JP4630848B2 - Energy absorption rope - Google Patents

Description

  The present invention relates to an energy absorption rope suitable for, for example, a fall prevention facility or a fall rock prevention facility.

Wire ropes used for fall prevention equipment and rock fall prevention equipment are required to have strength, tensile strength, and energy absorption performance with respect to cutting action in a direction perpendicular to the longitudinal direction. As a wire rope for such applications, a so-called GC rope (3 × 7 structure) with galvanization or aluminum galvanization is conventionally used, and it is installed with the expectation of absorbing the energy of fallen objects due to its elastic elongation. .
However, in this method of absorbing energy within the rope elastic range, from the viewpoint of energy absorption efficiency, when the energy of the falling object is large, a very thick rope or a large number of ropes will be used. Attached equipment such as anchors had to be large.

As a countermeasure for this, the present applicant has proposed Prior Document 1. In this prior document, a plurality of wire ropes having relatively different lengths are attached to an object, and the energy is absorbed by breaking the rope with a short length by sequentially breaking the rope with the short length, and then The long rope absorbs the remaining energy absorbed by the short rope.
However, in this prior art, a considerably large non-uniform force is applied to each of the rope strands, leading to breakage from a wire having a large load, and there is a concern that it is difficult to absorb sufficient energy in practice.
In addition, as a rope with high energy absorption ability, there are some types of fiber ropes and rubber ropes, but these can easily damage or cut the rope component when a pointed object acts on the surface, It cannot be used for fall prevention equipment or rock fall prevention equipment.

JP 2004-278256 A

  The present invention has been made in order to solve the above-described problems, and its object is to have anti-corrosion properties and good strength characteristics, and also has a very large energy absorption capability, for example, fall prevention. An object of the present invention is to provide an energy absorption rope that is extremely effective as a means for preventing equipment components falling or overturning in equipment or rock fall prevention equipment or preventing the structure from collapsing.

In order to achieve the above object, the present invention, in mass%, C: 0.05%, Si: 0.35%, Mn: 1.5%, P: 0.01%, S: 0.01%, Ni: 9.6%, Cr: 18.6% rest a austenitic stainless steel ropes consisting substantially Fe, was drawing a line of the chemical component composition, after processing twisted ropes, 1100 ° C. The solution heat treatment is performed by heating and then rapidly cooling , and has an elongation of 20% or more. The impact energy absorption amount (Ef) of the rope per meter = absorption coefficient (K) · tensile breaking load (Ps) (kN In m), 0.25 ≦ K <1.00 .

The rope strands are made of austenitic stainless steel wire and have an elongation of 20% or more when used as a rope. When a rope is used, a part of a specific rope is subjected to a higher load than others. Because the part is strengthened by the formation of work-induced martensite and the entire rope is uniformly deformed by dispersing the deformation to other parts, the absorbed energy until the rope breaks It can be remarkably increased to 10 times or more and 3 times or more of the plastic region absorbing rope, which enables the rope to be downsized and the generated equipment tension to be lowered. The strut structure can be simplified and economical.

Preferably, the amount of impact energy absorbed per rope (Ef) = absorption coefficient (K) · tensile breaking load (Ps) (kN · m), 0.25 ≦ K <1.00.

The rope, after drawing a line of the chemical component composition are those formed by solution heat treated after machining twisted rope.
According to this , the elongation can be remarkably increased.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows an example in which the energy absorbing rope according to the present invention is applied to a fall prevention means of ancillary equipment such as a sign post in a highway, high-speed railway, bridge, etc., 100 is a road, 101 is a target equipment, A sign main body 103 is fixed to the upper part of the column 102. The support column 102 is fixed to a side wall (rail) 104 having a lower end rising from a side surface of the road by a fixing bracket 105.

  Reference numeral 1 denotes an energy absorption rope for preventing the fall from the side wall, and each end is connected to a support metal fitting 106 attached to an intermediate portion of the support column 102 and the other end is fixed to left and right fixing metal fittings 107 and 107 fixed to the side wall. The energy absorbing rope 1 is connected when a vehicle that is connected and traveling on the road collides with the support column or an earthquake occurs, and the support column is separated from the fixed bracket 105 or is detached from the fixed bracket 105 and is over-the-counter / dropped. This creates tension and absorbs falling and falling energy.

