WO2012084386A1 - Screw anchor - Google Patents
Screw anchor Download PDFInfo
- Publication number
- WO2012084386A1 WO2012084386A1 PCT/EP2011/070754 EP2011070754W WO2012084386A1 WO 2012084386 A1 WO2012084386 A1 WO 2012084386A1 EP 2011070754 W EP2011070754 W EP 2011070754W WO 2012084386 A1 WO2012084386 A1 WO 2012084386A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- screw anchor
- hardness
- blank
- shaft
- carbonitriding
- Prior art date
Links
- 238000005256 carbonitriding Methods 0.000 claims abstract description 10
- 239000000463 material Substances 0.000 claims abstract description 7
- 238000004519 manufacturing process Methods 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 18
- 229910052799 carbon Inorganic materials 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- 238000000137 annealing Methods 0.000 claims description 3
- 238000010791 quenching Methods 0.000 abstract description 2
- 230000000171 quenching effect Effects 0.000 abstract description 2
- 235000019589 hardness Nutrition 0.000 description 27
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 239000001257 hydrogen Substances 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 3
- 238000004873 anchoring Methods 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/28—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases more than one element being applied in one step
- C23C8/30—Carbo-nitriding
- C23C8/32—Carbo-nitriding of ferrous surfaces
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/02—Pretreatment of the material to be coated
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/34—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases more than one element being applied in more than one step
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/80—After-treatment
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B25/00—Screws that cut thread in the body into which they are screwed, e.g. wood screws
- F16B25/001—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by the material of the body into which the screw is screwed
- F16B25/0026—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by the material of the body into which the screw is screwed the material being a hard non-organic material, e.g. stone, concrete or drywall
Definitions
- the invention relates to a method for producing a screw anchor and a screw anchor, in particular for screwing in concrete.
- Screw anchors are known from the prior art, which have a threaded shaft.
- the thread is intended to cut into the wall of a hole in concrete or a similar material, so that an undercut is formed, can be derived directly from the loads (ie without interposed dowels or other components) in the ground. So that the thread of the screw anchor can reliably cut into the concrete, the hardness on the surface of the screw anchor must be on the order of 600 HV or above.
- a screw anchor made of a low carbon steel is carbonitrided and quenched. In this way, the necessary hardness is achieved. Subsequently, the screw anchor is stress annealed to reduce or eliminate the stresses generated during quenching.
- the disadvantage of this method is that the boron, which is contained in the steel, causes a high hardness in the core. In particular, a hardness above 330 HV results in the core of the shaft. This hardness leads to a high risk of hydrogen embrittlement.
- the screw anchor which consists of a low-carbon steel, is carbonitrided and quenched.
- the blanks are annealed at a comparatively high temperature to lower the hardness of the screw throughout the shank to a uniform value.
- the tip of the anchor is induction hardened and quenched to achieve the necessary hardness for cutting the thread into the concrete.
- This method has the disadvantage that it is due to the annealing relatively long and the effort is relatively high overall, since the induction hardening an additional process step is necessary.
- such a screw anchor is less susceptible to hydrogen embrittlement.
- the object of the invention is to provide a method for the production of screw anchors for concrete, which is characterized by low process costs and can be produced with the screw anchor, which meet all international approval criteria, have a low risk of hydrogen embrittlement, cut well into concrete and have a high toughness.
- a method for producing a screw anchor in which initially a blank of Cq22Mn4 is provided.
- the blank is carbonitrided and then quenched.
- the blank is cold-formed and provided with a rolled thread before it is carbonitrided. In other words, all mechanical processing steps are performed before the blank is cured.
- the carbonitriding is carried out at a temperature in the range of 800 ° C to 950 ° C, especially in the range of 860 ° C to 900 ° C.
- This temperature range has been found to be beneficial for carbon diffusion;
- complete austenitization of the material takes place in this temperature range without grain growth occurring.
- flash annealing is performed, preferably performed at a temperature in the range of 200 ° C to 240 ° C.
- the object of the invention is also achieved by a screw anchor, which is characterized in that is used as the material Cq22Mn4 and in which the hardness of the shaft, measured 0, 1 mm below the surface, above 600 HV.
