperature. Isothermal annealing in that short time, good quality.

Four, three Thai SUNTHAI isothermal annealing cooling methods

(1) self-annealing temperature of the workpiece is cooled to isothermal temperature of the cooling speed can be, commonly used in the production of two furnace.

2) isothermal temperature is generally in the following Ar1 10-30 degrees Celsius, which is in the pearlite transformation temperature.

(3) optionally cooling after transformation

Five, three Thai SUNTHAI ball back method

(1) Ordinary ball back: heating the steel to a higher and Ac1 (typically Ac1 + 20-30 degrees Celsius), after incubation with 20-50 degrees Celsius / h slow cooling to 500 degrees Celsius, cooled baked.

(2) Isothermal ball back: ordinary ball back after the same heating temperature insulation, furnace cooled to a temperature slightly below the Ar1 isothermal, after the end of the isothermal cooled baked.

(3) return the ball back period: it is above and below the Ac1 alternately heating and cooling, the equivalent of several isothermal cold ball back.