JP5380892B2 - Wear-resistant steel plate with excellent workability and method for producing the same - Google Patents

Description

  The present invention is used in the fields of construction, civil engineering, mining, etc., for example, members such as power shovels, bulldozers, hoppers, buckets, etc., where wear due to contact with earth and sand becomes a problem The present invention relates to a wear-resistant steel plate suitable for use and a method for producing the same, and particularly to a material excellent in bending workability.

  For members that receive wear due to soil, sand, etc., steel materials having excellent wear resistance are used to extend the life. It is known that the wear resistance of steel materials is improved by increasing the hardness, and for materials that require wear resistance, quenching is performed on steel materials to which a large amount of alloy elements such as Cr and Mo are added. Steel materials that have been subjected to a heat treatment such as that have been hardened have been used.

  For example, Patent Document 1 includes C: 0.10 to 0.19%, steel containing appropriate amounts of Si and Mn, and Ceq limited to 0.35 to 0.44%, after hot rolling. There has been proposed a method for producing a wear-resistant steel sheet that is directly quenched or reheated to 900 to 950 ° C. and then quenched, tempered at 300 to 500 ° C., and having a steel sheet surface hardness of 300 HV or higher.

  Patent Document 2 includes C: 0.10 to 0.20%, and Si, Mn, P, S, N, and Al are adjusted to appropriate amounts, or 1 of Cu, Ni, Cr, Mo, and B is further added. Proposed method for manufacturing wear-resistant thick steel plates that harden steels containing more than seeds directly after hot rolling or after cooling and then reheat and quench to give a hardness of 340HB or more Has been.

  Patent Document 3 includes C: 0.07 to 0.17%, and Si, Mn, P, S, N, and Al are adjusted to appropriate amounts, or 1 of Cu, Ni, Cr, Mo, and B is further added. A steel containing more than seeds is immediately quenched after hot rolling, or once air-cooled and then re-heated and quenched, and the surface hardness is 321 HB or more, and the steel is excellent in bending workability. Manufacturing methods have been proposed.

  The techniques described in Patent Documents 1 to 3 improve wear resistance characteristics by adding a large amount of alloy elements and utilizing solid solution hardening, transformation hardening, precipitation hardening, etc. to increase the hardness. ing. However, when a large amount of alloy elements are added and solid solution hardening, transformation hardening, precipitation hardening, etc. are utilized to increase the hardness, the weldability and workability will decrease, and the manufacturing cost will be further reduced. Soaring.

  By the way, in the case of a member that requires wear resistance, depending on the use conditions, there may be a case where only the vicinity of the surface is hardened to improve the wear resistance, and the steel material used in such a case In this case, it is not necessary to add a large amount of alloying elements such as Cr and Mo, and it is considered that only the vicinity of the surface is made a quenched structure by performing a heat treatment such as a quenching process.

  However, in order to increase the hardness of the hardened structure, it is generally necessary to increase the solid solution C amount of the steel material. However, the increase in the solid solution C amount causes a decrease in weldability, a decrease in bending workability, and the like. Particularly, the decrease in bending workability restricts the bending work necessary as a member and restricts the use conditions.

For this reason, there is a demand for a wear-resistant steel sheet capable of improving the wear resistance without excessively increasing the hardness. Patent Document 4 includes C: 0.10 to 0.45%. , Si, Mn, P, S, N are adjusted to appropriate amounts, and further Ti: 0.10 to 1.0%, TiC precipitates having an average particle size of 0.5 μm or more, or TiC and TiN, TiS A wear-resistant steel excellent in surface properties that includes 400 / mm ² or more of composite precipitates and Ti * of 0.05% or more and less than 0.4% has been proposed.

  Further, in Patent Document 5, C: 0.05 to 0.45%, Si: 0.1 to 1.0%, Mn: 0.1 to 1.0%, Ti: 0.05 to 1.5 %, And a surface hardness of 401 or less in terms of Brinell hardness has been proposed for producing a wear-resistant steel sheet with improved bending workability.

