JPS6018248B2 - Rolling roll with strong neck part - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a composite roll having a new structure that is most suitable for a rolling roll having an elongated neck shape, a special shape requiring particularly strong strength at the neck end, and usage characteristics. Regarding provision.

The rolling roll is composed of a chest portion and a neck portion, and the ear portion is formed of a lunar outer shell portion and eight concentric portions that are integrally cast concentrically with the eight outer shell portions, The neck portion is the 8
It is formed of a bearing part that is integrally cast with the Tsukioka core part on both sides of the concentric part, and a neck end part that is integrally cast on both sides of the bearing part. Generally, composite rolls are used in which the outer shell, body core, and neck are made of different materials. Therefore, new formats are being researched and developed.

That is, these methods include a method in which the work roll is shifted (moved) in the axial direction, a method in which the work roll is forcibly suspended, and a method in which two work rolls are made to cross the axis of the backup roll. Therefore, the work rolls used in these rolling methods tend to have smaller diameters in the same part of the month.

Also, due to the type of rolling mill, the length of the neck needs to be longer than that of the follower roll, and the diameter of the neck is also 4.
It will be cut. In addition, in this type of roll, a larger stress is generated in the neck portion than in the past, and strong scratch resistance is particularly required. Figure 1 shows the general shape rolls currently in use, and Figure 2 shows the special shape rolls used in the new rolling method mentioned above, and the specific differences in shape and dimensions are summarized as follows. be.

〆N SoN/〆B 〇N
SoNnoDN DB conventional rolls are dominant
1000~1400 0.52~0.75 340
~500 2.0~3.6 650~840. Large vermilion roll 1500~2000 0.80~1
．． 20 130~330 3.8~13.0 5
00 to 760〆N: long neck) B: long body) ON: neck end diameter (long) DB: long body) As mentioned above, the rolls used for this new rolling method:
Generally, the neck length to body length ratio IN/18 is 0.8 to 1.2, or the neck length to neck diameter ratio IN/DN is 3.8 to 13.
It is characterized by having an elongated neck shape in which one or both of the neck ends has a smaller diameter than the bearing part.

By the way, the use characteristics of the neck part as a whole are also different from the part 8 of rolling rolls with such a special shape.As shown in Fig. 3, the chest part 1 in contact with the rolled material has wear resistance Roughness, crack resistance, etc. are required. On the other hand, the characteristics required for the neck part are different depending on the axial direction.The bearing part 2, which is close to the 8 parts 1, requires wear resistance and strong plowing properties against friction with the bearing, while the other part, which is far away from the part 1, The neck end 3 is elongated in shape and requires particularly strong toughness because it needs to withstand large stress. Also, with this specially shaped roll, as shown in Figures 2 and 3,
The neck end 3 has a part with a smaller diameter than the neck end Tsukubo DN, and depending on the rolling method, for example, a large thrust stress may occur on the working side W, or a large handling stress may occur on the driving side D. This part requires particular toughness. The present invention thus provides an elongated neck shape with a neck length to body length ratio IN/IB of 0.8 to 1.2 or a neck length to neck diameter ratio N/DN of 3.8 to 13.0. The target is a special rolling roll in which a large stress is generated at the neck end, and one or more of the body outer shell, ear concentric part, bearing part, and neck end are suitable for the usage characteristics. The object of the present invention is to provide a composite roll having a new roll structure in which both are made of different materials and the three are integrated by welding.

Among the composite work rolls used in the secondary hot strip mill finishing stand, those for the front stand include:
Generally, Adamite material and high chromium material are used for the outer shell of the body.

