CN1699613A - High-strength wear-resistant steel and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a high strength and wear resistant steel and its production process, which is particularly suitable for application in railway intersections. The compositions (wt%) are : C 0.25-0.55, Si 0.6-1.5,Mn 0.8-1.5,Cr 1-1.5,Mo 0.3-0.5, V 0.15-0.25, Ti 0.05-0.15, P<=0.03, S<=0.025. The production flow sheet is as follows: refining by arc furnace - refining by vacuum furnace - ladle refining outside of furnace - casting ingot - primary rolling in billet - forging in form - deforming heat treatment. As compared with the existing technologies, the present steel has the advantages of excellent wear resistance, high strength, high toughness, stable quality and low production cost.

Description

High-strength wear-resistant steel and manufacturing method thereof

technical field

The invention relates to alloy steel, in particular to a high-strength wear-resistant steel that can be used for railway turnouts and a manufacturing method thereof.

Background technique

With the development of railway transportation towards heavy load and high speed, higher requirements are put forward for the materials and inherent quality of railways. The high-manganese steel turnouts in active service have become more and more difficult to meet the needs of high-speed development of heavy-duty railway transportation, especially for turnout core rails with harsh service conditions, which must not only have sufficient wear resistance, but also require sufficient strength and toughness. Should have a stable inner quality. For this reason, both at home and abroad are trying to develop high-performance wear-resistant steel that can meet the requirements of heavy-duty and high-speed railway transportation. For example, the application number is 98112095.4. Mo-Ni is the main alloying element, and its comprehensive performance of wear-resistant steel has been improved. However, experiments have proved that the addition of the main alloying element Ni has no obvious effect on improving the performance of wear-resistant steel, and because Ni alloy materials are expensive, it will also lead to an increase in the production cost of wear-resistant steel. In addition, due to the lack of refining process in the manufacturing process of wear-resistant steel, especially the lack of measures to remove harmful gas hydrogen, there is a possibility of hydrogen accumulation inside the product, so that the product has delayed cracking that poses a great hazard to railway transportation. .

Contents of the invention

The object of the present invention is to solve the above problems and provide a high-strength wear-resistant steel with high strength, good wear resistance and low production cost. The high-strength wear-resistant steel is especially suitable for railway turnouts.

The object of the present invention is also to provide a manufacturing method that can effectively ensure the stable internal quality of the high-strength wear-resistant steel.

The technical solution for realizing the object of the present invention is: a kind of high-strength wear-resistant steel, its chemical composition (weight %) is:

C 0.25-0.55 Si 0.6-1.5 Mn 0.8-1.5 Cr 1-1.5 Mo 0.3-0.5

V 0.15-0.25 Ti 0.05-0.15 P≤0.03 S≤0.025

The rest is Fe and unavoidable impurities.

The preferred chemical composition (% by weight) of the high-strength wear-resistant steel of the present invention is:

(1) C 0.25-0.35 Si 0.6-0.9 Mn 0.8-1.2 Cr 1-1.2 Mo 0.3-0.4

V 0.15-0.2 Ti 0.05-0.09 P≤0.03 S≤0.025

The rest is Fe and unavoidable impurities.

(2)C 0.28-0.4 Si 0.8-1.2 Mn 1.1-1.5 Cr 1.2-1.5 Mo 0.4-0.5

V 0.18-0.25 Ti 0.06-0.1 P≤0.03 S≤0.025

The rest is Fe and unavoidable impurities.

(3) C 0.3-0.48 Si 0.6-0.8 Mn 0.9-1.2 Cr 1.1-1.3 Mo 0.3-0.4

V 0.18-0.24 Ti 0.08-0.12 P≤0.03 S≤0.025

The rest is Fe and unavoidable impurities.

The manufacture method of high-strength wear-resistant steel of the present invention is to adopt following technological process:

Electric arc furnace smelting→vacuum furnace refining→ladle refining outside the furnace→ingot casting→brief rolling→forging forming→deformation heat treatment.

The carbon content of the high-strength wear-resistant steel of the present invention is controlled between 0.25-0.55 to ensure that the material has excellent tensile, torsion, and bending properties, and obtains a good toughness material. The addition of alloying elements Si, Mn, Cr, Mo, V, Ti and the selection of a suitable ratio can effectively inhibit the recrystallization of austenite, prolong the residence time before quenching after deformation, and refine the grains to improve the strength of the material and plasticity.

The role of each process in the high-strength wear-resistant steel manufacturing process is as follows:

Electric arc furnace smelting: control and adjust the chemical composition, and initially purify the molten steel through the slagging process.

Refining in vacuum furnace: Pour the molten steel with qualified composition after smelting in electric arc furnace into the vacuum furnace for extraction and refining to fully remove the harmful gas in the molten steel.