- This screw anchor is characterized by a high hardness on the surface, so that the thread of the screw anchor reliably cuts into concrete or similar materials.
- the screw anchor is not susceptible to hydrogen embrittlement and has high toughness inside the shaft.
- the hardness of the shaft measured 0, 1 mm below the surface, is above 700 HV. Such hardness increases the cutting performance of the thread in concrete.
- a hardness in the range of 170 to 250 HV is present in the core. This ensures the desired toughness of the screw anchor.
- the hardness of the shaft drops rapidly from the outside to the inside below a value of 400 HV, in particular already lies below the surface at a depth of 0.5 mm below this value. This ensures that the shank of the screw anchor has the desired high toughness over most of its cross section.
- FIG. 1 shows schematically a screw anchor
- a screw anchor 1 is shown schematically, in particular a concrete screw containing a shaft 2 with a screw head 3, wherein the screw head is designed here as an external hexagon.
- the shank 2 has an anchoring area 5 which extends from a free front end 4 opposite the screw head 3 over approximately one third to approximately three quarters of the total length of the shank 2.
- the anchoring region 5 is characterized by threads 6 which extend helically along the longitudinal extent of the anchoring region 5.
- the material used for the screw anchor is a cold heading steel known as Cq22Mn4. This steel contains the following alloy components:
- the screw anchor shown in Figure 1 is made in the following manner: In a first step, a blank is provided by cold-forming, which is provided with a rolled thread. This blank is cleaned, in particular dephosphated. Subsequently, the blank is carbonitrided in an oven at a temperature of about 880 ° C, wherein in the atmosphere, a carbon content of 1% is present. Further, nitrogen is continuously supplied with a reaction gas. The entire process takes place under exclusion of air.
- the screw anchors are quenched and annealed at a temperature of about 220 ° C, i. low-stress annealed.
- This method results in a very high surface hardness and a fairly low hardness in the core of the shaft.
- hardnesses of the order of magnitude up to 750 HV are achieved on the surface, while a hardness of preferably below 250 HV is present in the interior of the core.
- An essential feature of the screw anchor obtained in this way is that the hardness drops very rapidly from the high values at the surface to much lower values. In particular, the hardness drops to a value of less than 400 HV1 at a depth of 0.5 mm below the surface.
- One such screw anchor combines a very high hardness of the thread with a high toughness inside the shaft.
- FIG. 2 shows the course of the hardness as a function of the distance from the surface. It can be seen that the hardness drops very quickly and is already at a depth of 0.5 mm below the surface in the order of 400 HV1.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- General Engineering & Computer Science (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
The invention relates to a method for producing a screw anchor (1) by means of the following steps: providing a blank made of Cq22Mn4, carbonitriding the blank, and quenching the blank. The invention further relates to a screw anchor, characterized in that Cq22Mn4 is used as the material and that the hardness of the shaft, measured 0.1 mm below the surface, is greater than 600 HV.
Description
[Schraubanker] [Screw]
Die Erfindung betrifft ein Verfahren zur Herstellung eines Schraubankers sowie einen Schraubanker, insbesondere zum Einschrauben in Beton. The invention relates to a method for producing a screw anchor and a screw anchor, in particular for screwing in concrete.
Aus dem Stand der Technik sind Schraubanker bekannt, die einen mit einem Gewinde versehenen Schaft aufweisen. Das Gewinde ist dafür vorgesehen, sich in die Wandung einer Bohrung in Beton oder einen vergleichbaren Werkstoff einschneiden, so dass ein Hinterschnitt gebildet ist, über den Lasten unmittelbar (also ohne zwischengeschalteten Dübel oder andere Bauteile) in den Untergrund abgeleitet werden können. Damit das Gewinde des Schraubankers sich zuverlässig in den Beton einschneiden kann, muss die Härte an der Oberfläche des Schraubankers in der Größenordnung von 600 HV oder darüber liegen. Screw anchors are known from the prior art, which have a threaded shaft. The thread is intended to cut into the wall of a hole in concrete or a similar material, so that an undercut is formed, can be derived directly from the loads (ie without interposed dowels or other components) in the ground. So that the thread of the screw anchor can reliably cut into the concrete, the hardness on the surface of the screw anchor must be on the order of 600 HV or above.
