JP3505047B2 - Steel wire for ACSR with low iron loss - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel stranded wire (A) used to reinforce an Al conductor wire of a cable for a transmission line.
The present invention relates to CSR (Aluminium Conductor Steel Reinforced) steel wire.

[0002]

2. Description of the Related Art ACSR, a US company, devised the ACSR.
Due to the light weight of Al, it is often used as a power transmission line. However, since Al has low strength, it is used in combination with a steel wire plated with Zn or Al at the center of the ACSR for reinforcement.
Usually, JIS SWRH62-77A is used for the said steel wire as an element wire, and the steel wire after cold drawing is twisted and used for 3-19 pieces. Such a core wire has strength, elongation, twist value,
Although there are regulations regarding breakage during wrapping tests, AC
There is no specific regulation on iron loss when used as SR. However, in the actual steel core wire for ACSR, there is a drawback that iron loss occurs due to an induced current because a current flows through a hard Al wire that is matched with the circumference of the steel stranded wire.
Although this iron loss causes a large transmission loss, at present, no measures are taken to prevent this iron loss.

Generally, electromagnetic steel sheets are used to reduce iron loss of transformers and motors. Grain-oriented electrical steel sheets in which crystal orientations are aligned with the rolling direction, non-oriented electrical steel sheets in which crystal orientations are randomly arranged. It has been known. In these electromagnetic steel sheets, steel containing C is used in the manufacturing process in order to control the crystal orientation, and in the final product, C is obtained by decarburization annealing or the like.
To 30ppm or less. This method requires a large manufacturing cost. Further, these are all related to thin plates, and there is no report on a method of reducing iron loss when a stranded wire is twisted with a surrounding hard Al wire.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a steel core wire for ACSR capable of reducing iron loss during power transmission by specifying the component system of steel wire and manufacturing conditions, and a manufacturing method thereof. .

[0005]

In order to solve such a problem, the present invention makes it possible to reduce the power loss during power transmission by limiting the composition of the steel material and selecting the manufacturing conditions of the steel material. The present invention provides a steel core wire for ACSR and a manufacturing method thereof. That is, the main points are as follows. (1) Weight%, C: 0.01% or less, Si: 0.6
% -6.5%, Mn: 0.10% -1.5%, balance F
A steel wire for ACSR having low iron loss, which is characterized by comprising e and unavoidable impurities. (2) A having a low iron loss as described in (1), characterized by containing Al: 0.002% to 0.050% by weight.
Steel wire for CSR. (3) wt%, Nb: 0.002% to 0.10%, T
i: 0.002% to 0.10% of 1 type or 2 types or more, The steel wire for ACSR with low iron loss as described in any one of (1) to (2) characterized by the above-mentioned. (4) By weight%, Cu: 0.02% to 0.5%, N
i: 0.02% to 0.5%, Cr: 0.02% to 0.5
%, Mo: 0.02% to 0.5%, Co: 0.02%
~ 0.5%, W: 0.02% to 0.5% of one or more kinds of the iron loss according to any one of (1) to (3). Low steel wire for ACSR. (5) The steel wire for ACSR having low iron loss according to any one of (1) to (4), characterized in that it contains V: 0.002% to 0.10% by weight. (6) B: 0.0002% to 0.0025% by weight
A steel wire for ACSR having low iron loss according to any one of (1) to (5), characterized in that (7)% by weight, Rem: 0.002% to 0.10%,
Ca: 0.0003% to 0.0030%, Mg: 0.0
003-0.01% of 1 type (s) or 2 or more types, The iron wire with low iron loss as described in any one of (1) thru | or (6) characterized by the above-mentioned. (8) Steel wire is plated with Zn, or in a weight ratio, Al: 2 to
12%, Si: 0.01 to 0.12%, the balance is hot dip plated using an alloy bath consisting of Zn and unavoidable impurities. (1) to (7) ASR coated steel wire with low iron loss. (9) The ACSR with low iron loss according to (8), characterized in that the steel wire after plating is drawn at a total area reduction rate of 20 to 80%.
For plated steel wire. (10) The steel wire for ACSR having a low iron loss according to (9), wherein the steel wire after drawing is subjected to bluing treatment at a temperature of 300 to 370 degrees. (11) The steel wire after drawing is heated at a temperature of 300 to 370 degrees and 20% to 50% of the tensile strength of the steel wire during heating.
% Of stress is applied to the plated steel wire for ACSR having low iron loss according to (9).

