SU692890A1 - Steel - Google Patents

Description

(54) STEEL

The invention relates to wear-resistant materials and can be used to make castings of improved quality. For the manufacture of products subjected to abrasive wear and wear, steel with a high content of manganese is widely used. The high requirements for wear resistance, toughness and toughness, which such steels must satisfy, make it necessary to alloy them not only with manganese, but also with other elements. Known steel 1, which contains, wt.% Carbon0.9-1.5 Manganese10-15 Silicon0.3-0.64 Copper. 0.5-3.0 Titanium 0.005-0.1 Cerium0.005-0.03 Cerado 0.025 Fosfordo 0.025 IronEstalled. The disadvantage of this steel is the low crack resistance of castings, i.e. capable of casting to maintain strength and ductility in the temperature range crystallization 1I. The purpose of the present invention is to develop manganese steel with enhanced crack resistance of castings with a high level of mechanical properties and wear resistance. The goal is achieved by the fact that the proposed steel additionally contains aluminum, calcium, magnesium and boron with the following ratio of components, wt%: Carbon Manganese 0.3-0.7 Silicon 0.5-3.0 0.005-0.1 0.005- 0.08 0.005-0.01 Aluminum 0.005-0.08 Calcium 0.005-0.05 0.0005-0.005 Else. Aluminum, interacting with nitrogen, when heated, forms easily soluble small-sized, 692 propane nitrides. This eliminates the harmful effects of free nitrogen. When titanium is introduced into steel, the efficiency of alumina will melt due to the austenitic grain grinding. The optimum aluminum content is in the range of 0.005-0.01 wt.%. A lower content does not provide a positive effect, and a higher, upper limit, causes the appearance of an excessive amount of oxides and nitrides, which, located at the grain boundaries, reduce the crack resistance and mechanical properties to the lowest values. The simultaneous introduction of calcium and magnesium into the composition of the steel, provided that it contains cerium, has a favorable effect on the whole complex of properties of the steel. After entering these elements, globularization occurs and shrink the total number of non-metallic inclusions. As Pbkazashtyysh 1 tani Usuttststvostvovyvayutsya the extremity of castings and fluidity of steel, its density increases and the amount of linear shrinkage decreases. This reduces the content of oxygen in the steel, which contributes to a more efficient nitride hardening when aluminum is introduced into the steel. The calcium and magnesium contents are balanced among themselves. (0.005-0.08 wt.% Calcium - and

0.42 0.82 0.02 0.01

0.7 1.2.

0.623.0

0.32.1

0.540.5

0.450.9

0.380.8

0.421.2

0.671.4

0.71.3. five

0.08

0,0070,030,050,002

0,0050,050,020,005

0.03

0,010,0050,030,0005

0,005

0.06

0,010,0080,0050,0008

0,0080,080,0070,002

0,008

0.0040.080.06 -.

0.09

0,0090,003,070,008

0,004

0,0120,0040,0040,006

0,003

0,0020,100,0020, 10 904 0.005-0.05 wt.% Magnesium), as well as with cerium and other elements. Their lower content is inefficient, and the content exceeding the upper limit results in the appearance of a large amount of silicates, colonized by grain boundaries, which reduces crack resistance and the mechanical properties of the steel. The introduction of boron into steel is primarily associated with an increase in its wear resistance. The boron content is less than 0.0005 weight. ineffective, and exceeding .0.005 wt.% results in metal brittleness. Since boron is readily associated with oxygen and nitrogen at temperatures of liquid steel, provided it is co-introduced with aluminum, calcium and magnesium, which are more powerful deoxidizing agents, the effectiveness of a favorable effect of boron on wear resistance increases. At the same time, titanium and aluminum, bonding nitrogen, prevent the formation of boron nitrides. The metal is molten into 60 kg of a 1-induction furnace. The additive of the complex modifier containing calcium, magnesium, boron, aluminum is carried out fractionally into the transfer buckets. The chemical composition of superior steel with a different composition of the input elements in wt.% Is presented in Table. 1. Table

Link and tests for mechash tests, cast from limestone || and the proposed were subjected to heat treatment according to the existing regime: quenching at a temperature of 1050 C.

In tab. 2 presents the results of mechanical tests, tests for abrasive wear and crack resistance of samples after heat treatment.

Table 2