KR101262503B1 - Steel sheet for oil sands slurry transportation system having excellent wear resistance and method for manufacturing the same - Google Patents

Abstract

One aspect of the present invention is by weight, C: 0.2-0.35%, Si: 0.1-0.5%, Mn: 0.5-1.8%, P: 0.03% or less, S: 0.03% or less, Al: 0.05% or less (0 By providing steel plates for oil sand slurry pipes having excellent abrasion resistance, including%), N: 0.01% or less (excluding 0%), balance Fe and other unavoidable impurities,
It is possible to make the pipe as a pipe, but can have excellent wear resistance even in the harsh wear environment of the oil sand slurry pipe, and also can obtain a steel sand sheet for oil sand slurry pipe excellent in economic efficiency and production efficiency.

Description

STEEL SHEET FOR OIL SANDS SLURRY TRANSPORTATION SYSTEM HAVING EXCELLENT WEAR RESISTANCE AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to an oil sand slurry pipe steel plate having excellent wear resistance and a method of manufacturing the same, and more particularly, to the wear occurring in the lower portion of the inner wall of the pipe when moving the oil sand slurry mixed with water for post-treatment of the oil sand. The present invention relates to a steel sheet for an oil sand slurry pipe having excellent resistance to the same, and a method of manufacturing the same.

Among the steel materials used in the oil sands industry, especially pipe steels used for transporting oil sand slurry, wear is caused by sand particles of 200 ~ 300㎛, and the replacement life is about one year. It is costly and time consuming.

Oil sand mining is largely divided into open pit mining and underground mining. In open pit mining, the application of slurry pipe systems is essential for the post-treatment of mining ore. The ground mining mixed with water has the form of a slurry, containing about 35% by weight of sand, and about 500 ppm of salt, and is transported at a speed of 3.5 to 5.5 m / sec. When transporting the slurry, sand particles are moved along the inner lower end of the pipe to erode the material, so that the pipe is rotated about three times a year to increase the service life of the material.

Carbide coating or surface heat treatment may be applied to the inside to delay the erosion and extend the life of the pipe.However, the cost of the reprocessing process exceeds the replacement cost of the material. There is a demand for development of a material having excellent resistance to erosion, that is, wear resistance.

In general, the wear resistance of the material is known to increase with the increase in hardness, but it is impossible to apply high hardness martensite because the increase in the hardness of the material should have the strength and ductility that can be corrugated due to the characteristics of the pipe material. Currently used oil sand slurry pipe steel is API grade line pipe steel, ferritic TMCP steel is used to increase the strength at the level that can be commercially piped in order to increase the wear resistance of the material, the wear resistance is currently used Examine the superior pipe steel technology.

First, Korean Patent Publication No. 1987-0010217 proposes a method of securing abrasion resistance by installing a ceramic plate inside a steel pipe, and Korean Patent Publication No. 2000-0046429 uses tungsten carbide or high chromium powder on the inner surface of a pipe. A method for producing a wear resistant pipe by forming a hardened growth welding layer is proposed.

However, both of them are reprocessing using high hardness materials to secure wear resistance on the surface of existing pipes, which are expensive due to reprocessing, and are reprocessed due to impact or defects. There is a disadvantage that the layer can be eliminated, which does not guarantee long-term wear resistance.

Next, Korean Patent Publication No. 2001-0066189 proposes a method of securing abrasion resistance and impact toughness by carburizing the surface of low carbon steel, but the pipe hardened by carburizing treatment does not only cause problems of welds. After abrasion of the surface hardened layer, there was a problem that a rapid wear of the matrix structure occurs.

In addition, Korean Patent Publication No. 2007-0017409 provides a method for producing steel having high mechanical strength and abrasion resistance, and the steel provided in the publication has a compositional weight% of 0.30% ≦ C ≦ 1.42%; 0.05% ≦ Si ≦ 1.5%; Mn <1.95%; Ni <2.9%; 1.1% ≦ Cr ≦ 7.9%; 0.61% ≦ Mo ≦ 4.4%; Alternatively V <1.45%, Nb <1.45%, Ta <1.45% and V + Nb / 2 + Ta / 4 <1.45%; Less than 0.1% boron, 0.19% (S + Se / 2 + Te / 4), 0.01% calcium, 0.5% rare earth, 1% aluminum, 1% copper; The remainder relates to a method for producing steels consisting of iron and other unavoidable impurities.