Im Stand der Technik sind insbesondere zwei Verfahren bekannt, um die gewünschte Härte zu erzielen. Bei einem Verfahren wird ein Schraubanker, der aus einem Stahl mit geringem Kohlenstoffgehalt besteht, carbonitriert und abgeschreckt. Auf diese Weise wird die nötige Härte erzielt. Anschließend wird der Schraubanker entspannungsgeglüht, um die beim Abschrecken entstehenden Spannungen zu verringern oder zu beseitigen. Der Nachteil dieses Verfahrens besteht darin, dass das Bor, das im Stahl enthalten ist, eine hohe Härte im Kern hervorruft. Insbesondere ergibt sich im Kern des Schafts eine Härte oberhalb von 330 HV. Diese Härte führt zu einem hohen Risiko von Wasserstoffversprödung. Bei einem anderen Verfahren wird der Schraubanker, der aus einem Stahl mit niedrigem Kohlstoffgehalt besteht, carbonitriert und abgeschreckt. Dann werden die Rohlinge bei einer vergleichsweise hohen Temperatur geglüht, um die Härte der Schraube im gesamten Schaft auf einen einheitlichen Wert abzusenken. Anschließend wird die Spitze des Ankers induktionsgehärtet und abgeschreckt, um dort die nötige Härte zum Einschneiden des Gewindes in den Beton zu erzielen. Dieses Verfahren hat den Nachteil, dass es aufgrund
des Anlassens relativ lang dauert und der Aufwand insgesamt relativ hoch ist, da mit dem Induktionshärten ein zusätzlicher Verfahrensschritt nötig ist. Allerdings ist ein solcher Schraubanker wenig anfällig für Wasserstoffversprödung. In the prior art, in particular, two methods are known in order to achieve the desired hardness. In one method, a screw anchor made of a low carbon steel is carbonitrided and quenched. In this way, the necessary hardness is achieved. Subsequently, the screw anchor is stress annealed to reduce or eliminate the stresses generated during quenching. The disadvantage of this method is that the boron, which is contained in the steel, causes a high hardness in the core. In particular, a hardness above 330 HV results in the core of the shaft. This hardness leads to a high risk of hydrogen embrittlement. In another method, the screw anchor, which consists of a low-carbon steel, is carbonitrided and quenched. Then, the blanks are annealed at a comparatively high temperature to lower the hardness of the screw throughout the shank to a uniform value. Subsequently, the tip of the anchor is induction hardened and quenched to achieve the necessary hardness for cutting the thread into the concrete. This method has the disadvantage that it is due to the annealing relatively long and the effort is relatively high overall, since the induction hardening an additional process step is necessary. However, such a screw anchor is less susceptible to hydrogen embrittlement.
Die Aufgabe der Erfindung besteht darin, ein Verfahren zur Herstellung von Schraubankern für Beton zu schaffen, das sich durch geringe Verfahrenskosten auszeichnet und mit dem Schraubanker hergestellt werden können, welche alle internationalen Zulassungskriterien erfüllen, ein geringes Risiko von Wasserstoffversprödung aufweisen, sich gut in Beton einschneiden sowie eine hohe Zähigkeit aufweisen. The object of the invention is to provide a method for the production of screw anchors for concrete, which is characterized by low process costs and can be produced with the screw anchor, which meet all international approval criteria, have a low risk of hydrogen embrittlement, cut well into concrete and have a high toughness.
Zur Lösung dieser Aufgabe ist erfindungsgemäß ein Verfahren zur Herstellung eines Schraubankers vorgesehen, bei dem zunächst ein Rohling aus Cq22Mn4 bereitgestellt wird. Der Rohling wird carbonitriert und anschließend abgeschreckt. Durch die geeignete Wahl des Ausgangsmaterials kann mit wenigen Verfahrensschritten ein Schraubanker hergestellt werden, der an der Oberfläche eine sehr hohe Härte aufweist, so dass sich sein Gewinde gut in Beton einschneidet, aber gleichzeitig im Kern eine hohe Zähigkeit hat. Insgesamt ergibt sich dadurch auch ein geringes Risiko von Wasserstoffversprödung. To achieve this object, a method for producing a screw anchor is provided according to the invention, in which initially a blank of Cq22Mn4 is provided. The blank is carbonitrided and then quenched. By a suitable choice of the starting material, a screw anchor can be produced with a few process steps, which has a very high hardness on the surface, so that its thread cuts well into concrete, but at the same time has a high toughness in the core. Overall, this also results in a low risk of hydrogen embrittlement.
