JPH02270944A - Roll stock having wear resistance and resistance to surface roughness and its production - Google Patents

Abstract

PURPOSE:To obtain a roll stock excellent in wear resistance and resistance to surface roughness by subjecting a powder of a ferrous alloy containing respectively prescribed amounts of C, Cr, Mo, W, V, and Co to sintering at a temp. in a specific solidus temp. range by a hot isostatic pressing method. CONSTITUTION:A powder of an ferrous alloy containing, by weight ratio, 1.2-3.5% C, 3-6% Cr, 4-6% Mo, 2-15% W, 2-10% V, and 15% Co is prepared. Subsequently, a metallic capsule 2 in which a cylindrical core material 1 is set is filled with the above alloy powder as illustrated in a figure and air is sucked through a vent hole 3 provided in the upper part of the capsule 2 to evacuate the inside of the capsule 2, and then, sintering is carried out in a temp. range between (solidus temp.) -50 deg.C and (solidus temp.) +50 deg.C by means of hot isostatic pressing. The resulting roll stock is improved in wear resistance and resistance to surface roughness and is suitable for use in hot rolling roll for iron or nonferrous metals.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a roll material with excellent wear resistance and roughness resistance, and a method for producing the same.

[Conventional technology]

Many of the commonly used rolling rolls are those that have been made into mold ingots, or those that have been forged into a roll shape after being made into ingots, and then machined and heat treated.

Such conventional rolls have insufficient wear resistance at high temperatures of about 500° C. or higher, and wear progresses rapidly. In order to improve wear resistance under such high temperatures,
For example, in JP-A No. 54-99759, high carbon atomized powder is consolidated by hot isostatic pressing (hereinafter referred to as HIP), and eutectic carbides of 20 μm or less are formed in the diameter direction, axial direction, and circumferential direction. A uniformly distributed hot rolling roll is described.

[Problem that the invention seeks to solve]

However, the inventor of the present invention found that the above-mentioned carbide with a diameter of 20 μm or less has low high-temperature hardness when used as a hot rolling roll, so it is difficult to expect a significant improvement in wear resistance compared to conventional casting rolls. I found out that there is no.

In addition, when manufactured using the conventional HIP method, alloy powder spots as shown in Figure 5 remain in the structure, and when tested in this state as a rolling roll, unevenness appears on the roll surface. It has been found that rough skin occurs and wear tends to progress.

Therefore, an object of the present invention is to provide a roll material with excellent wear resistance and roughness resistance, and a method for manufacturing the same.

[Means for solving problems]

As a result of various studies to achieve the above object, the present inventor has determined that HIP can be changed from solidus temperature -50°C to solidus temperature +5°C.
The present invention was completed by discovering that the process can be carried out at a temperature of up to 0°C. Here, the solidus line is the temperature at which a solid begins to liquefy upon heating.

In other words, the HIP is 50 to 10 below the solidus as in the conventional method.
When carried out at 0'C, alloy powder spots remain in the tissue at the end of HIP. If this is to be eliminated by heat treatment in a subsequent step, it is necessary to increase the heat treatment temperature until a portion of the liquid phase is formed. However, when a liquid phase is formed, shrinkage cavities occur during cooling and the strength of the material deteriorates. Therefore, it is necessary to eliminate the alloy powder spots in the structure during HIP. If the HIP temperature is more than 50°C lower than the solidus line, alloy powder spots will remain in the structure even if the pressure is increased a little, and if the HIP temperature is more than 50°C higher than the solidus line, alloy powder spots will remain in the structure. It was found that a large amount of liquid phase was generated and the structure approached that of melted lumber, resulting in a decrease in material strength.

In the structure obtained by the above method, there are no remaining alloy powder spots as shown in Figure 1, and the grain size of the carbide, which is the hard phase, has grown from the conventional 20 μm or less to 25 to 100 μm. I found out. If the grain size of the carbide, which is the hard phase, is 25 μm or less, the wear resistance will be poor when used as a rolling roll. If the grain size of the carbide exceeds 100 μ-, mechanical properties deteriorate and heat cracks are more likely to occur. Furthermore, the hard phase 25-100
If the carbide in μm is less than 5%, the wear resistance will be poor and 40%
%, mechanical properties deteriorate.

Next, a method for manufacturing the wear-resistant and rough-textured roll of the present invention will be explained. The alloy powder according to claim (1) is filled into a metal capsule 2 in which a cylindrical roll core material 1 is set, as shown in FIG. The interior of the metal capsule 2 is evacuated by suction, and then the T (IP) of the present invention is applied. As the metal capsule 2, for example, steel or stainless steel with a thickness of about 3 to 7III11 is used.

