KR100599177B1 - An abrasion-resistant steel and a weaving machine member made of an abrasion-resistant steel - Google Patents

Abstract

 The newly invented steel is comprised of 8.0-35.0 wt.% Cr, 0.05-1.20 wt.% C, and at least one of Ti, Nb, Zr, V and W is 0.05-3.0 wt.%, And the rest is essentially Is Fe, and has a structure in which the total amount of Ti, Nb, Zr, V, and / or W carbides dispersed in the steel matrix is adjusted to 0.1 wt.% Or more. The steel was endowed with excellent wear resistance by dispersion of carbide precipitation. These carbides have almost the same hardness as hard particles, such as alumina or silicon carbide, which cause abrasive wear. Because of this excellent wear resistance, weaving loom members, sewing needles, agricultural machinery parts such as mowing machines or cutter blades can be used for a long time.

Abrasion Resistant Steel, Abrasive Wear, Loom Member, Ti, Nb, Zr, V, W Carbide

Description

Loom member made of abrasion-resistant and wear-resistant steel {An abrasion-resistant steel and a weaving machine member made of an abrasion-resistant steel}

1 is a graph showing the relationship between hardness and wear coefficient.

2 is a graph illustrating the effect of the total amount of carbide precipitation on the wear coefficient.

3 is a graph illustrating the effect of the total amount of Ti and Nb carbide precipitation on wear resistance.

TECHNICAL FIELD The present invention relates to steel and includes environments or looms that are susceptible to abrasive wear (eg, flat steel healds, droppers, lead dents, tunnel leads). It is related to steel having excellent wear resistance and corrosion resistance even in an environment where it is exposed to abrasion state in contact with the yarns.

Steels of very high strength, such as steel used in knives or tools used in tools, are required for applications requiring wear resistance, for example, loom members that come in contact with yarns and other electrical and electronic parts that wear out in contact with other members. It has been used so far. These steels are one of the requirements for corrosion resistance due to their use environment.

Although cutters, tools, loom members, electrical members or electronic members greatly change their durability according to their use environment, the wear resistance of steel materials has the greatest impact on durability. In this regard, carbon steel having a metal structure hardened by quenching or cold working has been used for a member requiring wear resistance.

For example, steel hardened by quenching stainless steel SUS420J2 has been used in loom members such as pratt steel heels, droppers, lead dents and tunnel leads. Such loom members are affected by more and more severe wear environments due to the high speed processing for improving the material and increasing productivity of the yarns used in the fabric. As a result, the life of the member becomes shorter and shorter, and the member must be replaced with a new member more frequently.

Since abrasion is a phenomenon that occurs under very complex mechanisms, the cause of the abrasion at the worn area is not yet clear. However, high strength steels have been used in judging the required wear resistance. In short, the durability of the steel member has been evaluated with the steel member actually mounted on an existing machine. As a result, it takes a very long time to select the appropriate type of steel, and it is also very difficult to select the appropriate type of steel.

The wear resistance of steel can be improved by hardening or work hardening. However, the increase in productivity requires the use of coarse materials to be processed at high speeds or processing, and the wear environment is becoming increasingly severe. This severe wear environment reduces the durability of the steel member, resulting in breakage resulting from frequent replacement and wear of the steel member. Breakage caused by wear varies depending on the wear environment. And the hardness is not always proportional to the durability of the steel member. In this regard, it is important to be fully aware of the wear mechanism in the use environment for the development of steel suitable for such an environment.

Summary of the Invention

The present invention aims to provide a new steel that can sufficiently withstand abrasive wear through the dispersion of solid carbide precipitation in the steel base, and is made of steel that is particularly resistant to abrasion even in very severe abrasion environments and can be used for a long time. The purpose is to provide a loom member.

The newly invented steel is composed of 8.0-35.0 wt.% Cr, 0.05-1.20 wt.% C, and 0.05-3.0 wt.% At least one of Ti, Nb, Zr, V, and W. The amount of dispersed Ti, Nb, Zr, V and / or W carbide precipitations has a structure that is adjusted to a total of 0.1 wt.% Or more.

The loom member according to the present invention has a condition of 8.0-35.0 wt.% Cr, 0.05-1.0 wt.% C, 1.0 wt.% Si, 1.0 wt.% Mn, and 0.05-2.0 wt.% Total. Consisting essentially of one or two of 0.05-1.0 wt.% Ti and 0.05-1.50 wt.% Nb, except for unavoidable impurities, the remainder being Fe, and Ti and / or Nb dispersed in the steel matrix. The total amount of carbide precipitation is made of steel with a structure tuned to 0.1 wt.% Or more.