Vorzugsweise ist vorgesehen, dass der Rohling kaltgeformt und mit einem gewalzten Gewinde versehen wird, bevor er carbonitriert wird. Anders ausgedrückt werden alle mechanischen Bearbeitungsschritte durchgeführt, bevor der Rohling gehärtet wird. It is preferably provided that the blank is cold-formed and provided with a rolled thread before it is carbonitrided. In other words, all mechanical processing steps are performed before the blank is cured.
Vorzugsweise wird das Carbonitrieren bei einer Temperatur im Bereich von 800 °C bis 950 °C durchgeführt, insbesondere im Bereich von 860 °C bis 900 °C. Dieser Temperaturbereich hat sich als vorteilhaft für die Kohlenstoffdiffusion herausgestellt; außerdem findet in diesem Temperaturbereich eine vollständige Austenitisierung des Materials statt, ohne dass ein Kornwachstum eintritt. Preferably, the carbonitriding is carried out at a temperature in the range of 800 ° C to 950 ° C, especially in the range of 860 ° C to 900 ° C. This temperature range has been found to be beneficial for carbon diffusion; In addition, complete austenitization of the material takes place in this temperature range without grain growth occurring.
Dabei hat es sich als vorteilhaft herausgestellt, das Carbonitrieren in einer Atmosphäre mit 0,8 % bis 1 % Kohlenstoff-Anteil durchzuführen. Auf diese Weise ergibt sich der gewünschte Gefügeaufbau. It has been found to be advantageous to carry out the carbonitriding in an atmosphere with 0.8% to 1% carbon content. In this way, the desired structure structure results.
Vorteilhafterweise wird nach dem Carbonitrieren ein Entspannungsglühen durchgeführt, vorzugsweise bei einer Temperatur im Bereich von 200 °C bis 240 °C durchgeführt. Dies hat sich als guter Kompromiss herausgestellt zwischen den widersprüchlichen Anforderungen, einerseits die Prozesszeiten möglichst niedrig zu halten und andererseits den gewünschten Härteverlauf mit hoher Härte an der Oberfläche und großer Zähigkeit im Inneren des Schafts zu erzielen.
Die Aufgabe der Erfindung wird auch gelöst durch einen Schraubanker, der dadurch gekennzeichnet ist, dass als Material Cq22Mn4 verwendet wird und bei dem die Härte des Schafts, gemessen 0, 1 mm unterhalb der Oberfläche, oberhalb von 600 HV liegt. Dieser Schraubanker zeichnet sich durch eine hohe Härte an der Oberfläche aus, so dass sich das Gewinde des Schraubankers zuverlässig in Beton oder ähnliche Materialien einschneidet. Weiterhin ist der Schraubanker nicht anfällig gegen Wasserstoffversprödung, und er besitzt im Inneren des Schafts eine hohe Zähigkeit. Advantageously, after carbonitriding, flash annealing is performed, preferably performed at a temperature in the range of 200 ° C to 240 ° C. This has proven to be a good compromise between the contradictory requirements, on the one hand to keep the process times as low as possible and on the other hand to achieve the desired hardness profile with high hardness at the surface and high toughness inside the shaft. The object of the invention is also achieved by a screw anchor, which is characterized in that is used as the material Cq22Mn4 and in which the hardness of the shaft, measured 0, 1 mm below the surface, above 600 HV. This screw anchor is characterized by a high hardness on the surface, so that the thread of the screw anchor reliably cuts into concrete or similar materials. Furthermore, the screw anchor is not susceptible to hydrogen embrittlement and has high toughness inside the shaft.
Vorzugsweise ist vorgesehen, dass die Härte des Schafts, gemessen 0, 1 mm unterhalb der Oberfläche, oberhalb von 700 HV liegt. Eine solche Härte erhöht die Schneidleistung des Gewindes in Beton. It is preferably provided that the hardness of the shaft, measured 0, 1 mm below the surface, is above 700 HV. Such hardness increases the cutting performance of the thread in concrete.