Thereafter, the metal capsule 2 is removed by cutting it off with a lathe or the like, and is further subjected to heat treatment as shown in FIG. 4, for example. It is then processed into a predetermined shape to complete the desired roll.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. In addition, the evaluation of abrasion resistance and roughness resistance in the examples was carried out by installing a test roll with an outer diameter of 60 mm and a length of 40 mm into the rolling abrasion tester shown in Fig. 2, and under the test conditions shown in Table 1. After conducting the test, the depth of wear that occurred on the surface of the test roll was measured using a stylus surface roughness meter (SURFCOM).

Here, the rolling wear test machine shown in FIG. 2 includes a rolling mill 4, a heating furnace 7 for preheating the rolled material S, a cooling water tank 8 for cooling the rolled material S, a winder 9 for the rolled material, and a tension controller. It consists of 10.

Table 1 Alloy powders having the components shown in Table 2 were subjected to HIP treatment at the temperatures and pressures shown in Table 3. Carbide f1 after HIP treatment
(Area ratio) is also shown in Table 3.

Note that the material of the roll core material 1 is SCM440.

Table 3 Also, the solidus line of the alloy powder shown in Table 2 was measured to be 11
It was 90'C.

After the HIP treatment, the metal capsule 2 was shaved off using a lathe, and then heat treated in the pattern shown in FIG. The results of a structure investigation conducted in this state are shown in FIG. 5 for the conventional material and in FIG. 1 for the inventive material. Comparing both figures, it can be seen that the alloy powder spots are clearly eliminated by the present invention. Furthermore, it was confirmed that carbide, which is a hard phase, was growing according to the present invention.

The roll thus produced was evaluated for wear resistance and roughness resistance by the rolling simulation test described above.

The results were as shown in Table 4.

Table 4 [Effects of the Invention] According to the present invention, the abrasion resistance and roughness resistance of the roll are improved, and a wear-resistant and roughness-resistant roll suitable for hot rolling rolls for ferrous or non-ferrous metals can be obtained. can be provided. Note that the roll of the present invention is not limited to use at high temperatures as described above, but has remarkable wear resistance and roughness resistance even when used in rolls used at low temperatures such as cold rolling rolls. Can be used in large rolls.

[Brief explanation of drawings]

Figure 1 is a photograph showing the metal structure of the roll material of the present invention, Figure 2 is a photograph showing the metal structure of the roll material of the present invention.
The figure is a schematic diagram of an apparatus for measuring the abrasion resistance of rolls, Figure 3 is a sectional view of a capsule to explain the method of manufacturing the roll of the present invention, and Figure 4 is a schematic diagram of a device for measuring the abrasion resistance of rolls. FIG. 5 is a photograph showing the metal structure of a conventional roll material. Roll core material, 2: Capsule, 3: Deaeration hole, 4: Rolling machine, 5: Upper roll, 6: Lower roll, 7: Heating furnace, 8: Cooling water tank, 9: Winding machine, 10: Tensigon controller , P
eIB end, S: rolled material. 2mm Fig. 2 Fig. 4 Fig. 5 +12rrjm Hand, continuation I-fu 111 elder brother ``. 7. Mao:
・) 2. Name of the invention: Abrasion resistant, 1. Manufacturing capacity for rough-skinned roll material, at, and f.
・Relationship with the case of the person making the 3rd amendment Patent applicant telephone: Tokyo 1 284 4642゜Name (508) Hitachi Metals Co., Ltd. Representative Hiroshi Matsuno 1F:) 5 Correction i, the number of inventions will increase more (, 7゜ 6 Target of correction Drawing 14 Heat treatment time (hours)

Claims (2)

[Claims] (1) Chemical components are C1.2-3.5% by weight, Cr3
~6%, Mo4~10%, W2~15%, V2~10%
, Co, 1 to 15%, and the remainder being unavoidable impurities and Fe, which are molded by hot isostatic pressing, and carbides with a particle size of 25 to 100 μm are formed in an area ratio of 5 to 100 μm.
A wear-resistant and rough-skinned roll material characterized by containing 40% and having no alloy powder spots in its structure. (2) Chemical components are C1.2-3.5% by weight, Cr3
~6%, Mo4~6%, W2~15%, V2~10%,
An alloy powder consisting of 1 to 15% Co, the remainder being unavoidable impurities and Fe, was heated to a solidus temperature of -50 by hot isostatic pressing.
A method for producing a wear-resistant and rough-skinned roll material, characterized by sintering in a temperature range from °C to solidus temperature +50 °C.