Out-of-furnace ladle refining: Pour the vacuum pumped molten steel into the ladle, and then carry out hydrogen blowing refining on the ladle to fully float various harmful impurities in the steel to obtain the final purified molten steel.

Ingot casting: The final purified molten steel is poured into ingots or continuous casting slabs, ready for rolling.

Blooming: The rolling of steel ingots or continuous casting slabs into strips in preparation for forging.

Forging and forming: blanking the blooming steel billet, heating and forging and forming.

Deformation heat treatment: the forging formed after forging is controlled and cooled by the remaining heat to obtain the expected structure and performance.

Compared with the prior art, the present invention has the following advantages:

1. It has excellent wear resistance, high strength and high toughness indicators.

2. It has stable internal quality.

3. Low production cost.

Detailed ways

Preparation of main raw materials:

A3 steel scrap, no serious corrosion,

High carbon ferrochromium FeCr67C6.0

Medium carbon ferromanganese FeMn80C1.5

Ferrosilicon FeSi75-A

Ferromolybdenum FeMo60-A

Ferrovanadium FeV75-A

Ferro-Titanium FeTi30-A

According to the process of electric arc furnace smelting→vacuum furnace refining→ladle refining outside the furnace→ingot casting→brief rolling→forging molding→deformation heat treatment process, the railway turnout center rail is produced.

Embodiment one

Chemical composition and content are proportioned according to the following ratio (weight %):

C 0.27, Si 0.8, Mn 1.0, Cr 1.1, Mo 0.35, V 0.17, Ti 0.09, P≤0.03, S≤0.025.

After deformation oil quenching, temper at 480 to obtain tempered sorbite structure.

The mechanical properties are as follows:

Strength σ _b = 1410Mpa, hardness HRC = 43, impact toughness α _ku = 51J/cm ² , elongation δ ₅ = 10%.

Embodiment two

Chemical composition and content are proportioned according to the following ratio (weight %):

C 0.36, Si 1.1, Mn 1.2, Cr 1.2, Mo 0.4, V 0.18, Ti 0.08, P≤0.03, S≤0.025.

After deformation normalizing, temper at 380°C to obtain bainite + retained austenite structure.

The mechanical properties are as follows:

Strength σ _b = 1420Mpa, hardness HRC = 42, impact toughness α _ku = 65J/cm ² , elongation δ ₅ = 9.5%.

Embodiment Three

Chemical composition and content are proportioned according to the following ratio (weight %):

C 0.45, Si 0.7, Mn 0.8, Cr 1.15, Mo 0.36, V 0.19, Ti 0.10, P≤0.03, S≤0.025.

After deformation oil quenching, temper at 520°C to obtain tempered sorbite structure.

The mechanical properties are as follows:

Strength σ _b = 1620Mpa, hardness HRC = 48, impact toughness α _ku = 50J/cm ² , elongation δ ₅ = 9%.

Claims (5)

1, a kind of high-strength abrasion-proof steel is characterized in that its Chemical Composition (weight %) is as follows:

C?0.25-0.55 Si?0.6-1.5 Mn?0.8-1.5 Cr?1-1.5 Mo?0.3-0.5

V?0.15-0.25 Ti?0.05-0.15 P≤0.03 S≤0.025

All the other are Fe and unavoidable impurities.

2, high-strength abrasion-proof steel according to claim 1 is characterized in that its Chemical Composition (weight %) is as follows:

C?0.25-0.35 Si?0.6-0.9 Mn?0.8-1.2 Cr?1-1.2 Mo?0.3-0.4

V?0.15-0.2 Ti?0.05-0.09 P≤0.03 S≤0.025

All the other are Fe and unavoidable impurities.

3, high-strength abrasion-proof steel according to claim 1 is characterized in that its Chemical Composition (weight %) is as follows:

C?0.28-0.4 Si?0.8-1.2 Mn?1.1-1.5 Cr?1.2-1.5 Mo?0.4-0.5

V?0.18-0.25 Ti?0.06-0.1 P≤0.03 S≤0.025

All the other are Fe and unavoidable impurities.

4, high-strength abrasion-proof steel according to claim 1 is characterized in that its Chemical Composition (weight %) is as follows:

C?0.3-0.48 Si?0.6-0.8 Mn?0.9-1.2 Cr?1.1-1.3 Mo?0.3-0.4

V?0.18-0.24 Ti?0.08-0.12 P≤0.03 S≤0.025

All the other are Fe and unavoidable impurities.

5,, it is characterized in that manufacturing process flow is according to the manufacture method of claim 1,2,3 or 4 described high-strength abrasion-proof steels:

Outer ladle refining → the ingot casting of electric arc furnace smelting → vacuum oven refining → stove → just roll into base → forging molding → thermomechanical treatment.