Vorzugsweise ist vorgesehen, dass im Kern eine Härte im Bereich von 170 bis 250 HV vorliegt. Dies gewährleistet die gewünschte Zähigkeit des Schraubankers. It is preferably provided that a hardness in the range of 170 to 250 HV is present in the core. This ensures the desired toughness of the screw anchor.
Vorzugsweise ist vorgesehen, dass die Härte des Schafts von außen nach innen sehr schnell unter einen Wert von 400 HV abfällt, insbesondere bereits in einer Tiefe von 0,5 mm unterhalb der Oberfläche unterhalb dieses Werts liegt. Dies gewährleistet, dass der Schaft des Schraubankers über den Großteil seines Querschnitts die gewünschte hohe Zähigkeit hat. Preferably, it is provided that the hardness of the shaft drops rapidly from the outside to the inside below a value of 400 HV, in particular already lies below the surface at a depth of 0.5 mm below this value. This ensures that the shank of the screw anchor has the desired high toughness over most of its cross section.
Die Erfindung wird nachfolgend anhand einer Ausführungsform beschrieben, die in den beigefügten Zeichnungen dargestellt ist. In diesen zeigen: - Figur 1 schematisch einen Schraubanker; The invention will be described below with reference to an embodiment shown in the accompanying drawings. In the drawings: FIG. 1 shows schematically a screw anchor;
- Figur 2 den Verlauf der Härte in Abhängigkeit vom Abstand von der Ober fläche. - Figure 2 shows the course of hardness as a function of the distance from the upper surface.
In Figur 1 ist schematisch ein Schraubanker 1 gezeigt, insbesondere eine Betonschraube, die einen Schaft 2 mit einem Schraubenkopf 3 enthält, wobei der Schraubenkopf hier als Außensechskant ausgeführt ist. Der Schaft 2 weist einen Verankerungsbereich 5 auf, der sich von einem dem Schraubenkopf 3 gegenüberliegenden, freien Vorderende 4 über etwa ein Drittel bis etwa Dreiviertel der Gesamtlänge des Schafts 2 erstreckt. Der Verankerungsbereich 5 zeichnet sich durch Gewindegänge 6 aus, die sich schraubenförmig entlang der Längserstreckung des Verankerungsbereichs 5 erstrecken.
Als Material für den Schraubanker wird ein Kaltstauchstahl verwendet, der unter der Bezeichnung Cq22Mn4 bekannt ist. Dieser Stahl enthält die folgenden Legierungsbestandteile: In Figure 1, a screw anchor 1 is shown schematically, in particular a concrete screw containing a shaft 2 with a screw head 3, wherein the screw head is designed here as an external hexagon. The shank 2 has an anchoring area 5 which extends from a free front end 4 opposite the screw head 3 over approximately one third to approximately three quarters of the total length of the shank 2. The anchoring region 5 is characterized by threads 6 which extend helically along the longitudinal extent of the anchoring region 5. The material used for the screw anchor is a cold heading steel known as Cq22Mn4. This steel contains the following alloy components:
C: 0,20 bis 0,23 % C: 0.20 to 0.23%
Mn:0,90 bis 1 ,00 % Mn: 0.90 to 1, 00%
AI: 0,02 bis 0,05 % AI: 0.02 to 0.05%
Die genannten Bereiche beinhalten jeweils die genannten Werte im Sinne von größer gleich bzw. kleiner gleich. The ranges mentioned each contain the stated values in the sense of greater than or equal to the same.