  Although the structure of the rope 1 is not limited, the rope 1 is usually configured by twisting a plurality of strands obtained by twisting a plurality of strands. 2 and 3 (a) show examples of such ropes, 2 being a strand and 3 being a strand. In this example, it has a 7 × 19 structure in which seven strands 2 obtained by twisting 19 strands 3 are twisted. However, it goes without saying that the present invention is not limited to this, and a 3 × 7 structure in which three strands 2 in which seven strands 3 are twisted are twisted as shown in FIG. Etc. are also included.

The present invention uses austenitic stainless steel having the following chemical composition as the strand 3 of the rope 1.
C: 0.001 to 0.15% by mass, Si: 0.01 to 1.5%, Mn: 0.3 to 3.0%, P: 0.05% or less, S: 0.02% Hereinafter, Cr: 14.0 to 26.0%, Ni: 6.0 to 22.0% are contained, N: 0.02% or less, and the remainder is substantially made of Fe.
The reason for the limitation will be explained. C is added as a solid solution strengthening element, but the upper limit is set to 0.15% to ensure ductility, and the lower limit is set to 0.001% in terms of refining costs.
Si is also effective for strengthening, but if it becomes excessive, the ductility decreases, so the upper limit is 1.5%, and the lower limit is 0.01% necessary for deoxidation.
Mn is contained in an amount of 0.3% or more to stabilize austenite, while the upper limit is made 3% with the intention of not impairing corrosion resistance.
When P is included, there is almost no advantage in terms of properties, so there is little difficulty, but the refining cost is 0.05% or less.
S is also an unnecessary element, but the upper limit is made 0.02% in consideration of the cost of refining.
In order to obtain corrosion resistance as stainless steel, Cr is 14% or more, and the upper limit is 26% in terms of cost.
Ni austenites the structure, and the lower limit is 6% and the upper limit is 22% from the viewpoint of both corrosion resistance and cost.
Since N is in the direction of decreasing ductility, it is desirable that N be 0.02% or less.
Particularly preferably, by mass, C: 0.05%, Si: 0.35%, Mn: 1.5%, P: 0.01%, S: 0.01%, Ni: 9.6%, Cr : Use 18.6% of which substantially consists of Fe.

  Such austenitic stainless steel wires are known per se, and ropes twisted with such wires are also known in the art. However, conventional stainless steel ropes, as in Utility Model Registration No. 2592409, exclusively improve corrosion resistance. Was intended to be. Although stainless wire inherently has the characteristics of higher elongation than high carbon steel, it is generally lower in strength than ropes of high carbon steel, and it is necessary to compensate for it by work hardening. As a result, the elongation characteristics were suppressed, and no rope that actively used the elongation characteristics of the stainless steel rope was found.

  That is, when manufacturing a rope made of high carbon steel material, the raw material wire is subjected to a heat treatment called patenting, followed by wire drawing to form a strand, which is twisted to form a strand. It is customary to obtain the target rope by twisting.

  In the manufacture of stainless steel ropes, although the elongation is considerably large in the state of stainless steel strands, in order to make a rope, in the manufacturing process, the strands are processed into a predetermined diameter by cold drawing and the strands are converted into strands. Since the strands and strands are twisted into a rope, work hardening occurs due to such processing, so that the elongation when forming a rope is remarkably reduced. For this reason, conventionally, stainless steel ropes are not suitable for applications intended to absorb energy, or have been considered to be ineffective even when used.

In order to overcome such a problem, the present inventor tried to make a strand by drawing a stainless steel wire containing austenite having the chemical composition described above, and twisting it to make a strand. After twisting the book to obtain the target stainless steel rope, a solution heat treatment was performed (first embodiment).
As a result, surprisingly, a large elongation of 20% or more can be obtained uniformly, the tensile breaking load is Ps (kN), the absorption coefficient K, the impact energy absorption amount of the rope per meter Ef = K · Ps (kN · In m), it was found that the absorption coefficient K is 0.25 or more, and that the strand has an average strength of 400 to 900 MPa.

The method for obtaining the rope according to the first aspect of the present invention will be described in the process shown in FIG . That is, the raw stainless steel wire is drawn to the target wire diameter according to a conventional method, and the drawn stainless steel wire is twisted into a strand by a twisting machine. The twist pitch at this time is preferably about 9 to 11 times the strand diameter. Then, a plurality of the obtained strands are arranged on a twisting machine and twisted to obtain an elementary stainless steel rope having a target diameter. The twist pitch at this time is preferably about 6.0 to 7.5 times the rope diameter.
These are necessary for reducing the twist rate to less than 10% and improving the strength. The “twisting reduction rate” means the rate of decrease in the tensile breaking load of the rope as it is after twisting the rope and obtaining the strength of each strand.