However, since the present invention contains carbon of medium carbon steel or more, and uses a large amount of Ni, Cr, Mo, Nb, V, etc. as the alloying element, not only the manufacturing cost of the steel material increases but also the mechanical strength is high. It is difficult to use.

As another conventional technique, Korean Patent Laid-Open Publication No. 2000-0041284, which provides a method for manufacturing tool steel by spray molding, and a method of increasing toughness by miniaturizing carbide size using Mo. Is disclosed. However, the present invention also has a limitation in that it can be applied as a pipe material due to high manufacturing cost and strength, as in Korean Patent Publication No. 2007-0017409.

In addition, Korean Patent Laid-Open Publication No. 2004-0059177 provides a method for producing steel having excellent wear resistance, which is used for storing oil pipes of crude oil tanks, light distribution in the hull, and the like. 0.03 to 0.1%, Si: 0.1 to 0.3%, Mn: 0.05 to 1.2%, P: 0.05% or less, S: 0.035% or less, Al: 0.03% or less, Cr: 0.8 to 1.1%, Cu: 0.1 to 0.3% , Ni: 0.1-0.3%, steel that is composed of the remaining Fe and other unavoidable impurities, 1000-1200 steel controlled by Ca-Si in the form of wire and degassing so that the Ca content is 0.001 to 0.004% by weight. After reheating to &lt; RTI ID = 0.0 &gt; C, &lt; / RTI &gt; and hot rolling at a temperature of Ar ₃ or higher.

However, the present invention improves the wear resistance by improving the density of the rust layer by utilizing Cr, Cu, Ni, Ca, etc., but it is impossible to secure the wear resistance by using the rust layer in a severe wear environment such as an oil sand slurry pipe. There was a problem.

Therefore, the demand for steel plate for oil sand slurry pipe having excellent abrasion resistance and excellent economic efficiency and production efficiency even in severe abrasion environment such as the use environment of oil sand slurry pipe is increasing rapidly.

One aspect of the present invention provides a steel sheet for oil sand slurry pipes and a method of manufacturing the same, which can be conduited as a pipe, and has excellent wear resistance even in the harsh wear environment of the oil sand slurry pipe, and also has excellent economical efficiency and production efficiency.

One aspect of the present invention is by weight, C: 0.2-0.35%, Si: 0.1-0.5%, Mn: 0.5-1.8%, P: 0.03% or less, S: 0.03% or less, Al: 0.05% or less (0 A steel sheet for oil sand slurry pipes having excellent wear resistance, including%), N: 0.01% or less (excluding 0%), balance Fe and other unavoidable impurities.

At this time, the steel sheet further includes Cr: 1.5% or less, and the sum of Mn and Cr is preferably 2% or less.

In addition, the microstructure of the steel sheet is preferably made of 50 ~ 80 area% of pearlite and the balance ferrite.

Further, the spacing between the pearlite grains is more preferably 200 µm or less.

Moreover, it is preferable that the Vickers hardness value of the said steel plate is 180-220Hv.

Meanwhile, another aspect of the present invention is% by weight, C: 0.2-0.35%, Si: 0.1-0.5%, Mn: 0.5-1.8%, P: 0.03% or less, S: 0.03% or less, Al: 0.05 For steel slabs containing up to% (excluding 0%), N: up to 0.01% (excluding 0%), residual Fe and other unavoidable impurities,

Provided is a method for producing an oil sand slurry pipe steel sheet having excellent wear resistance that is cooled at a cooling rate of 0.2 ~ 4 ℃ / sec after hot rolling.

In this case, the steel slab further includes Cr: 1.5% or less, and the sum of Mn and Cr is preferably 2% or less.

Further, the cooling is more preferable to start the cooling in the temperature range of Ar3 ~ Ar3 + 200 ℃ and finish the cooling at 500 ℃ or less.

