JPS5924564A - Production of composite adamite roll - Google Patents

Abstract

PURPOSE:To prevent exactly and effectively the generation of gas in the stage of casting composite roll consisting of an outside layer of an adamite material having specific components, an inside layer of strong and tough material by adding a limited amt. of CaSi to the outside layer to be centrifugally cast thereby performing degassing. CONSTITUTION:CaSi is added at 0.01-0.2wt% in terms of Ca to the molten metal of an outside layer 1 of an adamite layer contg., by weight, 1.8-2.6% C, 0.2-1.2% Si, 0.4-1.5% Mn, <=0.1% P, <=0.1% S, 0.5-3.0% Ni, 0.5-4.0% Cr, 0.4-2.0% Mo and consisting of the balance Fe and unavoidable impurities just before the casting or in the mid-way of the casting thereof. The reason for limiting the amt. of the CaSi to be added lies in that if the amt. is <0.01wt%, the effect of degassing, more particularly in deoxidation is small and if it exceeds 0.2wt%, the addition is excessive.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a composite adamite roll, in which the outer layer is formed of a highly hard adamite interlayer and the unidirectional layer is formed of a suitably strong interlayer.

Generally, as shown in the figure, a composite roll is often used as a rolling roll, which is constructed by welding an outer layer (used layer) and an inner layer made of different materials into one piece. In other words, Fig. 1 shows an integrated body outer layer (1) and inner layer (δ phase) (2) like a roll for plate rolling, and Fig. 2 shows an aperture like an If-type copper-finished rolling roll. Regarding the hollow roll (sleeve) assembled and used in (3), an example is shown in which it has an integral two-layer structure of an outer layer (1) and an inner layer (2).

By the way, the Toga of the outer layer (used layer) of such a composite roll is required to have good abrasion resistance, heat crack resistance, surface roughness, etc., and so-called high hardness is suitable for this purpose. It is known that Adam's materials can be used. In general, centrifugal force nail construction is an excellent method for manufacturing composite rolls, but especially for intermediate and finishing stand rolls for large steel shapes such as channel steel and Type II steel, it is necessary to make the entire layer uniform. A: [
1 weave and 61U degrees, it is important to apply centrifugal Vi casting technology to obtain high quality products.6 However, the composite adapter produced by centrifugal casting is A difficult problem with mitrol is that it is prone to gas defects. In other words, in this type of composite roll, first the outer layer of adamite material, which will be specified later, is centrifugally cast, then a strong interlocking inner layer such as ductile cast iron is cast, and the two are welded and cast together. However, during centrifugal force casting of the outer layer, nest-like defects are likely to occur due to gas, which has the disadvantage of a high product failure rate.

The present invention solves the problems in manufacturing such a composite adamite roll, and the outer layer exhibits the good usability properties inherent to the high hardness adamite material, and a sound roll without defects can be reliably obtained. This was done for the purpose of providing such a manufacturing means.

That is, the present invention provides a method for casting a composite adamite roll that is constructed by welding and integrating an outer layer of adamite material and an inner layer of a tough material, each having a specific component range as detailed below. During centrifugal casting, CaSi is added to the outer layer molten metal immediately before or during casting to make the Ca content 0.
It is characterized by adding 01 to 0.2% by weight.

The present invention will be explained in detail below. As described above, the composite roll according to the present invention has an outer layer made of a high hardness adamite material having excellent wear resistance, heat crack resistance, roughness resistance, etc. The adamite material for the outer layer, which is the object of the present invention, has the following chemical components. That is, C1,8-26, Si 0
2-1.2, Mn0.4-1.5, PO11 or less,
5O11 or less, N i O, 5 to 5.0, CrCl2 to
4.0 and Mo0.4 to 20 at each MJit%, and the remainder consists of Feb and normal impurities. The reason for limiting the range of each component is as follows.

C1.8~2.6% C is eutectic cementite (hereinafter simply referred to as cementite)
It determines the amount of carbon dioxide and has a large influence on roll characteristics, and also has a degassing effect itself. If C is less than 8%, the cementite Rt is too small to exhibit the desired wear resistance, while if it exceeds C2, 6%, heat crack resistance deteriorates and the high C% prevents cracking due to gas. This is because it becomes less likely to occur and there is no need to apply the manufacturing method of the present invention.

Si0.2-1.2% Si has a deoxidizing effect, but if it is less than 0.2%, this effect cannot be expected, while if it exceeds 1.2%, the Si dissolved in the ferrite will deteriorate the toughness of the material. This is because it deteriorates the properties and heat crack resistance.

Mn0.4-1.5% M+1 exhibits the effect of removing the harmful effects of S, and 0.4% or more is necessary to improve wear resistance, but if it exceeds 1.5%, it will become too hard and will require tempering. This is because brittleness appears, which poses a problem in terms of heat crack resistance.

2061% or less P is an element that increases the fluidity of the molten metal and provides wear resistance, but it greatly deteriorates the toughness of the material and causes problems in heat crack resistance, so the less it is, the more desirable it is, and it should be 0.1% or less. .

