KR100634100B1 - High manganese steel having improved abrasion resistance and impact resistance and method for manufacturing the same - Google Patents

Abstract

The invention is 0.5 to 2% by weight of carbon (C), 0.5 to 1.5% by weight of silicon (Si), 5 to 30% by weight of manganese (Mn), 0.5 to 3% by weight of chromium (Cr) and 0.1 to 1.5 weight of vanadium (V) %, The remainder is composed of iron (Fe) and trace impurities, the content of carbon (C) and vanadium (V) of the components satisfy the formula [37 <21.4C + 28.8V <47] Phosphorus high manganese steel and its manufacturing method are provided.

High Manganese Steel, Wear Resistance, Impact Resistance, Jaw Crusher, Cone Crusher

Description

HIGH MANGANESE STEEL HAVING IMPROVED ABRASION RESISTANCE AND IMPACT RESISTANCE AND METHOD FOR MANUFACTURING THE SAME}

1 is a graph showing the change in yield strength according to the carbon (C) content and vanadium (V) content.

2 is a schematic diagram of an example of a jaw crusher to which high manganese steel according to the present invention can be applied.

3 is a schematic diagram of an example of a compactor to which high manganese steel according to the present invention can be applied.

4 shows the mold used in the examples (unit mm).

The present invention relates to a high manganese steel excellent in wear resistance and impact resistance and a method for producing the same.

Jaw crushers and Con crushers are machines used to produce aggregates. In general, the blasting gunpowder in the quarries to collect rock and then crushed continuously using a jaw crusher, a primary cone crusher and a secondary cone crusher to produce aggregate for construction such as sand, gravel.

The schematic diagram of the jaw crusher is shown in FIG. In the jaw crusher, the numerical plate and the lower part are fixed, but the upper part is composed of the equivalent plate which moves left and right by the rotation of the motor. The jaw crusher operates by discharging the crushed rock to the bottom by crushing the rock by the left and right movement of the upper plate when the rock is put on the upper plate.

The schematic diagram of the cone crusher is shown in FIG. The cone crusher is a method of discharging the rock crushed to the bottom by crushing the rock flowed to the upper by the mutual rotation and swing movement of the concave fixed to the top shell and the mantle fixed to the eccentrically assembled main shaft with the U-bolt. Works.

Jaw crusher equivalence plate, numerical plate, and concave and mantle of cone crusher are commonly referred to as liners. These liners are consumable parts of the crusher and act in direct contact with the rock or aggregate to break them down. Therefore, these liners are required to be impact resistant because of the risk of breakage due to impact generated during rock or aggregate fracture. In addition, these liners require abrasion resistance so that they can be used longer for improved productivity.

On the other hand, high-manganese steel is a material composed of the total amount of retained austenite structure at room temperature, unlike ordinary steel and excellent impact resistance. In addition, when sufficient plastic deformation is applied, the deformed portion is transformed and cured into high hardness martensite, and this part is excellent in wear resistance.

When the high manganese steel is applied to the liner of the jaw crusher or the cone crusher, the use surface of the liner of the jaw crusher or the cone crusher in contact with the stone is hardened by martensite by impact with the stone, and the wear resistance is excellent. The part has excellent impact resistance and can be used for a long time without being damaged during use.

In general, the high manganese steel used in the jaw crusher and the cone crusher liner is KS standard SCMn H11, and its chemical composition and mechanical properties are shown in Table 1 below.

standard Chemical composition (wt%) Yield strength The tensile strength Elongation Hardness C Si Mn P S Cr Fe SCMnH11 0.90 to 1.30 <0.80 11.00-14.00 <0.070 <0.040 1.50-2.50 Remaining amount > 40 > 75 > 20 > 192

The present inventors have found that the composition of high manganese steel having high impact resistance and wear resistance has a desired yield strength in a predetermined range because the high manganese steel has a low impact resistance when the yield strength is too large and the yield strength is too small.

Therefore, an object of the present invention is to provide a high manganese steel excellent in both impact resistance and wear resistance.

