摘要:
A process for producing grain-oriented electrical steel strip by means of thin slab continuous casting, comprising the following process steps: a) smelting a steel, b) continuously casting the smelt by thin slab continuous casting, c') heating up the thin slabs and subjecting the slabs to homogenization annealing at a maximum temperature of 1250°C, d) heating to a temperature between 1350°C and 1380°C, e) continuously hot rolling the thin slabs to form a hot-rolled strip, f) cooling and reeling the hot-rolled strip to form a coil, g) annealing the hot-rolled strip after reeling and prior to a subsequent cold rolling step, h) cold rolling the hot-rolled strip to the nominal usable thickness, i) subjecting the cold-rolled strip to recrystallization, decarburization and nitridation annealing, j) applying an annealing separator (non-stick layer) to the strip surface of the cold-rolled strip, k) subjecting the cold-rolled strip to secondary recrystallization annealing, forming a finished steel strip having a pronounced Goss texture, and I) stress-free annealing the finished steel strip, which has been coated with an insulating layer, provides an improved process for producing grain-oriented electrical steel strip by means of thin slab continuous casting. This is achieved in that the recrystallization, decarburization and nitridation annealing of the cold-rolled strip in process step h) comprises a decarburization annealing phase and a subsequent nitridation annealing phase, with an intermediate reduction annealing phase being interposed between the decarburization annealing phase and the nitridation annealing phase, and carried out at a temperature ranging from 820°C - 890°C, for a maximum period of 40 seconds, with a dry, gaseous annealing atmosphere, which contains nitrogen (N 2 ) and hydrogen (H 2 ) and acts on the cold-rolled strip, and which has a water vapor/hydrogen partial pressure ratio pH 2 O / pH 2 of less than 0.10 and wherein a cold-rolled strip is obtained, which primary recrystallized grains have a circle equivalent mean size (diameter) between 22μm and 25μm.
摘要:
The invention relates to a cold-rolled, annealed and pre-coated steel sheet for the production of press-hardened parts, formed by a steel substrate for thermal treatment, having a carbon content C0 of between 0.07% and 0.5%, said content being expressed by weight, and a metal pre-coating on at least the two main faces of the steel substrate, characterised in that the substrate comprises a decarburised zone on the surface of each of the two main faces, the depth p50% of the decarburised zone being between 6 and 30 micrometres, p50% being the depth at which the carbon content is equal to 50% of the above-mentioned C0 content, as well as being characterised in that the steel sheet does not contain an iron oxide layer between the substrate and the metal pre-coating.
摘要:
Die Erfindung stellt ein Verfahren zur Verfügung, dass die Erzeugung von Stahlband erlaubt, bei dem hohe Härte einerseits und gute Verformbarkeit andererseits miteinander optimal kombiniert sind. Zu diesem Zweck werden bei der Herstellung eines aus einem mindestens 0,4 Gew.-% Kohlenstoff enthaltenden Vergütungsstahl erzeugten, oberflächenentkohlten Stahlbands, folgende Arbeitsschritte durchlaufen: - Erzeugen des Stahlbands aus dem Vergütungsstahl; - Erwärmen des zu dem Open-Coil gewickelten Stahlbands auf eine Entkohlungsglühtemperatur, die bis zu 20 °C unterhalb der A c1 - Temperatur des jeweiligen Vergütungsstahls liegen kann und die A c3 -Temperatur des jeweiligen Vergütungsstahls nicht überschreitet; - Glühen des Stahlbands im Open-Coil unter einer entkohlenden Atmosphäre für eine Entkohlungsglühzeit von mindestens 90 Minuten, wobei das die entkohlende Atmosphäre bildende Entkohlungsgas durch die zwischen den Wickellagen des Open-Coils vorhandenen Zwischenräume strömt; - beschleunigtes Abkühlen des Stahlbands, so dass die ausgehend von der jeweiligen Oberfläche des Stahlbands gemessene Tiefe (At) der Entkohlung auf einen Bereich beschränkt ist, der jeweils kleiner als ein Viertel der Dicke des Stahlbands ist.
摘要:
The present invention concerns a method of preparing a sintered product having a tensile strength 750 MPa comprising the steps of compacting a water-atomised, annealed iron-based powder comprising, by weight %, Cr 2.5-3.5, Mo 0.3-0.7, Mn 0.09-0.3, O