Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
COPPER COATED MULTI-LAYERED PIPE
Document Type and Number:
WIPO Patent Application WO/2022/125001
Kind Code:
A1
Abstract:
The invention relates to a multi-layered pipe obtained by coating a metal strip with a soldering layer (1) consisting of a copper or a copper alloy using the Bundy production method, and where the metal strip is selected from a material with a high melting temperature of copper or copper alloy, preferably of steel, comprising layers of piping with an inner winding (10) and an outer winding (20) extending from the inner winding (10) to surround thereof. The invention is characterized in that the outer winding diameter (D) is in the range of 4.25 mm and 4.45 mm, the total wall thickness (L1) of the pipe layers is in the range of 0.45 mm and 0.55 mm and the tensile strength of the pipe is in the range of at least 290 MPa.

Inventors:
SAMAN BORA (TR)
Application Number:
PCT/TR2020/050838
Publication Date:
June 16, 2022
Filing Date:
September 14, 2020
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
NET BORU SANAYI VE DIS TICARET KOLLEKTIF SIRKETI BORA SAMAN VE ORTAGI (TR)
International Classes:
B21C37/06
Foreign References:
EP0449600A21991-10-02
FR2721373A11995-12-22
US5958602A1999-09-28
Attorney, Agent or Firm:
SOYLU PATENT ANONIM SIRKETI (TR)
Download PDF:
Claims:
8

CLAIMS

1- A multi-layered pipe obtained by coating a metal strip with a solder layer (1) consisting of a copper or a copper alloy using the Bundy production method, and where the metal strip is selected from a material with a high melting temperature of copper or copper alloy, preferably of steel, comprising layers of piping with an inner winding (10) and an outer winding (20) extending from the inner winding (10) to surround thereof, characterized in that the outer winding diameter (D) is between 4.25 mm and 4.45 mm, the total wall thickness (L1) of the pipe layers is between 0.45 mm and 0.55 mm, and the tensile strength of the pipe is at least 290 MPa as per the SAE J 527 standard.

2- A multi-layered pipe according to Claim 1 , characterized in that the outer winding (20) is wrapped in a single layer on the inner winding (10), doubling the number of the pipe layers thereof.

3- A multi-layered pipe according to any one of the preceding claims, characterized in that the outer winding diameter (D1 ) values are in the range of 4.30 mm to 4.40 mm.

4- A multi-layered pipe according to Claim 3, characterized in that the outer winding diameter (D) value is 4.35 mm.

5- A multi-layered pipe according to any one of the preceding claims, characterized in that the total wall thickness (L1 ) of the pipe layers is 0.50 mm.

6- A multi-layered pipe according to any one of the preceding claims, characterized in that the thickness of the soldering layer (1 ) is in the range of 1.9 microns to 2 microns.

7- A multi-layered pipe according to any one of the preceding claims, characterized in that it comprises a zinc-aluminum alloy coating layer (3) provided at an outer periphery (22) of the outer winding (20).

8- A multi-layered pipe according to cCaim 7, characterized in that it comprises a plastic sheath (4) provided on the zinc-aluminum coating layer (2) and an intermediate primary coating layer (3) suitable for plastic bonding provided between the zinc- aluminum coating layer (2) and the plastic sheath (4). 9

9- A multi-layered pipe according to any one of the preceding claims, characterized in that an inner diameter value (D2) of the inner winding (10) is in the range of 3.30 to 3.40 mm.

10- A multi-layered pipe according to any one of the preceding claims, characterized in that the tensile strength values of the pipe are in the range of 295 MPa to 299 MPa.

11- A multi-layered pipe according to any one of the preceding claims, characterized in that the yield strength values of the pipe are in the range of 205 MPa to 215 MPa.

12-A multi-layered pipe according to any one of the preceding claims, characterized in that the percentage variation of the pipe elongation amount is in the range of 14% to 24% for a pipe with a length of 50 mm.

13- A multi-layered pipe according to any one of the preceding claims, characterized in that the pipe hardness value is in the range of 45 MPa to 55 MPa according to the Rockwell hardness value.

