JPH01201441A - Alloy steel having excellent wear resistance - Google Patents

Abstract

PURPOSE:To improve the wear resistance of the title steel by regulating C, Si, Mn, Cr, etc., to the optimium contents in the relation with the Al contents in a martensitic stainless steel. CONSTITUTION:The alloy steel contains, by weight, 0.55-1.10% C, <=2.0% Si, <=2.0% Mn, 12-25% Cr and 0.05-1.10% Al, contains at need one or more kinds among 0.2-2.0% Ni, 0.2-3.0% Mo, 0.1-1.5% V, 0.05-0.7% Nb and 0.2-2.0% Cu and the balance consisting of Fe. The steel is used by executing a surface hardening treatment at least to the sliding surface. In the steel, at the time of quenching and tempering, Al forms solid solution into a matrix, increases the strength of the matrix by the fining of its crystal grains and improves the wear resistance and scuffing resistance. At the time of gaseous nitriding treatment, Al which has formed solid solution into the matrix is finely deposited as AlN to drastically increase the hardness of the nitriding layer, by which the wear resistance and the scuffing resistance are exceedingly improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an alloy steel having particularly excellent wear resistance and used for piston rings, rocker arms, binion shafts, etc. of internal combustion engines such as automobiles. .

[Prior Art] A piston ring for an internal combustion engine is composed of a pressure ring for keeping the combustion chamber airtight and an oil ring for preparing a lubricating oil film between the piston ring and the cylinder liner. Among these piston rings, the pressure ring is loosely fitted directly under the piston head and is subject to the influence of combustion gas, so it is required to have wear resistance, scuffing resistance, heat resistance, etc.

In recent years, as internal combustion engines have become lighter, have higher output, and have higher rotation speeds, pressure rings have been actively made thinner. This thinning of the piston ring reduces the weight of the piston ring, stabilizes the behavior of the piston ring within the piston ring groove, and improves lubricating oil consumption by reducing the thickness of the oil film.

However, as piston rings become thinner, the oil film thickness becomes thinner, wear increases, and the lifespan becomes shorter.
Rings made of silicon chrome steel or oil tempered are no longer suitable for use. In other words, it is difficult to manufacture cast iron rings that are thin in the axial direction, and their breakage resistance is insufficient, and silicone chrome steel rings have a relatively large cross-sectional area due to their low strength at high temperatures. In recent years, tool steel, spring steel, and stainless steel have been used as materials for piston rings.In particular, 13Cr martensitic stainless steel is used as the material for piston rings.゜65C-13,5Cr-0,3Mo
-0, IV) have been used as pressure rings with good results.

However, these piston rings made of martensitic stainless steel still have insufficient wear resistance and scuffing resistance when used in engines that experience severe frictional wear. In addition, pressure rings made of martensitic stainless steel and gas nitrided do not have sufficient strength when assembled to the piston, and if the joint is made wider than necessary (1
0T or more, ability 11-13TrT + ring width (+a+a
)”) There is a problem of breakage. Furthermore, this pressure ring has insufficient performance and has the problem of scuffing for internal combustion engines that have strict requirements for scuff resistance, and N1-P or N1-C is thin only on the sliding surface.

-P plating or these base platings with hard particles (
Plating is performed in which SisN-) is dispersed.

For this reason, it is desired that piston rings made of martensitic stainless steel have further improved wear resistance and scuffing resistance to extend the life of the piston rings.

Rocker arms are also required to have wear resistance as well as piston rings as parts for internal combustion engines of automobiles and the like. Since the engine rocker arm is in contact with the camshaft, it must have excellent wear resistance and scuffing resistance, and of course, it must also be resistant to attacks on the cam of the mating component. must be taken into consideration.

Binion shafts are also used in differentials of front-wheel drive vehicles and require wear resistance.

This pinion shaft uses low viscosity lubricating oil, so members that slide under severe conditions with high surface pressure, such as pinion gears and pinion shafts, require excellent seizure resistance and wear resistance. Conventional materials used in cars (SCr415, carburized and quenched) sometimes cause problems such as seizure and increased wear.

The pinion gear is made of carburized and quenched 5Cr415, and the finish of the inner diameter surface, which is the sliding surface with the pinion shaft, is approximately Rz6μ-. Therefore, the pinion gear and the pinion shaft are under a sliding condition of high surface pressure, no oil film is formed on the surface convex portions, and the sliding surfaces of the pinion shaft and pinion gear are worn due to the action of the ab cylinder.