According to the techniques described in Patent Documents 4 and 5, it is possible to produce precipitates mainly composed of coarse TiC during solidification and to improve wear resistance at low cost without excessively increasing the hardness. is there.
Japanese Patent Laid-Open No. 62-142726 JP-A 63-169359 Japanese Patent Laid-Open No. 1-142023 Japanese Patent No. 3089882 JP-A-4-41616

  However, in the technique described in Patent Document 4, since quenching heat treatment is performed and the structure is a martensitic structure as it is quenched, the strength is high and, as a result, the deformation resistance during bending is increased. However, it was difficult to say that it was easy, and left a problem in bending workability.

  In the technique described in Patent Document 5, in order to ensure bending workability, the surface hardness is specified to be 401 or less in terms of Brinell hardness, but since the added amount of the alloy element is large, the tensile strength exceeds 780 MPa, From the viewpoint of reducing the processing load, sufficient bending workability is not achieved.

  Moreover, it is indispensable to implement heat treatment even in the wear-resistant steel described in any one of Patent Documents 1 to 4, and problems remain in terms of manufacturing period and manufacturing cost.

  Therefore, an object of the present invention is to provide a wear-resistant steel plate that can be produced without being subjected to heat treatment while being hot-rolled, and has excellent wear resistance and bending workability, and a method for producing the same.

  In order to achieve the above-mentioned object, the inventors have conducted intensive research on various factors affecting wear resistance and bending workability, have a component system containing Ti and C, and the metal structure is rolled. The composite structure of the ferrite-pearlite structure is used as the base phase, and the hard second phase (hard phase: TiC) is dispersed in the matrix to ensure wear resistance while processing during bending. It has been found that the load can be reduced, that is, the bending workability can be improved.

The present invention was made by further study based on the obtained knowledge, that is, the present invention is
1. In mass%, C: 0.05 to 0.35%, Si: 0.05 to 1.0%, Mn: 0.1 to 2.0%, Ti: 0.1 to 0.8 %, Al: 0.1% or less, Mo: 0.05 to 1.0%, Cu: 0.1 to 1.0%, Ni: 0.1 to 2.0%, Cr: 0.1 to 1.0 % , W: 0.05 to 1.0%, B: 0.0003 to 0.0030%, or one or more of them, and DI * represented by the formula (1) is less than 60, and the balance The tensile strength (TS) is characterized in that it has a composition comprising Fe and inevitable impurities , and the metal structure has a ferrite-pearlite phase as a matrix phase and a hard phase is dispersed in the matrix phase. A wear-resistant steel plate with excellent workability of less than 800 MPa .
DI * = 33.85 × (0.1 × C *) ^0.5 × (0.7 × Si + 1) × (3.33 × Mn + 1) × (0.35 × Cu + 1) × (0.36 × Ni + 1) × (2.16 × Cr + 1) × (3 × Mo * + 1) × (1.5 × W * + 1) (1)
However, C * = C-1 / 4 * (Ti-48 / 14N), Mo * = Mo * (1-0.5 * (Ti-48 / 14N), W * = W * (1-0.5 X (Ti-48 / 14N),
C, Si, Mn, Cu, Ni, Cr, Mo, W, Ti, and N content (mass%)
2. The wear-resistant steel sheet according to 1, further comprising one or two of Nb: 0.005 to 1.0% and V: 0.005 to 1.0% by mass%.
3 . Furthermore, the abrasion-resistant steel plate according to 1 or 2 , wherein the dispersion density of the hard phase is 400 pieces / mm ² or more.
4 . The steel structure having the composition of 1 or 2 is hot-rolled and then cooled to 400 ° C. or less at a cooling rate of 2 ° C./s or less, and the metal structure has a ferrite-pearlite phase as a base phase, A method for producing a wear-resistant steel plate having excellent workability in which a hard phase is dispersed in the matrix phase and the tensile strength (TS) is less than 800 MPa .
5 . The method for producing wear-resistant steel having excellent workability according to 4 , wherein the rolling reduction at 920 ° C. or lower in hot rolling is 30% or more and the rolling end temperature is 900 ° C. or lower. .

