SU1046321A1 - Corrosion-resistant steel - Google Patents

Abstract

CORROSION-RESISTANT STEEL, containing carbon, silicon, manganese, chromium, titanium, vanadium, iron, characterized in that, in order to increase plasticity and improve weldability, it additionally contains rare-earth metals and barium in the following ratio of components, wt.%: Carbon0.04-0.10 Silicon0.30-0.60 Manganese0.30-0.60 Chrome14-18 Titanium0.10-0.70 Vanadium0.10-0.80 Rare-earth metals -0.010-0.10 Barium0.001- 0.05 Iron Else at the same time., I: N 50llP W OlqQ 7 / 8O) BOCT

Description

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NP The invention relates to metallurgy, in particular to steel for the manufacture of products of trade and technological food equipment, household appliances and consumer goods, in the automotive industry. Famous grades 08X18T1, 08X17T and 12X17 1 are known, high chromium content and titanium in which causes the appearance of the carbide phase, a significant amount of which is located at the grain boundaries, deteriorating the plastic properties of the metal. The closest to the technical, the essence and the achieved effect to the proposed is corrosion-resistant steel 08X18F2T, containing, by weight,%: carbon is not more than 0.08; chrome 17-19; titanium 0.8-1.0, vanadium 1.0-2.0; zirconium 0.01-0.03, the remaining iron 2. This steel belongs to the ferritic class and has the following mechanical properties after hot rolling heat treatment and alkali acid etching: tensile strength 50 kg / mm, relative elongation of 35%. The main drawback of steel is insufficient plasticity due to the presence of coarse carbides and carbonitrides of titanium and vanadium in the steel structure, a significant amount of which is located at the grain boundaries. The same structure is observed in welded joints, significantly embrittling them .. A significant improvement in the structure and properties in this steel can be achieved by introducing certain amounts of rare-earth and alkaline-earth metals. The latter, as surface-active, located mainly along the grain boundaries and in the defective places, promote the removal of carbon from the grain boundaries to the center of the grain, as well as the grinding of grains. The rare-earth and alkaline-earth metals themselves, such as: cerium, lanthanum, neodymium, calcium and barium, have become low carbon with up to 0.8% of carbides. The introduction of silikobari into steel contributes to a better deoxidation of the metal and, as a consequence, a more complete absorption of the SEM, and also increases the fluidity of the metal, which is very important when casting steel containing REM. Wider use of ferritic corrosion-resistant steels is constrained by the low ductility of the BASIC metal and its welded joints. Significant progress in improving ductility and weldability can be achieved by improving the state of grain boundaries, as well as the rational alloying of chromium corrosion-resistant steels. The aim of the invention is to improve the smoothness and the weldability of the steel. The goal is achieved by the fact that corrosion-resistant steel containing carbon, silicon, manganese, chromium, titanium, vanadium, iron, additionally contains rare-earth metals and barium in the following ratio of components, wt.%: Carbon0.04-0-0.10 Silicon0, 30-0.60 Manganese0.30-0.60 Chromium14-18 Titanium0.10-0.70 Vanadium0.10-0.80 Rare-earth metals0.010-0.1 Barium0.001-0.05 IronEverything Else, gi: ti l, 6Cv 6ougPzv and DI: ø., Steel may contain impurities, wt.%: sulfur to 0.025; phosphorus to 0,030. . In the open main induction furnace, the proposed steel was smelted. Chemical properties of steels are presented in table. 1. The ingots were subjected to rolling at 960 ° C with a reduction rate of 75%. Then, the resulting melts were rolled to a thickness of 3.8 mm at 1200 ° C, followed by alkaline acid etching. Cold rolling was performed on a laboratory rolling mill with a degree of reduction of 70%. Cold-rolled sheet was subjected to quenching from 920 ° C and alkaline acid etching. The sheets had a thickness of about 8.mm. The mechanical properties of the steel are presented in table. 2. When welding at optimal modes of samples from famous steel and samples made from pilot melts on welding machines of the type MT-2510 (GOST 297-61) and MSP-150-3 (GOST 297-52), it has been established that the quality of welded All samples are satisfactory. Tear resistance at tensile strength of 1 mm thick, type XX GOST 6996-66 was as follows: in the known steel 630 kgf; the proposed (experienced melting) in the range of 650-750 kgf. Welded joints of known steel allow deformation up to 15% when stretched without showing defects (cracks). The corresponding indicators of the proposed composition (experimental shops) were in the range of 18-30%.

It is important to observe the compliance of the chemical composition of the proposed steel with the above formula, since only this ratio of ferrite-forming and austenitic-forming elements with the corresponding 1 and coefficients can ensure a stable ferrite structure and avoid the appearance of a brittle component - martensite.

The savings from the introduction of the proposed steel instead of the currently used 12X18H10T steel will amount to RUB / t, while saving on scarce nickel

will be 100 kg per 1 ton of metal. The necessary data to calculate the economic effect obtained at the plant Zaporizhstal. With an annual demand of 1000 tons, the economic effect

will be 300 thousand rubles.

Tab. itsa

table 2

Claims (1)

CORROSION-RESISTANT STEEL containing carbon, silicon, manganese, chromium, titanium, vanadium, iron, characterized in that, in order to increase ductility and improve weldability, it additionally contains rare-earth metals and barium in the following ratio. components Carbon Silicon Manganese Chrome Titanium Vanadium Rare Earth Metals · Barium Iron with weight.%: 0.04-0.10 0.30-0.60 0.30-0.60 14-18 0.10-0.70 0.10-0.80 0.010-0.10 0.001-0.05 Rest B'es 7 / 8-