HIGH-RESISTANT SHEET METAL WHICH IS COLD ROLLED AND ALUMINIZED IN DUAL PHASE STEEL FOR AN ANTI-IMPLOSION BELT FOR A TELEVISION AND METHOD FOR THE MANUFACTURE THEREOF

摘要

The invention relates to a dual phase sheet metal which is cold rolled, can be used for the manufacture of an anti-implosion belt for a television and whose chemical composition comprises the following expressed in percentage by weight:: 0.03 % = CD 0.3 %, 1 % = Mn = 3 %, 0.05 % = Si = 2 %, 0.02 % = Al = 2 %, 0.02 % = Cr = 1 %, Mo = 1 %, S = 0.02 %, P = 0.2 %, N = 0.01 %, and optionally, one or several elements chosen from Ti, V, Zr, Nb, whereby the content of each element ranges from 0.001 and 0.2 %, and the rest of the composition comprises iron and impurities resulting from production. A slab or ingot of steel having the above-mentioned composition is heated at a temperature of 1100 -1300 DEG C; the slab or ingot is hot-rolled such that the temperature at the end of the rolling is higher than the temperature Ar3 of the steel, the steel thus obtained is cooled at a speed VR of 1 - 500 DEG C/s; then it is wound at a temperature of 300 -720 DEG C. After cold-rolling, the sheet metal is annealed at a temperature Tm which is higher than Ac1; it is cooled at a speed of more than 2 DEG C/s to reach the temperature of the aluminization operation, whereupon it is subsequently hardened in an aluminium-based bath at a temperature of 650 - 720 DEG C, subsequently cooled at a speed of more than 2 DEG C/s to reach room temperature. The microstructure of the steel is made up of ferrite and 5 - 30 % martensite and less than 2 % phases with carbides.