According to one aspect of the present invention, it is possible to pipe as a pipe by controlling the steel component system and microstructure, but can have excellent wear resistance even in the harsh wear environment of the oil sand slurry pipe, and also for the oil sand slurry pipe with excellent economic efficiency and production efficiency Steel sheet can be obtained.

1 is a graph showing a change in wear rate according to Vickers hardness.

In general, low carbon ferritic steels are easy to process and easy to control the strength of the TMCP process, but due to the low hardness value of the ferrite structure has a low resistance to wear. In particular, in a severe wear environment such as an oil sand slurry pipe, the erosion amount is 20 mm or more per year, and thus, it is usually difficult to have sufficient resistance to wear. In order to solve this problem, conventionally, it is known to apply a surface treatment to the inner wall of the pipe or to increase the hardness of the material itself.

However, the inventors have long recognized that wear of steel materials is caused by surface deformation and dropping of the deformation layer, and the improvement of wear resistance of the material is such that hardness and toughness are not destroyed even though the collided abrasive particles are thrown out. At the same time, it has been found that designing microstructures that can improve strain capacity is a solution to improved wear resistance.

Accordingly, the present invention does not use a material of high hardness such as bainite or martensite, and focuses on the fact that the overall hardness of the material itself is low but the hardness of cementite is high. This further improves the wear resistance.

Hereinafter, the steel plate of this invention is demonstrated.

First, one side of the present invention is a weight%, C: 0.2-0.35%, Si: 0.1-0.5%, Mn: 0.5-1.8%, P: 0.03% or less, S: 0.03% or less, Al: 0.05% or less A steel sheet for oil sand slurry pipes having excellent wear resistance including (except 0%), N: 0.01% or less (excluding 0%), balance Fe and other unavoidable impurities.

Hereinafter, the component system and the composition range will be described.

Carbon (C): 0.2-0.35 wt%

C is an element added to form a ferrite base structure to form a ferrite / ferrite composite structure. When the content is less than 0.2%, the amount of pearlite is insufficient to secure abrasion resistance, and when the content exceeds 0.35%, pearlite is used. While the amount of is increased, the amount of ferrite is reduced so much that the deformation capacity for wear decreases, so that the amount of addition is preferably controlled to 0.2 to 0.35%. More preferably, when controlling C to 0.25% or more from the viewpoint of wear resistance, more excellent resistance to abrasion can be obtained.

Silicon (Si): 0.1 ~ 0.5%

Si is an element that not only acts as a deoxidizer in the steelmaking process but also increases the strength of steel, and when the content is less than 0.1%, the above effect cannot be sufficiently obtained. When the content exceeds 0.5%, the impact toughness of the material is increased. It is preferable to limit the content of Si to 0.1 to 0.5 because it may worsen, the weldability is lowered, and may cause a problem of causing scale peelability during rolling.

Manganese (Mn): 0.5-1.8%

Mn is an element that increases the amount of pearlite without impairing the impact toughness, and in order to fully obtain the effect, Mn is preferably added at least 0.5%. However, if the amount is too large, bainite or martensite structures other than pearlite are formed. Since there is a problem that the weldability is lowered, it is preferable to limit the content to 0.5 to 1.8%.

Phosphorus (P): 0.03% or less

Since P is an element that degrades the weldability and deteriorates the toughness, it is preferable to control it as low as possible, and at least the content should be controlled so as not to exceed 0.03% to minimize the problem of deterioration of weldability, toughness and wear resistance.

Sulfur (S): 0.03% or less

S is an element that degrades the ductility, impact toughness and weldability of steel, and in particular, it is preferable to control it as low as possible, since it combines with Mn to form MnS inclusions and lowers the wear resistance of steel, and at least its content does not exceed 0.03%. Control shall be made.

Aluminum (Al): 0.05% or less (except 0%)

Al is an element that acts as a deoxidizer to remove oxygen by reacting with oxygen present in molten steel, but if the amount is too high, a large amount of oxide-based inclusions are formed to impair the impact toughness of the material. Therefore, the upper limit is 0.05. It is desirable to limit to%.

