JP2888553B2 - Manufacturing method of core rod driving type metal expansion anchor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the invention]

(Field of Industrial Application) The present invention relates to a method of manufacturing a metal rod-insertable metal expansion anchor used for manufacturing an anchor used for retrofitting a plate, metal, or the like to a base material such as concrete. It is. (Prior art) Conventionally, when electrical construction work, plumbing work, air-conditioning duct work, plant construction, shelf installation work, hardware installation work, etc. are performed after concrete or the like has been constructed, metal materials are added to the base material of concrete or the like. When you add
A metal anchor body having an extension is inserted into a preformed hole, and then the extension is opened to use a metal extension anchor which cuts into a concrete hole wall. As this kind of metal expansion anchor, a cone adoption type such as a cone driving type or a main body driving type combining a cone and an anchor body having an expansion portion expanded by the cone, or expanded by driving a core rod There is a core rod driving type in which an anchor body having an expanded portion and a core rod are combined, and the present invention relates to a core rod driving type metal expansion anchor used for manufacturing the latter core rod driving metal expansion anchor. It relates to a manufacturing method of Conventionally, when manufacturing this kind of core rod driving type metal expansion anchor, austenitic stainless steel is used as a material thereof, and an anchor body having an expanded portion expanded by core rod driving is formed by cutting. The anchor body is fixed to concrete by combining the expansion part with a core rod for expanding the expansion part and expanding the expansion part of the anchor main body by driving the core rod into a concrete hole wall. Plates and hardware were attached to the main body, and bolts and screws were screwed into the anchor main body. (Problems to be Solved by the Invention) However, in the case of the conventional metal rod driving type metal expansion anchor, austenitic stainless steel is used as a material of the anchor body, so that the cost is high and the metal is formed by cutting. There was a problem that productivity was poor and material yield was not good. (Object of the Invention) The present invention has been made in view of such a conventional problem, and is cheaper and cold-workable than austenitic stainless steel as a material of an anchor body of a core rod driving type metal expansion anchor. By using a ferritic stainless steel with a specific composition that is more excellent in toughness and rust resistance, the anchor body is manufactured by forging using the better cold workability of this ferritic stainless steel material. By increasing productivity and improving material yield, costs are reduced not only from the material side but also from the manufacturing side, and higher toughness and rust resistance increase the pulling force of anchors from concrete and other base materials. Provided is a method of manufacturing a metal rod-insertable metal expansion anchor that can prevent corrosion and rust from occurring over a long period of time. It is intended to be.

Configuration of the Invention

(Means for Solving the Problems) The manufacturing method of the core rod driving type metal expansion anchor according to the present invention is as follows: C: 0.020% or less, Si: 0.30% or less, Mn:
0.50% or less, P: 0.020% or less, S: 0.010% or less, Cr: 16.0
~ 25.0%, Cu: 1.0% or less, Ni: 1.0%, Mo: 3.0% or less, O:
0.010% or less, N: 0.025% or less, C + N: 0.040% or less, Nb /
(C + N): 10-20, if necessary, one or two of Ti: 0.03-0.5% and Zr 0.03-0.50%, the balance being Fe and stainless steel, the first step After hot rolling as
The following process is performed to form a forged material, and after the forging process is applied to the forged material as a third step, by performing a machining process as a fourth step, an anchor body having an expanded portion that is expanded by driving a core rod is formed. The present invention is characterized in that the configuration of the method of manufacturing a metal rod driving type metal expansion anchor is a means for solving the above-mentioned conventional problems. Next, the reason for limiting the component composition (% by weight) of the ferritic stainless steel used in the method of manufacturing a core rod driving type metal expansion anchor according to the present invention will be described. C: 0.020% or less C forms carbide by combining with Nb added or carbide forming elements such as Ti and Zr added as necessary or as needed, and the precipitated carbide serves as a starting point of rust to improve corrosion resistance. In some cases, the effect of Nb addition is reduced and the addition of Nb forms carbide NbC, thereby reducing the effect of Nb addition and deteriorating the toughness. Si: 0.30% or less Si has a deoxidizing action during steel melting,
Although it has the effect of increasing the oxidation resistance, a large amount of it deteriorates cold workability and toughness. Mn: 0.50% or less Mn has a deoxidizing and desulfurizing action when smelting steel, and also has an action to improve mechanical properties.However, if contained in a large amount, cold workability is impaired. 0.50% or less. P: 0.020% or less P must be reduced as much as possible because it reduces the cold workability of ferritic stainless steel.