Detailed Description of the Preferred Embodiments

The inventors collected a large number of specimens that were subjected to abrasion testing as well as samples damaged by abrasion. The damaged parts were examined under the microscope field of view. Most of the samples and specimens were observed to be broken and scratched in the worn area. For samples collected from the loom member, it was possible to observe the site of scratches that seemed to be scratched in a straight line in the worn part. Adhesion of hard particles, such as alumina or silicon carbide, was observed near the areas where they were worn, where the surfaces of the other members or yarns were in contact with the worn areas. Breakage and attachment of these hard particles demonstrate that wear occurs in the presence of hard particles. This wear is referred to as so-called abrasive wear, in which a steel member that is in contact with another member or yarn is rubbed or ground during vibration or sliding motion by hard particles present at the contact surface.

Abrasive wear is the most severe of the various wear phenomena. There is an urgent need to provide materials that withstand such abrasive wear.

In order to increase the wear resistance, the inventors first examined by quenching and hardening high carbon steel. Due to the increase in hardness after quenching, the weight loss due to abrasive wear was slightly reduced. Quench hardening, however, did not significantly improve wear resistance. That is, the addition of carbon for hardening the steel structure could not sufficiently improve the wear resistance. In the case of steel hardened by cold working, an improvement in wear resistance is also not achieved.

The present inventors proposed the reason why the durability of the steel material against the abrasive wear is not improved through tissue hardening or work hardening as follows. Hard particles such as alumina and silicon carbide are much harder than hardened or work hardened steel members. Since the hardened or hardened steel member is not sufficiently hard as hard particles such as alumina or silicon carbide, the hardened or hardened work is insufficient to suppress the abrasive wear.

While repeating tests for the study of wear mechanisms and for the study of materials that can withstand abrasive wear sufficiently, the inventors of the present invention have found that the steel material can be subjected to aggressive wear by dispersion of hard carbide precipitation in the steel base. Resistance was found to be significantly improved. Specifically, the present inventors have found that the quantitative effects of Ti, Nb, Zr, V and / or W carbide precipitation on the durability to abrasion resistant, Ti, Nb, Zr, V and / or W carbides are alumina or silicon carbide From the viewpoint of having almost the same hardness as the hard particles, the study was conducted. When a sufficient amount of Ti, Nb, Zr, V and / or W carbide precipitation is dispersed in the steel matrix, as shown in FIG. 1, abrasive suppression is suppressed compared to steel having the same hardness but no carbide precipitation. It became.

Newly invented steels contain 8.0-35.0 wt.% Cr. If the Cr content is less than 8.0wt.%, The effect of Cr on the corrosion resistance is bad. If the Cr content exceeds 35.0 wt.%, The hot workability of the steel is lowered, leading to an increase in production cost.

The steel contains 0.05 wt.% Or more carbon in order to precipitate in 0.1 wt.% Or more carbide in total. The additional C is not only consumed in the production of carbides, but also serves to effectively strengthen the steel structure. However, the addition of excess carbon above 1.20 wt.% Increases the quantitative precipitation of huge eutectic Cr carbides that have a detrimental effect on steel quality and hot workability.

At least one of Ti, Nb, Zr, V and W is 0.05-3.0 wt.% So that the amount of Ti, Nb, Zr, V and / or W carbide precipitation in the metal matrix is maintained at 0.1 wt.% Or more in total. Is added in the amount of. The lower limit of Ti, Nb, Zr, V and / or W carbide precipitation, 0.1 wt.%, Is a very important value. This figure was discovered by the inventors by studying the effect of carbide precipitation on wear resistance. If the total amount of carbide precipitation is maintained at 0.1 wt.% Or more, the steel shows very good wear resistance compared to steel without carbide precipitation. Precipitation of Ti, Nb, Zr, V and / or W carbides is achieved at a total amount of 0.1 wt.% Or more by adding Ti, Nb, Zr, V and / or W in a proportion of 0.05 wt.%. However, when Ti, Nb, Zr, V and / or W is added in excess of 3.0 wt.%, It causes a decrease in the fluidity of the molten steel in the steelmaking process, adversely affect the toughness and cause the generation of intermetallic compounds It also causes a rise in steel prices.