The present invention is 0.5 to 2% by weight of carbon (C), 0.5 to 1.5% by weight of silicon (Si), 5 to 30% by weight of manganese (Mn), 0.5 to 3% by weight of chromium (Cr) and 0.1 to 1.5 of vanadium (V). It includes the weight percent, the remaining amount is composed of iron (Fe) and trace impurities, the content of carbon (C) and vanadium (V) among the components satisfy the formula [37 <21.4C + 28.8V <47] Provides high manganese steel.

The high manganese steel according to the present invention may further comprise 0.05 to 0.2 wt% of titanium (Ti) and / or 0.05 to 0.2 wt% of aluminum (Al).

The present invention also provides a crusher liner made of high manganese steel according to the present invention.

In addition, the present invention

i) 0.5 to 2% by weight of carbon (C), 0.5 to 1.5% by weight of silicon (Si), 5 to 30% by weight of manganese (Mn), 0.5 to 3% by weight of chromium (Cr) and 0.1 to 1.5% by weight of vanadium (V) Dissolving raw materials containing% and the remaining amount of iron (Fe) and whose contents of carbon (C) and vanadium (V) satisfy the formula [37 <21.4 C + 28.8 V <47] ;

ii) casting the molten metal obtained in step i) into a mold;

iii) heat-treating the casting prepared in step ii) at 1000 to 1200 ° C.

It provides a method of manufacturing high manganese steel comprising a.

In the manufacturing method according to the present invention, in the initial and / or late stages of the tapping, which is the act of transferring the molten metal to the ladle for injection into the mold after the completion of dissolution in step i), 0.05 to 0.2 weight of aluminum and / or titanium, respectively. It may further comprise the step of injecting.

Hereinafter, the present invention will be described in detail.

First, the reason for limiting each component and their content constituting the high manganese steel according to the present invention will be described.

1) Carbon (C) 0.5 ~ 2.0 wt%

Carbon (C) is the most influential element in the mechanical properties of high manganese steel. When the content is insufficient, the yield strength is lowered, and when exceeded, excessive carbides are formed to increase the brittleness of high manganese steel. Specifically, it is as follows.

In general, when the carbon content is 0.5% by weight or less, the residual austenite matrix of high manganese steel is transformed into lath martensite having a low yield strength by processing deformation occurring in use. In addition, when the carbon content is 2.0% by weight or more, carbides are formed and the formed carbides are not fully dissolved by the subsequent heat treatment for homogenization of the high manganese steel, so that the high manganese steel has a problem of brittleness even after the heat treatment.

2) Silicon (Si) 0.5 ~ 1.5 wt%

Silicon is an element usually present in a certain amount in steel materials, which increases the deoxidation and castability of the casting. However, when the content is less than 0.5% by weight, the effect is insignificant, and when the content exceeds 1.5% by weight, there is a problem of lowering the mechanical properties of high manganese steel.

3) Manganese (Mn) 5 ~ 30 wt%

Manganese is the main element that forms the total structure of the high manganese steel as the total amount of retained austenite, and when the content is about 5% by weight or more, the total amount of retained austenite can be obtained at room temperature. In addition, when the manganese content exceeds 30% by weight there is a problem that the impact resistance of the high manganese steel is significantly lowered. Therefore, in the present invention, the manganese (Mn) content is preferably 5 to 30% by weight. As the manganese content increases, the solid solution of the high manganese steel material is strengthened and the yield strength is increased. In the present invention, the manganese content is more preferably 15% to 30% by weight, more preferably 19 to 21% by weight.

4) 0.5 to 3.0% by weight of chromium (Cr),

Chromium increases the matrix strength of high manganese steels and forms carbides to improve wear resistance. If the content is 0.5 wt% or less, the effect is insignificant, and if more than 3.0 wt% there is a problem that brittleness is significantly increased. In the present invention, the chromium content is more preferably 0.9 to 1.1% by weight.

5) Vanadium (V) 0.1 ~ 1.5 wt%

Vanadium is an element not included in the conventional KS standard SCMn H11. It is a strong carbide forming element that crystallizes carbides at high temperatures, and forms high hardness carbides to improve wear resistance. In addition, vanadium carbide crystallized before the matrix solidification of high manganese steel prevents grain coarsening, thereby improving both tensile strength and elongation. If the vanadium content is less than 0.1% by weight, the effect is insignificant, and if more than 1.5% by weight there is a problem that significantly increased brittleness.