It was as follows. S: 0.010% or less S must be reduced as much as possible because it reduces the cold workability of ferritic stainless steel.
It was as follows. Cr: 16.0 to 25.0% Cr is a basic element of ferritic stainless steel, and is set to 16.0% or more in order to obtain sufficient corrosion resistance. However, if contained in a large amount, the cold workability is reduced and the toughness is deteriorated. Cu: 1.0% or less Ni: 1.0% or less Mo: 3.0% or less Cu, Ni, Mo may be positively added to further improve the corrosion resistance of ferritic stainless steel,
The addition of a large amount of these has an adverse effect on cold workability and toughness, and in particular, the effect of Mo is remarkable. Therefore, even if Cu is contained, 1.0% or less, even if Ni is contained, 1.0% or less.
Hereinafter, even if Mo is contained, it must be 3.0% or less. O: 0.010% or less O is combined with various elements to form an oxide, and adversely affects cold workability and corrosion resistance. N: 0.025% or less N forms a nitride by combining with added Nb or a nitride forming element such as Ti or Zr added in an impurity or as needed, and the formed nitride becomes a starting point of rust. In some cases, the corrosion resistance is reduced, and the addition of Nb forms nitride NbN, thereby reducing the effect of Nb addition and deteriorating the toughness. C + N: 0.040% or less C and N combine with Nb added as described above to form carbonitrides, thereby reducing the effect of Nb addition and deteriorating toughness. To
0.040% or less. Nb / (C + N): 10 to 20 Nb is an element effective to improve the toughness of ferritic stainless steel, improve the cold workability, and further increase the maximum pull-out strength of the anchor. In order to obtain such an effect, Nb ≧ (C + N) × 10. However, if contained in a large amount, the toughness is rather deteriorated, so that Nb ≦ (C + N) × 20. Ti: 0.03-0.50%, Zr: 0.03-0.50% Ti and Zr further improve the toughness of ferritic stainless steel to improve cold workability, and further increase the maximum pull-out strength of the anchor. It is effective, so Ti is 0.03% or more and Zr is 0.03% if necessary
One or two of the above may be contained. However, even if it is contained in a large amount, the effect is saturated and the toughness is rather deteriorated. Therefore, even if it is contained, it is necessary to make Ti 0.50% or less and Zr 0.50% or less. When a rolled material is obtained from such a ferritic stainless steel material, hot rolling is performed as a first step on a steel material having the above-described composition. In this hot rolling, it is particularly desirable to perform hot working with a working ratio of 80% or more at a temperature of 1000 ° C. or less. This is because hot rolling, that is, wire rolling at a temperature of 1000 ° C. or less at a working rate (reduction rate) of 80% or more, makes it possible to further improve toughness. After the hot rolling, a secondary working is performed as a second step to obtain a forged material having a predetermined diameter. FIG. 1 exemplifies the results of examining the effects on the toughness (impact value) by the wire rolling heating temperature, the working temperature and the working rate (reduction rate) during wire rolling. I
Is a wire rod heating temperature of 1200 ° C and a processing rate (area reduction rate) at a temperature of 1000 ° C or less is 0%. Wire II is a wire rod heating temperature of 1050 ° C and a processing rate at a temperature of 1000 ° C or less. (Area reduction rate) is 80%, and wire III has a wire rolling heating temperature of 1000 ° C.