The steel may contain other elements such as Ni, Mo and Cu. For example, 0.2-5.0 wt.% Ni is effective for toughness and quench hardening, 0.1-3.0 wt.% Mo is effective for toughness and corrosion resistance, and / or 0.2-3.0 wt.% Cu is corrosion resistant. Effective against stress and corrosion corrosion cracking. As for other member elements contained in the steel, the C content is preferably adjusted to 0.05-1.50 wt.%, The Si content is preferably adjusted to 0.02-2.5 wt.%, And the Mn content is 0.02-3.0 wt. It is preferred to adjust to.%.

For steel used as a loom member, in order to keep the total amount of Ti and / or Nb carbide precipitates dispersed in the steel matrix at 0.1 wt.% Or more, 0.05-1.0 in a condition of 0.05-2.0 wt.% In total. One or two of wt.% Ti and / or 0.05-1.50 wt.% Nb is added. By adding Ti and / or Nb at a rate of 0.05 wt.%, The total amount of precipitation of Ti and / or Nb carbide is achieved at or above 0.1 wt.%. However, excessive addition of Ti of 1.0wt.% And Nb of 1.50wt.% Or excessive addition of Ti and Nb of 2.0wt.% Causes adverse effects on the flowability of molten steel during the forging process and on the toughness of the intermetallic compounds. Causes occurrence

The steel used as the loom member may also contain up to 1.0 wt.% Si, up to 1.0 wt.% Mn. Si can be added as a deoxidizer during the smelting process. However, when Si content is 1.0 wt.% Or more, it will cause toughness to worsen. Mn can also be added as another antacid in the smelting process. However, when the Mn content is 1.0 wt.% Or more, the proportion of excess austenite particles during quenching increases, leading to a decrease in hardness and toughness.

Example 1

Various steels having the components shown in Table 1 were produced in a conventional smelting process and cast into slabs. Each slab was subjected to solution treatment and hot rolled to a thickness of 5 mm. The hot rolled steel strip was heat-treated in an oven at 870 ° C. for 9 hours and then cooled.

Steel used in the examples Example No. Alloy Components and Content (wt.%) week C Si Mn Ni Cr Ti Nb Zr V W One 0.21 0.59 0.59 0.17 9.57 0.10 0.04 0.05 - -   Invention 2 0.30 0.62 0.64 0.15 11.58 0.19 0.02 - 0.06 0.08 3 0.39 0.51 0.61 0.04 12.82 0.40 - - - - 4 0.22 0.53 0.57 0.03 13.04 - 0.41 - - - 5 0.61 0.54 0.58 0.04 13.13 0.26 0.18 - - - 6 0.29 0.58 0.61 0.21 13.43 0.31 0.25 0.15 0.12 - 7 0.68 0.57 0.65 0.19 13.48 1.12 - - - - 8 0.34 0.51 0.62 0.17 18.52 0.13 0.17 - - 0.23 9 0.91 0.56 0.61 0.12 23.51 0.16 1.15 0.08 - 0.11 10 1.22 0.52 0.59 0.16 31.48 - 2.98 - - - 11 0.24 0.58 0.59 0.15 1.35 - - - - -   Comparative Example 12 0.21 0.52 0.61 0.04 5.32 - - - - - 13 0.32 0.55 0.62 0.21 6.59 - - - - - 14 0.41 0.48 0.59 0.03 10.11 - - - - - 15 0.59 0.54 0.58 0.03 11.93 - - - - - 16 0.68 0.54 0.64 0.17 13.48 0.03 0.03 - 0.01 - 17 1.26 0.59 0.61 0.15 13.52 0.04 0.04 0.01 - 0.02

The test pieces of the abrasion test were cut out into annealed hot rolled steel strips, heated at 1100 ° C. for 15 minutes and then cooled at room temperature. The carbide precipitation dispersed in each test piece was measured quantitatively. In addition, the corrosion resistance as well as the durability against the abrasion of each specimen were investigated as follows.

Carbide Determination

A test piece having carbide precipitation adjusted in proportion by the solution treatment and precipitation treatment was immersed in an iodide alcohol solution and dissolved therein by ultrasonic irradiation. The amount of carbide remaining in the solution was measured. The state of the carbide was confirmed by X-ray diffraction, and the amount of each metal element was measured by wet analysis and gas analysis.

Evaluation of Weight Loss Due to Abrasive Wear Resistance

Durability against abrasion wear was demonstrated using a pin-on-disc friction and wear test machine. A cylindrical test piece with a contact surface of 5 mm diameter was fixed to the pin, while abrasion paper using silicon carbide particles was attached to the disk. The pinned specimens were loaded with load F (= 4000gf) and rubbed with a rotating disk at a friction speed of 0.7 m / sec along the length L (= 0.5 km). Then, the weight loss W (kPa) of the test piece was measured. The wear factor C was calculated from the value measured according to the formula C = W / (L × F) for the evaluation of wear resistance.

