KR100382513B1 - Guide Roll alloy With Heatproof And Wearproof - Google Patents

Abstract

An object of the present invention is to provide an alloy for use in the manufacture of a guide roll for transporting wire rods having heat resistance fatigue resistance and abrasion resistance.

The present invention is formed by adding an appropriate amount of Nb and Zr to an alloy element composed of C, Si, Cr, Mo, Ni, Co, Ti, V, and W, and is resistant to high heat and is not easily worn or worn out. It is a characteristic.

Description

Guide Roll Alloy With Heatproof And Wearproof}

The present invention relates to an alloy having heat resistance and abrasion resistance for use in the manufacture of guide rolls (or rolled rolls) used in wire rod processing, and is particularly composed of C, Si, Cr, Mo, Ni, Co, Ti, V, W. The present invention relates to a guide roll alloy which further improves the characteristics of thermal fatigue resistance, abrasion resistance and high thermal strength by adding two Nb and Zr to the alloy element.

In general, the guide roll, which must be used during wire rod processing, rotates at high speed in contact with a high temperature wire rod, and thus a material having high temperature strength and high temperature wear resistance must be used. Furthermore, the guide rolls are used in very severe thermal fatigue environments due to the rapid repetition of heating by contact with hot wires and cooling by roll cooling water, so that the roughness of the guide roll surface, which greatly affects the quality of the wire rods, is almost thermal fatigue. Dominated by

For this reason, in order to improve the quality and productivity of wire rods, high speed steel rolls made of alloying elements such as Cr, Mo, and W are used.

However, the above guide rolls, which are used in conventional wire processing, also have the surface of the guide rolls due to thermal fatigue caused by heating by contact with the material to be rolled during use and thermal shock caused by rapid repetition of cooling by the coolant. It is getting rough.

In particularly severe cases, it tends to progress to the peeling of the guide roll surface. For example, these types of defects include: (1) scab, (2) crushed or partially split (split) like beans, and (3) Scrach. , Line Mark, ④ Turtle Cracking (Network Type Heat Crack), ⑤ Fine cracking due to heat and cooling (Heat Crack), ⑥Roll Break, ⑦Deposition (or burnout) And sticking, a phenomenon in which the wire rod surface is detached and adheres to the surface).

As a result of the reduction in strength of the roll as described above, the acceleration and deceleration caused by the inertia force of the roll itself is slowed, and the slip ratio with the material to be rolled is also severe, which acts as a factor of degrading product quality.

Accordingly, an object of the present invention is to solve the above-mentioned shortcomings and to add Nb and Zr elements to element alloys of C, Si, Cr, Mo, Ni, Co, Ti, V and W to form a rolled material ( It is to provide an alloy of guide rolls with excellent heat resistance, abrasion resistance, corrosion resistance, cracking resistance and impact resistance, which can minimize the surface defects of wire rods to obtain more beautiful products and minimize the deviation of wire rod surfaces. .

In order to achieve the above object, the guide roll alloy having heat resistance and abrasion resistance of the present invention is composed of C: 0.7 to 1.5, Si: 1.0 to 2.0, Cr: 0.5 to 2.5, and Mo: 2.5, which is composed of the weight percent related to the invention of claim 1. Nb: 35-40.3% by weight and Zr: 11-43.2% by weight with respect to -5.0, Ni: 0.2-1.2, Co: 0.5-5.0, Ti: 0.4-1.0, V: 1.0-2.5, and W: 15-28 It is characterized by the addition and composition.

In the above, Nb and Zr may be added in a premixed alloy state.

The addition of Nb makes the greatest contribution to preventing heat break by improving heat resistance, corrosion resistance, and improving toughness. In the above, the content of Nb may be arbitrarily adjusted within the range not exceeding 100 parts by weight (%) when mixed with the alloying elements of the C, Si, Cr, Mo, Ni, Co, Ti, V, W, If the content of Nb is too high, the hardness is lowered, so the content is 40.3% by weight or less. On the contrary, if the content is too small, the hardness is increased but the toughness is weakened. The content of Zr is not less than 35% by weight. Further, when added in the same manner as Zr, age hardening is imparted, and treatment with Ti improves the occurrence of cracks.

