Patenting an isotherm heat treatment. The material is quenched
fast from the austenitizing temperature in a warm bath on a predefined temperature.
The temperature of the warm bath shall lie below the temperature of the ferrite
line of the ZTU-diagram. After patenting there shall be a fine sorbitic structure.
Perhaps, amounts of lamellar pearlite are also availably. In any case the formation
of ferrite has to be avoided because ferrite reduces the endurance strength of
the wire. This also is the case at coarse slags and surface defects. A distinctive
banded structure arises at the drawing of the patented wire. The wires manufactured
so can achieve a very high strength. There are the unalloyed steels depending on
straining class with the name type A, B, C and D.
drawn wire out of ~ C60