At high temperatures, offset yield strength of steel decreases. Therefore, atoms can be released from the compulsory state of affairs and reduce internal stresses. Of course, there is no structural change in this case.
Forms before machining, parts – forging or – casting and welding components.
The hardened steel evolves as much as possible into a soft structural condition.
Hyper otoktoid steels are heated up to 720-680 Celsius degree and hypo-octoid steels up to 730-750 Celsius degree. Depending on the size of the work piece, it remains at this temperature for several hours and then cools slowly in the furnace. The softening effect can be achieved by an oscillatory annealing and very close to the top or bottom line of the PSK.
Long cementite sheets are deformed into round grain beads thus the work piece is easily chipped.
With soft annealing, you can prepare steel tools for hardening. If the hardened parts should be machined, first the annealing will be soft. The proper structure for shaping is created by soft annealing.
With normal annealing, the uniform structure and fine grain are formed with rounded beads.
First, the work piece is slowly heated to around 600 ° C and then warmed up to 50 ° C above the GSK line. The work piece is kept for a period of time at this temperature so that the entire cross-section reaches this temperature (about 20 minutes for a diameter of 50 mm). Cooling is done in dwelling air.
With normal ablation, the structure is completely rebuilt. The fine grain structure is created. Coarse grains are undesirable because they make the steel brittle.
Non-uniform structure and coarse grains of forging, welding, rolling, traction and casting are normalized, that is, with normal annealing, structure becomes uniform and fine grain. The coarse grain structure is produced in a long-term annealing or annealing at high temperature. Normal annealing re-grains the structure.