In addition, high-alloy grain material is generally used for the latter stage. On the other hand, high-grade cast iron or ductile wrought iron is used for the core material of these conventional rolls. The chemical components and properties of conventional composite roll materials are listed below. Chemical component Wt) ○ Si Mn Ni or M
o Mg Hardness Bow girl strength Elongation (outer shell)

(Hs) Sanyu Nen Toru) (Many) Adamite material 12~2.8 03~1.0 0.5~1.5 2
0 or less 0.5-3.0 0.2-1.0 4
5~65 High chromium material 2.0~3.2 0.5~1.
5 0.5~1.5 0.5~2.0 10~25 0
．． 2-3.0 60-80 high alloy grain material 2
．． 8-3-5 0.5-1.5 0.5-12 3.5
~5.0 1.0~2.5 0.6 to 0.2
70~85 Core material) High grade cast iron 2.8~3.7
0.5-1.5 0.4-1.2 0.3-1.5 0
．． 3-10 0.2 or less 40-50 20-
30 0.1~0.3 Tactile cast iron 3.0~3.8
1.5-2.5 0.4-1.0 2.0 or less 0.4
~1.0 0.2 or less 0.0 Group Kujo 40~50 40~
50 0.5 to 1.0 However, as a result of intensive research by the present inventors, when a conventional composite roll is applied as is to a roll for the shape intended by the present invention, the neck end It was found that it was unusable in any case due to insufficient strength.

That is, in the case of high-grade cast iron, it clearly lacks strength as shown in the above table, and even in the case of ductile cast iron, it still lacks strong balling properties for necks with elongated and special shapes. In addition, since the neck portion of the rolling roll according to the present invention is elongated, after the outer grain portion of the body is cast by far D force as in the conventional method, the centrifugal force casting mold is made into a static casting mold, and the Tsukioka core portion and the neck portion are cast into a static casting mold. In the method of integrally casting the end portion, a deep shrinkage cavity-like defect occurs at the neck end portion along the roll axis, making manufacturing difficult.

Therefore, the present invention aims to provide the outer grain portion la as shown in FIG.
The body core part lb and the bearing part 2 are integrally formed using appropriate roll materials such as those listed above, as in the case of conventional composite rolls, while the neck end part 3, which requires even stronger rolling properties, is For one or both of these, it is formed from a strong material different from that which forms the moon concentric part lb and the bearing part 2, and each of these is made of a different material from the trunk outer shell part la.
, the body core lb, the bearing 2 and the neck end 3 are integrated together to form a composite roll. The materials used to form the trunk core part lb, the bearing part 2, and the neck end part 3 are those that are superior in hardness, strength, elongation, etc. to conventional high-grade cast iron, high-grade cast iron, or ductile cast iron.

In other words, the bearing part 2 must also have wear resistance.
A product with higher rice toughness than conventional high-grade cast iron is required, with hardness Hs 40-50 and tensile strength 40-55K9/
It is made of a material that satisfies the base and elongation of 0.5 to 1.5%. On the other hand, the neck end 3 has more toughness than wear resistance.
In particular, since hardness is required, the hardness should not be too high, but on the other hand, rotational wear must also be taken into consideration, so it is necessary to set the hardness to Hs 35 to 45. The tensile strength is 55k9/m or more, more preferably 6
It must be made of a material that satisfies a weight of 5 kg/ground or more and an elongation of 1.5% or more. Suitable materials for forming the bearing portion 2 and neck end portion 3 that are suitable for such purposes include ductile cast iron materials and strong ductile cast iron materials having the following chemical compositions.

Chemical components Shiwt grandson) ○ Si Mn Ni ○r M
o Mg Hardness Own strength Elongation LHs) L&Careful) 8 concentric part 3.0~3.8 1.5
~2.5 0.4~1.02. o or less o.・~1. o
o. 2 or less o. o Group Kujo 40-50 40-55
0.5-1.5 and bearing neck end 3.0-3.
8 1.8-2.5 0.4 or less 20 or less 0.4 or less 0.2 or less 0.03 or more 35-45 55-80
1.5 to 12.0, that is, this ductile cast iron material and strong ductile cast iron material are well suited to the usage conditions and requirements of the bearing portion 2 and neck end portion 3.