And processing rate (area reduction rate) at a temperature of 1000 ° C or less is 95%
The results are shown in the case where hot rolling was performed, followed by annealing at 850 ° C., and then a Charpy impact test was performed. As shown in Fig. 1, by performing hot working at a temperature of 1000 ° C or less and a working rate (area reduction rate) of 80% or more during wire rod rolling, the transition temperature of the Charpy impact value is lowered and the toughness is remarkably increased. It is clear that it will improve. After performing the hot rolling in the first step, a forging material is obtained by performing secondary processing as a second step.
In this secondary processing, it is also desirable, if necessary, to select from the following exemplary embodiments and appropriately adopt it. In one embodiment, in the secondary processing as the second step, after the primary processing rate of 25% or more is added, 700 to 8
A heat treatment is performed at a temperature of 50 ° C. that does not cause recrystallization, a coating treatment is applied, and a finish drawing with a surface reduction rate of 10% or less is performed to obtain a forging material. In this case, the primary processing rate is set to 25% or more to achieve the necessary crystal grain refinement, and the heat treatment is performed at a temperature of 700 to 850 ° C. that does not recrystallize, so that the strength is suitable for the next step of forging. Will be able to Then, when performing a coating treatment after performing such a heat treatment, a oxalate coating or a resin coating is formed to prevent galling in the next step of forging,
It is possible to improve the life of a mold during forging. Further, after applying this coating treatment, it is desirable to perform finish wire drawing with a reduction in area of 10% or less so that the adhesion of the coating on the surface of the forged material is further improved. If the area reduction rate at the time of wire drawing becomes larger than 10%, the strength increases and the forging property in the next step decreases, so it is desirable that the area reduction rate be 10% or less. On the other hand, in another embodiment of the secondary processing as the second step, after the processing of the primary processing rate of 30% or more is added, 950 is applied.
Heat treatment is performed at a temperature of recrystallization of ~ 1100 ° C, and after coating treatment, finish drawing with a surface reduction rate of 10% or less is performed to obtain a forging material. In this case, it is possible to recrystallize in the subsequent heat treatment by making the primary processing rate 30% or more of the strong processing, and the toughness is improved by performing the heat treatment at a temperature of 950 to 1100 ° C for recrystallization. It will be possible to do it. At this time, if the heat treatment temperature is too high, the crystal grains are coarsened, so that the temperature is desirably 1100 ° C. or less. Then, when performing the coating treatment after performing such a heat treatment, the oxalate coating or the resin coating is formed in the same manner as in the above-described embodiment. In this case, the die life can be improved, and after this coating treatment is performed, the area reduction rate is 10% or less as in the above embodiment, and the finished wire is drawn to obtain a forged material. . After the forged material is obtained in the second step, the forged material is subjected to forging (forward extrusion, backward extrusion, etc.) as the third step to obtain a molded anchor body. In this case, it is possible to further improve the toughness of the anchor body molded product by such a forging process.
For example, in the case of cold forging with a reduction ratio of 50% for a forging material having the characteristics shown in line III of FIG. As shown by the broken line, the toughness is further improved. Next, as a fourth step, machining (pleating, knurling, tapping, milling, etc.) is performed on the molded anchor body thus obtained, thereby expanding the core rod by driving. To obtain an unsurfaced anchor body having a portion. Further, if necessary, a surface treatment for improving rust resistance is performed on the unsurfaced anchor body as a fifth step.
In this case, as a surface treatment for improving rust resistance, for example,
Using an aqueous solution containing 10 to 50% nitric acid (HNO ₃ ) and 0.2 to 5% sodium bichromate (Na ₂ Cr ₂ O ₇ ) at a temperature of 25 to 90 ° C.