According to the present invention, a wear-resistant steel sheet having improved bending workability without deteriorating the wear resistance can be obtained without performing heat treatment after hot rolling. Production is possible, and it has a remarkable industrial effect.

The reason why the component composition and the metal structure are defined in the wear-resistant steel sheet according to the present invention will be described.
[Ingredient composition] In the following%, all are mass%.

C: 0.05 to 0.35%
C improves the wear resistance by improving the hardness of the matrix in the metal structure, and forms Ti carbide as a hard second phase (hereinafter also referred to as a hard phase), thereby improving the wear resistance. In order to obtain such an effect, it is necessary to contain 0.05% or more.

  On the other hand, if the content exceeds 0.35%, the carbide as the hard phase becomes coarse, and cracks are generated starting from the carbide during bending. For this reason, C was specified in the range of 0.05 to 0.35%. In addition, Preferably it is 0.15-0.30%.

Ti: 0.1-1.2%
Ti, together with C, is an important element in the present invention, and is an essential element that forms Ti carbide as a hard phase that contributes to improved wear resistance. In order to obtain such an effect, the content of 0.1% or more is required.

  FIG. 1 shows the influence of the Ti addition amount on the wear resistance, and FIG. 2 shows the influence of the Ti addition amount on the tensile strength (YS, TS). In FIG. 1, the vertical axis represents the wear resistance ratio in which the amount of wear in the rubber wheel wear test is compared with the amount of wear of mild steel (SS400).

  When the Ti addition amount is 0.1% or more, the wear resistance is as high as that of a general wear-resistant steel, and TS is reduced to 800 MPa or less. That is, it is possible to improve workability while having wear characteristics equivalent to those of a conventional wear-resistant steel plate subjected to quenching heat treatment.

  The test steel in the rubber wheel abrasion test is Mass%, and a steel piece containing 0.33% C-0.35% Si-0.82% Mn-0.05 to 1.2% Ti is rolled to 19 mmt. Then, it manufactured by cooling at a cooling rate: 0.5 degree-C / s.

  About the obtained steel plate, the tensile characteristic and the abrasion test were implemented. In the tensile test, a JIS No. 5 test piece was taken and a tensile test was performed in accordance with the provisions of JISZ2201, and tensile properties (tensile strength: TS, yield strength: YS) were obtained.

  The abrasion test was performed by a rubber wheel abrasion test in accordance with ASTM G65, and the test result was arranged as a wear resistance ratio in which the ratio of the abrasion amount of the mild steel (SS400) and the abrasion amount of each test steel plate. The larger the wear resistance ratio, the better the wear characteristics.

  As a comparative test, the same test as described above was carried out for wear-resistant steel sheets produced by general heat treatment. The obtained results are shown in FIGS. 1 and 2 for conventional steel. Here, a general wear-resistant steel sheet is 0.15 mass% C-0.35 mass% Si-1.50 mass% Mn-0.13 mass% Cr-0.13 mass% Mo-0.01 mass% Ti-. A steel sheet having a composition of 0.0010 mass% B is hot-rolled, then reheated to 900 ° C., and then subjected to quenching heat treatment, and refers to a steel sheet having a Brinell hardness of about 400 HB.

  On the other hand, if the Ti content exceeds 1.2%, the hard phase (Ti-based carbide) becomes coarse, and cracks occur starting from the coarse hard phase during bending. For this reason, Ti was limited to 0.1 to 1.2%, preferably 0.1 to 0.8%.

Si: 0.05-1.0%
Si is an effective element as a deoxidizing element, and in order to obtain such an effect, the content of 0.05% or more is required. Si is an effective element that contributes to high hardness by solid solution strengthening by solid solution in steel. However, if the content exceeds 1.0%, ductility and toughness are reduced, and the amount of inclusions is further increased. Cause problems. For this reason, it is preferable to limit Si to 0.05 to 1.0% of range. In addition, More preferably, it is 0.05 to 0.40%.