14-A multi-layered pipe according to any one of the preceding claims, characterized in that the junction distance (L2) between the first edge (12) of the inner winding (10) and a second edge (24) of the outer winding (20) is in the range of 1 mm to 1.7 mm.

15-A multi-layered pipe according to cCaim 14, characterized in that the ratio of the wall thickness (L1) to the junction distance (L2) is in the range of 2 to 4 and the burst pressure value is at least 1150 bar.

Description:
COPPER COATED MULTI-LAYERED PIPE

TECHNICAL FIELD

Present invention relates to a multi-layered, particularly double-walled pipes produced by the Bundy production method.

STATE OF THE ART

Single-layered pipes made of copper alloys are used as an alternative to corrosion-proof steel pipes. Single-layered pipes made of copper alloys have the disadvantage of causing problems due to the single wall. Cold drawing during production may cause cracks later on due to internal stresses. Stress cracks also occur in these copper pipes with the effect of chemicals on the entrance of the pipes with spray water and air currents.

Compared to single-walled pipe, multi-layered pipe production is designed to produce pipes that are more durable and do not form tension cracks. Generic type pipe production methods are used in multi-layered pipe production. With the generic production method, it is ensured that negative stresses that may cause cracks do not occur during the strip production. Crack formation is minimized during the rolling process, for example the cold drawing process of small pipes. Researches indicate that the fatigue strength of a multi-layered pipe is significantly higher than that of a single-layered pipe made of the same material. The burst pressure of the pipes can also be regarded as the strength value of the main material.

EP0255465A2 relates to the design of the multi-layered pipes. Here, the pipe, particularly, a pipe for hydraulic brake systems of motor vehicles, is produced and brazed by the Bundy production method from a flat metal strip coated at least on one side with a soldering layer. The application describes the coating of the metal strip with copper or copper alloy to provide the longest flexural and fatigue strength of the pipe, as well as the greatest resistance to high mechanical loading under internal pressure. BRIEF DESCRIPTION OF THE INVENTION

Object of the invention is to ensure the production of light multi-layered pipes in accordance with safety standards.

In order to achieve the mentioned objects, the invention is a multi-layered pipe obtained by coating a metal strip with a soldering layer consisting of a copper or a copper alloy using the Bundy production method, and where the metal strip is selected from a material with a high melting temperature of copper or copper alloy, preferably of steel, comprising layers of piping with an inner winding and an outer winding extending from the inner winding to surround thereof, characterized in that the outer wrap diameter is between 4.25 mm and 4.45 mm, the total wall thickness (L1 ) of the pipe layers is between 0.45 mm and 0.55 mm, and the tensile strength of the pipe is at least 290 MPa as per the SAE J 527 standard. This piping embodiment meets all standard requirements for braking systems of motor vehicles. With the use of outer winding diameter values and wall thickness in the given ranges, the required tensile stress and yield strength point values are in accordance with the requirements of the standard, while a low weight pipe structure is provided. Thus, a cost advantage is ensured by using less material, and the total weight of motor vehicles is reduced, helping to reduce carbon emissions.

In a preferred embodiment of the invention, the outer winding is arranged so as to double the number of pipe layers, and the inner winding is wrapped in a single layer. In this way, the total number of windings of the pipe layer doubles. Production can be made from a metal sheet with a narrower width, with the double-layered pipe. Surprisingly, when the outer winding diameter value and wall thickness are selected, the double-layered pipe can be obtained without creating a pot when bent between the rollers by the Bundy method. In case of more layers, metal strip cannot be obtained by the Bundy method in accordance with the SAE J 527 standard.

