CN116083803A - Age hardening type light high manganese steel and preparation method thereof - Google Patents

Abstract

The object of the invention is to provide an age-hardening light-weight high-manganese steel and a preparation method thereof in view of the technical problems existing in the existing high-manganese steel for wear-resistant parts. The mass percent of the chemical composition of the high manganese steel of the present invention is 1.3% to 1.4% C, 0.3% to 0.6% Si, 28.0% to 32.0% Mn, 8.5% to 9.0% Al, P<0.015% and S<0.015%. The amount is Fe and unavoidable impurities. The invention provides a light-weight high-manganese steel with good wear resistance, low production cost and long service life and a preparation method thereof through reasonable composition design and heat treatment process design.

Description

A kind of age-hardening type lightweight high manganese steel and preparation method thereof

technical field

The invention belongs to the technical field of iron and steel material production, and in particular relates to a light-weight high-manganese steel and a preparation method thereof.

Background technique

In the field of metallurgical and mining technology, wear-resistant parts have always been very important parts with a high wear rate, mainly used in the fields of ball mill liners, cone crusher liners and forklift teeth. The working environment is complex and the workload is huge, and its performance and service life directly affect the working efficiency and production cost of mining equipment. At present, traditional high manganese steel is widely used in wear-resistant liners in my country, but the yield strength and initial hardness are low. If the work hardening effect cannot be fully exerted, the wear resistance of traditional high manganese steel cannot meet the needs of mining equipment. In recent years, some ultra-high manganese steel lining plates have appeared, such as the patent of publication number CN102433508A, which provides a kind of ultra-high manganese steel lining plate and its preparation method, although its wear resistance is 30% higher than that of ordinary high manganese steel, but When used on large-scale mining equipment, due to the heavy weight of the liner, the energy consumption is increased, resulting in a less obvious comprehensive effect of the increased wear resistance; and patent No. CN1080327 discloses a low-alloy wear-resistant liner and its manufacturing process , the invention has a higher production cost due to the addition of expensive molybdenum and copper.

Therefore, it is necessary to further develop high manganese steel for wear-resistant parts.

Contents of the invention

The object of the present invention is to provide an age-hardening light-weight high-manganese steel and a preparation method thereof in view of the technical problems existing in the existing high-manganese steel for wear-resistant parts. The invention provides a light-weight high-manganese steel with good wear resistance, low production cost and long service life and a preparation method thereof through reasonable composition design and heat treatment process design.

One of the technical solutions of the present invention is an age-hardening light-weight high-manganese steel, whose chemical composition mass percentage is 1.3%-1.4%C, 0.3%-0.6%Si, 28.0%-32.0%Mn, 8.5%- 9.0% Al, P<0.015% and S<0.015%, the balance is Fe and unavoidable impurities.

The effect of the chemical composition of age-hardening type lightweight high manganese steel of the present invention is:

C: Carbon is the main element that determines the mechanical properties and wear resistance of high manganese steel, and its function is to produce solid solution strengthening and promote the formation of austenite. The carbon content of high manganese steel is generally 0.9-1.5w.t.%. When the content is too high (over 1.5w.t.%), the high manganese steel is prone to embrittlement; when the carbon content is too low, it will lead to insufficient wear resistance. In the present invention, the carbon content is designed to be 1.3%-1.4% in order to increase the wear resistance of the light ultra-high manganese steel and to control the volume fraction of precipitated carbides during the aging process.

Al: It is very difficult to control the addition of aluminum elements in the molten steel for the metallurgical process, and it is easy to cause pores to form inside the ingot, making the material not dense enough. And aluminum is an element that shrinks the austenite zone. In order to obtain the austenite structure at room temperature, the content of aluminum must be well controlled. The addition of aluminum can significantly reduce the material density and provide a chemical driving force for the precipitation of carbides. Therefore, the present invention designs the aluminum content to be 8.5% to 9.0%.

Si: Within the conventional content range, the addition of silicon is mainly to assist deoxidation. When silicon dissolves in austenite, it affects the solubility of carbon in austenite, promotes the precipitation of carbides, and can increase the yield strength to a certain extent. However, when the silicon content is high, carbides are precipitated along the grain boundaries, resulting in a large amount of coarse grains in the high manganese steel, which reduces impact toughness and wear resistance. Therefore, the present invention designs the silicon content to be 0.3% to 0.6%.

