All-Steel Fitting

Abstract

In the method according to the invention, a wire (11) provided with teeth (15) passes sequentially through a first inductor (16) and a second inductor (18). The inductors (16, 18) function at different frequencies and generate different temperatures. The first inductor (16) heats in particular the base section (17), which is not to be hardened, to a high temperature below the austenitizing temperature range. The second inductor (18) heats the teeth (15) to a still higher second temperature within the austenitizing temperature range. Defined, hardened teeth of consistently high quality result at quenching.

Claims

1. Method for the production of an all-steel card clothing for carding machines, wherein the method comprises: providing a wire (11) having a base section (17) and a wall section (23) that extends away from the base section (17) and has a lower thickness (D15) than said base section, applying recesses (14) in the wall section (23) of raw material wire (12) in order to form teeth (15), in feed-through mode, heating at least the base section (17) of the wire (11) to a first temperature (t1), in feed-through mode, at least sectionwise induction heating the wall section (23) of the wire (11), said wire having been preheated at least on the base section (17), by at least one inductor (18) at a specific frequency (f2) to a second temperature (t2), wherein the second temperature (t2) is higher than the first temperature (t1), in feed-through mode, quenching at least the wall section (23) of the wire (11) with a cooling medium.

2. Method according to claim 1, further comprising producing the recesses (14) in feed-through mode by a punching process.

3. Method according to claim 1, wherein the first temperature (f1) is below an austenitizing temperature range (tA) and that the second temperature is within the austenitizing temperature range (tA).

4. Method according to claim 1, wherein heating to the first temperature (t1) takes place in feed-through mode by at least one first inductor (16) at a first frequency (f1), in which case the inductor (18) for heating the wire (11) to the second temperature (t2) is a second inductor (18) that operates at a second frequency (f2) that is higher than the first frequency (f1).

5. Method according to claim 4, wherein the second frequency (f2) is at least five times that of the first frequency (f1).

6. Method according to claim 1, wherein the first frequency (f1) is at most 5 MHz and the second frequency is at least 10 MHz.

7. Method according to claim 1, further comprising, after quenching, passing the wire (11) through a third inductor (29) that is operated at a third frequency (f3) that is lower than the second frequency (f2) in order to heat the wire (11) to a third temperature that is at least lower than the second temperature (t2) and preferably lower than the first temperature (t1).

8. Method according to claim 1, wherein at least the induction heating at the second frequency (f2) to the second temperature (t2) takes place under protective gas.

9. Method according to claim 1, further comprising brushing the wire (11) at least on one lateral surface.

10. All-steel card clothing comprising a wire (11) defining a longitudinal direction (L), said wire having a base section (17) and a wall section (23) with teeth (15) having a tooth height (H15), said wall section having at least one section (19) having increased hardness and extending away from the base section (17), wherein the base section (17) has a greater thickness (D17) than the wall section (23), and the wall section (23) has a boundary following a straight line defining a transition zone (24) extending parallel to the longitudinal direction (L), in which transition zone wall section has the increased hardness begins and a width (H24) of which amounts to at most 20% of the tooth height (H15).

11. All-steel card clothing according to claim 10, wherein the wall section (23) has teeth (15) and that the transition zone (24) is formed within the teeth.

12. All-steel card clothing according to claim 10, wherein a tooth gullet (21) is formed between the teeth (15), in which case a distance of the transition zone (24) from the tooth tip (20) amounts to at least 70% of the tooth height (H15).

13. All-steel card clothing according to claim 10, wherein the wall section (23) has teeth (15) between which one tooth gullet (21), respectively, is formed, and that the transition zone (24) contacts or contains the tooth gullet (21), or extends below said tooth gullet.

14. All-steel card clothing according to claim 10, wherein the wall section (23) has a cross-section that is configured trapezoidally or triangularly tapering away from the base section (17).

15. All-steel card clothing according to claim 10, wherein each tooth (15) has a tooth tip (20) and a straight tooth back (30), said tooth back extending up to the tooth tip (20).

16. All-steel card clothing according to claim 10, wherein the all-steel card clothing is largely metallic bright and free of scales, respectively, in which case said card clothing is free of traces of a chemical burr removal or subsequent processing, as well as free of traces of any mechanical finishing on both sides.

Description

[0024] Additional details of advantageous parts of the invention can be inferred from the claims, the description and the drawings. They show in

[0025] FIG. 1 a schematized block diagram of the process of the inventive induction hardening of a wire of an all-steel card clothing;

[0026] FIG. 2 a schematized perspective representation of the wire for the production of an all-steel card clothing;

[0027] FIG. 3 a cross-sectional view of the wire according to FIG. 2;

[0028] FIG. 4 a lateral view of a detail of the wire according to FIG. 3;

[0029] FIG. 5 the progression of hardness of a tooth of the wire according to FIGS. 3 to 4; and

[0030] FIG. 6 a cross-sectional representation of a detail of the wire similar to FIG. 3, illustrating the zone of hardness transition.