[Problems to be Solved by the Invention] The present invention was made in view of the above-mentioned problems with piston rings, rocker arms, and binion shafts made of stainless steel. To provide pressure ring and oil ring (sight rail) materials that can achieve higher output and higher speeds in internal combustion engines by further improving wear resistance, and
The purpose of the present invention is to provide a material for a rocker arm that reduces the attack on mating materials and has increased wear resistance, and a material for a nion shaft that has both seizure resistance and wear resistance.

[Means for Solving the Problems] As a result of extensive research into the wear resistance of conventional martensitic stainless steel, the present invention has found that the addition of AI is effective in reducing hot heating during the process of manufacturing fine wire from steel ingots. Based on the idea that wear resistance can be significantly improved with almost no deterioration in machining and cold workability, we investigated the optimal content range for C, Si, Mn, Cr, etc. in relation to A1 content. Once the invention has been completed by starting,

That is, the alloy steel excellent in wear resistance of the present invention has a weight ratio of Coo as the first invention. 55-1.10%, Si;2
．． 0% or less, Mn: 2.0% or less, Cr: 12-25%
, Al; 0.05 to 1.10%, and the remainder consists of Fe and impurity elements. However,
The second invention further includes NI: 0.2 to 2.0% in addition to the first invention.
Mo: 0.2-3.0%, V: 0.1-1.5%, Nb
0.05 to 0.7%, Cu; 0.2 to 2.0%, and the remainder is Fe and impurity elements. The gist of the third invention is to apply a surface hardening treatment to at least the sliding surface of the first invention steel, and the gist of the fourth invention is to use the steel of the second invention by applying a surface hardening treatment to at least the sliding surface. It is something to do.

[Function] The reason why the steel of the present invention exhibits superior performance due to the inclusion of A1 is as shown in the 400x micrograph shown in Fig. 1 showing the metallographic structure of the first invention B steel and Fig. 2 showing the metallographic structure of the comparative steel. As shown in the 400x micrograph, the diagram showing the relationship between the grain size and area ratio of carbides with a grain size of 2 μm or more in the invention steel and comparative steel in Figure 3, and Table 1, (i) Spherical carbide shape. (ii) equalization of carbide particle size (reduction of coarse carbides); and (iii) in the case of nitridation, increase in hardness of the nitrided layer due to fine precipitation of AIN.

(Left below) Table 1 (For comparison purposes, steel B which does not contain A1 was melted and used.) Addition of AI is similar to other carbide-forming elements (C, Cr, Mo,
, Nb, and W), it is possible to achieve the target significant improvement in wear resistance and scuff resistance with a small addition amount, prevent increase in cylinder bore wear, and hardly reduce hot workability. It has excellent properties in several respects.

The following can be said in detail about the case where the above effect is applied to a piston ring.

(i) About the top ring (first pressure ring) Figure 4 shows a perspective view of the top ring 10.The top ring is the piston ring that is most required to have scuff resistance, and the required value is determined by each engine. There is a big difference depending on the type of stainless steel, but in the case of conventional 13Cr martensitic stainless steel, there was a problem that scuffing occurred unless gas nitriding was performed. Only surface treatments such as hard chrome plating, thermal spraying, and N1-P base composite plating were used.

Even when the steel of the present invention is quenched and tempered, it can be used as is because it has scuff resistance equivalent to that of 13Cr martensitic stainless steel treated with gas nitriding. Even for engines with stricter requirements for scuff resistance, if surface treatment is performed, values exceeding those of conventional hard chrome plating can be obtained, and good results can be obtained without causing scuff.

The wear resistance of conventional 13Cr martensitic stainless steel is not necessarily 1 minute, and the nitriding depth is 90 μm and 120 μm for engines with strict requirements. However, as the nitriding depth increases, ring 1
When assembling the 0-joint 12, the strength and fatigue strength are 11 (lower than 11), which sometimes causes the problem of breakage.

Since the strength of the steel of the present invention has been improved, the above-mentioned problem of breakage does not occur even with the same nitriding depth as in the conventional steel.Furthermore, due to the significant improvement in wear resistance, the nitriding depth is The thickness can be made shallower, the strength can be further improved, and the gas nitriding treatment time can be shortened, making mass production even more possible.

Furthermore, since the reduction in the amount of wear can minimize the deterioration of oil consumption performance and blow-by gas performance due to wear, it is possible to prevent the overall deterioration of engine performance.