6) Titanium (Ti) 0.05 ~ 0.2 wt%

Titanium forms titanium nitride in the production of high manganese steel to remove nitrogen gas, and acts as a carbide nucleation site to promote grain refinement. If the titanium content is 0.05% by weight or less, the effect is insignificant, when 0.2% by weight or more there is a problem that significantly increased brittleness.

7) Aluminum (Al) 0.05 ~ 0.2 wt%

Aluminum forms aluminum oxide or aluminum nitride in the manufacture of high manganese steel to remove oxygen gas or nitrogen gas (N ₂ ), and acts as a carbide nucleation site to promote grain refinement. If the aluminum content is 0.05% by weight or less, the effect is insignificant, and when 0.2% by weight or more, there is a problem in that brittleness is significantly increased.

8) Equation 37 <21.4 C + 28.8 V <47

The present inventors have found that it is desirable to make the yield strength of the high manganese steel within the range of 50 to 60 kg / mm ² in order to improve both the impact resistance and the wear resistance of the high manganese steel. Specifically, it is as follows.

Both carbon and vanadium are the most potent hardening and carbide forming elements of the high manganese steel matrix structure, and as the content thereof increases, the yield strength of the high manganese steel increases. However, when the yield strength is excessively large, there is a disadvantage in that the elongation falls. Therefore, it is preferable to adjust the yield strength of high manganese steel to an appropriate range. In this invention, it is preferable that the yield strength of high manganese steel is 50-60 kg / mm <^2> .

The inventors of the present invention control the yield strength of high manganese steel to the above range when the content of carbon and vanadium, which have the greatest influence on the yield strength of high manganese steel, is satisfied to satisfy the formula of 37 <21.4C + 28.8V <47. It turns out that you can. As described below, the change in yield strength according to the carbon content and the vanadium content obtained in the example is shown in FIG. 1. Through this, it can be seen that the yield strength of the high manganese steel falls within the range of 50 to 60 kg / mm ² when the content of carbon and vanadium in the components of the high manganese steel of the present invention satisfies the above formula.

The manufacturing method of the high manganese steel which concerns on this invention using the above-mentioned component is as follows.

First, 0.5 to 2% by weight of carbon (C), 0.5 to 1.5% by weight of silicon (Si), 5 to 30% by weight of manganese (Mn), 0.5 to 3% by weight of chromium (Cr), and 0.1 to 1.5 weight of vanadium (V) Molten material is obtained by dissolving raw materials containing% and a residual amount of iron and whose contents of carbon (C) and vanadium (V) satisfy the formula [37 <21.4C + 28.8V <47].

As a melting method, after a predetermined amount of primary scrap iron, high manganese steel recovery scrap metal, and medium carbon ferro manganese are put into an electric furnace, respectively, melting is performed. After the charged raw materials are dissolved, the primary component analysis is performed. After primary component analysis, a predetermined amount of high-carbon ferro-manganese, medium-carbon ferro-manganese, silly manganese, and ferrovanadium are added. Secondary component analysis is carried out, and after adding a small amount of the alloy less than the target component and tapping. At this time, it is preferable to make melting temperature into 1540-1600 degreeC. Subsequently, the tapping is preferably performed by tapping the ladle at a temperature of solidification temperature +70 to 80 ° C after measuring the solidification temperature with a solidification temperature measuring instrument having a built-in thermocouple.

When a large amount of minute gas defects are present inside and outside the grains of a cast made of high manganese steel according to the present invention, the mechanical properties of the cast may be deteriorated. In order to prevent this, aluminum is added in an amount of 0.05 to 0.2 wt% at the beginning of the tapping process. At the end of the tapping process, titanium is added at 0.05 to 0.2% by weight to perform deoxidation and denitrification.