Next, the raw stainless steel rope is wound as it is in-line or around a coil having a required length, and is inserted into a solution heat treatment apparatus to perform solution heat treatment. The solution heat treatment is performed at 980 to 1150 ° C. for 2 to 10 minutes, and then rapidly cooled by water cooling or the like.
The reason for this condition is to sufficiently solidify the structure. Under these conditions, the elongation is 20% or more, preferably 35-60%, and the rope yield ratio is 0.7 or less. The tensile yield ratio of the strands of loosened rope is 0.3 to 0.7. Yield ratio = yield point / tensile breaking load, but the rope yield ratio means a 0.2% permanent elongation load excluding the rope structure elongation.

As another method, a stainless steel wire that has been subjected to solution heat treatment before drawing the raw stainless steel wire to a predetermined target wire diameter and twisting the drawn wire to a strand , and then to the solution heat treatment Are twisted to form a strand, and then twisted to obtain a target rope. The conditions for the solution heat treatment are 980 to 1150 ° C., 2 to 10 minutes, and the cooling method may be water cooling.
However, the solid solution heat treated stainless steel wire is soft, and the surface is easily scratched during the stranding and rope twisting process. If this scratch is left untreated, this scratch becomes the starting point of the rope breakage, and the obtained rope is sufficient There is a high risk of breaking without absorbing energy.
For this reason, as a member of a manufacturing facility that comes into contact with a wire, such as a guide roll and a voice, a member made of a soft material such as a synthetic resin is used instead of a hard material. In addition, the back tension of the strands when twisting is taken into consideration, the twist pitch is set to about 10 to 15 times the strand diameter to prevent work hardening when twisting, and a plurality of strands obtained are obtained. Are twisted and twisted to obtain an elementary stainless steel rope having a target diameter. The twist pitch at this time is preferably about 7.0 to 13 times the rope diameter.

The rope of the present invention is made into a product through the steps as described above, and is used as shown in FIG.
In FIG. 1 and FIG. 2, since many strands are twisted together in a rope, when external force is applied to this, the stress added to these strands is not equal. The wire with the highest stress undergoes plastic deformation and causes plastic elongation. However, with normal steel ropes, the steel wire is not very hard to work, so this wire breaks with almost no deformation being shared by other wires. The other lines also break one after another, and the energy absorption becomes small.

In order to prevent this, it is necessary that the wire that is first plastically deformed is greatly hardened by work hardening. In the present invention, as described above, the stainless steel wire containing austenite is used as the element wire, and the solution heat treatment is performed, so that the overall elongation becomes very large.
When a tensile load is applied to the rope in the above-described use state, the strands undergo plastic deformation, thereby generating work-induced martensite, thereby obtaining a large work hardening. By doing so, it is possible to distribute the deformation to other lines without concentrating the deformation only on a certain line. As a result, the entire rope element bears a uniform force, and since the local breakage does not occur, the entire rope can be subjected to a very large deformation.

FIG. 5 shows the load-elongation relationship when a tensile load is applied to the rope.
In the figure, line A is a rope of a type that absorbs energy in the elastic region (hard steel wire type), and area SA obtained by integrating the load-displacement under line A is energy.
The line B is a rope of a type that absorbs energy in the plastic region (ordinary stainless steel wire rope), and the area SB obtained by integrating the load-displacement under the line B is energy.
The line C is a rope of the type that absorbs energy in the plastic region of the present invention, and the area SC obtained by integrating the load-displacement under the line C is energy. Compared to elasticity, plastic absorbs energy more, but the elongation is not so large, so it is less effective.In the present invention, however, the martensitic transformation during tensile deformation strengthens the part where the wire diameter becomes thinner in each part of the rope. Since the effect | action which carries out is remarkable, a fracture | rupture is suppressed and remarkable deformability is shown.
When the material is austenitic stainless steel, a large decrease in ductility is inevitable because a large number of strands are twisted.In the present invention, such a significant decrease in ductility is achieved by applying a solution heat treatment. It can be almost completely prevented.

〔Concrete example〕
Next, specific examples are shown in Table 1. Table 1 shows the results of trial production of the rope of the present invention, a normal stainless steel rope, and a hard steel wire rope, and the breaking strength, elongation, absorbed energy per 1 m, and energy absorption coefficient. Is shown.
The production conditions of the rope of the present invention are as follows. Moreover, the manufacturing conditions of the conventional rope are as follows.