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The technical idea that forms the basis of the present invention is as follows. Generally, iron loss can be separated into hysteresis loss and eddy current loss. The former is known to be affected by crystal orientation and steel purity. In the case of a plate, (11
0) It is desirable that [001] orientation (so-called Goss orientation) is integrated, and the higher the purity, the better. However, since the high-strength steel wire has a high strength by containing a large amount of C, in the case of reducing C, it is necessary to take a strengthening means to replace it. Furthermore, since wire drawing develops a strong fibrous texture, it is almost impossible to obtain a crystal orientation other than the texture unique to the wire drawing material. On the other hand, the latter eddy current loss decreases as the specific resistance increases, so Si
It is known that the addition is effective. High Si
Steel has low ductility and easily breaks when actually drawn. In order to comprehensively solve such problems, the present inventors have made various studies and found the following solutions.

In order to reduce the hysteresis loss, it is essential to reduce the C content. Therefore, it is necessary to compensate the decrease in strength due to the decrease in C by another method. In general, the higher the C content, the greater the increase in strength due to wire drawing.
If the amount is reduced, higher strength due to wire drawing cannot be expected so much. However, by increasing Si instead of C, it is possible to increase the amount of strength increase due to wire drawing. If Si is simply increased, wire drawing workability is hindered and the wire is easily broken during wire drawing. However, by lowering the amount of C, strength can be increased without hindering wire drawing workability, and hysteresis loss can be reduced. Can also be reduced. In order to maintain good wire drawing workability, it is necessary to keep the contents of C and Si within a predetermined range.

The reasons for limiting the chemical composition and the metal structure will be described in detail below. First, the reasons for limiting the components of the present invention will be described. C is an element effective for strengthening the wire rod, but its content must be strictly limited in order to significantly increase iron loss. If it exceeds 0.01%, the iron loss is significantly deteriorated, so the content is made 0.01% or less. On the other hand, the lower limit of C is not particularly limited, and the smaller the better, the better.

Si is effective as a deoxidizing element and increases the specific resistance to reduce the eddy current loss. If the content is less than 0.6%, the effect is small. On the other hand, if it exceeds 6.5%, the wire drawability deteriorates, so the content range is made 0.6% or more and 6.5% or less. Mn is an element effective in toughening a metal, and if it is added in an amount of less than 0.10%, a sufficient effect cannot be obtained. On the other hand, if the content exceeds 1.5%, the toughness of the deposited metal deteriorates.

Both Ti and Nb function effectively in terms of grain refinement and precipitation hardening when added in a small amount, but if the added amount is too small, the effect cannot be obtained. In order to increase the loss, the addition amount of both Nb and Ti is Ti: 0.002% to 0.10%, Nb: 0.00
It is limited to the range of 2% to 0.10%. Cu, Ni, C
Each of r, Mo, and W can increase the strength of steel, but if the addition amount is small, the effect of increasing strength due to solid solution strengthening cannot be obtained, and addition of an excessive amount deteriorates ductility. The amount of Cu: 0.02% to 0.5%, Ni: 0.
02% to 0.5%, Cr: 0.02% to 0.5%, M
o: 0.02% to 0.5%, W: 0.02% to 0.5%
It is limited to the range of.

V is effective in increasing the strength of the steel, but if the addition amount is small, the effect cannot be obtained, and if the addition amount is excessive, the iron loss increases, so the addition amount is 0. It is limited to the range of 0.002% to 0.10%. B is an element that improves the hardenability of steel. In the case of the present invention, the addition thereof can increase the strength of steel,
If the amount of addition is small, the hardenability does not improve, and excessive addition increases the precipitates of B and impairs ductility, so the content is made 0.0002% to 0.0025%.