A passivation process with a time of 5 to 60 minutes can be performed. The non-surface-treated or surface-treated anchor body thus obtained is used in combination with a core rod, and by driving the core rod into the anchor body, the expanded portion cuts into the wall surface of a hole previously formed in concrete. Fixed by that. (Examples) Various stainless steel materials having the chemical components shown in Table 1
The steel wire was heated to ℃ and forged to a diameter of 60 mm, and further rolled to obtain a steel wire, which was annealed at 850 ° C. Next, for each of the above-mentioned steel wire rods, the heating rate (area reduction rate) at a temperature of 1000 ° C. or less was set to the value shown in Table 1 with the wire rolling heating temperature also being the value shown in Table 1. When hot working is performed under the hot rolling conditions, and then secondary working is performed on each rolled wire, the primary wire drawing rate, heat treatment temperature, coating treatment, and area reduction rate also shown in Table 1 are applied.
A secondary wire with a finish wire drawing of 10% or less was added to obtain a drawn wire having a diameter of 4.88 mm. Next, after the drawn material 1 shown in FIG. 2 is obtained by cutting the drawn wire except Nos. 1 and 2 in Table 1, the forged body 2 in the first step shown in FIG. By performing several steps of forging, a molded anchor body 3 shown in FIG. 3 (b) was obtained. At this time, the anchor body molded product 3
Reduction rate (d ² / D ² ) expressed by outer diameter D and inner diameter d
X100 (%) was found to be even better to be about 15 to 45%. It was also found that the ratio of the long diameter (L / d) represented by the length L and the inner diameter d was more preferably about 6 to 12. The forging property of each material in this forging process was also the result shown in Table 1. Next, FIG. 4 (a) which is the same as that shown in FIG. 3 (b)
4 (b) with respect to the molded anchor body 3 shown in FIG.
Rolling process to form the asayama processed part 4a shown in FIG.
An unsurface-treated anchor main body 5 was obtained by performing a milling process in which only two axial grooves 4b shown in FIG. 4 (c) were formed in the circumferential direction at 180 ° intervals by a milling machine. Next, for the unsurfaced anchor main body 5 shown in FIG. 4 (c), degreasing using an alkaline degreasing bath → chemical polishing using a chemical abrasive → water washing → neutralization → using an alkaline abrasive Barrel polishing (which can also be said to be a physical polishing process and may be only one of the above-mentioned chemical polishing processes) → water washing → passivation process (350 cc / nitric acid, 3 g of sodium bichromate / temperature 50 ~ 60 ° C, time 60 minutes) → Washing →
By performing a passivation treatment through drying (however, the passivation treatment column in Table 1 is applied to those indicated as “Yes”), a core having an internal tapered portion 6a as shown in FIG. 5 is obtained. A core rod driving type cone driving metal expansion anchor 8 was obtained by combining the surface treated anchor main body 7 having the expansion portion 7a expanded by the rod 6 and the core rod 6. Also,
In Conventional Examples 1 and 2, a metal expansion anchor (8) was obtained by cutting. Metal expansion anchor body 7 obtained here
Has an outer diameter of 5.0 mm, a head diameter of 9.0 mm, and a total length under the neck of 30 mm. Next, in order to evaluate the rust resistance of the surface-treated anchor body 7, a salt spray test (35 ° C, 5 ° C) in accordance with JIS Z2371 was conducted.
% NaCl, 96 hours). The results are also shown in Table 1. In Table 1, ◎ indicates that the rust resistance was fairly good, ○ indicates that the rust resistance was good, and △ indicates that the rust resistance was too low. It was not good, and x mark shows that rust resistance was bad. Core rod driving type metal expansion anchor 8 shown in FIG.
In this example, the diameter is
The head of the core rod 6 was inserted into the drilled hole with a drilled hole of 5.4 mm formed by a jig (not shown).
