RU2225893C1 - Wear-resistant steel - Google Patents

Abstract

FIELD: steelmaking. SUBSTANCE: invention relates to making steels under conditions of intensive abrasive wear and alternating dynamic loads. Steel contains, wt %: carbon 0.6-0,7m silicon 1.0-1.8, manganese 2.0-3.6, aluminum 0.6-1.0, and chromium at most 0.5, provided that carbon-to-silicon ratio is 0.43-0.75, manganese-to-silicon ratio no higher than 4.5, and ratio of aluminum to summary content of carbon, silicon, and manganese is 0.13-0.2. Thus obtained steel is characterized by optional balance of technological (low tendency to crack formation both at heat treatment and at pressurization, good calcination ability) and operational (high wear resistance under conditions of intensive abrasive wear and impact loads of large-size parts) properties. EFFECT: improved technological and operational properties of steel and reduced cost. 2 tbl

Description

The invention relates to metallurgy, in particular to the production of steels operating in conditions of intense abrasive wear and subjected to alternating dynamic loads.

It is known to use for the manufacture of parts subjected to alternating dynamic loads of wear-resistant steels with a high manganese content, for example, steel 110G13L, containing, wt.%:

Carbon 0.9-1.3

Silicon 0.4-1.0

Manganese 11.5-14.5

Nickel Up to 0.5

Chrome Up to 0.5

Iron Else

or steel with improved properties, containing, wt.%:

Carbon 0.9-1.5

Silicon 0.15-0.8

Manganese 12.0-15.0

Aluminum 2.5-3.2

Chrome 2.1-2.3

Iron Else

(ed. certificate. No. 648647, IPC C 22 C 38/38, 1977).

The manufacture of parts from such steels is only possible by casting due to the tendency to rivet even with small deformations. The disadvantage of the steels under consideration is their low manufacturability - it is impossible to obtain parts by pressure treatment (forging, stamping) and mechanical processing is difficult. In addition, given that these steels are hardened by hardening under shock loads, they are not sufficiently durable without such loads.

Therefore, when using such steels for the manufacture of teeth of excavator buckets, in order to increase wear resistance, it is necessary to use hard alloy surfacing (Sormait).

Also known are wear-resistant steels subjected to pressure treatment, for example, steel containing, wt.%:

Carbon 0.52-0.75

Manganese 0.8-1.7

Silicon 0.85-1.2

Aluminum 0.06-0.5

Titanium 0.01-0.06

Iron Else

(Auth. Certificate. No. 1497262, IPC С 22 С 38/14, 1988).

The closest in composition to the offer, selected as the closest analogue, steel containing, wt.%:

Carbon 0.7-0.9

Silicon 0.5-0.8

Manganese 0.8-1.2

Aluminum 0.1-0.4

Chrome 0.9-1.2

Sulfur Not more than 0.03

Phosphorus Not more than 0.03

Iron Else

(Auth. Certificate. 199412, IPC C 22 C 38/18, 1965).

In this steel, wear resistance is achieved by observing the ratio of alloying elements C / Mn of 0.8; C / Cr 0.68-0.70; Mn / Cr 0.8-0.58, the concentration of chromium, along with the concentration of manganese, plays a leading role. After quenching in oil from 820 to 840 ° C and tempering at 200-240 ° C, the steel has a hardness of 58-60 HRC in combination with impact strength (and _H = 0.9-1.2 kgf · m / cm ² ). Judging by these data, steel has a fairly low hardenability and is unsuitable for passive parts.

When creating the invention, the task was to obtain cheap technological steel with high performance characteristics for the manufacture of massive parts operating in conditions of intense abrasive wear and alternating (shock) loads.

The problem is solved with the content of components in steel, wt.%:

Carbon 0.6-0.7

Silicon 1.0-1.8

Manganese 2.0-3.6

Aluminum 0.6-1.0

Chrome Not more than 0.5

Iron Else

the ratio of carbon content to silicon content of 0.43-0.75, manganese content to silicon content of not more than 4.5 and aluminum content to the total content of carbon, silicon and manganese 0.13-0.20.

By preliminary calculation of the phase composition and experimental data, it was found that steel with a content of components, wt.%:

Carbon 0.6-0.7

Silicon 1.0-1.8

Manganese 2.0-3.6

Aluminum 0.6-1.0

Iron Else

when the ratio of carbon content to silicon content of 0.43-0.75, manganese content to silicon content of not higher than 4.5 and aluminum content to the total content of carbon, silicon and manganese 0.13-0.20. It has an optimal ratio of technological (low tendency to crack formation during both heat treatment and pressure treatment, good hardenability) and operational properties (high wear resistance in conditions of intensive abrasive wear and impact loads of large parts).

Given the presence of a low chromium content in the original ore, steel may contain up to 0.5% chromium.

Steel does not require special conditions for smelting and can be smelted, for example, in an open induction furnace. Casting was carried out in dry sand and clay molds. After homogenizing annealing, rods were obtained from the castings. After the heat treatment (quenching from 860 ° C in hot water and tempering at 460 ° C) steel has a yield stress σ _T> 147 kgf / mm ^2, tensile strength σ _B> 175 kgf / mm ² and the toughness KCU = 1,8 kgf / cm ² , hardness HRC = 48 and decreased value of residual stresses in the metal.

Example

For example, three melts with different contents of alloying elements were carried out and the properties of the obtained steel were investigated. The data are given in table 1.

From the rods, hot stamping was obtained parts - the teeth of the buckets of excavators.

The parts were subjected to comparative abrasion tests with a standard part made of steel 110G13L, hardened by Sormait surfacing.

The tests were carried out in a sandblasting chamber by blowing silicon carbide (fraction of 50 μm) with a working area of 50 × 50 mm. The test results are shown in table.2.

Claims (1)

Wear-resistant steel containing carbon, silicon, manganese, aluminum and chromium, characterized in that it contains components in the following composition, wt.%: Carbon 0.6-0.7 Silicon 1.0-1.8 Manganese 2.0-3.6 Aluminum 0.6-1.0 Chrome Not more than 0.5 with a ratio of carbon to silicon content of 0.43-0.75, manganese content to silicon content of not higher than 4.5 and aluminum content to the total content of carbon, silicon and manganese 0.13-0.2.