Mn: 0.1 to 2.0%
Mn is an effective element that contributes to high hardness by solid solution strengthening, and in order to obtain such an effect, it needs to be contained in an amount of 0.1% or more. On the other hand, the content exceeding 2.0% reduces weldability. For this reason, it is preferable to limit Mn to the range of 0.1 to 2.0%. In addition, More preferably, it is 0.1 to 1.60%.

Al: 0.1% or less Al acts as a deoxidizer, and such an effect is recognized with a content of 0.0020% or more, but a large content exceeding 0.1% is the cleanliness of steel. Reduce. For this reason, it is preferable to limit Al to 0.1% or less.

Cu: 0.1-1.0%, Ni: 0.1-2.0%, Cr: 0.1-1.0%, Mo: 0.05-1.0%, W: 0.05- 1.0%, B: 0.0003 to 0.0030%, one or more Cu: 0.1 to 1.0%
Cu is an element that improves the hardenability by dissolving in a solid solution, and the content of 0.1% or more is necessary to obtain this effect. On the other hand, the content exceeding 1.0% decreases the hot workability. For this reason, it is preferable to limit Cu to 0.1 to 1.0% of range. In addition, More preferably, it is 0.1 to 0.5%.

Ni: 0.1 to 2.0%
Ni is an element that improves hardenability by solid solution, and such an effect becomes remarkable when the content is 0.1% or more. On the other hand, the content exceeding 2.0% significantly increases the material cost. For this reason, it is preferable to limit Ni to 0.1 to 2.0% of range. In addition, More preferably, it is 0.1 to 1.0%.

Cr: 0.1 to 1.0%
Cr has the effect of improving hardenability, and in order to obtain such an effect, the content of 0.1% or more is required, but the content exceeding 0.1% lowers the weldability. . For this reason, it is preferable to limit Cr to 0.1 to 1.0% of range. In addition, More preferably, it is 0.1 to 0.8%. More preferably, it is 0.4 to 0.7%.

Mo: 0.05-1.0%
Mo is an element that improves hardenability. In order to acquire such an effect, 0.05% or more of content is required. On the other hand, if it exceeds 1.0%, weldability is lowered. Therefore, Mo is preferably limited to a range of 0.05 to 1.0%. In addition, More preferably, it is 0.05 to 0.40%.

W: 0.05-1.0%
W is an element that improves hardenability. In order to acquire such an effect, 0.05% or more of content is required. On the other hand, if it exceeds 1.0%, weldability is lowered. Therefore, W is preferably limited to a range of 0.05 to 1.0%. In addition, More preferably, it is 0.05 to 0.40%. In addition, since Mo and W are dissolved in TiC, they also have an effect of increasing the amount of hard phase.

B: 0.0003 to 0.0030%
B is an element that segregates at the grain boundary, strengthens the grain boundary, and contributes effectively to improvement of toughness. In order to obtain such an effect, the content of 0.0003% or more is necessary. On the other hand, the content exceeding 0.0030% lowers the weldability. For this reason, it is preferable to limit B to 0.0003 to 0.0030% of range. In addition, More preferably, it is 0.0003 to 0.0015%.

DI * <60
In the present invention, DI * (hardenability index value) is DI * = 33.85 × (0.1 × C *) ^0.5 × (0.7 × Si + 1) × (3.33 × Mn + 1) × (0 .35 × Cu + 1) × (0.36 × Ni + 1) × (2.16 × Cr + 1) × (3 × Mo * + 1) × (1.5 × W * + 1), where C * = C−1 / 4 × (Ti−48 / 14N), Mo * = Mo × (1-0.5 × (Ti−48 / 14N), W * = W × (1−0.5 × (Ti−48 / 14N)) And DI * <60, where C, Si, Mn, Cu, Ni, Cr, Mo, W, Ti, and N are contents (mass%).