(ii) Regarding oil rings Oil rings have high contact surface pressure due to tension, and depending on the engine, wear is greater than that of the top ring. However, since the reduction in contact surface pressure associated with wear increases oil consumption, the requirements for wear resistance are extremely strict. 6 The wear resistance of the steel of the present invention is extremely excellent and can solve the above problem.

Figure 5 shows a three-piece combination type oil ring 30.
FIG. 14 is a piston, 1
6 is a groove of the oil ring of the piston, 18 is a cylinder bore, 20 is a sight rail, and 22 is a spacer expander. In the case of the sight rail 20 of this three-piece combination type oil ring 30, even when gas nitriding is performed and used, the nitriding depth is limited to 30 to 60 μ- because of restrictions on improving strength. Therefore, for engines that will be used for a long period of time, it is important to have scuff resistance and wear resistance when the base material (quenched and tempered material) is exposed due to the erosion of the nitrided layer, but as mentioned above for the top ring, good results have been obtained. get.

In addition, in the case of an oil ring, not only the sliding surface with the cylinder bore 18 but also the three-piece combination oil ring 30
Now, sight rail 20 and space.

Abrasion resistance is also required at the contact portion with the ear portion of the Saex bander 22, and the steel of the present invention can fully meet this requirement.

Although the steel of the present invention exhibits sufficient wear resistance even when used as is,
Furthermore, the effect can be significantly improved if the steel is subjected to surface treatment such as nitriding, plating, thermal spraying, etc. The steel of the present invention is preferably subjected to heat treatment before being subjected to nitriding treatment. Examples of heat treatment include quenching and tempering, Examples include quenching (which also serves as tempering in nitriding treatment). The nitriding treatment is performed on the surface including the sliding surface, and any of gas nitriding, gas soft nitriding, salt bath nitriding, tuftride, and ion nitriding can be applied.

Next, the reasons for limiting the chemical composition of the steel for piston rings of the present invention will be described.

C, 0.55-1°10% C is an element that obtains the necessary hardness during hardening and at the same time forms carbides to provide high strength and wear resistance. 0
．． If it is less than 55%, the amount of carbide produced is small and the wear resistance obtained due to the presence of carbide is poor. However, if it exceeds 1.10%, the particle size of the carbide becomes large and wears out the cylinder liner, which is the mating material, and cold workability into the piston ring shape becomes impossible, so the upper limit was set at 1.10%. .

Si: 2.0% or less Si is added as a deoxidizing element during refining and is an element that provides heat resistance, but if added in large amounts it impairs cold workability such as drawing, so the upper limit should be set at 2.0%. %.

Mn: 2.0% or less Mn is added as a deoxidizing element during refining like Si,
Although it is an element that increases toughness, it impairs cold workability when added in large amounts, so the upper limit was set at 2.0%.

Cr: 12-25% Cr combines with C to form carbide, which has the effect of improving wear resistance, corrosion resistance and fabric strength, and further increasing the hardness of the nitrided hardened layer.

If the content is less than 12%, these effects, especially the improvement in wear resistance, are insufficient, so the content is made to be 12% or more. However, if a large amount of Cr is contained, the above-mentioned effects become less pronounced, and on the contrary, the toughness decreases and cold formability is inhibited, so the upper limit of Cr is set at 25%.

Al: 0.05 to 1.10% Al is dissolved in the matrix during quenching and tempering, increases the strength of the matrix by making the crystal grains finer, and improves wear resistance and scuff resistance. As mentioned above, during quenching and tempering, AI improves wear resistance and scuff resistance by spheroidizing carbides and making the grain size uniform. Also,
During the gas nitriding process, the A1 solid solution in the matrix
becomes AlN0b"& ,t(H precipitation, which causes a significant increase in the hardness of the nitrided layer. This significantly improves wear resistance and scuffing resistance, and prevents increase in cylinder bore wear. Furthermore, the abutment Significantly improves the strength during the expansion test.To obtain these effects, 0
．． It is necessary to add 0.5% or more, and the greater the amount added, the greater the effect. However, even if the content exceeds 1.10%, the effect is lost in m3, and the surface properties deteriorate during hot and cold rolling due to the formation of inclusions Al2O3 (significant decrease in strength when surface scratches remain), hardenability and Since this decreases heat resistance and makes the nitride layer brittle, the upper limit was set at 1°10%.

