SU1145045A1 - Steel for weldments - Google Patents

Abstract

STEEL FOR WELDED CONSTRUCTIONS containing carbon, silicon, manganese, nitrogen and iron, characterized in that, in order to increase the strength of the welded joint, it additionally contains oxygen at the following ratio of components, wt.%: Carbon 0.22-0.32 Silicon0 02-0.10 Manganese0.45-0.70 Nitrogen0.005-0.010 Oxygen 0.017-0.030 IronEstal

Description

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The invention relates to ferrous metallurgy, in particular, to the composition of iron-based alloys, and can be used in the production of heat-strengthened welded reinforcement of a periodic profile and bar steel. Known steel lj, containing wt.%: Carbon. 0.17-0.21 Silicon 0.03-0.1 Manganese 0.25-0.4 Chromium 0.08-0.15 Nickel 0.08-0.15 Aluminum 0.03-0-0.06 Vanadium 0.001-0.006 Copper 0.08 -0.18 Nitrogen, 0.003-0.01 Oxygen, 0.003-0.01 Iron Remaining The disadvantages of the well-known steel are the low manufacturability of its production during smelting in steelmaking aggregates using conventional pig iron with low content of sulfur and phosphorus; unreliability of thermo-strengthened reinforcement of large diameters due to insufficient hardenability and weldability of At-Shs class made from thermo-strengthened reinforcement. The closest in technical essence and achievable properties to the invention is steel 2J, containing May. %: 0.05-0.2 Carbon Silicon j 0.1 0.5-0.1 Manganese 0.005-0.15 0.035-0.1 Phosphorus Iron Else The disadvantage of the known steel is the low quality of the welded joint, characterized by the presence of cracks and low flow. The purpose of the invention is to increase the strength of the welded joint. This goal is achieved by the fact that steel containing carbon, flue, manganese, nitrogen and iron, in addition, contains oxygen at the following ratio of components, wt.%: 0.22-0.32 Carbon 0.01-0.10 Silicon 0.45-0.70 Manganese 0.005-0.010 0.017-0.030 Oxygen Rest Iron As an impurity, the steel may contain,%: sulfur up to 0.05; phosphorus to 0,040; chromium to 0.3; Nickel to 0.3; copper to 0.3. The low carbon content in combination with moderate doping with manganese, as well as the presence of nitrogen, ensure its weldability by resistance butt welding. The lower limit of carbon content (0.22) was chosen in order to ensure high strength of the welded joint of thermally hardened reinforcement. The upper limit (0.32) is due to the fact that a higher carbon content unnecessarily increases the strength characteristics of heat-strengthened reinforcement and reduces its ductility. The lower limit on the oxygen content (0.017) is determined by the achievement of uniform distribution of shrinkable porosity and the provision of minimum technological cutting during rolling and high strength of the welded joint, and the upper limit (0.030) by the fact that at higher oxygen content the ductility of the thermally hardened reinforcement is reduced; The sensitivity of steel to brittleness increases. Experimental melting was carried out in a two-bath steel-making unit. Casting of reinforcing steel was carried out from above into MK-12 type molds extended to the bottom with a cupel pan through a glass with a diameter of 100 mm. Ingots with a mass of 12.9 tons were rolled from a hot head on a blooming 1300, and then on a continuous billet mill, a square of 80 mm was rolled onto a billet, which was then rolled onto thermally reinforced reinforcement with a diameter of 12 mm. The chemical composition and properties of the produced steel are given in the table.

S 1145045

The table shows that the proposed-offer steel is technological.

steel has a higher level than all stages of metallurgical strength of a welded joint during the manufacture. The use of proposed weld-welding of heat-treated steel makes it possible, without degraded reinforcement, to meet the requirements of the quality of the finished product to reduce

none of the class At-Shss. alloying element consumption by 16%.

Claims (1)

STEEL FOR WELDED STRUCTURES, containing carbon, silicon, manganese, nitrogen and iron, characterized in that, in order to increase the strength of the welded joint, it additionally contains oxygen in the following ratio, wt.%: Carbon Silicon Manganese Nitrogen Oxygen Iron 0.22-0.32 0.02-0.10 0.45-0.70 0.005-0.010 0.017-0.030 Rest f 1 1145045