  FIG. 3 shows the effect of DI * on wear resistance, and FIG. 4 shows the effect of DI * on tensile strength (YS, TS). In FIG. 3, the vertical axis shows the wear resistance ratio in which the wear amount in the rubber wheel wear test is compared with the wear amount of mild steel (SS400). The larger the wear resistance ratio, the better the wear characteristics.

  3 and 4, when DI * is less than 60, it is recognized that the wear amount is comparable to that of general wear-resistant steel, despite the low tensile strength: TS of 800 MPa or less. It is done.

  On the other hand, when DI * is 60 or more, the wear resistance is excellent, but the tensile strength is 800 MPa or more and the workability is poor. When DI * is 60 or more, it is assumed that a ferrite-bainite structure is formed.

  The test steel in the rubber wheel abrasion test is 0.34% C-0.22% Si-0.55% Mn-0.22% Ti in mass%, and one of Cu, Ni, Cr, Mo, W Alternatively, a steel slab containing 2 or more types and having a DI * of 40 to 120 was rolled to 8 mmt and then air-cooled (cooling rate: 1.2 ° C./s).

  About the obtained steel plate, the tensile characteristic and the abrasion test were implemented. In the tensile test, a JIS No. 5 test piece was sampled and a tensile test was performed in accordance with the provisions of JISZ2201, and tensile properties (tensile strength TS, yield strength YS) were obtained.

  The rubber wheel wear test was conducted in accordance with ASTM G65, and the test results were organized as the wear resistance ratio in terms of the ratio between the wear amount of mild steel (SS400) and the wear amount of each steel plate.

  The above-described components are basic components, and excellent wear resistance can be obtained. In the present invention, in order to further improve the wear resistance, a hard second phase is formed, which is an element that contributes to wear resistance. Certain Nb and V can be contained as selective elements.

Nb: 0.005 to 1.0%,
Nb is an element that, when added in combination with Ti, forms a composite carbide of Ti and Nb ((NbTi) C), disperses as a hard second phase, and contributes effectively to improved wear resistance. is there. In order to obtain such an effect of improving wear resistance, it is necessary to contain 0.005 or more. On the other hand, if the content exceeds 1.0%, the hard second phase (Ti, Nb composite carbide) becomes coarse, and cracks start from the hard second phase (Ti, Nb composite carbide) during bending. To do. For this reason, when adding, it is preferable to limit Nb to 0.005 to 1.0% of range. In addition, More preferably, it is 0.1 to 0.5%.

V: 0.005-1.0%
V is added in combination with Ti to form Ti and V composite carbides ((VTi) C) and is dispersed as a hard second phase in the same way as Nb, and is effective in improving wear resistance. Is an element that contributes to In order to obtain such an effect of improving wear resistance, a content of 0.005% or more is required.

  On the other hand, if the content exceeds 1.0%, the hard second phase (Ti, V composite carbide) becomes coarse, and cracking occurs starting from the hard second phase (Ti, V composite carbide) during bending. To do. For this reason, when adding, it is preferable to limit V to 0.005 to 1.0% of range. In addition, More preferably, it is 0.1 to 0.5%.

  When Nb and V are added in combination, the hard second phase is merely (NbVTi) C, and the effect of improving the wear resistance is obtained. When N is contained, carbonitrides may be formed in addition to carbides, but the same effect can be obtained.

However, when the amount of N added exceeds 0.01%, the proportion of N in the carbonitride increases and the hardness of the hard second phase decreases, so there is a concern about deterioration of wear resistance. Therefore, the N addition amount is preferably 0.01% or less.
[Metal structure]
The wear-resistant steel sheet according to the present invention has a metal structure having a ferrite-pearlite phase as a base phase and a hard phase (hard second phase) dispersed in the base phase. The base phase means having a volume ratio of 90% or more, and in the steel sheet according to the present invention, two phases of ferrite and pearlite occupy 90% or more of the whole.

  Furthermore, among these, it is desirable that the ferrite phase has a volume fraction of 70% or more and a ferrite phase having an equivalent circle diameter and an average particle diameter of 20 μm. In consideration of workability, it is preferable that the base phase has a Brinell hardness of 300 HB or less.

