JPH0215606B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention aims to improve the toughness of high-strength, low-expansion alloy wires, particularly Fe-Ni alloy wires with a tensile strength of 100 Kg/mm2 or ^more , such as elongation characteristics, twisting characteristics, and winding and unwinding characteristics. The present invention relates to a method for manufacturing a low expansion alloy wire. Conventional low expansion alloys include Fe-36%Ni, known as Invar, and Kovar, known as Kovar.
Fe-Ni alloys such as Fe29%Ni-17%Co are known, but their strength is at most 80-90Kg/mm ² even when the degree of cold working is 90% or more. value is
It had an excellent winding cycle of around 200 times, and also had excellent winding and unwinding characteristics and elongation. Recently, there has been a desire to develop high-strength, low-expansion alloy wires, such as wires for the central part of low-sag overhead power transmission lines (ACSR), which have a tensile strength of 100 Kg/ ^mm2. For example, it has a very high coefficient of linear expansion of 130 to 140 Kg/mm ² , and an average coefficient of linear expansion of 5.0 at room temperature to 300°C.
Materials with low expansion characteristics of ×10 ^-6 /°C or less are required. This requires a strength increase of more than 50% compared to normal Fe-Ni alloys, and the reduction in toughness in this case has been a major obstacle in material development. In view of the above points, the present inventor cold-works Fe-Ni alloys containing various additive elements to produce wires, and examines the tensile strength, elongation, twisting characteristics, and winding characteristics of the wires. The return characteristics and expansion characteristics were investigated. As a result, we found that Mo, W, Ta,
By adding elements such as Nb, Ti, Al, Si, Cr, C and Mn, the work hardenability of the matrix Fe-Ni alloy is increased, and the tensile strength of the wire is increased to 130 by cold working. ~140Kg/ ^mm2 , and Ni
By limiting the amount of Ni + Co to an appropriate amount, the average coefficient of thermal expansion from room temperature to 300℃ can be reduced from 3 to 300℃.
A value of 5×10 ⁻⁶ /°C was obtained. However, the characteristics that are indicators of toughness, such as twisting characteristics, winding and unwinding characteristics, and elongation characteristics, are different from that of ordinary Fe-Ni.
There is no problem with alloy wire, but the final use size is 100
When it comes to high-strength materials such as Kg/mm ² or more, if the processing process is inappropriate, the elongation may drop below 1.5%, the torsion value may drop significantly, or the winding diameter will meet the requirements for winding and unwinding characteristics. In some cases, the diameter was 4 to 5 times larger, which is inappropriate for a steel core for power transmission lines. Therefore, the inventor of the present invention developed a product with a final use size of 100Kg/
As a result of various studies on processing processes for Fe-Ni alloys having a tensile strength of mm ² or more, we determined that the degree of cold working before stripping should be 30% or less, and that the degree of cold working should be 550 to 800% after stripping or during the wire drawing process after stripping. By carrying out strain relief annealing in the temperature range of ℃, Fe
-We have discovered a method for manufacturing a high-strength, low-expansion alloy wire that can make the elongation, twisting, and winding and unwinding characteristics of the Ni-based alloy wire equal to or higher than those of conventional steel wire used in ACSR. In the present invention, the degree of cold working before peeling is specified as 30% or less because increasing the strength during peeling increases the surface distortion of the peeled material, and in order to remove the distortion, the annealing temperature is set to 800°C. However, if this temperature is set to 800°C or higher, the elongation property in the final use size will be less than 1.5% in the wire drawing state. Of course, if the Fe-Ni alloy wire is not used in the processed state, for example, if hot-dip Zn plating is applied at the final size, the elongation properties will be restored due to the thermal effect during hot-plating, but even in this case, the processing will not be possible. If the elongation in the condition is low, the elongation after fitting will be less than 1.5. Also, after peeling or during wire drawing after peeling, 550 to 800
The reason for specifying that strain relief annealing be carried out in the range of It is used
This is because properties equivalent to ACSR steel cores can be obtained; if the strain relief annealing temperature is less than 550°C, the strain will not be released, and if it exceeds 800°C, not only will the strength decrease, but the elongation properties will deteriorate due to coarsening of the crystals. This is because it deteriorates. In order to reduce the degree of cold working before stripping to 30% or less, this can be achieved by matching the rising size of hot working to the stripping diameter or by performing temper annealing during wire drawing. This temper annealing can be set to conditions where strain is released by strain relief annealing at 800°C or lower. In the present invention, peeling refers to Fe-
This refers to the process of removing surface flaws and oxide scale from Ni-based alloy wire, and what is Fe-Ni-based alloy wire?
Also includes those coated with Zn, Al, and Ni after strain relief annealing. The present invention will be explained in detail below with reference to Examples. Example An Fe-Ni alloy having the composition shown in Table 1 was melted,
After degassing, it was cast to obtain an ingot. This ingot was then forged into a billet and hot worked to obtain a rough wire. Next, after carrying out cold working before peeling and strain relief annealing after peeling under the conditions shown in Table 2, 3.2
Wire drawing was performed on a mmφ wire.

【table】

【table】

[Table] Table 3 shows the results of examining the tensile strength, twisting characteristics, etc. of the obtained strands.

[Table] From the above table, the alloy wire produced by the method of the present invention has a high tensile strength of 130 Kg/mm ² or more, similar to the comparative example, and a low coefficient of linear expansion of 2 to 4 × 10 ^-6 /°C. Ta. Moreover, according to the method of the present invention, elongation is high;
It has good twisting properties, and the winding and unwinding properties do not break even when wound to a smaller diameter, and the overall toughness of elongation, twisting, and winding and unwinding properties is excellent, making it suitable for ACSR steel cores, etc. It has been demonstrated that an Fe-Ni alloy wire suitable for applications requiring high strength and low expansion properties can be obtained.

Claims (1)

[Claims] 1. For high-strength, low-expansion alloy wires made from Fe-Ni alloys, the degree of cold working before stripping is reduced to 30%.
550 after peeling or during wire drawing after peeling.
A method for manufacturing a high-strength, low-expansion alloy wire, characterized by performing strain relief annealing at ~800°C.