The addition of Zr plays the most important role in improving the corrosion resistance of the tool steel and the strength to withstand high temperatures, and in particular, has a great resistance to chemicals. In addition, the content of Zr is preferably adjusted arbitrarily within the range not exceeding 100 parts by weight (%) when mixed with the alloying elements of the C, Si, Cr, Mo, Ni, Co, Ti, V, W. When the addition amount of Zr is too high, the corrosion resistance, fire resistance, etc. are improved, but there is a problem that the hardness is lowered, so that the content is 43.2% by weight or less, on the contrary, when the addition content is too small, the hardness is It is improved, but the corrosion resistance, fire resistance, etc. have a problem of falling, so the possible content is 11% by weight or more.

C forms carbide with Cr, W, etc., and contributes to improving the mechanical strength and wear resistance of the alloy at high temperatures. However, if the C content is too high, carbides such as Cr or W are excessively formed, which reduces the C content in the present. Therefore, the C content is 1.5% by weight or less. On the contrary, when the amount of C added is too small, the mechanical strength or the wear resistance The heat resistance is significantly reduced, and the homogeneity of the tissue is lost, and the corrosion resistance to the roll is lowered. Therefore, the content thereof is 0.7% by weight or more.

The Si is an important element for improving the high temperature resistance, oxidation resistance, carburizing resistance and nitriding resistance, but if excessive, the alloy film and the oxide film inevitably occur on the alloy itself and alloy surface as well as the toughness of the alloy. The content of Si is 1.0% by weight or more because the food content is less than 2.0% by weight because of deterioration of the food resistance, and on the contrary, when the amount is too small, the high temperature, oxidation resistance, carburizing resistance and nitriding resistance may be weakened. do.

Cr is the most basic element for maintaining oxidation resistance at high temperatures. Since the roll for wire guide itself is a high temperature of 100 ℃ or more at this time, it is preferable to maintain the content of Cr in the above range to prevent durability degradation due to oxide film precipitation. If too much, the acid content (Cr₃O₃) is not only formed on the surface of the alloy, but also contains a large amount of Cr, which inevitably lowers the Ni content, which may deteriorate the corrosion resistance of the guide roll. On the other hand, when too small, since oxidation resistance may weaken, Cr content shall be 0.5 weight% or more.

The Mo forms carbide to give abrasion resistance, and solid solution to the matrix to improve hardenability, and precipitates fine carbide by tempering again to increase the temperature softening resistance and the high temperature strength. In addition, addition of Mo gives finer crystal grains, proper oxidation characteristics, and the like. However, if the amount of Mo added is too high, the toughness may be expanded and high hardness may not be maintained at a high temperature. Therefore, the Mo content may be 5.0% by weight or less. On the contrary, if the amount is too small, the strength may be weakened and wear resistance may be weakened. Mo content is made into 2.5 weight% or more.

W is an element added to increase the high temperature strength, forming a carbide in the same state as Mo to give abrasion resistance, and have a greater effect than Mo in improving softening resistance and high temperature strength at elevated temperatures. In terms of toughness, Mo is more advantageous. However, when too much Mo and W are added too much, the toughness is lowered, so it is 28% by weight or less. On the contrary, when the content is too small, the content is 15% by weight because it may weaken the wear resistance like Mo. The above-mentioned V precipitates fine carbides during tempering, in particular, increases the temperature softening resistance on the high temperature side, improves the high temperature strength, and further refines the crystal grains to impart excellent toughness with Ni addition. . In particular, the toughness improvement effect by refinement | miniaturization of a crystal grain is large. However, if the addition amount is too large, rough and large carbides are formed, and the toughness is lowered to 2.5% or less. On the contrary, if the addition amount is too low, the addition effect as described above cannot be obtained.

The Co is generally added to the alloy because it enhances the strength at high temperature to improve durability, but if too much, toughness is lowered, so the content is less than 5.0%, on the contrary, if it is too low, the same effect is not obtained. Since it is impossible to do so, make it 0.5% or more as possible.

Ni is added to improve the hardenability and at the same time improve the propagation resistance of the crack, improve the adhesion of the oxide film produced at elevated temperature to increase the wear resistance, if the content is too excessive, the ductility is expanded Since it is impossible to maintain high hardness at high temperature, the content is 10% by weight or less, and if the amount is too small, the effect is not obtained by weakening of high hardness, so that the content is 0.2% by weight or more.

Ti is added when it is necessary to further refine the alloy strength because the crystal grains are refined. When excessively, coarse intermetallic compounds are formed and precipitated in the molten alloy, and at the same time, the effect of improving the alloy strength is lowered, so that the content is 1.0% by weight or less. Since the effect of addition may not be obtained, the content is made into 0.4 weight% or more.

Hereinafter, a more preferred embodiment of the present invention will be described in detail.

