JPH0564229B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a wire for producing steel wool and a method for producing the same. (Conventional technology and its problems) Steel wool is usually produced by drawing low carbon steel wire and then cutting it in the longitudinal direction, and is used as a scrubber for polishing general kitchen utensils, removing rust, and removing paint. In addition to being used for industrial purposes, it has recently been used for disc brakes and composite materials with synthetic resins, and demand for it is increasing. The characteristics required of wire rods for steel wool production are: (1) long life of cutting tools, (2) high yield with little generation of microscopic powder and debris during cutting, and (3) high yield of steel wool itself. Examples include having appropriate elasticity and strength. As mentioned above, since steel wool is manufactured by cutting, the wire rod for manufacturing steel wool is required to have good machinability, that is, a long tool life as shown in (1). In addition, the remarkable difference between normal cutting and steel wool cutting is that the parts that become chips in the former are used as steel wool in the latter, and the chips that become steel wool do not curl and have a stable size. The essential condition is that it can be cut continuously in a straight shape. Furthermore, the generation of ultrafine powder and debris (hereinafter referred to as ultrafine cutting debris), which is considered desirable in normal cutting processes, reduces the yield and pollutes the working environment in steel wool manufacturing. It is important to suppress it to a minimum. For this reason, existing free-cutting steels to which various elements are added to improve machinability cannot be used as wire rods for producing steel wool. Currently, P and N are used as wire rods for producing steel wool.
It has been proposed that S and Ca be added in combination (Japanese Patent Application Laid-Open No. 55-6437). On the other hand, methods for controlling the composition and amount of nonmetallic inclusions in steel in addition to the steel composition have also been published (Japanese Patent Laid-Open No. 53-54114, Japanese Patent Laid-open No. 60-24347). In addition, in the production of steel wool, the width
Because conventional chips are cut out in the form of continuous strips of 50 to 120 μm,
There is a strong demand for uniformity in the material quality of the steel wire material. For this reason, in wire rods for producing steel wool, sufficient consideration must be given to the uniformity of the structure in addition to controlling the form and amount of nonmetallic inclusions. For this reason, in the past, the wire rods were often air panted (Japanese Patent Publication No. 14212/1983,
(Publication No. -54114) (Problems to be Solved by the Invention) All of the conventional wire rods mentioned above have the effect of extending tool life, but they have a limit in terms of the amount of microscopic cutting chips generated. There is a problem that there is a large margin, and the above-mentioned air patenting has a problem that the uniformity of the structure is still insufficient. (Means for Solving the Problems) The present invention provides a novel wire material for steel wool production and its use, which stably achieves a significant reduction in ultrafine cutting waste that has not been achieved with conventional steel wool production materials. The purpose is to provide a manufacturing method. The present invention particularly utilizes the combined effect of P and Ca, controls the amounts of S and O to fully exhibit the effect, and further controls the cooling rate after wire rolling to an appropriate range. The present invention provides a manufacturing method characterized by the following, and a wire rod for producing steel wool manufactured by this manufacturing method. That is, in the present invention, C: 0.05 to 0.20wt%, Si: 0.1wt% or less, Mn:
0.5-1.5wt%, P: 0.07wt% or less, S: 0.02wt%
Below, N: 0.003-0.01wt%, O: 0.006-0.03wt
%, further containing Ca in the range obtained by the following formula, and the balance being Fe and unavoidable impurities. 0.0020−0.024×P(wt%)≦Ca(wt%)≦0.0040−0.024×P(wt%) And, C: 0.05 to 0.20wt%, Si: 0.1wt% or less, Mn:
0.5-1.5wt%, P: 0.07wt% or less, S: 0.02wt%
Below, N: 0.003-0.01wt%, O: 0.006-0.03wt
%, and further contains Ca in the range obtained by the following formula,
Steel with the balance consisting of Fe and unavoidable impurities is hot-rolled, and after rolling is finished, it is heated in a temperature range of 850 to 550℃.
A method for manufacturing a wire rod for steel wool production, characterized by cooling at a cooling rate of ~40°C/s, 0.0020−0.024×P (wt%)≦Ca (wt%)≦0.0040−0.024×P (wt%) It is. (Function) Next, the reason for limiting the ingredients of the present invention will be explained. Note that the percentages shown below are wt%. C is an essential component to give steel wool appropriate strength and elasticity, so it is added at least 0.05%, but if it exceeds 0.20%, the amount of cementite becomes excessive and the steel wool becomes brittle, so the upper limit should not be set.
It was set at 0.20%. Although Si is an essential element for deoxidizing steel, its ferrite solid solution strengthening action increases the generation of microscopic cutting chips. Therefore, the upper limit was set at 0.1%. Mn is indispensable as a deoxidizing element for steel, and has a remarkable effect of reducing the amount of cementite and homogenizing the structure of the wire rod, so it is added in an amount of 0.5% or more.
If it exceeds 1.5%, cutting resistance increases, so 1.5% is set as the upper limit. N is normally used in large amounts in free-cutting steel, and N is also increased in wire rods for steel wool production, but like Si, it dissolves in ferrite and makes it brittle, resulting in an increase in the generation of microscopic cutting chips. Therefore, the upper limit of N is 0.01
%. On the other hand, if it is less than 0.003%, the surface properties of the steel wool will be poor and the smoothness will be impaired, so the lower limit was set at 0.003%. The present inventors have elucidated the influence of the mutual association of P, Ca, S, and O described below on the generation of cutting chips through a number of basic studies, and as a result, the content of these elements has been determined to be within an appropriate range. It was discovered that if controlled to the same extent, a remarkable combined effect can be obtained and the generation of microscopic cutting chips can be significantly reduced. Like N, P improves the surface properties of steel wool, but as a solid solution strengthening element, it dissolves in ferrite and makes it brittle, so an increase in cutting debris is unavoidable. Therefore, the present inventors used the samples shown in Table 1 to research a method for reducing the generation of microscopic cutting chips while maintaining the surface quality improvement effect of P. As a result, as shown in Figure 1, the P content was We have newly discovered that by adding an appropriate amount of Ca that depends on the amount of Ca, a low rate of microchip generation, as shown in the figures (unit: %), can be obtained.