Here, the reasons for limiting the components of both of the above materials will be described.

8 The amount of graphite and carbide in the concentric part and bearing part C is determined by the balance with the amount of Si. If it is less than 3.0%, there will be insufficient graphitization, and if it is more than 3.8%, it will be over graphitized and become a brittle material. It is.

If Si is less than 1.5%, graphitization will be insufficient;
% or more, excessive graphitization occurs, which is undesirable. In addition, since the shell outer shell material is generally made of a material with low Si content, if the inner surface is remelted and mixed into the core, the Si content will be lower than that of the melted component. It is necessary to consider that. Mn affects the matrix and carbide morphology, and if the content is too large, it will harden and lack strength, so the upper limit is set at 1.0%.

Although it is preferable to keep the content to 0.4% or less, it may be contained in an amount of 0.4% or more due to difficulty in adjusting the dissolved components. Ni mainly plays a role in hardening the matrix, but in the case of the main material, Ni is also mixed in from the high-alloy grain material that forms the outer shell of the body.
．． 0% or less is necessary and sufficient.

Cr is a carbide-forming element, and if it is more than 1.0%, it becomes hard and the toughness is insufficient, and if it is less than 0.1%, the hardness of the bearing portion is too low.

Although Mo does not originally need to be included, it is included by being mixed in from the outer shell of the body.

This is because if the content exceeds 0.2%, the material becomes hard, resulting in a lack of fishiness.

Mg is required to be 0.03 or more for graphite spheroidization.

Neck End The strong rutting material forming the neck end has the same basic composition as the above-mentioned ductile cast iron, but differs in the following component content in order to further enhance strong plowing properties.

Si and Mn promote graphitization and actively improve toughness with low hardness. 8-2.5%, Mno. The composition is adjusted to 4 or less. In addition, in order to reduce the amount of carbide and improve the grade, Cro. It will be kept below 4%. As mentioned above, ductile cast iron material with a specific composition is used for the 8 concentric parts and the bearing part,
When a highly rutted ductile cast iron material with a specific composition is used for the neck end, the compositions of the two are similar, so the weldability between the bearing and the neck end becomes extremely good.

Next, a method for manufacturing a roll according to the present invention will be briefly described.

In casting the composite roll of the present invention, it is preferable to centrifugally cast the outer shell portion la in the same manner as in the prior art. However, as means for welding and integrating the concentric part lb, the bearing part 2, and the neck end part 3 over the Tsukioka outer shell part la of the lever, there are generally the following two methods. That is, one step is to cast the body core part lb and the bearing part 2, then first cast the lower neck end, then cast the body core part and the bearing part, and then cast the upper neck end as necessary. This is a method of casting molten metal of different materials. The other method is to weld and cast the body outer shell part la, body core part lb, and bearing part 2 into one body, as in the case of obtaining a conventional composite roll, and then cast the neck end part 3 with molten metal of a different material. This is a method of casting and integrating the two. In any case, the mold for the neck end 3 is arranged,
It is preferable to increase the toughness by making the grain finer by rapid cooling and solidification. In this way, in the present invention, eight concentric parts lb
Since the bearing part 2 and the neck end part 3 are separated and integrally cast, when they are integrally cast, the neck end part 3
Also, since the bearing part 2 is thicker and has a larger heat capacity than the neck end part 3, if the neck end part 3 is cast integrally with the end face of the bearing part 2, weldability will be extremely good. Become.

The present invention will be described with reference to specific embodiments.

(Example) 8 same diameter DB650? , body length IB1700, neck length DN2150, neck length IN1800, i.e. IN
/IB=1.00 1N/DN=8.37, each having a shape as shown in FIG. 4, was integrally welded and cast by centrifugal force casting using materials having the following chemical components.
Ball-shaped wide-flavored soup Mimatsu Rifunariyo Hiiragi Q? As shown in the test results in the mold table, the outer shell, body core, bearing, and neck end are made of different materials depending on the conditions of use. Each part has the required properties, and the neck end in particular has sufficient strength.