Ni; 0.2 to 2.0% Ni is an element that imparts corrosion resistance, toughness, and hardenability. Especially when adding AI, which has a strong tendency to form ferrite,
Prevents ferrite formation at high temperatures and improves hardenability and hot workability. If the content is less than 0.02%, the above effect is small, so the lower limit was set at 0.2%. However, if the content exceeds 2.0%, cold workability will be impaired, so the upper limit was set at 2.0%.

Mon0.2-3.0% Mo is an element that forms carbides similarly to C, increases the hardness of the nitrided layer during nitriding, improves wear resistance, and enhances high-temperature strength, and achieves these effects. For 0.
The content must be 2% or more.

However, if it is contained in an amount of 3.0% or more, the above-mentioned effects become less pronounced and at the same time the hot workability is reduced, so the upper limit was set at 3.0%.

V, 0.10-1.50%, Nb, 0.05-0.70
% (1) and Nb are elements that increase temper softening resistance and high-temperature strength, as well as refine carbides, and form nitrides through nitriding treatment to increase the hardness of the surface layer. In order to obtain the above effect, V is 0.10% or more,
It is necessary to contain Nb at 0.05% or more. However, V
, 1.5% or more, and Nb: 0.70% or more will reduce hot workability due to the formation of coarse eutectic carbides, so the upper limits were set to 1.5% and 0.70%, respectively.

Cu; 0.2 to 2.0% Cu is an element that increases the corrosion resistance and oxidation resistance of steel and strengthens the dough 1. To obtain such an effect, 0.2
It is necessary to add 0% or more. However, adding more than 2.0% impairs hot workability and increases resistance to nitriding, which is undesirable, so the upper limit was set at 2.0%.

[Example] Next, the effect of the present invention will be clarified by an example comparing it with conventional steel.

<Example 1> 13Cr martensitic stainless steel was melted in an electric furnace as the present invention steel and conventional steel having the chemical components shown in Table 2. In Table 2, steels A to C are first invention steels or third invention steels, and D to 0 steels are second invention steels or fourth invention steels. Further, P steel is a conventional steel, 13Cr martensitic stainless steel, and Qm is a conventional steel with hard chromium plating.

(Left below) The melted test steel was cast, hot-rolled, quenched and tempered (target hardness Hv 350-450), and then subjected to a wear test of 10 x 15.7 x 6.3 m. It was processed into a 30 x 30 x 5 baking test piece for use as a test piece and a baking test piece. A wear test was conducted on the obtained wear test piece under the following conditions.

(Abrasion test using LWF-11 tester @) Compatible material
Fe Load: 60 kg Time: 120 minutes Speed: 0.3 theory/see Lubricating oil: After supplying 1.5 cc/sin of low viscosity engine oil, the amount of wear on the sliding surface of the wear test piece was measured.
The results are shown in Table 3.

Subsequently, another wear test piece was subjected to 530°C in an ammonia gas stream.
It was heated to ~590°C and gas nitrided for 5 hours or more.

When the surface hardness was measured after gas nitriding, Hvl OO
It was 0 or more. The wear test piece after the nitriding treatment was subjected to a wear test under the same conditions as above. The amount of wear on the sliding surfaces measured after the test is also shown in Table 3.

Next, a seizure test was performed on the seizure test piece produced in the same manner as the wear test piece under the following conditions, and the seizure load was
It is also shown in the table.

(Mechanical laboratory type constriction and abrasion test @ Seizure test using machine) Compatible material, Fe Load: Increase by 25 kg every 2 minutes until seizure occurs Speed: 1.2 theory/see Lubricating oil: Low viscosity Engine oil dripping lubrication seizure load: The seizure load is defined as the load where the friction coefficient suddenly exceeds 0.2 (see the margin below). In terms of depth, compared to the 5°8μ theory of conventional materials,
A~0 steel, which is the steel of the present invention, has a 1.20~4. The wear depth in the case of gas nitrided material, which is OOμ-, is 3
．． 5 μ theory, A~0 steel, which is the steel of the present invention, has a value of 0.20~
2. It's OOμ Kabura.

In all cases, it was confirmed that the steel of the present invention exhibited excellent wear resistance.

In addition, in the seizure test, the seizure load for the quenched and tempered material was 100.0 for the conventional material, whereas the A
~0 steel is 137.5 to 150.0, and the baking load for gas nitrided material is 137.5 kg for conventional material.
On the other hand, it was confirmed that the steel of the present invention exhibited excellent scuff resistance in both cases.

Next, when assembling the piston ring to the end of the piston ring, it is necessary to widen the abutment by 10T or more, so assembling strength is required.