<Example 1>

It was dissolved in an induction furnace (Induction Furnance), and then cast at room temperature to cut the ingot of the cross-gate to make an ingot (Ingot), which is a transformation point Heat treatment at to obtain an alloy having heat resistance and wear resistance. The test results for the durability and mechanical strength of the guide roll made using the alloy thus obtained were as shown in Tables 2 and 3 below.

<Example 2>

Table 1 was prepared in the same composition ratio as in Example 2 in the same manner as in Example 1 to obtain an alloy having heat resistance and wear resistance, and to the durability and mechanical strength of the guide roll made using the alloy thus obtained The test results were as shown in Table 2 and Table 3 below.

<Example 3>

Table 1 was prepared in the same composition ratio as in Example 3 in the same manner as in Example 1 to obtain an alloy having heat resistance and wear resistance, and the durability and mechanical strength of the guide roll made using the alloy thus obtained The test results were as shown in Table 2 and Table 3 below.

<Example 4>

Table 1 was prepared in the same composition ratio as in Example 4 in the same manner as in Example 1 to obtain an alloy having heat resistance and wear resistance, and the durability and mechanical strength of the guide roll made using the alloy thus obtained The test results were as shown in Table 2 and Table 3 below.

division C Si Cr Mo W V Co Ni Ti Nb Zr Invention Example 1 0.7 2.0 0.5 2.5 15 1.0 0.5 0.2 0.4 40.3 36.9 Example 2 1.5 2.0 2.5 5 25 2.0 2.0 1.2 1.0 35 22.8 Example 3 0.7 1.0 1.5 2.5 20 1.0 2.0 5 - 26.8 39.5 Example 4 1.5 1.0 2.0 5 30 2.5 5.0 10 - 32 11 Announcement lecture (comparative example) SKH 2 0.73 to 0.83 0.40 or less 3.80 to 4.50 - 17-19 0.80 to 1.20 - - - - - SKH 3 0.73 to 0.83 0.40 or less 3.80 to 4.50 - 17-19 0.80 to 1.20 4.50-5.50 - - - - SKH 4 0.73 to 0.83 0.40 or less 3.80 to 4.50 - 17-19 1.00-1.50 9.00 to 11.00 - - - - SKH 10 1.45-1.60 0.40 or less 3.80 to 4.50 - 17-19 4.20-5.20 4.20-5.20 - - - -

<Unit: weight%>

division Tensile Strengthkg / ㎠ Strength (kg / mm²) Elongation (%) Hardness (HRC) Invention Example 1 100 70 14 75 Example 2 115 81 16 80 Example 3 117 85 15 85 Example 4 120 90 14 90 Announcement lecture (comparative example) SKH2 80 65 16 70 SKH3 82 70 14 75 SKH4 85 72 15 75 SKH10 70 72 16 75

Product Name Specifications and specifications unit Guarantee tone Guide roller 100φX 145L EA 75,000 Guide roller 100φX 145L EA 75,000 Guide roller 100φX 145L EA 75,000 Guide roller 100φX 145L EA 75,000 Guide roller 100φX 145L EA 75,000 Guide roller 100φX 145L EA 75,000 Guide roller 100φX 145L EA 75,000

As can be seen from the above table, when the alloy of the present invention is used as a base material for the manufacture of the guide roll, it is not only excellent in high temperature strength and high temperature toughness that can withstand the high load generated by high-speed rolling, but also wear resistance and heat resistance. It can be seen that excellent.

As described above, the present invention is prepared by adding an appropriate amount of Nb and Zr to an alloy element composed of C, Si, Cr, Mo, Ni, Co, Ti, V, and W. As can be seen, the guide roll with the improved heat resistance, abrasion resistance, corrosion resistance, cracking resistance and impact resistance, which can minimize the surface defect of the rolled material (wire) and obtain a more beautiful product, as well as minimize the deviation of the wire surface. Has the effect of obtaining an alloy.

Claims (3)

C: 0.7-1.5, Si: 1.0-2.0, Cr: 0.5-2.5, Mo: 2.5-5.0, Ni: 0.2-1.2, Co: 0.5-5.0, Ti: 0.4-1.0, V: 1.0 -2.5, W: Alloy of the guide roll which has heat resistance and abrasion resistance formed by adding Nb: 35-40.3 weight% and Zr: 11 -43.2 weight% with respect to 15-28. delete The alloy of the guide roll having heat and wear resistance according to claim 1, wherein the Nb and Zr are mixed with each other beforehand.