[0012] Rem, Ca and Mg are effective in combining with S or oxygen to refine the metal structure. If a small amount is added, S remains as it is, and excessive addition causes an increase in iron loss. Therefore, Rem: 0.002% to 0.10
%, Ca: 0.0003% to 0.0030%, Mg:
It is added in the range of 0.0003% to 0.01%. Al is effective as a deoxidizing element. If the content is less than 0.002%, there is no effect, and if it exceeds 0.05%, surface defects are likely to occur, so the content is 0.002% to 0.05%.
The range is 0%.

Next, the limiting conditions of the manufacturing conditions in the present invention will be described. The steel wire of the present invention does not need to have a particular manufacturing process. That is, the steel ingot or slab smelted and cast in the normal steelmaking process is used as a starting point to perform slab rolling as required, and a steel wire is produced in the normal wire rod rolling process. There are various operating conditions in each process, but any of them is effective.

Generally, the steel wire used for ACSR needs to be plated with Zn or an alloy such as Al-Zn in order to impart corrosion resistance. Corrosion resistance is improved even with normal Zn plating, but better corrosion resistance is exhibited when Al is added, so the Al amount may be selected according to the severity of the operating environment. However, if the amount of Al is less than 2%, the effect of improving corrosion resistance is insufficient, and if it exceeds 12%, the melting point rises and the plating temperature increases, leading to a decrease in the strength of the steel wire. Therefore, the amount of Al in the plating bath is limited to 2% or more and 12% or less by weight. On the other hand, the reason for adding Si to the plating bath is to prevent Fe from leaching out from steel facilities and equipment such as a plating bath and to suppress the generation of dross in the plating bath. When the amount of Si added is less than 0.01%, dross occurs, and when it exceeds 0.12%, Si is not dissolved in the plating bath. Therefore, the amount added is limited to 0.01% or more and less than 0.12%.

Since the strength generally decreases after the plating process, a wire drawing process (after draw) is performed after plating to compensate the strength. At that time, if the total area reduction rate is less than 20%, the strength is not sufficiently recovered, and if it exceeds 80%, the ductility is remarkably deteriorated. Therefore, the range of the total area reduction rate is limited to 20% or more and less than 80%. Since elongation as a product deteriorates when such wire drawing is performed, it is necessary to heat again to secure the elongation. If the heating temperature at that time is less than 300 ° C., the elongation is not sufficiently recovered, and if it exceeds 370 ° C., the plating layer is softened. Therefore, the heating temperature range is limited to 300 ° C. or more and less than 370 ° C. Further, in order to increase the strength lowered by plating, it is effective to apply stress during heating. If the load stress at that time is less than 20% of the tensile strength of the steel wire at room temperature, the strength increase is insufficient, and if it exceeds 50%, plastic deformation occurs locally and ductility deteriorates. 20% to 50% of the tensile strength of steel wire at room temperature
Limited to:

[0016]

EXAMPLES Next, the present invention will be described in detail based on examples. First, the steel wires having the components shown in Table 1 were manufactured by refining (partially vacuum melting) by a normal converter method, continuous casting (partial steel ingot method + slabbing), and wire rod rolling (hot rolling). Furthermore, the strength was adjusted by drawing to a predetermined diameter by cold drawing. After cold drawing, some of the products were subjected to plating, afterdrawing, bluing, and warm stretching under the conditions shown in Table 2. The mechanical properties and corrosion resistance magnification of these steel wires are also shown in Table 2. Here, the corrosion resistance magnification was calculated by the following formula.

[0017]

[Equation 1]

[0018]

[Table 1]

[0019]

[Table 2]

Each of these steel wires was wound in a ring shape with a diameter of 270 mm about 6 times, and further 700 wires were wound around the primary side and 20 wires were wound around the secondary side, and the iron loss was measured. For the measurement of iron loss, the relationship between magnetic flux density and magnetic field strength under alternating current was measured. The frequency was 50 Hz. Magnetic field strength (Hm) is 10
In the range of 00 to 4000 (A / m), the magnetic flux density (B
m) was changed in the range of 0.2 to 1.5 (T) to measure the iron loss. Table 3 shows the measurement results of iron loss.

