CS270808B1 - Low-alloy low-carbon welding steel - Google Patents

Abstract

Low-alloyed,low-carbon weldable steel is designated for two-sided and/or one-sided zinc metal-coated strips primarily for the automotive industry and bent profiles with a basic carbon content of up to 0.06%, sulphur from 0.002 up to 0.025%, phosphorus between 0.005 and 0.035%, manganese from 0.1 up to 0.3%, silicon between 0.05 and 0.2% and aluminum from 0.03 up to 0.08% of weight. This steel contains alloying compounds in the extent of 0.05 up to 0.25% of molybdenum and 0.05 up to 0.15% of zirconium provided that the total share of the alloying compounds does not exceed 0.50% of the weight.

Description

(57) Low-alloy low-carbon weldable vinegar for double-sided or one-sided coated strips of zinc or its alloys, in particular for the automotive industry and bent sections with a basic carbon composition of 0,06%, sulfur of 0,002 to 0,025 phosphorus of 0,005 to 0,035 manganese from 0.1 to 0.3 silicon from 0.05 to 0.2% and aluminum from 0.03 to 0.088% by weight. This steel obsahuje contains alloying ingredients in the range of 0.05 to 0 ^ 25% molybdenum and 0.05 to 0.15% zirconium, with a total proportion of alloying ingredients not exceeding 0.50% by weight.

0 808

(11) (13) B1 (51) Int. Cl. ⁵ C 22 C 38/00

The present invention relates to low alloy steels for hot-rolled and cold-rolled metallized sheet metal sheets, in particular for automotive industry and general purpose bent profiles, to increase corrosion resistance to thermal and atmospheric erosion of flutter alone, while reducing the weight of plating coatings mutual adhesion.

For the aforementioned purposes of using sheet metal, for example, for bent profiles, and in particular for rosettes and exhausts in the automotive industry, low-carbon, deep-drawn or cold-rolled structural steels are used. These steels, in addition to the disadvantageous mechanical properties, exhibit an insufficient degree of resistance to atmospheric influences and, in particular, to thermal effects on, for example, car exhausts. Even with the necessary plating for the above purposes, it is necessary to apply coatings with a higher weight, about 275 gm ² , on both sides, with relatively high surface roughness after cold rolling. Insufficient corrosion resistance! These steels limits the possibility! One-sided plating of sheet metal solving pressing problems during processing of body panels, for example. Unsuitable Structure of materials, especially on the surface of sheets in the so-called. intermetallic phase, while not allowing the necessary adhesion and binding of the metallization coating to the sheet surface. The above-mentioned conventional steels, due to their unsuitable strength properties and without special surface and heat treatment before or after the metal plating of the sheets, require relatively large sheet thicknesses for the said high-weight products as well as difficult welding of the sheets so coated. The problem is solved in many cases by the development of plating materials and technologies.

The low-alloy low-carbon weldable steel according to the invention solves these problems. SUMMARY OF THE INVENTION The low-alloy low-carbon weldable steel having a basic carbon composition of up to 0.06%, a manganese of 0.1 to 0.3%, a silicon of 0.05 to 0.2%, an aluminum of 0.03 to 0.3% 0.08% and with a sulfur content of 0.002 to 0.025% and a phosphorus of 0.005 to 0.035 contains further alloying components in the range of 0.05-0.25% molybdenum and 0.05-0.15% by weight of titanium. Preferably, the steel is further alloyed with zirconium in the range of 0.05 to 0.15% by weight, the total proportion of all alloying components not exceeding 0.50% by weight.

The advantages of the steel according to the invention are mainly that the new low carbon steel formed exhibits a significantly higher corrosion resistance! against atmospheric as well as combined thermal influences, both without plating and after plating, which enables plating with a lower coating weight and / or coating. one-sided plating advantageous for demanding stamping, e.g. car bodies. Appropriate alloying of the steels improves the strength properties of the sheets 8 by reducing the weight of the steel products. In particular, however, the combination of the anticorrosive components, namely silicon with the above-mentioned alloying elements, at the same time form a quaternary phase of bonding with the zinc plating as well as its alloys, including the zinc-aluminum alloy developed in the surface intermeralic layer. d As a result, the weldability of the plated sheets is increased without compromising their corrosion resistance. Steel also enables more effective and rational use of other technologies of pre-treatment before and after metal plating.

An example of low alloy steel according to the invention:

The steel contains 0.04% carbon, 0.21% manganese, 0.15% silicon, 0.012% sulfur, 0.015% phosphorus, 0.095% zirconium, 0.045% aluminum, 0.090% molybdenum and 0.11% titanium, the rest iron.

Claims (2)

OBJECT OF THE INVENTION 1 · Low-alloyed cast steel for cold-rolled and cold-rolled cold-rolled and cold-rolled metal sheets, especially for the automotive industry, for example, exhaust pipes and bodywork and bent general purpose profiles, zinc plating or zinc alloys and / or zinc alloys and aluminum with the addition of silicon and titanium or magnesium, with a basic carbon composition of up to 0,06%, a sulfur of 0,002 to 0,025 of phosphorus of 0,005 to 0,035 of manganese of 0,1 to 0,3 of silicon of 0,05 to 0,2% and % aluminum, from 0.03 to 0.08% by weight, further comprising alloying components in the range of 0.05 to 0.25% molybdenum and 0.05 to 0.15% by weight of titanium. 2. Low-alloy steel according to claim 1, characterized in that it is further alloyed with 0.05 to 0.15% by weight of zirconium, the total proportion of all said alloying components not exceeding 0.50% by weight.