In addition, Example 1 shows a conventional roll in which the outer shell of the ear is made of high-alloy grain material, and the entire body core and neck are made of the same material. Regarding the same outer shell materials according to the present invention, Examples 2 and 5 use high alloy grain material, Example 3 uses adamite material, and Example 4 uses high chromium material. Mechanical properties such as hardness in the table are measured values after optimal heat treatment was applied to each shell material. The microscopic structures of the bearing and neck end of Example 2 are shown in FIGS. 5 and 6 in comparison.

Further, as a result of observing the boundary between the bearing portion and the neck end portion, it was found that the two were extremely well welded and integrated in all of the examples of the present invention. As described above, the present invention provides a trunk outer shell portion,
Since the roll is constructed by forming the two core parts, one or both of the bearing part and the neck end from different materials, and then integrating the three parts into one, "conventional composite rolls cannot cope with this problem. However, even for new types of rolls with elongated necks and large stress occurring at the neck ends, we can provide composite rolls that can satisfy all the required properties in each part, with special strength and toughness at the neck ends. It is designed to be able to fully respond to the intended use that requires it.

In addition, since the body core, bearing, and neck end are separated and integrally cast, deep shrinkage defects will not occur at the neck end even if the neck is long and thin, and the bearing will not form at the neck end. The rolling roll according to the present invention is thicker than the bearing part and has a larger heat capacity.
The neck end is very well integrated into the bearing part.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view showing an example of the shape of a conventional rolling roll, and FIG. 2 is a side view showing an example of the shape of a rolling roll to which the present invention is applied.

FIG. 3 is a partially enlarged sectional view of a rolling roll to which the present invention is applied, and FIG. 4 is a half-sectional side view showing an example of the structure of the rolling roll according to the present invention. 5 and 6 are microscopic photographs showing the structure of an example of the composite roll according to the present invention, with FIG. 5 showing the bearing portion and FIG. 6 showing the neck end portion. 1... Torso, la...
・Body outer shell, lb...Body core, 2...Bearing part, 3...Neck end.

Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1. The body is formed of an outer shell made of adamite material or alloyed cast iron, and a core part that is integrally cast concentrically with the outer shell, and In a rolling roll in which a neck portion is formed by a bearing portion integrally cast with the body core portion on both sides of the body core portion and a neck end portion integrally cast on both sides of the bearing portion, the neck length l_N and body length l_B
The ratio l_N/l_B between l_N and the neck end diameter D_N is 0.8 to 1.2, or the ratio l_N/D_N between l_N and the neck end diameter D_N is 3.8 to 1.
3.0, and one or both of the neck ends have a smaller diameter than the bearing, and the shell outer shell, the core and bearing, and one or both of the neck ends are made of different materials. The bearing part has a hardness of 40 to 50 and a tensile strength of 40 to 5.
5kg/mm^2, elongation 0.5-1.5%, and one or both of the neck ends have hardness Hs35-45, tensile strength 55-80kg/mm^2, and elongation 1.5-12%. A rolling roll with a strong neck part. 2 The material forming the core part and the bearing part has a C:3.0~
3.8% Cr: 0.1-1.0% Si: 1.5-2.
5% Mo: 0.2% or less Mn: 0.4-1.0% M
It is a spheroidal graphite cast iron containing g: 0.03% or more and Ni: 2.0% or less, the balance being Fe and impurities, and the material forming one or both of the neck ends has a C: 3.0 to 3.0%.
3.0% Cr: 0.4% or less Si: 1.8-2.5%
Mo: 0.2% or less Mn: 0.4% or less Mg: 0.
The rolling roll having a strong neck portion according to claim 1, which is made of tough spheroidal graphite cast iron containing 0.03% or more and 2.0% or less of Ni, and the balance being Fe and impurities.