Corrosion Resistance Evaluation

The corrosion resistance of the test piece was measured through rust generated on the surface of the test piece after the test piece was subjected to a 5% salt spray test for 72 hours.

The test results are shown in Table 2.

Effect of total amount of carbide precipitation on the wear factor Invention Comparative Example Example No. Total amount of carbide precipitation (wt.%) Wear factor mm ² / kgf × 10 ^-8 Corrosion resistance Example No. Total amount of carbide precipitation (wt.%) Wear factor mm ² / kgf × 10 ^-8 Corrosion resistance One 0.21 250 No rust 11 0 2006 Rust occurrence 2 0.38 139 12 0 2112 3 0.46 116 13 0 1998 4 0.43 124 14 0 1985 No rust 5 0.50 107 15 0 1805 6 0.91 59 16 0.05 1650 7 1.28 42 17 0.09 1125 8 0.52 103 The total amount of carbide precipitation is the sum of Ti, Nb, Zr, V and W carbide precipitation. A wear factor of 1000 mm ² / kgf × 10 ^-8 is considered to be acceptable. 9 1.63 30 10 3.26 15

Molten Cr occurred in all the specimens of Comparative Examples 11-13 having a content of less than 8 wt.%. However, no rust was observed on the surfaces of Example 1-10 and Comparative Examples 14-17. Through this result, it is recognized that Cr content of 8wt.% Or more is required to secure corrosion resistance.

About all the test pieces of the comparative example 11-15 in which there is no distribution of carbide precipitation, a wear coefficient C is a big value exceeding ¹⁸ mm <2> / kgfx10 <^-8> . Since the wear coefficient C tends to decrease as the carbide precipitation increases as previously seen, the present inventors graphically illustrate the relationship between the wear coefficient C and the total amount of carbide precipitation, and as shown in FIG. It was confirmed. That is, the wear coefficient C decreases as the total amount of carbide precipitation increases, and surprisingly decreases when the total amount of carbide precipitation becomes 0.05 wt.% Or more. By adjusting the total amount of carbide precipitation to 0.1 wt.% Or more, the wear coefficient C was reduced to a value of less than 1000 m 2 / kgf x 10 ^-8 . This low value is less than half the wear factor of the specimen without carbide precipitation, and the newly invented steel is very good at wear resistance.

Example 2

Various steels having the compositions shown in Table 3 were produced in a conventional smelting process and cast into slabs. Each slab was solution treated and hot rolled to a thickness of 5 mm. The hot rolled steel strip was heat treated in an oven at 870 ° C. for 9 hours and then cooled. The annealed steel strips were washed with acid. A cold rolled steel strip of 0.30 mm thickness was then made by repeating cold rolling and annealing.

Steel used in the examples Example No. Alloy Components and Content (wt.%) week C Si Mn Ni Cr Ti Nb One 0.23 0.55 0.57 0.16 9.92 0.12 0.11   Invention 2 0.31 0.59 0.61 0.14 10.53 0.22 0.12 3 0.33 0.61 0.59 0.19 13.26 0.59 0.41 4 0.65 0.53 0.59 0.19 13.12 1.25 0 5 0.32 0.56 0.63 0.17 13.52 0 1.06 6 0.88 0.51 0.59 0.14 13.56 0.71 0.76 7 1.21 0.54 0.62 0.16 18.48 1.63 0.59 8 0.32 0.51 0.59 0.17 4.31 0.008 -  Comparative example 9 0.62 0.49 0.58 0.15 13.37 0.04 0.02 10 1.19 0.52 0.64 0.19 13.49 0.04 0.04 11 0.33 0.44 0.56 0.11 13.41 - - SUS420J2

Test pieces for abrasion testing were cut into individual cold rolled steel strips and made of flat steel heels as loom members. Each test piece was placed in an oxygen free atmosphere at 1050 ° C. for 1 minute. Then cooled to room temperature.

The amount of carbide precipitation in each test piece was measured. And the corrosion resistance of the test piece was proved by the same method as Example 1. Abrasion resistance was evaluated as follows.