Ferner sind die folgenden Legierungsbestandteile vorhanden: Si: maximal 0,15 % In addition, the following alloying constituents are present: Si: maximum 0.15%
P: maximal 0,02 % P: maximum 0.02%
S: maximal 0,02 % S: maximum 0.02%
Ni: maximal 0, 1 % Ni: maximum 0, 1%
Cr: maximal 0, 1 % Cr: maximum 0, 1%
Cu: maximal 0, 1 % Cu: maximum 0, 1%
Mo: maximal 0,02 % Mo: maximum 0.02%
Der in Figur 1 gezeigte Schraubanker wird in der folgenden Weise hergestellt: In einem ersten Schritt wird ein Rohling durch Kaltformen bereitgestellt, der mit einem gerollten Gewinde versehen ist. Dieser Rohling wird gereinigt, insbesondere entphosphatiert. Anschließend wird der Rohling in einem Ofen bei einer Temperatur von etwa 880 °C carbonitriert, wobei in der Atmosphäre ein Kohlenstoffgehalt von 1 % vorhanden ist. Ferner wird mit einem Reaktionsgas kontinuierlich Stickstoff zugeführt. Das gesamte Verfahren findet unter Luftabschluss statt. The screw anchor shown in Figure 1 is made in the following manner: In a first step, a blank is provided by cold-forming, which is provided with a rolled thread. This blank is cleaned, in particular dephosphated. Subsequently, the blank is carbonitrided in an oven at a temperature of about 880 ° C, wherein in the atmosphere, a carbon content of 1% is present. Further, nitrogen is continuously supplied with a reaction gas. The entire process takes place under exclusion of air.
Nach dem Carbonitrieren werden die Schraubanker abgeschreckt und bei einer Temperatur von etwa 220 °C angelassen, d.h. spannungsarm geglüht. After carbonitriding, the screw anchors are quenched and annealed at a temperature of about 220 ° C, i. low-stress annealed.
Dieses Verfahren resultiert in einer sehr hohen Härte an der Oberfläche und einer recht niedrigen Härte im Kern des Schafts. Insbesondere werden an der Oberfläche Härten in der Größenordnung bis 750 HV erzielt, während im Inneren des Kerns eine Härte von vorzugsweise unterhalb 250 HV vorliegt. Ein wesentliches Merkmal des auf diese Weise erhaltenen Schraubankers besteht darin, dass die Härte sehr schnell von den hohen Werten an der Oberfläche auf sehr viel niedrigere Werte absinkt. Insbesondere sinkt die Härte in einer Tiefe von 0,5 mm unterhalb der Oberfläche auf einen Wert von unter 400 HV1 ab. Ein
solcher Schraubanker kombiniert eine sehr hohe Härte des Gewindes mit einer hohen Zähigkeit im Inneren des Schafts. This method results in a very high surface hardness and a fairly low hardness in the core of the shaft. In particular, hardnesses of the order of magnitude up to 750 HV are achieved on the surface, while a hardness of preferably below 250 HV is present in the interior of the core. An essential feature of the screw anchor obtained in this way is that the hardness drops very rapidly from the high values at the surface to much lower values. In particular, the hardness drops to a value of less than 400 HV1 at a depth of 0.5 mm below the surface. One such screw anchor combines a very high hardness of the thread with a high toughness inside the shaft.
In Figur 2 ist der Verlauf der Härte in Abhängigkeit vom Abstand von der Oberfläche zu sehen. Es ist zu erkennen, dass die Härte sehr schnell absinkt und bereits in einer Tiefe von 0,5 mm unter der Oberfläche in der Größenordnung von 400 HV1 liegt.
FIG. 2 shows the course of the hardness as a function of the distance from the surface. It can be seen that the hardness drops very quickly and is already at a depth of 0.5 mm below the surface in the order of 400 HV1.
Claims
1. Verfahren zur Herstellung eines Schraubankers (1) mittels der folgenden Schritte: - es wird ein Rohling aus Cq22Mn4 bereitgestellt, 1. A method for producing a screw anchor (1) by means of the following steps: - a blank of Cq22Mn4 is provided,
der Rohling wird carbonitriert, the blank is carbonitrided,
der Rohling wird abgeschreckt. the blank is quenched.
2. Verfahren nach Anspruch 1 , dadurch gekennzeichnet, dass der Rohling kaltgeformt und mit einem gewalzten Gewinde (6) versehen wird, bevor er carbonitriert wird. 2. The method according to claim 1, characterized in that the blank is cold formed and provided with a rolled thread (6) before it is carbonitrided.
3. Verfahren nach Anspruch 1 oder Anspruch 2, dadurch gekennzeichnet, dass der Rohling vor dem Carbonitrieren gereinigt wird, insbesondere entphosphatiert. 3. The method according to claim 1 or claim 2, characterized in that the blank is cleaned before carbonitriding, in particular entphosphatiert.
4. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass das Carbonitrieren bei einer Temperatur im Bereich von 800 °C bis 950 °C durchgeführt wird. 4. The method according to any one of the preceding claims, characterized in that the carbonitriding is carried out at a temperature in the range of 800 ° C to 950 ° C.
5. Verfahren nach Anspruch 4, dadurch gekennzeichnet, dass das Carbonitrieren bei einer Temperatur im Bereich von 860 °C bis 900 °C durchgeführt wird. 5. The method according to claim 4, characterized in that the carbonitriding is carried out at a temperature in the range of 860 ° C to 900 ° C.
6. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass das Carbonitrieren in einer Atmosphäre mit 0,8 % bis 1 % Kohlenstoff-Anteil durchgeführt wird. 6. The method according to any one of the preceding claims, characterized in that the carbonitriding is carried out in an atmosphere with 0.8% to 1% carbon content.
7. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass nach dem Carbonitrieren ein Entspannungsglühen bei einer Temperatur im Bereich von 200 °C bis 240 °C durchgeführt wird. 7. The method according to any one of the preceding claims, characterized in that after carbonitriding, a flash annealing at a temperature in the range of 200 ° C to 240 ° C is performed.
8. Schraubanker (1), insbesondere hergestellt nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass als Material Cq22Mn4 verwendet wird und dass die Härte des Schafts (2), gemessen 0, 1 mm unterhalb der Oberfläche, oberhalb von 600 HV liegt. 8. screw anchor (1), in particular produced according to one of the preceding claims, characterized in that as the material Cq22Mn4 is used and that the hardness of the shaft (2), measured 0, 1 mm below the surface, above 600 HV.
9. Schraubanker (1) nach Anspruch 8, dadurch gekennzeichnet, dass die Härte des Schafts (2), gemessen 0, 1 mm unterhalb der Oberfläche, oberhalb von 700 HV liegt. 9. screw anchor (1) according to claim 8, characterized in that the hardness of the shaft (2), measured 0, 1 mm below the surface, above 700 HV.
10. Schraubanker (1) nach Anspruch 8 oder Anspruch 9, dadurch gekennzeichnet, dass im Kern eine Härte im Bereich von 170 bis 250 HV vorliegt. 10. screw anchor (1) according to claim 8 or claim 9, characterized in that the core has a hardness in the range of 170 to 250 HV.
1 1. Schraubanker (1) nach einem der Ansprüche 8 bis 10, dadurch gekennzeichnet, dass die Härte des Schafts (2) von außen nach innen sehr schnell unter einen Wert von 400 HV abfällt. 1 1. screw anchor (1) according to one of claims 8 to 10, characterized in that the hardness of the shaft (2) falls from outside to inside very quickly below a value of 400 HV.
12. Schraubanker (1) nach Anspruch 11 , dadurch gekennzeichnet, dass die Härte des Schafts (2) in einer Tiefe von 0,5 mm unterhalb der Oberfläche unter einem Wert von unter 400 HV liegt. 12. screw anchor (1) according to claim 11, characterized in that the hardness of the shaft (2) at a depth of 0.5 mm below the surface is below a value of less than 400 HV.