Nitrogen (N): 0.01% or less (excluding 0%)

N interferes with the growth of austenite grains by forming nitrides in combination with Al, Ti, Nb, V and the like, and thus helps to improve the toughness and strength of the steel, but if the content is too high, N in solid solution exists. Since this adversely affects the toughness of the steel, it is desirable to limit the content not to exceed 0.01%.

That is, in one aspect of the present invention by considering the special environment in which the oil sand slurry pipe is used, by suggesting the above-described component system and composition range, it is possible to greatly contribute to improving the wear resistance of the steel sand slurry pipe.

At this time, the steel sheet further includes Cr: 1.5% or less, and the sum of Mn and Cr is preferably 2% or less. Cr is an element that lowers the transformation temperature of steel and increases the amount of pearlite, and as the amount of pearlite increases, the wear resistance of the material is increased by cementite, and thus, the addition of Cr further increases the wear resistance. It can be improved.

However, if the amount is too large, low temperature transformation tissues such as bainite or martensite are formed, which acts as a cause of impairing impact toughness, and therefore, the content thereof is preferably controlled to 1.5% or less. At the same time, since the impact toughness caused by the formation of the low temperature transformation tissue not only Cr but also Mn has the same effect, it is necessary to control the total content of Mn and Cr not to exceed 2.0%.

In addition, the microstructure of the steel sheet is preferably made of 50 ~ 80 area% of pearlite and the balance ferrite. In the severe wear environment such as the use of oil sand slurry pipes, the inventors found that abrasion is mainly caused by deformation of the surface and dropping of the deformation layer, rather than forming a structure having high hardness such as bainite or martensite. The hardness of the steel is sufficient to keep the level of unbreakable while repelling the wear particles, and more importantly, to improve the deformation capacity.

Therefore, even if the hardness of the entire material is not high, including perlite of 50% by area due to the high hardness of cementite, it is possible to obtain hardness that is not destroyed even though the abrasive particles bounce off, and at the same time, the area fraction of pearlite Is limited to 80% or less, and the balance is made of ferrite, thereby obtaining excellent deformation capacity of ferrite.

As described above, the microstructure of the present invention is composed of a mixed structure of pearlite and ferrite, and by controlling the fraction as described above, the oil sand slurry is not broken while being spoiled while also having excellent deformation capacity. It is possible to obtain a steel sheet having the best wear resistance in a severe wear environment such as a pipe use environment.

In addition, since wear particles having a size of 200 to 300 μm collide with each other when wear occurs in an oil sand slurry pipe, the spacing between particles of pearlite grains is larger than the size of the wear particles in order for the wear particles to be reflected without directly deforming the ferrite. Small is more effective. Therefore, in order to prevent the abrasive particles from directly colliding with the soft ferrite, it is more preferable to control the interparticle spacing of the pearlite grains to 200 µm or less to be smaller than the abrasive particles.

When having the component system and the microstructure as described above can obtain a steel sheet having a Vickers hardness value of 180 ~ 220Hv. It is very important to maintain the Vickers hardness value in the oil sand slurry pipe steel plate. If the hardness value of the matrix structure is less than 180 Hv, the hardness is too weak and the deformation caused by the wear particles is severe, resulting in poor wear resistance. If the hardness value exceeds 220Hv, the hardness is excellent, but the capacity for deformation decreases, which may result in a decrease in wear resistance. Therefore, it is more preferable to control the said Vickers hardness value to 180-220Hv.

Hereinafter, the manufacturing method of the steel plate of this invention is demonstrated.

Another aspect of the present invention is by weight, C: 0.2-0.35%, Si: 0.1-0.5%, Mn: 0.5-1.8%, P: 0.03% or less, S: 0.03% or less, Al: 0.05% or less (Except 0%), N: 0.01% or less (except 0%), for a steel slab containing remainder Fe and other unavoidable impurities, abrasion resistance to cool at a cooling rate of 0.2 ~ 4 ℃ / sec after hot rolling Provided is a method for producing a steel sheet for an excellent oil sand slurry pipe. In this case, the steel slab further includes Cr: 1.5% or less, and the sum of Mn and Cr is preferably 2% or less.