5O 11% or less S is also 0.1% or less to make the side chamber vulnerable like P 6 Ni O, 5 to 3.0% Ni delays A1 change and increases base hardness, so i1
Is it less than 60.5% effective in improving wear resistance? This is because the effect is small with Ij ~, while on the other hand, if it exceeds 6.0%, it becomes hard and brittle, resulting in poor heat crack resistance, and untransformed structure tends to remain, resulting in poor skin roughness resistance, which is not desirable. .

Cr 0.5-4.0% Cr is required at 0.5% or more to stabilize cementite and improve the wear resistance of the base, but 4.0%
This is because if it exceeds this, stirrup cracks are likely to occur and heat crack resistance deteriorates.

Mo 0.4-2.0% Mo has the same effect as Ni, and in order to obtain the effect of improving hardness and surface 1 abrasion resistance, it must be O, 4' 2. To avoid problems in terms of
0% or less.

High-hardness adamite 4 (the quality is as described above) of the outer layer targeted by the present invention, while the inner layer is made of high-hardness adamite 4, depending on the need for strength against the problem of roll neck breakage and sleeve breakage. A tough material such as high grade cast iron, ductile cast iron or graphite steel is selected.

However, if we cast the outer FJ with mutual centrifugal force as described above,
As mentioned above, it is easy to generate gas defects (usually microscopic cavities about 1 mm in diameter for cotton), and if such a material is used for any length of time, the defects will be transferred to the rolling margin, so it is necessary to prevent them. be done. Therefore, in order to achieve this objective, the present invention
It is characterized by adding CaSi and performing degassing treatment during centrifugal force casting of the outer layer. The addition method to the outer layer molten metal may be either immediately before or during casting. A range of 2% to 0.2% is good. That is, if it is less than [1.01%, the effect of Ca addition is small, and if it exceeds 0.02%, it becomes excessively added. In general, the addition of Ca is recognized to be effective in degassing, especially in deoxidation, but the reason why Ca5t is added as Ca5t in the wood invention is that it is easy to dissolve into the molten metal and that Ca is reliably contained in the molten metal. Because it has no purpose. With the addition of casi, St is added and Si
Although the water content is increased, it goes without saying that the St enemy that is added after the addition should be added to the range of 0.2 to 1.2% by d1r.

Although Ti, Al, and Zr are generally known as degassing agents, C
These can be used in combination with aSi, and in that case it is expected that a greater effect of preventing casting defects will be obtained. However, since these elements deteriorate the fluidity of the molten metal, the total content of these elements, whether added alone or in combination, should be suppressed to 0.1% by weight or less.

It has been confirmed by actual results that the composite adamite roll manufactured by adding an appropriate amount of CaSi during centrifugal casting of the outer layer exhibits a remarkable gas defect prevention effect.

In the method for manufacturing composite adamite rolls of the present invention, after the above-mentioned outer N casting, R is carried out according to the conventional method. In other words, after the outer layer is centrifugally cast (horizontal, inclined, or vertical type) L7, the inner layer is subsequently cast by centrifugal force casting or static casting at an appropriate timing, and the outer and inner layers are welded and integrated. A composite roll for the desired purpose is cast.

In the case of tilted type or vertical type centrifugal force casting, when statically casting the inner layer, it is possible to start casting the inner layer while the mold is in the process of stopping rotation.

In addition, in the composite adamite roll that is the object of the invention, the outer layer and inner layer of uO may have a thickness of 20 mm as required.
An intermediate layer of about 40w1 can be cast. This not only improves the soundness of the welded portion, but also prevents welding of the outer layer into the inner layer material, thereby contributing to preventing deterioration of the toughness of the inner layer material.

In addition, regarding the heat treatment of the composite adamite roll that is the subject of the present invention, after casting, in order to improve toughness, wear resistance, and roughness resistance, heat treatment is performed in which the temperature is raised in the austenite region O, and the accompanying A1 It is preferable to perform tempering and strain relief heat treatment below the transformation temperature.

Next, the improvement effect achieved by implementing the present invention will be explained using specific examples. The defective rate of conventional composite adamite rolls is approximately 20% (
50 pieces were manufactured). On the other hand, when CaSi was added to the outer layer under the following two addition conditions, no defects due to gas defects occurred even in the results of 20 tests.

Addition example 1 Ca content in CaSi: 12%, CaSi addition j7J:
: 0.4% addition example 2 Ca content in CaSi: 45%, CaSi addition -53:0
3% or more, the invention involves the casting of composite Adamite rolls, in which Cadi degassing treatment is performed during centrifugal casting of the outer layer made of high hardness Adamite (JU) quality. This makes it possible to accurately and effectively prevent the problem of gas defect generation, which has conventionally frequently occurred in this type of roll.

[Brief explanation of drawings]

FIGS. 1 and 2 are half-tier diagrams showing an example of the structure of a composite adamite roll.

Claims (1)

[Claims] 1, C1,8~2.6%5i02~1.2, Mn0
．． 4-1.5, PO01 or less, So, 1 or less, NiO
,5-3.0, CrO,5-4.0, Mo0.4-2
．． When casting a roll in which an outer layer of adamite material containing 0% by weight and the balance consisting of Fed and ordinary impurities is welded and integrated with an inner layer consisting of a strong side, the outer layer is Immediately before or during casting of the molten metal, add CaSi to the molten metal at a concentration of 0.01 to 0.2% as Ca content.
A method for producing a composite adamite roll, characterized by adding the following: