Tension member or compression member having corrosion-resistant thread flanks

Abstract

The present application relates to a statically permanently loadable tension member or compression member (10) for a structure, which member comprises, on both end portions (12), thread flanks (14) of a thread for receiving a connection component. According to the invention, the thread flanks (14) are provided at least partially with a rolled zinc surface (16).

Claims

1. A statically permanently loadable tension member for a structure, the tension member comprising: a tension member body including end portions and thread flanks of a thread provided on each end portion and configured to receive a connection component, the tension member body configured as a solid round material of higher-strength steel, the thread flanks being raised at least in sections with respect to a non-threaded part of the tension member body having a round cross-section, the thread flanks being provided at least partially with a rolled zinc surface configured as corrosion protection.

2. The tension member according to claim 1, wherein the zinc surface is rolled in a manner that does not involve removal of the zinc surface.

3. The tension member according to claim 1, wherein the tension member body has a continuous fibre flow in the base material in the end portion.

4. A method of producing a statically permanently loadable tension member for a structure, the tension including thread flanks of a thread on both end portions thereof, the thread flanks configured to receive a connection component, wherein the tension member is configured as a solid round material of higher-strength steel, wherein the thread flanks are raised at least in sections with respect to a non-threaded part of the tension member and are provided at least partially with a rolled zinc surface configured as corrosion protection, according to one of the preceding claims, the method acts of: providing the round material with a desired diameter or just below the desired diameter for later rolling, then applying a zinc layer to produce the zinc surface, and then non-cutting re-forming the two end portions to produce the thread flanks, wherein the re-forming is carried out by one or more rotating tools, while the tension member does not rotate.

5. The method according to claim 4, wherein an act of galvanising, in particular hot-dip galvanising, is not performed after the act of re-forming to produce the thread flanks.

6. A tension member for a structure, wherein the tension member is produced by a method according to claim 4.

7. The tension member according to claim 1, wherein the zinc surface is hot-dip galvanised.

8. The tension member according to claim 1, wherein the surface of the tension member body is completely provided with zinc.

9. A system comprising at least two tension members according to claim 1, wherein the threads of at least one end portion of the at least two tension members have the same thread load capacity and determine a respective threshold tensile force of the at least two tension members.

10. The tension member according to claim 3, wherein the tension member body has a continuous fibre flow in the base material between the end portions.

11. The tension member according to claim 1, wherein the surface of the tension member body is completely provided with zinc with the exception of its end faces.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows a tension member from the prior art according to a first known production method.

(2) FIG. 2 shows a tension member from the prior art according to a second known production method.

(3) FIG. 3 shows a tension member from the prior art according to a third known production method. The zinc layer is removed in the thread region.

(4) FIG. 4 shows a tension member according to a preferred embodiment, which is trimmed to a desired diameter having diameter 28. The rolled thread is shown in the end region 12. The thread flanks 14 have the outer diameter 26, which is larger than the trim diameter 28. The thread flanks have a continuous, dimensionally accurate zinc layer 16 that is intensively bonded to the steel or even incorporated into the steel.

(5) FIG. 5 shows a schematic sectional view of a severed fibre flow in the case of a cut thread.

(6) FIG. 6 shows a schematic sectional view of a continuous fibre flow in the case of a rolled thread with a preferably continuous zinc layer on the fibre flow.

MANNERS OF IMPLEMENTING THE INVENTION

(7) FIG. 4 shows a preferred embodiment of a tension member 10 for a structure, which member comprises, on at least one end portion 12, thread flanks 14 of a thread for receiving a connection component. The thread flanks 14 are completely provided with a rolled zinc surface 16.

(8) As is illustrated in the comparison of FIGS. 5 and 6, cut threads, i.e. threads produced by machining, differ from rolled threads, i.e. threads produced by non-cutting machining, i.e. cold forming. FIG. 6 shows a continuous fibre flow 18 in the material from which the thread flanks 14 were produced. This continuous fibre flow 18 means that the fibres of the material were not interrupted by the forming of the thread flanks 14, but were rather re-formed. In contrast, an interrupted fibre flow 37 can be seen in a cut thread. Thread cutting creates the form of the thread simply by removing material by cutting, thus interrupting the individual fibres of the base material. This reduces the strength of the base material as compared to the continuous fibre flow 18 of FIG. 6. During rolling, the thread roller penetrates into the steel surface, thereby displacing material which then pushes up next to the groove and forms the outer thread flank, provided that the trim diameter and the tool are precisely matched to one another. For this reason in particular, a rolled thread is more resistant to dynamic loads and thus fatigues less quickly.

(9) Shown adjacent to the end portion 12 in FIG. 4 is a non-threaded part 20 of the tension member 10, which transitions in a continuous manner into the thread flanks 14 in the end portion 12. In other words, there is no abrupt narrowing in diameter from the non-threaded part 20 to the end portion 12, such as is illustrated in particular in FIGS. 2 and 3, wherein the thread region was trimmed before thread rolling to allow for a dimensionally accurate thread.

(10) The embodiment of the tension member 10 shown in FIG. 4 was prepared by pre-trimming the original round material over its entire length such that after application of the zinc layer to produce the zinc surface 16, the diameter allows the production of the dimensionally accurate thread on the rolling machine, taking into account the specified tolerances. The zinc layer forming the zinc surface 16 is thereby not removed, but is applied after the optional pre-trimming and then re-formed together with the material of the member.

(11) For this reason, the starting diameter 24 was reduced also in the non-threaded part 20 to the pre-trimmed, reduced diameter 28 that was used to produce the thread with the thread diameter 26. However, it is fundamentally also possible for the tension member 10 to not be pre-trimmed over its entire length, but rather only in the region of the thread, provided that the zinc layer is applied only after pre-trimming and prior to re-forming. The diameter 26 is always larger than the trim diameter 28.

(12) The end face 22 of the tension member 10 in the embodiment shown in FIG. 4 is preferably provided with an organic or other corrosion protection, but can, however, also be configured without corrosion protection.

(13) The preferred embodiment described above provides a tension member or compression member for a structure, which member has improved corrosion protection as compared to the prior art as well as improved strength with respect to fatigue and dynamic loads and can be produced more efficiently.