[0031] FIG. 1 shows a device 10 for the production of a wire 11 as is required for the assembly of an all-steel card clothing of a clothing roll. The device 10 is disposed for the production of this wire 11 of a profile wire 12 that is moved in its longitudinal direction L through the stations of the device 10.

[0032] Among other things, the device 10 comprises a punching station 13 that is disposed to apply recesses 14 to the profile wire 12 (FIG. 2) and thus form teeth 15. Upstream of the punching station 13 it is possible to provide one or more alignment stations or other stations. Additionally or supplementarily, a grinding station or the like may be arranged downstream of the punching station. Additional stations, for example, for aligning the profile wire 12 or the wire 11, may be provided as needed upstream or downstream of the punching station 13 as needed; however, they are not shown.

[0033] A heating station, e.g., in the form of a first conductor that is disposed for the inductive heating of the wire 11, is arranged downstream of the punching station 13. In so doing, the first inductor 16 generates a field that covers at least the base section 17 of the wire, howeveroptionallyalso its teeth 15. The first inductor 16 operates at the first frequency f1 between 100 kHz and 5 MHz, preferably between 500 kHz and 2 MHz, in the present exemplary embodiment at 1 MHz. In so doing, the wire 11 is preferably heated to a first temperature t1 of preferably higher than 300 C. in the region of the base section 17 of said wire. In the present exemplary embodiment the temperature t1 is 700 C. to 750 C. Preferably it is set in such a manner that there will be no hardening of the base region 17 during subsequent quenching.

[0034] At some distance (e.g., a few decimeters) from the first inductor 16, there is provided a second inductor 18 that operates at a clearly higher frequency f2. It is at least 5, preferably at least 10 and most preferably at least 20 times higher than the first frequency f1. For example, the second frequency f2 is 20 MHz to 30 MHz, preferably 27 MHz. In doing so, the second inductor 18, is preferably configured in such a manner that it covers only the teeth 15 or a section of each tooth 15. There is no active cooling between the inductors 16 and 18. Rather, the wire 11 passes the distance in less than 2 seconds, preferably less than 1 second.

[0035] FIG. 4 shows a tooth 15 having a tooth height H15 that extends perpendicular to the longitudinal direction from the tooth gullet 21 to the tooth tip 20. Furthermore a section 19 of the tooth 15 is defined, said section extending from the tooth tip 20 to approximately its center or slightly further in the direction of the tooth gullet 21. The section 19 has a height H19 that preferably amounts to more than 70%, better more than 80% of the tooth height H15. In any event, however, the second inductor 18 covers at least the section 19 of each tooth 15 or also a slightly greater region. Preferably, however, the second inductor 18 does not cover the tooth gullet 21. The second inductor 18 and, if desired, also the first inductor 16, may work in an inert gas atmosphere, e.g., of nitrogen. This gas atmosphere may be moved up to a quenching station 22.

[0036] After passing through the inductors 16 and 18, the hot wire 11 reaches the quenching station 22. In doing so, the base section 17 has a temperature t1 below the austenitizing temperature range tA, whereas the section 19 of each tooth 15 has a temperature t2 within the austenitizing temperature range tA. The temperature gradient from the section 19 to the base section 17 has the effect that the wire 11while it is moving into the quenching station 22hardens uniformly in particular in the section 19 but that the rest of the wire 11 remains unhardened.

[0037] As is obvious from FIG. 3 the base section 17 has a thickness D17 to be measured transversely to the longitudinal direction and perpendicularly to the lateral surface, said thickness being greater than the thickness D15 to be measured on each tooth 15. The thermal energy storage capacity of the base D17 is greater than the thermal energy storage capacity of each tooth 15. However, too great a heat flow from the tooth 15 to the base section 17 before the quenching station 22 is reached is avoided due to raising the temperature of the base section 17 to the first temperature t1.