Quenched and tempered materials have sufficient assembly strength, but gas nitrided materials are brittle, and conventional materials have almost no margin at 11-13T, and may occasionally break due to material variations and variations in the amount of expansion. As shown in Table 2, the steel of the present invention has excellent assembly strength in that it will not break unless it is 20T or more. This is the result of an expansion test conducted on a piston ring for a bore diameter of φ86+s- (B dimension 2.0 m, T dimension 3.15 s, nitriding depth 90 μm).

In addition, the hardness of the gas nitrided materials is shown in Table 3. The hardness of the steels A to G, which are the steels of the present invention, is 1335, compared to 1180 for conventional materials.
~1450, confirming that the nitrided layer of the steel of the present invention exhibits high hardness.

In addition, in piston rings such as keystone rings where fatigue strength is an issue, there is a problem of breakage, especially when made of brittle materials such as gas nitrided materials or when brittle composite plating is plated on the sliding surface with the cylinder wall. There is. Table 4 shows the results of a fatigue test conducted on the piston ring in a dilute sulfuric acid aqueous solution at a constant amplitude stress of 50 kg/transport-2.

Table 4 Compared to the fatigue strength of the conventional material 2X10', the present invention steel [D, E
, F, G] was confirmed to be significantly improved to 1 to 3×10′.

Furthermore, Table 5 shows the wear ratio of the cylinder bore when a 150-hour durability test was conducted using a 2000 cc in-line 4-cylinder engine for the present invention B@ and comparative steel (steel B that does not contain A1).

Table 5 (Top ring treated with gas nitriding) Cylinder bore wear increases by 1.80 times when the area ratio of angular coarse chromium carbides is as large as <0.98 as in the comparison steel0 Invention Bm In this case, the chromium carbides are rounded, and the area ratio of coarse carbides is 0.
．． Since it is as small as 54%, the cylinder bore wear is the same as that of conventional materials, but there is no increase in cylinder bore wear.

(Example 2) A rocker arm butt for a vertical engine was manufactured using B, E, and Jm shown in Table 2 as test materials and 5KDII equivalent steel as a comparison steel. After tempering, heat treatment at 530-590℃
The samples were subjected to salt bath nitriding treatment for more than 1 hour, and tested under the following test conditions to measure the amount of rocker arm butt wear and the amount of cam wear. The results are shown in Table 6.

Test conditions for motoring test Engine speed: 2000 rotations Test time: 200 hours Valve spring load: 150% or more (for mass-produced engine assembly relative to the load) Lubricating oil: Durable oil Camshaft 2 alloy cast iron No. 6 As shown in the table above, the reason why the steel of the present invention shows better results than the comparison steel is because of the improvement in wear resistance due to an increase in the amount of carbides and the refinement of the carbide diameter (as shown in Table 7 below). This is thought to be due to a decrease in aggressiveness toward the mating material due to a decrease in coarse carbides.

(Leaving space below) Table 7 (Example 3) Using C and G steels shown in Table 2 as test materials and 5Cr415 and SCM440 as conventional steels, pinion shafts for differentials of FF vehicles were manufactured and tested in actual vehicles. As a test, motion conditions in which the pinion gear makes relative motion on the pinion shaft (figure-of-eight turns, driving with an emergency tire mounted on one wheel,
50,000km on rough roads (including muddy and slippery surfaces)
Figure 6 shows the stepped wear depth of the sliding surface of the pinion shaft when the pinion shaft is traveled for m. For conventional materials, 5Cr415/carburized and quenched is 40 μs, SCM440/soft-nitrided is 25 μs, and the stepped wear depth is In contrast, the steel of the present invention had a small wear amount of 2.2 to 5 μm and 1/8 to 115, and was confirmed to have excellent wear resistance.

Regarding seizure resistance, a mechanical test was conducted using a new type of wear tester, which correlated with seizure during a draft running test of a differential gear.The same test steel as above was tested for seizure resistance. The test conditions are 10
00 rpm (1st and 2nd wheel/S), under oil bath lubrication (low viscosity lubricating oil), increase the load by 25 kg every 2 minutes, measure the load at which seizure occurs (seizure load), and report the results. It is shown in Figure 7. In this test, if there is a seizure load of 250 kg or more, seizure will not occur even under conditions where differentials frequently occur.Therefore, the steel of the present invention has excellent seizure resistance. This was confirmed.