In a preferred embodiment of the invention, the outer winding diameter values are between 4.30 mm and 4.40 mm. It has been found that the selected outer winding diameter range yields better results than other values, especially against burst pressure. This makes it possible to obtain a safe multi-layered pipe and use it for a purpose with high safety requirements, such as brake hydraulic pipe. In a preferred embodiment of the invention, the outer winding diameter value is 4.35 mm. Selected value has been determined to provide the best weight/tensile strength performance ratio as the multi-layered pipe produced by the Bundy method as per the SAE J 527 standard

In a preferred embodiment of the invention, the total wall thickness of the pipe layers is 0.50 mm. Selected wall thickness has a tolerance of 5 microns upwards or downwards. It has been observed that this value allows to obtain pipes with equal inner diameter and outer diameter at every point without disrupting the structural form against the force applied by the pulleys in the pulling direction during the production of double-layered pipes with the Bundy method.

In a preferred embodiment of the invention, the thickness of the soldering layer is between 1.9 microns and 2 microns. The selected soldering layer thickness is suitable for the outer winding diameter value and forms the impermeable solder coating thickness.

A preferred embodiment of the invention comprises a zinc-aluminum alloy coating layer provided on an outer periphery of the outer winding. In this way, corrosion of the pipes produced is prevented and the component life of the produced pipes is extended.

A preferred embodiment of the invention comprises a plastic sheath provided on the zincaluminum coating layer and an intermediate primary coating layer suitable for plastic bonding provided between the zinc-aluminum coating layer and the plastic sheath. In this way, the plastic sheathed pipe adheres securely on the zinc-aluminum (Galfan) coating layer, and the plastic sheath protects the multi-layered pipe from impacts and scratches.

In a preferred embodiment of the invention, the inner diameter value of the inner winding is in the range of 3.30 to 3.40 mm. Thus, operational hydraulic pressure can be obtained in hydraulic brake systems.

In a preferred embodiment of the invention, the tensile strength values of the pipe are between 295 MPa and 299 MPa. In this way, it is ensured that the pipe has a longer lifetime under dynamic load.

In a preferred embodiment of the invention, the yield strength values of the pipe are between 205 MPa and 215 MPa. In this way, the value of the pipe against deformation becomes compatible with safety standards. In a preferred embodiment of the invention, the percentage variation of the pipe elongation amount is adjusted in the range of 18% to 24% for 50 mm pipe length. In a preferred embodiment of the invention, the pipe hardness value is in the range of 45 MPa to 55 MPa according to the Rockwell hardness value. This value is for 30 tons.

In a preferred embodiment of the invention, a junction distance between the inner winding start point and the outer winding end point is selected in the range of 1 mm to 2 mm. Thus, it has been determined that the displacement at the junction points of the inner and outer windings is minimized after the multi-layered pipe production using the Bundy method with the mentioned values. This is especially true for the minimum displacement in the doublelayered pipe.

In a preferred embodiment of the invention, the ratio of the wall thickness to the junction distance is selected in the range of 2 to 4 and the burst pressure value is selected as at least 1150 bar. At the winding junction points of the pipes obtained by the Bundy method, resistance is provided against the pressures applied in the hydraulic systems.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a cross-sectional illustration of a representative embodiment of the double-layered pipe according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

In this detailed explanation, the development according to the invention is explained only for a better understanding of the subject without any limiting effect.

In Figure 1 , the double-layered pipe according to the invention is cross-sectionally shown. A metal strip is produced using the Bundy production method in multi-layered pipe production. Obtaining a multi-layered pipe by gradually rolling the horizontally extending metal sheet from the end portion of the aforementioned metal sheet is called the Bundy production method and is disclosed in the US patent numbered US1431368, which is hereby incorporated by reference. The metal strip is preferred as steel in this application. The multi-layered pipe comprises a soldering layer (1 ) made of copper or copper alloy provided to an outer periphery (22) of the metal strip. The soldering layer (1 ) is provided around the metal strip by means of soldering, thereby forming a protective layer. Thanks to the soldering layer (1 ), the pipe is protected against mechanical impacts. A polyurethane sheath (4) is coated in a layer structure with an intermediate primary coating layer (2) suitable for a zinc-aluminum coating layer (3) on the soldering layer (1 ). Primer structure coating was used as the intermediate primer coating layer (2). The protective sheath (4) on the zinc-aluminum coating layer (3) on the multi-layered pipe with the intermediate primer layer (2) adheres more firmly on the pipe. The zinc-aluminum coating layer (3), on the other hand, ensures that the multilayer pipe is resistant to corrosion. Alternatively, E-zinc coating can be used as the zinc-aluminum coating layer (3).