The molten metal is then poured into the mold at the appropriate temperature to obtain a casting. The injection temperature is preferably 40 to 50 ° C higher than the liquidus temperature of the molten metal. In this case, the liquidus temperature of the molten metal may be measured by a solidification temperature measuring instrument having a built-in thermocouple. When the injection temperature is low, casting defects such as a glass diameter can be obtained, and when high, a coarse grain or columnar structure can be obtained.

The structure of the high manganese steel can then be homogenized by heat treating the casting. The heat treatment may be carried out in a manner of 2 hours per inch of the maximum thickness of the casting at a temperature of 1000 to 1200 ° C, preferably 1150 ° C. If the heat treatment temperature and time is insufficient, carbides determined in the kitchen state may not be completely employed. If the heat treatment temperature and time exceeds the standard, grain coarsening may deteriorate the mechanical properties of the high manganese steel.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to illustrate the present invention, and the scope of the present invention is not limited thereto.

[Manufacture of High Manganese Steel Castings]

12% primary scrap iron, 70% recovered high manganese steel, 5% medium carbon ferro-manganese (72 wt% Mn, 2.3 wt% C, Fe balance) were added to the electric furnace, and then dissolved. After the charged raw materials were dissolved, primary component analysis was performed. Approximately 4% of high carbon ferromangan (72% by weight of Mn, 6.6% by weight of C, Fe balance), about 5% of medium carbon ferromangan, about 4% of silly manganese (60% by weight of Mn, after Si) 15% by weight, C 2% by weight, Fe balance) and about 0.6% of ferrovanadium (80% by weight, 20% by weight of iron) were added. Secondary component analysis was carried out, and after adding a small amount of the alloy less than the target component and tapping. The melting temperature was 1540-1600 degreeC at this time. After the coagulation temperature was measured by a coagulation temperature measuring instrument with a built-in thermocouple, the ladle was tapped at a temperature of coagulation temperature + 70 to 80 ° C. At this time, 0.1% Al was added to the ladle for deoxidation and denitrification.

Each molten metal was injected into a Y-type mold as shown in FIG. 4 at a temperature of solidification temperature + 40 to 50 ° C. After the injection was completed, the mold was removed after 3 hours of sufficient solidification to prepare a casting for producing a tensile test specimen and a hardness test specimen.

When the casting operation was completed, the product was heat treated at 1150 ° C. for 2 hours per inch of product thickness and quenched in a water bath. Tensile and hardness specimens were prepared by lathe machining for each of the high manganese steels after heat treatment. And hardness. The measured mechanical properties are shown in Table 2 below.

In addition, the mechanical properties of the five products of the commercially available KS standard SCMn H11 were measured and shown in Table 2 below.

division  number Chemical composition Property evaluation result C Si Mn P S Cr V Yield strength (kg / mm ² ) Tensile Strength (kg / mm ² ) Elongation (%) Hardness (HB) Example One 1.29 0.45 20.09 0.065 0.009 1.01 0.452 52.1 83.7 29.5 201 2 1.23 0.47 20.52 0.069 0.002 0.98 0.511 55.9 83.6 25.9 220 3 1.22 0.42 19.59 0.055 0.002 1.02 0.393 53.1 84.6 27.0 218 4 1.28 0.58 20.08 0.059 0.005 0.98 0.624 59.75 81 19.6 227.5 5 1.27 0.57 19.40 0.054 0.002 0.94 0.337 53.5 81.5 26 227 6 1.53 0.73 19.91 0.062 0.002 1.23 0.485 59.6 61.8 1.3 227 7 1.35 0.55 20.73 0.068 0.004 1.07 0.712 61.8 79.8 15.6 235 8 1.29 0.53 20.13 0.053 0.002 0.89 0.632 57.9 78.1 17.7 225 9 1.33 0.47 20.17 0.062 0.002 1.00 0.552 57.6 73.95 14.0 227 Comparative example One 1.09 0.40 10.40 0.050 0.004 2.01 0 43.2 66.4 24.4 180 2 1.16 0.39 11.42 0.074 0.007 1.55 0 43.5 79.5 33.2 197 3 1.05 0.69 11.73 0.031 0.002 1.78 0 43.5 83.4 36.9 185 4 1.16 0.39 11.42 0.074 0.006 1.55 0 43.8 78.7 31.7 197 5 1.16 0.57 11.98 0.056 0.003 1.90 0 46.1 75.9 25.6 190

Using the results of Examples 1 to 9, the change in yield strength according to carbon content and vanadium content is shown in FIG. 1. Through this, it can be seen that the high manganese steel having the composition according to the present invention has a yield strength within a predetermined range.