The reason why the steel of the present invention exhibits excellent wear resistance and seizure resistance is that, unlike conventional materials, the surface is undulated by fine grained chromium carbonitrides of 2 to 12 μm in diameter due to soft nitriding and carbon precipitated from the carbides. It is obtained by precipitates (considered to be grain boundary cementite).

[Effects of the Invention] As explained above, the alloy steel with excellent wear resistance of the present invention improves the wear resistance of conventional martensitic stainless steel piston rings, rocker arms, and pinion shafts.
In order to further improve properties such as scuff resistance and extend life, AI is added in an amount of o, os”i~1.10%, and C, Si
, Mn, Cr, etc., in relation to the A1 content.The optimal content range has been found in relation to the A1 content, and the wear resistance and scuff resistance are improved by making the carbide spheroidal and making the particle size uniform. By surface treatment such as gas nitriding treatment, AI that has been dissolved in the matrix is finely precipitated as AIN, further improving wear resistance and scuff resistance. Furthermore, the steel of the present invention has a number of excellent effects, such as significantly improved assembly strength, high hardness, and fatigue strength superior to conventional steel.

[Brief explanation of the drawing]

Figure 1 is a 400x micrograph showing the metal structure of the invented steel, Figure 2 is a 400x microscope photo showing the metallographic structure of the comparison steel, and Figure 3 is the carbide grain size and area ratio of the invention steel and comparative steel. FIG. 4 is a perspective view of the pressure ring, FIG. 5 is an AT sectional view showing the sliding state of a three-piece combination type oil ring, and FIG. 6 is a binion made of conventional material and steel of the present invention. FIG. 7 is a diagram showing the stepped wear depth of the shaft, and FIG. 7 is a diagram showing the seizure load of the conventional material and the steel of the present invention. 10...Pressure ring, 12...Joint, 14...
Piston, 18... Cylinder bore, 20... Sight rail, 22... Spacer expander, 30...
oil ring. Patent applicant Aichi yJm Co., Ltd. Same as above Toyota Motor Corporation drawings JR book (
Contents (Xj,..., Heaven 71shi) No. 11. 2121 L7 construction data (No change in content No. 3121 Carbide particle size <pm> Fig. 4 Fig. 5 Section =;, △ri 1゛] Volume: 2 No change) Fig. 6 Cleaning of drawings of imported materials (changed in content; Zino Figure 7 Carburizing and quenching Soft-nitriding Soft-nitriding (C steel) Method of writing amendments to procedures for imported materials) January 19, 1989 Patent Application No. 230543 2, Name of the invention: Crushed alloy steel 3 with corrosion resistance; Relationship to the case of the person making the amendment Patent applicant address: 1 Wanowari, Arao-cho, Tokai-shi, Aichi Prefecture Name: Aichi Steel Corporation Representative: Masuo Amano 4 , agent〒450

Claims (4)

[Claims] (1) C: 0.55-1.10%, Si; 2.
0% or less, Mn; 2.0% or less, Cr; 12 to 25%,
An alloy steel with excellent wear resistance characterized by containing 0.05 to 1.10% Al, with the remainder consisting of Fe and impurity elements. (2) C: 0.55-1.10%, Si; 2.
0% or less, Mn; 2.0% or less, Cr; 12 to 25%,
Contains Al; 0.05 to 1.10%, and further contains Ni; 0
．． 2-2.0%, Mo; 0.2-3.0%, V; 0.1
~1.5%, Nb; 0.05-0.7%, Cu; 0.2
An alloy steel with excellent wear resistance characterized by containing one or more of ~2.0% of Fe and the remainder consisting of Fe and impurity elements. (3) C: 0.55-1.10%, Si; 2.
0% or less, Mn; 2.0% or less, Cr; 12 to 25%,
An alloy steel having excellent wear resistance, which contains Al; 0.05 to 1.10%, the balance is Fe and impurity elements, and is used after surface treatment is applied to at least the sliding surface. (4) C: 0.55-1.10%, Si; 2.
0% or less, Mn; 2.0% or less, Cr; 12 to 25%,
Contains Al; 0.05 to 1.10%, and further contains Ni; 0
．． 2-2.0%, Mo; 0.2-3.0%, V; 0.1
~1.5%, Nb; 0.05-0.7%, Cu; 0.2
An alloy steel with excellent wear resistance, characterized in that it contains one or more of ~2.0%, the remainder consists of Fe and impurity elements, and is used with surface treatment applied to at least the sliding surface. .