Table 1 Mechanical Test Results

Above table demonstrates the appropriate values for safety standards, test results for multilayered pipes with a diameter of 4.75 mm and test results for multi-layered pipes with a diameter of 4.35 mm, in comparison. Multi-layered pipes must have mechanical properties in accordance with predetermined safety standards of the production. For example, the appropriate standard value determined as tensile strength has been determined as a minimum of 290 MPa. The appropriate value determined for the yield strength has been determined as a minimum of 170 MPa. The maximum hardness value has been determined as 65 HR 30 T using the Rockwell test. The elongation margin has been determined as a minimum of 14% for a pipe with a length of 50 mm. In the preferred application, value measurements were made in accordance with the predetermined safety standards. The tensile strength of the multilayer pipe has been determined as 297 MPa with the tensile test. In addition, the yield strength point was determined as 211 MPa in the tests. According to the Rockwell hardness test, the hardness value of the multi-layered pipe was determined as 51 HR 30 T. The elongation percentage of a 50 mm long multi-layered pipe with tensile stress has been determined as 21.40%. In this way, a multi-layered pipe is obtained in accordance with predetermined safety standards. A 33% lighter pipe with a diameter of 4.35 mm is obtained, which is close to the safety standards provided by pipes with a diameter of 4.75 mm. The multi-layered pipes are less in weight, ensuring a cost advantage. In the preferred embodiment, a light multi-layered pipe is obtained in accordance with the above-mentioned safety standards. The diameter values and the thickness of the pipes are changed in order to reduce the current weight value of the multi-layered pipe. The embodiment comprises an inner winding (10) and an outer winding (20) surrounding the inner winding (10) within the pipe layers. The inner winding (10) diameter value has been determined as 3.30 mm. The outer winding (20) diameter value has been determined as 4.35 mm. The inner winding (10) has an inner diameter of 3.35 mm. The inner winding (10) comprises a first edge (12). The outer winding (20) surrounding the inner winding (10), on the other hand, comprises an outer edge (24) where the winding starting from the first edge (12) ends. The total displacement as a result of winding is defined as a junction distance (L2). The overlap length (L2) is determined to be 1.1 mm in the preferred embodiment. The total thickness of the windings, the soldering layer (1), the intermediate primary coating layer (2) and the zinc-aluminum coating layer (3) forms a wall thickness (L1 ). The wall thickness (L1 ) dimension has been chosen as 0.50 mm in the preferred application. The ratio of the wall thickness (L1 ) and the overlap length (L2) has been determined as 2.20. With this ratio, it is ensured that the burst pressure of the pipe is fixed as 1150 bar in accordance with the safety standards. With the use of inner winding (10) and outer winding (20) diameter values and wall thickness (L1 ) in the given values, a light multi-layered pipe that provides the above-mentioned mechanical properties (tensile strength, yield strength, hardness value and elongation percentage) is obtained.

The resulting multilayer pipes can be shaped, expanded on the ends of the pipes, and shaping can be performed on the pipe. These multi-layered pipes can be used in the automotive industry, refrigeration industry, household appliances, hydraulic lines, control lines, cooling and heating lines, heat exchangers, central lubrication pipes and the like. Furthermore, they can be used in pressure vessels, pressurized gas containers, tank systems and nuclear technology.

REFERENCE NUMBERS

1 Solder Layer

2 Zinc-Aluminum Coating Layers

3 Intermediate Primer Coating Layers

4 Protective sheath

10 Inner Windings

12 First edge 20 Outer Windings

22 Outer Periphery

24 Second Edge

D1 Outer Winding Diameter

D2 Inner Winding Diameter

L1 Wall Thickness

L2 Ride Length