Mn: As the main alloying element, manganese expands the austenite phase region and stabilizes the austenite structure. Castings with large cross-sections and complex structures should have higher manganese content. For castings with strong impact, low-carbon and high-manganese are used. Therefore, improving wear resistance without reducing impact toughness is the development of light-weight high-manganese steel. an important direction. Therefore, the present invention designs the manganese content to be 28.0%-32.0%.

P and S: Phosphorus and sulfur, as harmful elements, produce eutectics of MnS and P, which are distributed on grain boundaries and reduce impact toughness. With the increase of P content, the service life of castings is reduced, and the segregation of C and Mn is easy to occur in high manganese steel, which will aggravate the harmful effect of phosphorus, and its content must be strictly controlled. Therefore, the present invention designs the content of phosphorus and sulfur below 0.015%.

Further, the above-mentioned age-hardening light-weight high-manganese steel has a density of 6.61-6.64 g/cm ³ .

The second technical solution of the present invention is the preparation method of the above-mentioned age-hardening light-weight high manganese steel, the steps are as follows:

(1) Smelting high manganese steel:

According to the above-mentioned high-manganese steel mass ratio and ingredients, first melt pure iron, carbon, silicon and manganese elements, and add aluminum element when the temperature rises to 1570-1585°C; Tapping at ℃; then pouring into the mold cavity within the temperature range of 1400℃～1450℃, when the surface temperature of the casting does not exceed 400℃, the casting is separated;

(2) Aging treatment:

Heat the casting at a heating rate of 70-100°C/h to 1030-1060°C, keep it warm for 1.5-3 hours, and then cool it to room temperature with water; then heat it up to 540-560°C at a heating rate of 50-70°C/h, and keep it warm for 1- 3h, then air cooled to room temperature.

Further, according to the above preparation method of age-hardening light-weight high-manganese steel, the tensile strength of the light-weight high-manganese steel produced is 818.7-1088.5 MPa, and the yield strength is 743.2-1030.9 MPa.

Further, in the preparation method of the above age-hardened light-weight high-manganese steel, the obtained light-weight high-manganese steel has an elongation after fracture of 8.4-33.3%, an impact toughness (V-shaped notch) of 33-96 J/cm ² , and a hardness of It is 240~293HB.

Further, in the preparation method of the above-mentioned age-hardened light-weight high-manganese steel, the wear percentage of the prepared light-weight high-manganese steel is 0.56-0.65% under low impact load (0.5J); under high impact load (4J) , The wear percentage is 0.41-0.52%.

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

1. The invention optimizes the alloy design and has a lower density. The density of the high manganese steel is about 6.63g/cm ³ , which is 15%-20% lower than that of the traditional high manganese steel. Besides, the steel grade of the present invention also has excellent hardness, strength and wear resistance.

2. The castings of the present invention do not contain precious metals such as copper and molybdenum. Compared with the wear-resistant castings of medium and low alloys, the cost of the castings of the present invention is significantly reduced, and its cost performance is higher.

Description of drawings

Fig. 1 is the material metallographic structure diagram of embodiment 1;

Fig. 2 is the picture of light high manganese steel in embodiment 1;

Among them, (a) and (b) are scanning photo (SEM) pictures, A and B in picture (b) are κ-carbide and austenite matrix respectively; (c) and (d) are energy spectrum analysis pictures (EDS).

Detailed ways

In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will describe in detail with reference to the drawings and specific embodiments.

The invention provides an age hardening light high manganese steel and a preparation method thereof.

Example 1

The composition content of age hardening light high manganese steel is shown in Table 1:

Table 1. Alloy element composition of light high manganese steel (unit: wt.%)

Smelting and casting: Smelting high manganese steel in a vacuum melting furnace, first melting pure iron and elements such as carbon, silicon and manganese, and adding aluminum element when the temperature rises to 1580°C. The smelting time is 1.5h. Steel is tapped at 1530°C to 1560°C. After that, it is poured into the cavity of the metal mold within the temperature range of 1400°C to 1450°C, and the casting is separated when the surface temperature of the casting does not exceed 400°C.

Aging treatment: Use an electric furnace that can precisely control the heating rate, temperature, and holding time to heat-treat the casting, heat up to 1050°C at a heating rate of 80°C/h, keep it warm for 1.5h, and then water-cool to room temperature; then use a heating rate of 60°C/h The heating rate was raised to 550°C, kept for 2 hours, and then air-cooled to room temperature.