In the abrasion test, synthetic fiber yarns (TFD75 / 36F, 120 μm in diameter) were run through mail holes in flat steel heels made as test specimens. The flat steel heels were rotated at 800 r.pm (sliding speed of 0.1 m / sec) for 10 hours, while the flat steel heels were brought into contact with the yarns under the condition that the yarns were subjected to a tension of 50 g. Then, the wear depth at the contact surface was measured, and the weight loss of the worn mail portion was also measured in contact with the yarn. Wear resistance of each specimen was evaluated from the M (%) value (= D _i / D _o × 100) calculated from the ratio of D _o , the wear depth of stainless steel SUS420J2, based on the wear depth D _i of each specimen. It became. 50% or less of an M value is required to achieve twice the superior wear resistance of conventional flat steel heels made of stainless steel SUS420J2.

The test results are shown in Table 4.

Rust occurred on the surface of the test piece of Comparative Example 8 having a Cr content of less than 8.0 wt.%. However, no rust was observed on the surface of the test specimens of other examples having a Cr content of 8.0 wt.% Or more. Through these results, it is recognized that an amount of Cr of 8.0 wt.% Or more is required to secure corrosion resistance. All the M values of Examples 8 to 10, in which Ti and Nb carbide precipitates were distributed in a total amount of less than 0.1 wt.%, Were not so smaller compared to the conventional member (Example 11). On the other hand, all of the test specimens of Example 1 in Example 7 in which the total amount of Ti and Nb carbide precipitation were distributed at a ratio of 0.1 wt.% Or more had an M value of less than 30%. This low M value means that the life of flat steel heels made of newly invented steel is three times longer than that of conventional flat steel heels.

The present inventors graphically illustrate the relationship between the total amount of Ti and Nb carbide precipitation and the M value. And as shown in Figure 3 it was confirmed that they are related to each other. As clearly seen in Fig. 3, the M value decreases as the total amount of Ti and Nb carbide precipitation increases. And when the total amount of carbide precipitation is 0.1 wt.% Or more, a sharp decrease in M value occurs. By adjusting the total amount of carbide precipitation to 0.1 wt.% Or more, the M value is reduced to 50% or less. These small M values mean that the flat steel heels made of newly invented steel are twice as long as conventional flat steel heels.

Carbide precipitation, abrasion and corrosion resistance of each flat steel heald Example No. Amount of carbide precipitation (wt.%) Abrasion Resistance M Value (%) Corrosion resistance week TiC NbC Total amount One 0.13 0.10 0.23 29.5 No rust   Invention 2 0.26 0.10 0.36 23.2 No rust 3 0.70 0.44 1.14 12.6 No rust 4 1.41 0 1.41 13.1 No rust 5 0 1.11 1.11 11.1 No rust 6 0.81 0.80 1.61 9.2 No rust 7 1.90 0.59 2.49 8.5 No rust 8 0.01 0 0.01 99.1 Rust occurrence  Comparative example 9 0.04 0.02 0.06 89.2 No rust 10 0.05 0.03 0.08 69.5 No rust 11 0 0 0 100 No rust SUS420J2

As mentioned above, according to the present invention, the newly invented steel has a total amount of Ti, Nb, Zr, V and / or W carbide precipitation in the steel base at a ratio of 0.1 wt. Compared with hardened steel, the wear resistance is excellent. These carbides have almost the same hardness as hard carbides, such as alumina or silicon carbide, which lead to abrasive wear. Because of this good wear resistance, steel machine parts such as loom members, sewing machine needles, mowing machines or cutter blades can be used for a long time. In particular, steels in which Ti and / or Nb carbide precipitation is distributed in a total amount of 0.1 wt.% Or more are excellent in wear resistance, and thus are suitable as loom members such as flat steel heels, droppers, lead dents or tunnel leads. .

Claims (2)

8.0-35.0 wt.% Cr, 0.05-1.20 wt.% C, Ti, Nb, Zr, at least one of V and W is mainly composed of 0.05-3.0 wt.%, The remainder is mainly Fe, steel base Steel having excellent abrasion resistance, having a structure in which the total amount of one or more carbide precipitates among Ti, Nb, Zr, V, and W distributed within is adjusted to 0.1-3.26 wt.%. 8.0-35.0 wt.% Cr, 0.05-1.20 wt.% C, Si up to 1.0 wt.%, Mn up to 1.0 wt.%, 0.05-1.0 wt.% Under 0.05-2.0 wt.% Total Is composed mainly of at least one of Ti and 0.05-1.50wt.% Of Nb, the remainder is mainly Fe, and the total amount of precipitation of at least one carbide of Ti and Nb in the steel matrix is 0.1-3.26wt.%. Loom members made of steel with good abrasion and corrosion resistance to fibers with controlled tissue.

Images