  The hard phase is preferably a Ti-based carbide such as TiC, and examples include TiC, (NbTi) C, (VTi) C, or TiC in which Mo and W are dissolved.

In addition, although the magnitude | size of a hard phase is not specifically limited, From a viewpoint of abrasion resistance, it is preferable to set it as about 0.5 micrometer or more and 50 micrometers or less. Moreover, it is preferable that the dispersion density of a hard phase shall be 400 pieces / mm < ² > or more from a viewpoint of abrasion resistance.

The size of the hard phase is determined by measuring the area of each hard phase, calculating the equivalent circle diameter from the same area, arithmetically averaging the obtained equivalent circle diameter, and calculating the average value as the size of the hard phase in the steel sheet. (Average particle diameter).
[Production method]
The wear-resistant steel sheet according to the present invention is prepared by melting the molten steel having the above-described composition by a known melting method and using a continuous casting method or an ingot-decomposition rolling method as a steel material such as a slab having a predetermined size. Is preferred.

  In order to adjust the hard phase to a predetermined size and number, for example, when a continuous casting method is used, a cooling rate of 0.2 to 10 ° C. in a temperature range of 1500 to 1200 ° C. of a slab having a thickness of 200 to 400 mm. It is preferable to adjust the cooling so as to be in the range of / s.

  Even when the ingot-making method is used, it goes without saying that the size of the ingot and the cooling conditions need to be adjusted so that the desired size and number of hard phases can be obtained.

  Next, the steel material is immediately hot-rolled without being cooled, or after being cooled, re-heated to 950 to 1250 ° C. and then hot-rolled to obtain a steel plate having a desired thickness. After hot rolling, it is cooled at an average cooling rate of 2 ° C./s or less without heat treatment.

  When the cooling rate exceeds 2 ° C./s, a ferrite-pearlite structure cannot be obtained, the tensile strength becomes 800 MPa or more, the working load at the time of bending the steel sheet increases, and the workability deteriorates. Therefore, it shall be 2 degrees C / s or less.

  The hot rolling condition is not particularly limited as long as it can be a steel plate having a desired size and shape, but considering the toughness, which is a performance to be provided as a steel plate, the surface temperature is reduced at 920 ° C. or less. It is necessary that the rate is 30% or more and the rolling end temperature is 900 ° C. or less.

  The wear-resistant steel plate according to the present invention does not need to be subjected to heat treatment after hot rolling, and can be used for various applications that require bending while hot rolling.

Molten steel having the composition shown in Table 1 is melted in a vacuum melting furnace to form a small steel ingot (50 kg) (steel material), and then heated to 1050 to 1250 ° C. and hot-rolled to obtain a thickness of 6 to 100 mm. This was a test steel plate. Each steel plate was subjected to a structure observation, a tensile test, an abrasion test, a Charpy impact test, and a bending test.
[Tissue observation]
The test specimen for structure observation was subjected to nital corrosion after polishing, and the position of 1 mm below the surface layer was determined by using an optical microscope (magnification: 400 times) to identify the structure, the ferrite particle diameter and the size and number of the hard phase. It was measured. In the observation field of view, the structure occupying 90% or more was defined as the base phase, and the size of the hard phase was the average particle diameter determined by the method described above.
[Tensile test]
In accordance with JISZ2201, the JIS No. 5 test piece was sampled and subjected to a tensile test in accordance with JISZ2241 to determine tensile properties (yield strength: YS, tensile strength: TS). Tensile strength (TS) <800 MPa and yield strength (YS) <600 MPa are within the scope of the present invention.
[Abrasion test]
The test piece was t (plate thickness) × 20 × 75 (mm), and a rubber wheel abrasion test was performed using abrasion sand in accordance with ASTM G65. After the test, the amount of wear of the test piece was measured.