In the steel slab applied to the present invention, since a large amount of hardenable elements such as C, Mn, or Cr are added, bainite or martensite structures may be formed without controlling the cooling conditions, thereby obtaining a mixed structure of ferrite and pearlite. . Therefore, it is very important to secure the wear resistance suitable for the use environment of the oil sand slurry pipe by controlling the cooling conditions to obtain the mixed structure of the present invention.

First, it is preferable to perform normal hot rolling on the steel slab having the composition as described above, and then to cool at a cooling rate of 0.2 to 4 ° C / sec. If the cooling rate exceeds 4 ° C / sec, low temperature transformation tissues such as bainite or martensite may be generated, and thus it is difficult to obtain a mixed structure of ferrite and pearlite, and therefore, the upper limit is preferably limited to 4 ° C / sec. Do.

However, if the cooling rate is too low, less than 0.2 ° C / sec, not perlite is formed but carbides are spheroidized to form a structure in which spheroidized carbides are present together in the ferrite. In this case, sufficient hardness cannot be secured and wear particles may collide directly with the ferrite. Therefore, it is preferable to control so that a cooling rate may be 0.2 degreeC / sec or more, and air cooling may be sufficient as it exists only in the said range.

Further, the cooling is more preferable to start the cooling in the temperature range of Ar3 ~ Ar3 + 200 ℃ and finish the cooling at 500 ℃ or less. If the cooling start temperature is less than the Ar3 point, cooling starts in a state in which phase transformation to austenite is not sufficiently performed, and thus, the structure to be obtained in the present invention cannot be secured, and the cooling start temperature exceeds Ar3 + 200 ° C. If it means that the rolling is made in excess of Ar3 + 200 ℃, there is a big problem that the crystal grains are very coarse, it is preferable to limit the cooling start temperature to a temperature range of Ar3 ~ Ar3 + 200 ℃.

In addition, it is preferable to limit the cooling end temperature to 500 ° C. or less. If the cooling end temperature exceeds 500 ° C., all tissues are not transformed from austenite to pearlite / ferrite mixed tissues, but the tissues remain as austenite without transformation. Because of this, a problem may arise in that the pearlite fraction cannot be sufficiently secured. Therefore, it is desirable to limit the cooling end temperature to 500 ° C or lower.

Hereinafter, the present invention will be described in detail by way of examples, which are intended for a more complete description of the present invention, and the scope of the present invention is not limited by the following individual examples.

( Example )

First, a steel slab was manufactured through continuous casting after preparing molten steel having the composition shown in Table 1. All of the cast slabs were hot rolled under normal conditions and then cooled to the conditions shown in Table 2 to prepare steel sheets.

division C Si Mn P S Al N Cr Mn + Cr Inventive Steel 1 0.245 0.25 1.76 0.008 0.003 0.035 0.005 - 1.76 Invention river 2 0.253 0.18 1.55 0.009 0.007 0.037 0.008 0.11 1.66 Invention steel 3 0.256 0.32 1.74 0.008 0.004 0.029 0.007 0.31 2.05 Inventive Steel 4 0.297 0.44 1.49 0.008 0.006 0.041 0.005 - 1.49 Invention steel 5 0.307 0.22 1.57 0.007 0.004 0.033 0.009 0.19 1.76 Inventive Steel 6 0.312 0.23 0.92 0.007 0.002 0.035 0.003 0.78 1.70 Invention steel 7 0.347 0.21 1.43 0.006 0.003 0.030 0.006 - 1.43 Inventive Steel 8 0.351 0.31 1.38 0.009 0.003 0.029 0.006 0.19 1.57 Invention river 9 0.348 0.36 1.05 0.008 0.007 0.033 0.005 0.41 1.46 Invented Steel 10 0.339 0.22 1.06 0.007 0.008 0.038 0.004 0.58 1.64 Comparative River 1 0.041 0.23 1.21 0.006 0.0006 0.037 0.005 0.1 1.31 Comparative River 2 0.066 0.16 1.56 0.009 0.0018 0.022 0.004 0.03 1.59 Comparative Steel 3 0.055 0.15 2 0.007 0.0016 0.027 0.003 0.31 2.31 Comparative Steel 4 0.1 0.29 1.29 0.006 0.0019 0.031 0.005 0.44 1.73 Comparative Steel 5 0.384 0.22 1.57 0.007 0.004 0.033 0.009 0.21 1.78 Comparative Steel 6 0.392 0.31 1.38 0.008 0.003 0.029 0.006 0.2 1.58 Comparative Steel 7 0.259 0.32 1.92 0.006 0.004 0.029 0.007 0.19 2.11