* Invention rope 1:
Structure: 7 × 19, Z twist, diameter 18.0 mm.
Chemical component composition: austenitic stainless steel C: 0.05%, Si: 0.35%, Mn: 1.5%, P: 0.01%, S: 0.01%, Ni: 9.6% , Cr: 18.6%
Process:
(1) A raw material wire having a diameter of 5.5 mm is extracted 4 times in the cold to 3.5 mm, heat-treated at 1100 ° C. for 5 minutes under water cooling conditions, and then extracted 9 times until the wire diameter becomes 1.19 mm. To get a strand.
(2) The 19 strands obtained in the above process were twisted in the Z direction to produce a core strand, and the 19 strands were twisted in the S direction to produce a side strand.
(3) Six side strands were twisted in the Z direction on the core strand to produce a rope.
(4) The wound rope was placed in an annealing furnace, heated at 1100 ° C. for 5 minutes, and subjected to a solution heat treatment that was water-cooled.
In addition, ropes having a diameter of 6.3 mm (the rope 2 of the present invention) and 28.0 mm (the rope 3 of the present invention) were prepared in the same process as the rope 1 of the present invention.

* Conventional rope 1:
: Structure 7 × 19, Z twist, diameter 18.0 mm.
Chemical composition: Austenitic stainless steel Same as the rope of the present invention
This invention rope 1 and (1)-(3) are the same. There is no (4).

* Conventional rope 2:
: Structure 7 × 19, Z twist, diameter 18.0 mm.
High carbon steel rope: structure 7 × 19, Z twist, diameter 18.0 mm.
Chemical composition: Hard steel C: 0.62%, Si: 0.20%, Mn: 0.48%, P: 0.016%, S: 0.014%
Process:
(1) A raw material wire having a diameter of 5.5 mm was drawn four times to 3.5 mm in a cold state, heat treated under a cooling condition in a lead bath after 980 ° C. for 1.5 minutes, and then the wire diameter was 1.19 mm. The wire was obtained by drawing 9 times until
(2) The 19 strands obtained in the above process were twisted in the Z direction to produce a core strand, and the 19 strands were twisted in the S direction to produce a side strand.
(3) Six side strands were twisted in the Z direction on the core strand to produce a rope.

FIG. 6 shows the relationship between the absorbed energy per meter and the rope breaking load of the ropes 1 to 3 of the present invention and the conventional ropes 1 and 2.
As can be seen from Table 1 and FIG. 6, the rope of the conventional product 2 is significantly inferior in energy absorption performance, and the rope of the conventional product 1 has somewhat higher energy absorption performance than the conventional product 2, but is still considerably low. . On the other hand, it can be seen that the rope of the present invention has extremely high energy absorption performance. This is due to the fact that the austenite contained in the strands is transformed into martensite by plastic deformation and strengthened by using plastic deformation to improve the ductility by solution heat treatment in the state of the rope or strands. This is because the energy absorbing ability was remarkably enhanced by dispersing the force applied to the film and suppressing breakage.

  The rope of the present invention is a sacrificial means for preventing the fall or fall of equipment components in fall prevention equipment or rock fall prevention equipment (for example, rock fall prevention fences, rock fall prevention nets), or preventing the structure from collapsing, or It can be used for metal ropes in fields where energy absorption performance is required, such as impact mitigation means at the time of collision.

(A) is a side view which shows the usage example of the energy absorption rope concerning this invention, (b) is a front view similarly. It is a fragmentary perspective view which shows an example of this invention rope. (A) is sectional drawing which shows an example of this invention rope, (b) is sectional drawing which similarly shows another example. It is a manufacturing-process figure of the 1st aspect of this invention . It is a load-elongation diagram of this invention rope and a conventional rope. It is a diagram which shows the relationship between the absorbed energy per 1m of this invention rope and a conventional rope, and a rope breaking load.

1 rope of the present invention 2 strand 3 strand

Claims (1)

By mass% : C: 0.05%, Si: 0.35%, Mn: 1.5%, P: 0.01%, S: 0.01%, Ni: 9.6%, Cr: 18.6 % remainder a austenitic stainless steel ropes consisting substantially Fe, was drawing a line of the chemical component composition, after processing twist the rope, and heated at 1100 ° C. the solution heat treatment to thereafter rapidly cooled The impact energy absorption amount (Ef) of the rope per meter (Ef) = absorption coefficient (K) · tensile breaking load (Ps) (kN · m) 0.25 ≦ K <1.00 energy absorption rope characterized by the above-mentioned.

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