According to the density measurement, the density of the light high manganese steel casting sample obtained in this embodiment is 6.63g/cm ³ . According to GB/T228.1/2010 "Metallic Materials Tensile Test Part 1: Room Temperature Test Method", GB/T229-2020 "Metallic Materials Charpy Pendulum Impact Test Method", GB/T231.1-2018 "Metallic Materials Brinell Hardness Test Part 1: Test Method" and T/CFA010604-3-2016 "Impact Abrasive Wear Test Method for Iron and Steel Materials" were used to measure the mechanical properties of the lightweight high manganese steel casting samples obtained in this example.

The mechanical properties of the light high manganese steel obtained in this example are: tensile strength is 1041.7MPa, yield strength is 1002.7MPa, elongation after fracture is 17.6%, impact toughness (V-notch) is 62J/cm ² , The hardness is 269HB. At low impact load (0.5J) the percent wear was 0.57%; at high impact load (4J) the percent wear was 0.48%.

Example 2

The composition content of age hardening light high manganese steel is shown in Table 2:

Table 2. Alloy element composition of light high manganese steel (unit: wt.%)

Smelting and casting: Smelting high manganese steel in a vacuum melting furnace, first melting pure iron and elements such as carbon, silicon and manganese, and adding aluminum element when the temperature rises to 1580°C. The smelting time is 1.5h. Steel is tapped at 1530°C to 1560°C. After that, it is poured into the cavity of the metal mold within the temperature range of 1400°C to 1450°C, and the casting is separated when the surface temperature of the casting does not exceed 400°C.

Aging treatment: Use an electric furnace that can precisely control the heating rate, temperature, and holding time to heat-treat the casting, heat up to 1050°C at a heating rate of 80°C/h, keep it warm for 1.5h, and then water-cool to room temperature; then use a heating rate of 60°C/h The heating rate was raised to 550°C, kept for 3 hours, and then air-cooled to room temperature.

According to the density measurement, the density of the light high manganese steel casting sample obtained in this embodiment is 6.63g/cm ³ . According to GB/T228.1/2010 "Metallic Materials Tensile Test Part 1: Room Temperature Test Method", GB/T229-2020 "Metallic Materials Charpy Pendulum Impact Test Method", GB/T231.1-2018 "Metallic Materials Brinell Hardness Test Part 1: Test Method" and T/CFA010604-3-2016 "Impact Abrasive Wear Test Method for Iron and Steel Materials" were used to measure the mechanical properties of the lightweight high manganese steel casting samples obtained in this example.

The mechanical properties of the light high manganese steel casting obtained in this example are: the tensile strength is 1088.5MPa, the yield strength is 1030.9MPa, the elongation after fracture is 8.4%, and the impact toughness (V-shaped notch) is 33J/ ^cm2 , the hardness is 293HB. At low impact load (0.5J) the percent wear was 0.56%; at high impact load (4J) the percent wear was 0.52%.

Example 3

The composition content of age hardening light high manganese steel castings is shown in Table 3:

Table 3. Alloy element composition of light high manganese steel (unit: wt.%)

Smelting and casting: Smelting high manganese steel in a vacuum melting furnace, first melting pure iron and elements such as carbon, silicon and manganese, and adding aluminum element when the temperature rises to 1580°C. The smelting time is 1.5h. Steel is tapped at 1530°C to 1560°C. After that, it is poured into the cavity of the metal mold within the temperature range of 1400°C to 1450°C, and the casting is separated when the surface temperature of the casting does not exceed 400°C.

Aging treatment: Use an electric furnace that can precisely control the heating rate, temperature, and holding time to heat-treat the casting, heat up to 1050°C at a heating rate of 80°C/h, keep it warm for 1.5h, and then water-cool to room temperature; then use a heating rate of 60°C/h The heating rate was raised to 550°C, kept for 1 hour, and then air-cooled to room temperature.

According to the density measurement, the density of the light high manganese steel casting sample obtained in this embodiment is 6.63g/cm ³ . According to GB/T228.1/2010 "Metallic Materials Tensile Test Part 1: Room Temperature Test Method", GB/T229-2020 "Metallic Materials Charpy Pendulum Impact Test Method", GB/T231.1-2018 "Metallic Materials Brinell Hardness Test Part 1: Test Method" and T/CFA010604-3-2016 "Impact Abrasive Wear Test Method for Iron and Steel Materials" were used to measure the mechanical properties of the lightweight high manganese steel casting samples obtained in this example.

