SU870479A1 - Fire-resistant steel - Google Patents

Description

(54) HEAT-RESISTANT STEEL

one

The invention relates to the field of foundry, in particular, to heat-resistant steel, operating in aiTperaTcix energy under oxidation conditions at high temperatures, as well as the presence of sulfur dioxide.

Heat resistant steel is known, containing, by weight. Carbon. 0.1 Silicon 1f 3-1,5 Manganese 0.3-0.6 Chromium 1I7-2 Aluminum 7.8 Iron Remaining. 15 This steel has unsatisfactory technological properties and scaling resistance, especially when operating in environments with high temperature and the presence of sulfurous gases.

The most important aspect of the steel to be described is heat-resistant steel containing, in wt.%:

Carbon0,2-0,35

Hrom20,0-22,0

Silicon. 0.8-1.5

Manganese Not more than 0.8 30

Cerium and lantaid0, 8-1

Iron Else 2.

Technological properties (casting, fluidity, crack resistance, weldability) and scaling resistance of this steel are unsatisfactory, which hinders the use of this steel as heat-resistant. Taking into account the reduced fluidity of steel, thin-walled sections of castings, as well as small castings using the casting method, are not possible.

The aim of the invention is to improve the technological properties and scale resistance,

To achieve this goal, the described steel containing carbon, chromium, silicon, manganese, rare earth metals, and iron additionally contains molybdenum, titanium, and aluminum with a proportion of components singing, wt.%:

Carbon0,2-0,6

Silicon0,3-2,5

Molybdenum 0.01-1.0 Aluminum0.8-1.5

chrom20.0-27.0

Manganese 0.3–1.0 Titanium 0.05–0.29 Rare Earth Metals 0.05–0.25 Iron Else It has been established experimentally that the optimal carbon limits are 0.2–0.6 wt.%. When the content (carbon is less than 0.2 wt.% In steel, its fluidity sharply deteriorates, in connection with which such steel is usually cast into ingots, and then subjected to more severe plastic deformation. However, this increases the cost; steel carbon content over 0.6, the casting properties are significantly improved, however, the scaling resistance decreases dramatically. The chromium content limits 20.00–27, 0 wt.% ensure stability against oxidation at high temperatures. steel, and when the content of u 27.0 wt.% Scale resistance increases dramatically, however, technological properties deteriorate. The introduction of silicon into steel (especially, but more than 1 wt.%) increases the scaling resistance of steel. Less than 0.3 wt.% silicon in steel with It is difficult to obtain smelting in furnaces using widely used charge materials. The silicon content of 2.5 wt.% sharply deteriorates the mechanical properties of steel, although the scaling increases. Similar to silicon, obtaining manganese of 0.3 wt.% Is also difficult. The most likely manganese content at the upper limit in smelting in furnaces using ordinary blended materials is not more than 1 wt.%. This element in large quantities 1 0.3 21.3 0.9 0.71 Known Describing20,220.20 0.3 0.3 0.91 ma 30.41 24.1 1.23 0.61 0.49 40.6 27.0 2.5 1.0 1.0

The steel was smelted in an induction furnace 60 using a 60 kg crucible with a chrome-magnesite lining by remelting.

Aluminum was introduced into the crucible before the release of steel, rare earth metal-. 65

ly introduced into the bucket. The steel pouring temperature was 1560 + 1 ° C.

The results of determination of technological and mechanical properties, as well as scaling resistance, are given in Table. 2. undesirable because of the negative effect on the scaling resistance. Molybdenum within the specified limits has a positive effect on the mechanical properties and scaling resistance of steel. With its content of 0.01 wt.%, This effect does not manifest itself, and the introduction of 1.0 wt.% Is not economical due to the high cost of ferromolybdenum. The introduction of titanium within the claimed limits ensures that the carbon present in the steel is bonded, and the ductility and scaling resistance is determined. Titanium in the amount of O, V w / v% already has a noticeable effect on the mentioned properties. The titanium content of more than 0.29 wt.% Is not economical, although it increases the heat resistance of steel and grinds its grain. Similarly to silicon, aluminum dramatically increases the oxidation resistance of chromium steel with a content of 20 wt.% Chromium and more. With a content in steel of 0.8 wt.% Aluminum and more, these steels have a satisfactory resistance to scaling, however, with an increase in the aluminum content of more than 1.5 wt.%, The fluidity of the steel decreases sharply. Rare earth metals provide a significant improvement in scaling resistance, foundry and mechanical properties. The most satisfactory limits are 0.05-0.25 wt.% (By calculation). At the same time, the introduction of rare earth metals and less than 0.05 wt.% Is not very sensitive, and more than 0.25 wt.% Is uneconomical and has a negative effect on the scaling resistance and casting properties. When smelting steel, the same raw materials were used, smelting, casting and testing were carried out using the same technology (see Table 1). . Table 1 0.06 0.08 0.8 0.05 0.8 0.8 0.07 0.07 0.05 0.15 1.31 0.05 0.05 0.15 0.29 1.5 0.05 0,0,5 0,25

Thus, the technological properties; fluidity, linear shrinkage, crack resistance and weldability, mechanical properties; The tensile strength, impact strength, and scaling resistance of the steel composition described (Tables 2, 2–4) are higher compared to the known steel.

Claims (2)

Invention Formula Heat resistant, containing carbon, chromium, silicon, manganese, rare earth metals, and iron, which, in order to improve technological properties and scaling resistance, it additionally contains molybdenum, titanium Table 2 and aluminum in the following ratio, wt.% :. Carbon0,2-0,6 Chrom20.0-27.0 Silicon0,3-2,5 Manganese 0.3-1.0 Molybdenum 0,01-1,0 Titan0.05-0.29 Aluminum0.8-1.5 Rare Earth metals0.05-0.25 Iron. The rest Sources of information taken into account in the examination 1 Copyright certificateSSSR 158297, cl. C 22 C 38/18, 1965. 2. USSR author's certificate 177624, cl. C 22 C 38/18, 1966.