13. Schraubanker (1) nach einem der Ansprüche 8 bis 12, dadurch gekennzeichnet, dass der Kerndurchmesser des Schraubankers mindestens 12 mm beträgt. 13. screw anchor (1) according to one of claims 8 to 12, characterized in that the core diameter of the screw anchor is at least 12 mm.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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DE102010063675.4 | 2010-12-21 | ||
DE201010063675 DE102010063675A1 (en) | 2010-12-21 | 2010-12-21 | Screw |
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WO2012084386A1 true WO2012084386A1 (en) | 2012-06-28 |
Family
ID=45044575
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/EP2011/070754 WO2012084386A1 (en) | 2010-12-21 | 2011-11-23 | Screw anchor |
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DE (1) | DE102010063675A1 (en) |
WO (1) | WO2012084386A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2014040995A1 (en) * | 2012-09-12 | 2014-03-20 | Hilti Aktiengesellschaft | Method for producing a self-tapping screw |
EP2835542A1 (en) | 2013-08-07 | 2015-02-11 | HILTI Aktiengesellschaft | Self-tapping screw |
WO2015022049A1 (en) * | 2013-08-13 | 2015-02-19 | Fischerwerke Gmbh & Co. Kg | Concrete screw |
FR3038354A1 (en) * | 2015-07-03 | 2017-01-06 | Sarl Francois Inglese | PITCH OF SUSPENSION |
EP4029964A1 (en) | 2021-01-14 | 2022-07-20 | Hilti Aktiengesellschaft | Hardening of a zinc coated screw body |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102013206388A1 (en) | 2013-04-11 | 2014-10-16 | Hilti Aktiengesellschaft | Anchor with spreading area and cutting thread |
DE102013206387A1 (en) | 2013-04-11 | 2014-10-16 | Hilti Aktiengesellschaft | anchor |
EP3620673A1 (en) * | 2018-09-10 | 2020-03-11 | fischerwerke GmbH & Co. KG | Concrete screw |
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JP2001247937A (en) * | 1999-05-21 | 2001-09-14 | Koji Onoe | High strength screw and steel for high strength screw |
WO2003046229A1 (en) * | 2001-11-28 | 2003-06-05 | Ejot Verbindungstechnik Gmbh & Co. Kg | Fastening element made of a carbon-containing steel and method for the production thereof |
JP2008144266A (en) * | 2006-11-16 | 2008-06-26 | Koji Onoe | Tapping screw for high-tension steel sheet, and manufacturing method for the same |
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DE2531944A1 (en) * | 1975-07-17 | 1977-02-03 | Schraubenkombinat Veb | High strength cold formed parts such as steel bolts - made by drawing and upsetting to eliminate need for heat treatment |
WO1988005991A2 (en) * | 1987-02-18 | 1988-08-25 | Sfs Stadler Ag | Fixing device and method for the manufacture of same |
DE10315957A1 (en) * | 2003-04-08 | 2004-10-28 | Ejot Gmbh & Co. Kg | Screw with a partially hardened functional tip and process for its manufacture |
DE102008017821A1 (en) * | 2008-04-08 | 2009-10-22 | Continental Automotive Gmbh | Fastening element and turbocharger with variable turbine geometry |
EP2168697A1 (en) * | 2008-09-30 | 2010-03-31 | Mage Ag | Drill screw production method |
DE202009011665U1 (en) * | 2009-08-27 | 2009-12-10 | Röttgers, Christoph | Stainless steel drilling screw |
-
2010
- 2010-12-21 DE DE201010063675 patent/DE102010063675A1/en not_active Withdrawn
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2011
- 2011-11-23 WO PCT/EP2011/070754 patent/WO2012084386A1/en active Application Filing
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2001247937A (en) * | 1999-05-21 | 2001-09-14 | Koji Onoe | High strength screw and steel for high strength screw |
WO2003046229A1 (en) * | 2001-11-28 | 2003-06-05 | Ejot Verbindungstechnik Gmbh & Co. Kg | Fastening element made of a carbon-containing steel and method for the production thereof |
JP2008144266A (en) * | 2006-11-16 | 2008-06-26 | Koji Onoe | Tapping screw for high-tension steel sheet, and manufacturing method for the same |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2014040995A1 (en) * | 2012-09-12 | 2014-03-20 | Hilti Aktiengesellschaft | Method for producing a self-tapping screw |
EP2835542A1 (en) | 2013-08-07 | 2015-02-11 | HILTI Aktiengesellschaft | Self-tapping screw |
WO2015022049A1 (en) * | 2013-08-13 | 2015-02-19 | Fischerwerke Gmbh & Co. Kg | Concrete screw |
FR3038354A1 (en) * | 2015-07-03 | 2017-01-06 | Sarl Francois Inglese | PITCH OF SUSPENSION |
EP4029964A1 (en) | 2021-01-14 | 2022-07-20 | Hilti Aktiengesellschaft | Hardening of a zinc coated screw body |
WO2022152431A1 (en) | 2021-01-14 | 2022-07-21 | Hilti Aktiengesellschaft | Hardening of a zinc coated screw body |
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