division Applicable Steel Grade Ar3 (℃) Cooling start temperature (℃) Cooling rate (° C / s) Cooling end temperature (℃) Inventory 1 Inventive Steel 1 697 750 0.4 300 Inventive Example 2 Invention river 2 710 750 0.4 300 Inventory 3 Invention steel 3 692 750 1.0 250 Honorable 4 Inventive Steel 4 702 800 1.0 250 Inventory 5 Invention steel 5 690 800 3.5 400 Inventory 6 Inventive Steel 6 731 800 3.5 400 Honorable 7 Invention steel 7 692 790 2.0 200 Comparative Example 1 Inventive Steel 8 716 770 6.0 100 Comparative Example 2 Invention river 9 715 780 5.3 300 Comparative Example 3 Invention river 9 715 770 0.1 200 Comparative Example 4 Invented Steel 10 743 800 4.7 350 Comparative Example 5 Invented Steel 10 743 800 1.0 600 Comparative Example 6 Comparative River 1 803 750 0.4 200 Comparative Example 7 Comparative River 2 768 750 0.4 250 Comparative Example 8 Comparative Steel 3 732 750 0.4 300 Comparative Example 9 Comparative Steel 4 773 800 16.1 300 Comparative Example 10 Comparative Steel 5 666 800 2.5 300 Comparative Example 11 Comparative Steel 6 679 850 2.5 350 Comparative Example 12 Comparative Steel 7 677 850 2.0 250

The structure of the microstructure of the steel sheet manufactured under the above conditions was analyzed, and the pearlite fraction and hardness were measured and shown in Table 3 below, and the amount of wear was expressed as a ratio with respect to Comparative Example 1.

division Microstructure Perlite fraction (area%) Hardness (Hv) Abrasion compared with Comparative Example 1 Inventory 1 Pearlite / Ferrite 60 200 40 Inventive Example 2 Pearlite / Ferrite 70 210 35 Inventory 3 Pearlite / Ferrite 55 185 57 Honorable 4 Pearlite / Ferrite 65 205 42 Inventory 5 Pearlite / Ferrite 60 200 38 Inventory 6 Pearlite / Ferrite 75 215 35 Honorable 7 Pearlite / Ferrite 70 210 37 Comparative Example 1 Martensite - 350 100 Comparative Example 2 Bainite - 320 120 Comparative Example 3 Ferrite (Spherical Carbide) - 135 150 Comparative Example 4 Bainite - 300 95 Comparative Example 5 Austenitic / Ferrite - 120 140 Comparative Example 6 ferrite - 130 135 Comparative Example 7 ferrite - 130 125 Comparative Example 8 Bainite - 290 90 Comparative Example 9 Martensite - 340 105 Comparative Example 10 Pearlite / Ferrite 90 240 70 Comparative Example 11 Pearlite / Ferrite 92 250 80 Comparative Example 12 Bainite - 305 90

Inventive Examples 1 to 7 were used as the invention steel, the cooling conditions after hot rolling also belonged to all of the scope of the present invention, the pearlite fraction appeared to be 55 ~ 75% and the balance structure of the remaining ferrite, hardness 185 ~ 215Hv Appeared. In other words, it has sufficient hardness to resist abrasion and also contains 25 to 45 area% of ferrite structure, so it has excellent deformation capacity, and shows a very low wear rate of 35 to 57% compared to Comparative Example 1, showing excellent wear resistance. You can check it.