[0038] The wall section 23 extends away from the base section 17 that, typically, has a rectangular cross-section, in which case the wall section may have a triangular or, as shown, a trapezoidal cross-section. Upon passing through the second inductor 18, a temperature transition zone 24 is provided on the wire 11, in which zone the temperature drops from the second high temperature t2 (for example, 950 C.) to the first low temperature t1 (e.g., 5501 C.) that is to be measured below the temperature transition zone 24 on the remaining section of the wall 23 and the base section 17. Accordingly, during the quenching process after passing through the quenching station 22, the hardness progression as depicted in FIG. 5 occurs in the wire 11. A uniform hardness of greater than 800 HV 0.5 is achieved in section 19. The temperature transition zone 24 became a transition zone 24 of the hardness transition, wherein the hardness of greater than 800 HV 0.5 drops to approximately 200 HV 0.5 or lower. This zone exhibits a vertical hardness expansion H24, measured away from the base section 17, and, preferably, amounts to only 20% of the tooth height H15. The temperature transition zone 24 forms a straight strip extending in longitudinal direction L and having a width that corresponds to the height H24. This strip may be arranged at a distance A from the tooth gullet 24. However, it is also possible and advantageous to reduce the distance A to zero, so that the base-section-side boundary of the zone 24 is in contact with the tooth gullet 21. Furthermore, it is possible to lay the transition zone 24 even deeper, so that the tooth gullet 21 is located in the region of the hardness transition of the transition zone 24.

[0039] FIG. 6 shows the transition zone 24 in cross-section. The boundaries of the transition zone 24as indicated by lines 25, 26, may extend straight through the wall section 23 or the respective tooth 15 in transverse direction. However, it is also (preferably) possible for the transition zone 24 to be delimited along curved lines 27, 28 by the hardened or unhardened region. The lines 25 and/or 26 may be oriented parallel to the gullet surface 17a of the base section 17. Accordingly, each of the lines 27 and/or 28 on both sides of the tooth 15 end at the same height. Preferably, the lines 27, 28 follow arcs that are curved toward the gullet surface 17a. Preferably, the center of curvature is located on the side of each line 27, 28 remote from the base section 17preferably, again within the cross-section of the tooth 15. The boundaries of the transition zone 24 are visible in the cross-sectional view of the all-steel card clothing. However, due the corresponding setting of the temperature t1 of the base section 17 and the setting of the dwell time of the wire 11 on its path between the first inductor 16 (or another heating station) and the second inductor, the thermal load (source or sink) of the base section 17 can be adjusted in such a manner that the lines 25 and/or 26 extend obliquely with respect to the gullet surface 17a. It then applies to the lines 27 and/or 28 that they end on both sides of the tooth 15 at different heights.

[0040] In the method according to the invention, a wire 11 provided with teeth 15 passes sequentially through a first inductor 16 and a second inductor 18. The inductors 16, 18 operate at different frequencies f1, f2 and generate different temperatures t1, t2. The first inductor 16 heats in particular the base sections 17, which are not to be hardened, to a high temperature t1 below the austenitizing temperature range tA. The second inductor 18 heats the teeth 15 to a still higher second temperature t2 within the austenitizing temperature range tA. Defined, hardened teeth of consistently high quality result at quenching.

[0041] In order to improve the properties of the wire 11, in particular for reducing tensions, the wire may pass through a third inductor 29. The latter operates at a third frequency f3 that may be between 500 kHz and 5 MHz and is preferably between 1 MHz and 2 MHz. The frequency f3 may correspond to the first frequency f1. The temperature t3 generated by the third inductor 29 is an annealing temperature of, e.g., a few hundred degrees Celsius.

[0042] Furthermore, the wire 11 may be moved through a burr-removal stationbefore or after annealing. In this station, punching burrs that have potentially formed when the recesses 14 were punched can be removed, e.g., by brushes, that act only on one flat side of the teeth 15.

[0043] In the method according to the invention, a wire 11 provided with teeth 15 passes sequentially through a first inductor 16 and a second inductor 18. The inductors 16, 18 function at different frequencies and generate different temperatures. The first inductor 16 heats in particular the base section 17, which is not to be hardened, to a high temperature below the austenitizing temperature range. The second inductor 18 heats the teeth 15 to a still higher second temperature within the austenitizing temperature range. Defined, hardened teeth of consistently high quality result at quenching.

LIST OF REFERENCE SIGNS

[0044] 10 Device [0045] 11 Wire [0046] 12 Profile wire [0047] 13 Punching station [0048] 14 Recesses [0049] 15 Teeth [0050] H15 Tooth height [0051] 16 First inductor or other heat source [0052] 17 Base section [0053] t1 First temperature [0054] f1 First frequency [0055] 18 Second inductor [0056] t2 Second temperature [0057] f2 Second frequency [0058] 19 Section of the tooth 15 [0059] 20 Tip of the tooth 15 [0060] 21 Gullet of the tooth [0061] H19 Height of section 19 [0062] 22 Quenching station [0063] tA Austenitizing temperature range [0064] D17 Thickness of the base section 17 [0065] D15 Thickness of the tooth 15 [0066] 23 Wall section [0067] 24 Temperature transition zone [0068] H24 Height of the zone [0069] A Distance [0070] 25, 26, 27, 28 Lines [0071] f3 Third frequency [0072] t3 Third temperature [0073] 29 Third inductor/other heat source [0074] 30 Tooth back