[Table] However, if P exceeds 0.07%, the effect of Ca cannot be observed, so the upper limit of P was set at 0.07%.
The appropriate range of P and Ca shown in FIG. 1 can be expressed as equation (1). 0.0020−0.024×P(wt%)≦Ca(wt%)≦0.0040−0.024×P(wt%)……(1) In order to fully exhibit the above effect of Ca, Ca
reacts with O in the steel to form nonmetallic inclusions mainly composed of CaO, namely gehlenite (2CaO・Al ₂ O ₃・
SiO ₂ ) to form inclusions with a composition close to rankinite (3CaO.2SiO ₂ ), and these inclusions must be finely and uniformly dispersed. For this reason, O in steel
The amount shall be 0.006% or more and 0.03% or less. On the other hand, when there is a large amount of coexisting S, around CaO
Since CaS becomes CaO−CaS type inclusions, Ca
Not only does it not have sufficient effect, but MnS
Since a large amount of steel wool is produced, continuous steel wool cannot be obtained. Therefore, the lower the amount of S, the better, and the upper limit was set at 0.020%. Conventionally, a material for steel wool to which Ca and S are added in combination has been published (Japanese Patent Application Laid-Open No. 1983-6437), and in this case, S is 0.05% or more. but,
When the amount of S is large as described above, nonmetallic inclusions mainly composed of CaO cannot be formed, and therefore, the excellent effect based on the combined effect of P and Ca referred to in the present invention cannot be obtained. Furthermore, Japanese Patent Application Laid-Open No. 60-24347 proposes a material for manufacturing steel wool that contains 0.008% or less of Ca, but in this case, Ca is added to increase the elasticity of steel wool. This is essentially different from the present invention, which makes it possible to reduce extremely fine cutting debris by the combined effect of P and Ca. In addition, Ca free-cutting steel, which is made by adding Ca to machine structural steel, has already been put into practical use, but most of this type of free-cutting steel is mainly composed of anorthite (Cao・Al ₂ O ₃・2SiO ₂ ). The composition has been adjusted to like this
It is known that when high-speed cutting is performed at 150 to 200 m/min using a cemented carbide tool containing TiC, CaO-based composite inclusions adhere to the carbide tool surface and have the effect of extending tool life. ing. On the other hand, inclusions mainly composed of CaO, which are effective in combination with P in the present invention, have a higher CaO content than anorthite.
The content rate is high, and its effect is the reduction of ultra-fine cutting chips, which is superior to the above Ca free-cutting steel.
This effect is completely different from that of Ca. The effects of the present invention can be obtained regardless of the cutting tool and cutting speed. Next, the reason for limiting the cooling rate after wire rod rolling in the method of the present invention will be described. The present inventors have developed P
For wire rods with a high New findings have been obtained that cooling at an appropriate cooling rate before growth is much more effective than conventional air patenting. That is, below 850℃, where austenite transforms to form ferrite or pearlite during the cooling stage after rolling;
As shown in Table 2, the temperature range of 550℃ or higher is as follows:
A new finding was obtained that not only does the striped structure completely disappear by rapid cooling at 1° C./S or higher, but also that the ferrite crystal grains become extremely fine and regularized compared to air patenting.