In Comparative Examples 1, 2, 4 and 9, the cooling rate is too fast to show the low temperature transformation structure of bainite or martensite, and thus the hardness is very high. On the contrary, the amount of wear compared to Comparative Example 1 is poor because the deformation capacity is not good. It is very high, 95-120%, indicating that the wear resistance was not good.

On the contrary, in Comparative Example 3, the cooling rate was too slow, and the carbides did not form pearlite but were spheroidized to form a structure in which ferrite and spherical carbides exist together. Accordingly, the hardness value was as low as 135 Hv, and the wear amount was 150% compared to Comparative Example 1, which shows that the wear resistance was very bad.

In Comparative Example 5, since the cooling end temperature was 600 ° C. and exceeded 500 ° C., all of the austenite remained unaltered, and thus the hardness value was low as 120 Hv.

Comparative Examples 6 and 7 had a significantly low content of carbon, resulting in a ferrite alone structure with little pearlite structure, and thus had a low hardness of 130 Hv, and thus a very high wear amount of 135% compared to Comparative Example 1.

In Comparative Examples 8 and 12, the content of manganese was too high, resulting in low temperature transformation tissue such as bainite. As a result, the hardness was 290 to 305 Hv, but the deformation capacity was low, and the wear resistance was 90% compared to Comparative Example 1. You can see that it is not good.

In Comparative Examples 10 and 11, the carbon content was so high that the hardness increased to 240-250 Hv as the amount of pearlite increased, but the ferrite was reduced to 8-10% by area, resulting in lower deformation capacity. Abrasion resistance of 70 to 80% was confirmed that the wear resistance is not good compared to the invention example.

In addition, the present inventors measured the wear rate of the inventive steels 1, 2, and 3 according to the change in hardness, respectively, by varying the cooling conditions in order to check the relationship between hardness and wear resistance in detail, and are shown in a graph of FIG. 1. . As a result, when the hardness is in the range of 180 ~ 220Hv, the wear rate was the lowest and it was confirmed that the wear resistance is excellent.

Claims (8)

By weight%, C: 0.2-0.35%, Si: 0.1-0.5%, Mn: 0.5-1.8%, P: 0.03% or less, S: 0.03% or less, Al: 0.05% or less (excluding 0%), N : Steel plate for oil sand slurry pipe having excellent wear resistance including 0.01% or less (excluding 0%), balance Fe and other unavoidable impurities.
The method according to claim 1,
The steel sheet further comprises Cr: 1.5% or less, and the steel sand for excellent oil-sand slurry pipes with a sum of Mn and Cr of 2% or less.
The method according to claim 1 or 2,
The microstructure of the steel sheet is an oil-sand slurry pipe steel plate excellent in wear resistance consisting of 50 ~ 80 area% pearlite and the balance ferrite.
The method according to claim 3,
The steel plate for oil sand slurry pipes having excellent wear resistance, wherein the spacing between the pearlite grains is 200 μm or less.
The method of claim 4,
Steel plate for oil sand slurry pipes excellent wear resistance Vickers hardness value of the steel sheet is 180 ~ 220Hv.
By weight%, C: 0.2-0.35%, Si: 0.1-0.5%, Mn: 0.5-1.8%, P: 0.03% or less, S: 0.03% or less, Al: 0.05% or less (excluding 0%), N : For steel slabs containing 0.01% or less (excluding 0%), balance Fe and other unavoidable impurities,
A method for producing an oil sand slurry pipe steel sheet having excellent wear resistance after being hot rolled and cooled at a cooling rate of 0.2 to 4 ° C / sec.
The method of claim 6,
The steel slab further comprises Cr: 1.5% or less, and the sum of Mn and Cr is 2% or less, the production method of the steel sand for oil-sand slurry pipes excellent in wear resistance.
The method according to claim 6 or 7,
The cooling is a method of producing a steel sand slurry pipe for excellent wear resistance to start the cooling in the temperature range of Ar3 ~ Ar3 + 200 ℃ to end the cooling at 500 ℃ or less.

Images