6b is driven toward the top of the anchor body 7, so that the tapered portion 6a of the core bar 6 expands the expanded portion 7a of the anchor body 7 and bites into the concrete drill hole wall surface to be fixed. Then, when the maximum pulling strength after being poured into concrete having a concrete strength of 200 kgf / cm ² was examined, the results are also shown in Table 1. As shown in Table 1, a conventional example manufactured by cutting from austenitic stainless steel (SUS304)
When the No. 1 anchor body is used, the maximum pull-out strength is good, but the productivity is poor due to the cutting process,
In addition, the material yield is low, and the material cost is high. In addition, when the anchor body of the conventional example No. 2 made of austenitic stainless steel (SUS303) by cutting is used, the rust resistance is high. The steel material of Comparative Example No. 3 made of austenitic stainless steel (SUSXM7) was also poor in formability, and the steel material of ferritic stainless steel (SUS430) was manufactured by forging. When the anchor body of No. 4 was used, the rust resistance was not good, and when the anchor body of Comparative Example No. 5 which did not contain Cu and Ni in the ferritic stainless steel was used, the rust resistance was not so good. It was not good. In contrast, an anchor body manufactured by applying forging and machining to a forging material made of ferritic stainless steel of a predetermined component has good forging properties during forging and has a high rust resistance. It is also recognized that the maximum pulling strength is large and the value of the maximum pulling strength is large. When hot working at a temperature of 1000 ° C or less and a working ratio of 80% or more is applied during the first step of hot rolling. It is possible to further increase the maximum pull-out strength by satisfying specific conditions even in the secondary processing in the second step. It has been found that the rust resistance can be further improved by performing a passivation treatment for improving rust resistance as a fifth step after the machining in the fourth step. 6 and 7 show another embodiment of the present invention, in which a predetermined hot-rolling heating temperature, a working ratio at a temperature of 1000 ° C. or less, and a primary drawing working ratio in secondary working. As shown in FIG. 6, a shallow mountain processed portion 14a is formed by a rolling machine on a molded product of the anchor body obtained by performing a heat treatment temperature, a coating process, and a forging process, and a threaded portion 14c. Tapping to form a hole with a tapping machine, and axial grooves
By performing a milling process of forming four pieces of 14b at 90 ° intervals in the circumferential direction by a milling machine, an unsurfaced anchor body 15 is obtained. By performing the passivation process, a core obtained by combining the core bar 16 with the surface-treated anchor body 17 having the extended portion 17a expanded by the core bar 16 having the tapered portion 16a as shown in FIG. This shows a case in which a rod driving type metal expansion anchor 18 is obtained. The anchor body 17 having the shape shown in FIG. 7 also has good forging property during forging, and has excellent rust resistance. The maximum pull-out strength in a state where the metal expansion anchor 18 combining the anchor main body 17 and the core rod 16 was driven into concrete also showed a large value.

EFFECT OF THE INVENTION The manufacturing method of the core rod driving type metal expansion anchor according to the present invention is as follows: C: 0.020% or less; Si: 0.30% or less;
n: 0.50% or less, P: 0.020% or less, S: 0.010% or less, Cr: 16.
0 to 25.0%, Cu: 1.0% or less, Ni: 1.0% or less, Mo: 3.0% or less, O: 0.010% or less, N: 0.025% or less, C + N: 0.040% or less, Nb / (C + N): 10 to 20 , If necessary Ti: 0.03-0.5
0% and Zr: one or two of 0.03 to 0.50%, ferritic stainless steel material containing the balance of Fe and impurities is subjected to hot rolling as a first step and then to secondary processing as a second step To obtain an anchor body having an expanded portion that is expanded by driving a core rod by applying a forging process to the forged material as a third step and then performing a machining process for a fourth step. Therefore, by forming by forging, the productivity is remarkably improved and the material yield is also remarkably improved, so that the cost can be reduced from the manufacturing side, and rust is generated due to its excellent rust resistance. And extremely high maximum pull-out strength after retrofitting to concrete walls, etc., and use conventional austenitic stainless steel Leads to significantly better effect that it is possible to achieve reduction in cost from the material surface as compared with the case that.