In addition, as shown in Table 2, the high manganese steel casting prepared in Examples 1 to 5 has a yield strength of about 10 kg / mm ² , tensile strength of about 6 kg / mm ² , compared to commercially available high manganese steel castings, The Brinnell hardness was about 30 HB higher. In addition, the high-manganese steel castings of Examples 1 to 5 reduced the elongation by only about 5% by weight compared with the above-described strength and hardness improvement. From the above results, it can be seen that the high manganese steel casting prepared in the embodiment according to the present invention has excellent mechanical properties as a whole compared to the conventional high manganese steel casting.

Experimental Example of Application to Crusher Liner

In order to evaluate the actual use, the jaw crusher liner was manufactured and mounted on the jaw crusher producing aggregate to measure the aggregate production. Fabrication of the liner was carried out in the same manner as the production of high manganese steel castings in the examples. The components of the liner and the uptime of the manufactured liner, aggregate production until liner disposal are shown in Table 3 below.

Jaw crusher Liner Test company High Manganese Steel Uptime (Hr) Aggregate production (m ³ ) manufacturer product name manufacturer division INI Steel FSK-4230 INI Steel SCMn H11 Gangil Industrial Development (Asan Site) Same as Comparative Example 1 350 40002 Same as Comparative Example 2 280 30487 Same as Comparative Example 3 180 18621 Same as Comparative Example 4 290 30956 Same as Comparative Example 5 225 23227 Comparative example mean 265 28659 Invention Same as Example 1 510 47553

As shown in Table 3 above, the aggregate production up to the disposal of the liner according to the present invention was improved by about 166% by volume compared to a liner made of a conventional general SCMn H11 high manganese steel product. Since the same stone was used in the examples and the comparative examples, the specific gravity is the same, so the volume% may be interpreted to represent the same ratio as the weight%.

Manganese alloy steel according to the present invention is excellent in both wear resistance and impact resistance because the yield strength falls within a predetermined range. Therefore, the manganese alloy steel according to the present invention is useful as a liner such as jaw crusher or cone crusher.

Claims (7)

0.5 to 2% by weight of carbon (C), 0.5 to 1.5% by weight of silicon (Si), 5 to 30% by weight of manganese (Mn), 0.5 to 3% by weight of chromium (Cr) and 0.1 to 1.5% by weight of vanadium (V) And the remaining amount is composed of iron (Fe) and trace impurities, and the content of carbon (C) and vanadium (V) among the components satisfies the formula [37 <21.4C + 28.8V <47] It is made of knight, high manganese steel, characterized in that the yield strength is 50 ~ 60 kg / mm ² . The high manganese steel of claim 1, wherein the high manganese steel further comprises 0.05 to 0.2 wt% of titanium (Ti) and 0.05 to 0.2 wt% of aluminum (Al). delete delete A crusher liner made of the high manganese steel of claim 1. i) 0.5 to 2% by weight of carbon (C), 0.5 to 1.5% by weight of silicon (Si), 5 to 30% by weight of manganese (Mn), 0.5 to 3% by weight of chromium (Cr) and 0.1 to 1.5% by weight of vanadium (V) % And residual amount of iron (Fe), and the content of carbon (C) and vanadium (V) among the components after melting the raw material satisfying the formula [37 <21.4C + 28.8V <47] 0.05 to 0.2% by weight of aluminum in the step of tapping, and tapping step of adding 0.05 to 0.2% by weight of titanium at the end of tapping; ii) casting by injecting the molten metal obtained in step i) into a mold; iii) heat treatment step of heat-treating the casting prepared in step ii) at 1000-1200 ° C. for 2 hours per inch of maximum thickness Method of manufacturing high manganese steel comprising a. delete

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