[Table] It was not previously known that the fine-grained structure obtained by controlled cooling after wire rolling significantly reduces the generation of microscopic chips when cutting steel wool, and this is now clear for the first time. This is a new fact. On the other hand, the cooling rate in the above temperature range is
If the temperature exceeds 40℃/S, not only will a stable ferrite + pearlite structure not be obtained and the generation rate of microscopic cutting chips will increase, but also the strength of the wire will become too high, making both wire drawing and cutting difficult, so the upper limit is set. 40
℃/S (Example)

【table】

[Table] Steels having the chemical compositions shown in Nos. 1 to 15 in Table 3 were each melted in a converter, and billets were produced in some cases by the ingot method and in others by the continuous casting method. Next, the billet was heated to 1100°C in a heating furnace, and subjected to drawing wire rod rolling and controlled cooling. Controlled cooling was performed by blast cooling, air/water cooling, or molten salt cooling. After pickling and lubrication, the wire rod was drawn from 6.35 mm to a specified size. The target value of the steel wire strength after wire drawing is 98 to 102 Kgf/mm ² . The tool materials used for cutting steel wool are high-speed steel and cemented carbide containing TiC (P type), and the cutting speeds are low (55 m/min) and high (160 m/min).
We selected two levels (min) and investigated their effects. In Table 3, No. 2 is C, No. 3 is Si, and No. 4 is N.
However, in No. 5, S is a steel outside the scope of the present invention, and No.
For No. 1 to No. 5, the influence of C, Si, N, and S was investigated, and for No. 6 and No. 10, O is outside the scope of the present invention; This study investigated the influence of O. Furthermore, No. 11 to No. 14 are results in which the influence of tool material and cutting speed was investigated using the steel of the present invention. No. 15 is a comparative example with increased P and N and Ca
This is an example of a conventional wire rod for producing steel wool that does not contain carbon dioxide and has low O content. As shown in Table 3, according to the present invention, the generation rate of extremely fine chips is significantly reduced regardless of the cutting conditions. Furthermore, all steel wool produced using the wire rod of the present invention exhibits good properties. (Effects of the Invention) As described above, according to the present invention, the amount of microscopic cutting waste generated can be significantly reduced, so it is possible to improve the yield and the working environment in the production of steel wool.

[Brief explanation of drawings]

Figure 1 is a diagram showing the effect of combined addition of P and Ca on the generation rate of microscopic chips during steel wool cutting.

Claims (1)

[Claims] 1 C: 0.05 to 0.20wt%, Si: 0.1wt% or less, Mn: 0.5 to 1.5wt%, P: 0.07wt% or less, S: 0.02wt% or less, N: 0.003 to 0.01wt %, O: 0.006 to 0.03wt%, further containing Ca in the range obtained by the following formula,
A wire rod for producing steel wool, the balance of which is Fe and unavoidable impurities. 0.0020−0.024×P(wt%)≦Ca(wt%)≦0.0040−0.024×P(wt%) 2 C: 0.05–0.20wt%, Si: 0.1wt% or less, Mn: 0.5–1.5wt%, P : 0.07 wt% or less, S: 0.02 wt% or less, N: 0.003 to 0.01 wt%, O: 0.006 to 0.03 wt%, further containing Ca in the range obtained by the following formula,
Steel with the balance consisting of Fe and unavoidable impurities is hot-rolled, and after rolling is finished, it is heated in a temperature range of 850 to 550℃.
A method for producing a wire rod for producing steel wool, characterized by cooling at a cooling rate of ~40°C/s. 0.0020−0.024×P(wt%)≦Ca(wt%)≦0.0040−0.024×P(wt%)