The test results were evaluated by the wear resistance ratio = (abrasion amount of mild steel plate) / (abrasion amount of each steel plate) with the wear amount of the mild steel (SS400) plate as a reference (1.0). The larger the wear resistance ratio, the better the wear resistance, and the scope of the present invention is the wear resistance ratio: 4.0 or more.
[Charpy impact test]
In accordance with JISZ2202, the V-notch impact test specimen is taken in the L direction from the position of 1/4 in the plate thickness direction, and in accordance with JISZ2242, the Charpy impact test is performed at a test temperature of 0 ° C. to absorb Charpy. Seeking energy. The number of test pieces was three, and the average value was obtained.
[Bending test]
If the width is 50 mm and the thickness of the test steel sheet is 45 mm or more in accordance with the provisions of JISZ2204, a test piece ground from one side and reduced to a thickness of 25 mm is collected, and the thickness of the test steel sheet When the thickness was less than 45 mm, a specimen having the same thickness was collected, and a bending test was performed in accordance with the provisions of JISZ2248. The bending test was carried out by a push bending method with a bending radius of r = 1.5 t.

  Table 2 shows the results of the structure observation, tensile test, and wear test. Examples of the present invention (steel plates No. 1 to 6, steel plates No. 8 and 9) have excellent wear resistance despite the tensile strength (TS) <800 MPa and the yield strength (YS) <600 MPa. Steel plate.

  The Charpy absorbed energy was 27 J or higher when the rolling finishing temperature was 900 ° C. or lower. On the other hand, the comparative example is inferior in bending workability because the YS and TS are high even if the wear resistance is inferior to that of the present invention example or the wear resistance is equivalent.

The figure which shows the influence of the amount of Ti addition on abrasion resistance. The figure which shows the influence of Ti addition amount which has on tensile strength (YS, TS). The figure which shows the influence of DI * which has on wear resistance. The figure which shows the influence of DI * which acts on tensile strength (YS, TS).

Claims (5)

In mass%, C: 0.05 to 0.35%, Si: 0.05 to 1.0%, Mn: 0.1 to 2.0%, Ti: 0.1 to 0.8 %, Al: 0.1% or less, Mo: 0.05 to 1.0%, Cu: 0.1 to 1.0%, Ni: 0.1 to 2.0%, Cr: 0.1 to 1.0 % , W: 0.05 to 1.0%, B: 0.0003 to 0.0030%, or one or more of them, and DI * represented by the formula (1) is less than 60, and the balance The tensile strength (TS) is characterized in that it has a composition comprising Fe and inevitable impurities , and the metal structure has a ferrite-pearlite phase as a matrix phase and a hard phase is dispersed in the matrix phase. A wear-resistant steel plate with excellent workability of less than 800 MPa .
DI * = 33.85 × (0.1 × C *) ^0.5 × (0.7 × Si + 1) × (3.33 × Mn + 1) × (0.35 × Cu + 1) × (0.36 × Ni + 1) × (2.16 × Cr + 1) × (3 × Mo * + 1) × (1.5 × W * + 1) (1)
However, C * = C-1 / 4 * (Ti-48 / 14N), Mo * = Mo * (1-0.5 * (Ti-48 / 14N), W * = W * (1-0.5 X (Ti-48 / 14N),
C, Si, Mn, Cu, Ni, Cr, Mo, W, Ti, and N content (mass%)   The wear-resistant steel sheet according to claim 1, further comprising one or two of Nb: 0.005 to 1.0% and V: 0.005 to 1.0% in terms of mass%. Furthermore, the abrasion-resistant steel plate according to claim 1 or 2 , wherein a dispersion density of the hard phase is 400 pieces / mm ² or more. The steel structure having the composition according to claim 1 or 2 is hot-rolled and then cooled to 400 ° C or less at a cooling rate of 2 ° C / s or less, and the metal structure converts the ferrite-pearlite phase into a base phase. And a method for producing a wear-resistant steel sheet having excellent workability in which the hard phase is dispersed in the matrix phase and the tensile strength (TS) is less than 800 MPa . The hot-rolled wear resistant steel with excellent workability according to claim 4 , wherein the rolling reduction at 920 ° C or lower is 30% or more and the rolling end temperature is 900 ° C or lower. Production method.

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