[Brief description of the drawings]

FIG. 1 is a graph illustrating the results of examining the effect on the toughness (impact value) of the wire rod heating temperature, the processing temperature and the processing rate (reduction rate) during wire rod rolling, and FIG. 2 is an example of the present invention. 1
3 (a) and 3 (b) are cross-sectional views showing the shape of the forging body at the beginning and at the end of forging, and FIGS. 4 (a) and 4 (b). (C) is a left-half cutaway front view of the anchor body at the time of each finishing process, FIG. 5 is a left-half cutaway front view of a core rod driving type metal expansion anchor, and FIG. 6 is a left side of the anchor body according to another embodiment. FIG. 7 is a front view of the left half of a metal rod driving type metal expansion anchor using the anchor body of FIG. 6, and FIG. 5,15… untreated surface anchor body, 6,16… core rod, 7,17… surface treated anchor body, 7a, 17a… expansion part by driving core rod, 8,18… core rod Driving metal expansion anchor.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-90514 (JP, A) JP-A-3-90242 (JP, A) JP-A-1-140205 (JP, A) JP-A-54-54 158364 (JP, A) Hikaru Hei 1-122104 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) C21D 8/06 B21K 1/74

Claims (6)

(57) [Claims] (1) By weight%, C: 0.020% or less, Si: 0.30% or less, Mn: 0.50% or less, P: 0.020% or less, S: 0.010% or less, C:
r: 16.0-25.0%, Cu: 1.0% or less, Ni: 1.0% or less, Mo: 3.0
% Or less, O: 0.010% or less, N: 0.025% or less, C + N: 0.040
% Or less, Nb / (C + N): 10-20, a ferritic stainless steel material composed of the balance Fe and impurities, subjected to hot rolling as a first step, and then subjected to secondary processing as a second step to form a forged material. And a third step of subjecting the forged material to a forging process, followed by a fourth step of machining to obtain an anchor body having an expanded portion that is expanded by driving a core rod. A method for manufacturing a rod driving type metal expansion anchor. 2. In% by weight, C: 0.020% or less, Si: 0.30% or less, Mn: 0.50% or less, P: 0.020% or less, S: 0.010% or less, C:
r: 16.0-25.0%, Cu: 1.0% or less, Ni: 1.0% or less, Mo: 3.0
% Or less, O: 0.010% or less, N: 0.025% or less, C + N: 0.040
% Or less, Nb / (C + N): 10 to 20, Ti: 0.03 to 0.50%, and Zr: one or two of 0.03 to 0.50%, with the balance being Fe and stainless steel material composed of impurities,
After hot rolling as a first step, secondary processing is performed as a second step to form a forged material, and as a third step, forging is performed on the forged material, and then, machining is performed as a fourth step. A method of manufacturing a metal rod-insertable metal expanded anchor, comprising obtaining an anchor body having an expanded portion expanded by driving of a core rod. 3. The core rod driving method according to claim 1, wherein in the hot rolling in the first step, hot working is performed at a temperature of 1000 ° C. or less and a working rate of 80% or more. Method of manufacturing a metal expansion anchor. 4. The primary processing rate in the secondary processing of the second step.
After 25% or more processing, heat treatment at a temperature that does not cause recrystallization at 700 to 850 ° C
The method for producing a metal rod-insertable metal expansion anchor according to any one of claims (1), (2) and (3), wherein the drawn wire is subjected to finish drawing of 10% or less to obtain a forged material. 5. The primary processing rate in the secondary processing of the second step.
After 30% or more processing, heat treatment at 950-1100 ° C for recrystallization temperature
The method for producing a metal rod-insertable metal expansion anchor according to any one of claims (1), (2) and (3), wherein the drawn wire is subjected to finish drawing of 10% or less to obtain a forged material. 6. The method according to claim 1, wherein after the machining in the fourth step, the surface of the anchor body is subjected to a surface treatment for improving rust resistance as a fifth step. Item 3) The method for producing a metal rod-insertable metal expansion anchor according to any one of Items (4) and (5).