Spring out of patented drawn wire
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.
patented drawn wire out of ~ C60