The mechanical properties of the light high manganese steel casting obtained in this example are: tensile strength is 818.7MPa, yield strength is 743.2MPa, elongation after fracture is 33.3%, and impact toughness (V-shaped notch) is 96J/ ^cm2 , the hardness is 240HB. At low impact load (0.5J) the percent wear was 0.65%; at high impact load (4J) the percent wear was 0.41%.

Example 4

The composition content of age hardening light high manganese steel castings is shown in Table 3:

Table 3. Alloy element composition of light high manganese steel (unit: wt.%)

Smelting and casting: Smelting high manganese steel in a vacuum melting furnace, first melting pure iron and elements such as carbon, silicon and manganese, and adding aluminum element when the temperature rises to 1570°C. The smelting time is 1h. Steel is tapped at 1530°C to 1560°C. After that, it is poured into the cavity of the metal mold within the temperature range of 1400°C to 1450°C, and the casting is separated when the surface temperature of the casting does not exceed 400°C.

Aging treatment: use an electric furnace that can precisely control the heating rate, temperature, and holding time to heat-treat the castings, heat up to 1030°C at a heating rate of 70°C/h, hold for 2 hours, and then water-cool to room temperature; then heat at 50°C/h Speed up to 540°C, keep warm for 2 hours, and then air cool to room temperature.

According to the density measurement, the density of the light high manganese steel casting sample obtained in this embodiment is 6.63g/cm ³ .

Example 5

The composition content of age hardening light high manganese steel castings is shown in Table 3:

Table 3. Alloy element composition of light high manganese steel (unit: wt.%)

Smelting and casting: Smelting high manganese steel in a vacuum melting furnace, first melting pure iron and elements such as carbon, silicon and manganese, and adding aluminum element when the temperature rises to 1585°C. The smelting time is 1.25h. Steel is tapped at 1530°C to 1560°C. After that, it is poured into the cavity of the metal mold within the temperature range of 1400°C to 1450°C, and the casting is separated when the surface temperature of the casting does not exceed 400°C.

Aging treatment: Use an electric furnace that can precisely control the heating rate, temperature, and holding time to heat-treat the casting, heat up to 1060°C at a heating rate of 100°C/h, keep it warm for 3 hours, and then water-cool to room temperature; then heat at 70°C/h Speed up to 560°C, keep warm for 2 hours, and then air cool to room temperature.

According to the density measurement, the density of the light high manganese steel casting sample obtained in this embodiment is 6.63g/cm ³ .

The above description is a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, these improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (6)

1. The age hardening type light high manganese steel is characterized by comprising, by mass, 1.3% -1.4% of C, 0.3% -0.6% of Si, 28.0% -32.0% of Mn, 8.5% -9.0% of Al, less than 0.015% of P and less than 0.015% of S, and the balance of Fe and unavoidable impurities.

2. The age hardened light weight high manganese steel according to claim 1, wherein the high manganese steel has a density of 6.61 to 6.64g/cm ³ 。

3. The method for preparing age-hardening type light high manganese steel according to claim 1, which is characterized by comprising the following steps:

(1) Smelting high manganese steel:

the high manganese steel is prepared according to the mass ratio of claim 1, pure iron, carbon, silicon and manganese are melted, and aluminum is added when the temperature is increased to 1570-1585 ℃; smelting for 1-1.5 h, and tapping at 1530-1560 ℃; then pouring the mixture into a die cavity at the temperature of 1400-1450 ℃, and separating the casting when the surface temperature of the casting is not more than 400 ℃;

(2) Aging treatment:

heating the casting to 1030-1060 ℃ at a heating rate of 70-100 ℃/h, preserving heat for 1.5-3h, and then cooling to room temperature; heating to 540-560 ℃ at a heating rate of 50-70 ℃/h, preserving heat for 1-3h, and then air cooling to room temperature.

4. The method for producing age-hardened light high manganese steel according to claim 3, wherein the tensile strength of the light high manganese steel is 818.7-1088.5 MPa and the yield strength is 743.2-1030.9 MPa.

5. The method for producing age-hardened light-weight high-manganese steel according to claim 3, wherein the elongation after fracture of the light-weight high-manganese steel is 8.4 to 33.3% and the impact toughness is 33 to 96J/cm ² The hardness is 240-293 HB.

6. The method for producing age-hardened light high manganese steel according to claim 3, wherein the wear percentage of the produced light high manganese steel is 0.56 to 0.65% under low impact load; the abrasion percentage is 0.41-0.52% under high impact load.

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