[0021]

[Table 3]

As shown in Table 2, the steel of the present invention has an extremely low C
Although it is steel, it has a tensile strength of over 1000 MPa. Furthermore, it has a relatively good elongation and can withstand the specifications of ACSR. It can be seen that the corrosion resistance can be ensured by applying the plating, but particularly when the Zn—Al plating is applied, the corrosion resistance ratio is large and the effect is remarkable.

Further, as shown in Table 3, the steel of the present invention has extremely low iron loss. In particular, the iron loss tends to be lower as the C content is lower and the Si content is higher, but any iron loss of the steels of the present invention is halved compared to the 0.82% C steel currently used. I understand.

[0024]

INDUSTRIAL APPLICABILITY As described above, the present invention is excellent in strength, elongation, corrosion resistance, and far lower in iron loss than conventional steels. This makes it possible to significantly reduce power loss when used as the core wire of ACSR, and bring about a great effect on energy saving.

Front page continuation (72) Inventor Hiroshi Oba 1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel Co., Ltd. Kimitsu Works Ltd. (72) Inventor Masao Yabumoto 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Co., Ltd. ceremony Corporate Technology Development Division (58) Fields surveyed (Int.Cl. ⁷ , DB name) C22C 38/00-38/60

Claims (11)

(57) [Claims] 1. By weight%, C: 0.01% or less, Si: 0.6% to 6.5%, Mn: 0.10% to 1.5%, and the balance being Fe and inevitable impurities. A steel wire for ACSR having a low iron loss. 2. Al: 0.002% to 0.0 by weight.
The steel wire for ACSR having a low iron loss according to claim 1, wherein the steel wire contains 50%. 3. Nb: 0.002% to 0.1% by weight.
0%, Ti: 0.002% to 0.10%, one or two
The steel wire for ACSR having a low iron loss according to any one of claims 1 and 2, containing at least one kind. 4. By weight%, Cu: 0.02% to 0.5%, Ni: 0.02% to
0.5%, Cr: 0.02% to 0.5%, Mo: 0.02% to
0.5%, Co: 0.02% to 0.5%, W: 0.02% to
0.5% of 1 type (s) or 2 or more types is contained, A with low iron loss as described in any one of Claim 1 thru | or 3 characterized by the above-mentioned.
Steel wire for CSR. 5. V: 0.002% to 0.10.
%, The steel wire for ACSR having a low iron loss according to any one of claims 1 to 4. 6. B: 0.0002% to 0.0 by weight.
025% is contained, The steel wire for ACSR with low iron loss of any one of Claim 1 thru | or 5 characterized by the above-mentioned. 7. In weight%, one or more of Rem: 0.002% to 0.10%, Ca: 0.0003% to 0.0030%, Mg: 0.0003 to 0.01%. A having a low iron loss according to any one of claims 1 to 6, characterized by containing A.
Steel wire for CSR. 8. A steel wire is Zn-plated, or in a weight ratio, Al: 2 to 12%, Si: 0.01 to 0.12%, and the rest is hot-dip plated using an alloy bath containing Zn and inevitable impurities. The plated steel wire for ACSR having a low iron loss according to any one of claims 1 to 7. 9. A steel wire after plating has a total area reduction rate of 20 to 80%.
9. The plated steel wire for ACSR having a low iron loss according to claim 8, which is drawn. 10. The steel wire after drawing is 300 ° C. or higher and 370 ° C.
The steel wire for ACSR with low iron loss according to claim 9, which is subjected to bluing treatment at the following temperature. 11. A steel wire after drawing is 300 ° C. or higher and 370 ° C.
It is heated at the following temperature and the tensile strength of the steel wire during heating is 20
The plated steel wire for ACSR with low iron loss according to claim 9, wherein a stress in the range of 50% to 50% is applied.