WO2021013462A1

WO2021013462A1 - Multi-layer composite pipes and multi-layer composite sections made from double- or multi-layer composite coils

Info

Publication number: WO2021013462A1
Application number: PCT/EP2020/067779
Authority: WO
Inventors: Andreas Basteck; Torsten Gieseke; Martin METZING
Original assignee: Thyssenkrupp Steel Europe Ag
Priority date: 2019-07-25
Filing date: 2020-06-25
Publication date: 2021-01-28
Also published as: DE102019211064A1

Abstract

The invention relates to a cold- or hot-formed metal semi-finished product made from a hot- or cold-rolled multi-layer composite-coil flat steel semi-finished product. The invention also relates to a method for producing same, and to a corresponding use.

Description

Multi-layer composite pipes and multi-layer composite profiles made from two- or multi-layer composite coils

The invention relates to a cold-formed or hot-formed semi-finished metal product made from a hot-rolled or cold-rolled multi-layer composite coil flat steel product. The invention also relates to a method for its production and a corresponding use.

Certain applications require the use of pipes / profiles with different chemical and physical properties on the inside of the pipe / profile, outside or in the individual layers between the inside and outside of the pipe / profile.

Previous processes solved this problem by roll cladding of different work materials, joining different inner and outer tubes / profiles with subsequent positive locking, as well as the production of a discontinuously manufactured or cold-rolled material sandwich as a starting material for the multi-layer pipes / profiles.

For example, DE 10 2008 048 969 A1 teaches the arrangement of two steel strips on top of each other, which are then shaped into a preform of a pipe, the steel strips being arranged in a sandwich-like coaxial manner. In the subsequent process step, the pre-formed pipe is joined to form a closed pipe, for example welded. In DE 203 17 565 U1, the production of a high-pressure line pipe is disclosed in which ver different layers or pipes are coaxially fitted into one another and then pressed with a suitable tool. DE 102 02 214 B4 discloses a multilayered strip or sheet metal material for the production of pipes. The multilayer material is produced by first producing a hollow body from a first steel material by centrifugal casting, the interior of which is filled with a molten steel material and the filled body is hot-rolled after being heated to drawing temperature. WO 2018/158130 A describes the UO-forming or roll profiling of a composite material containing a second layer made of a soft steel alloy, which is connected at least on one side over the entire surface and with a material fit to a first layer made of a steel alloy with a martensitic structure. The two layers are defined by the tensile strength and hardness of the alloys. Other material composites, in particular made of different steel alloys, are known in the prior art, for example from the German Offenlegungsschrift DE 10 2008 022 709 A. The object of the present invention is to überwin the disadvantages of the prior art and to provide an optimization of the material and form-fitting connection and the resulting technical advantages, as well as the improvement of the economic efficiency of the process by using a continuously produced starting material. Furthermore, the coils made available for cold forming should be integrated into existing standard processes, such as roll profiling or tube forming, without requiring complex and cost-intensive changes in the respective process chain. In addition, steel-based pipes and profiles are to be made available which, due to their composition, meet a wide variety of requirements, such as hardness, deformability, temperature, abrasive or chemical resistance and / or weight savings, where possible after forming little further steps to produce the end product are required. For reasons of cost alone, it should be possible to replace alloys and base materials known to the person skilled in the art and easily produced. These tasks are solved by the subjects of the claims.

In one embodiment, the invention relates to a cold-formed or hot-formed semi-finished metal product made from a hot-rolled or cold-rolled multi-layer composite steel flat product with the following features: a) a thickness of at least 0.8 mm to a maximum of 25.0 mm, preferably at least 1.0 mm, 1.25 mm, particularly preferably 1.5 millimeters and preferably a maximum of 20.0 mm, 15.0 mm, particularly preferably 12.5 mm; b) comprising or consisting of a first layer made of a steel alloy and at least one further metallic layer which is fully and cohesively connected to the first layer, c) a difference between the values of the yield point of the first layer and the at least one further layer of at least 10 MPa and a maximum of 2000 MPa, preferably at least 20, particularly preferably at least 30, in particular at least 40 MPa and preferably at most 1500 MPa, 1000 MPa, 900 MPa, 800 MPa, 700 MPa, particularly preferably 600 MPa, in particular 500 MPa; d) an intermediate layer is arranged between the first layer and the at least one further layer, e) the intermediate layer and / or the transition from one layer to the intermediate layer has a concentration gradient on at least one of the elements from the group containing or consisting of: C, Al, Si, Mn, P, S, N, Ti, B, Cu, Sn, Sb, Ca, As, Cr, Ni, Mo, V, Nb.

In the context of the present invention, the concentration gradient relates to the percentage, ie the concentration of one of the above-mentioned elements. At least one or more of these elements are contained in the alloy of the first layer in a precisely defined concentration in addition to Fe. The sum of all elements of the alloy results in 100% (this means weight percent).

During the production of the hot-rolled or cold-rolled multi-layer composite steel flat semi-finished product to be used according to the invention, diffusion processes take place which lead to a mixing of the individual layers of the material composite. This forms the intermediate layer. The intermediate layer is the product of the diffusion processes in the production of the hot-rolled or cold-rolled multilayer composite flat steel product to be used according to the invention. The intermediate layer is therefore, in contrast to the first layer made of a steel alloy and the at least one further metallic layer, not a layer that is used as the starting material. In one alternative, the intermediate layer is the full-surface and cohesive connection between the layers that are used as the starting material or are referred to as such. For example, carbon can diffuse from a layer that has a higher carbon content into a layer that has a lower carbon content. Through these diffusion processes, a material can be formed during the hot forming which has flowing material properties over the thickness. The intermediate layer and / or the transition from one layer to the intermediate layer therefore has a concentration gradient, i.e. H. The concentration of at least one of the above-mentioned elements changes over a certain area of the cross section.

The terms multi-layer composite steel flat semi-finished product, preferably as multi-layer composite coil, multi-layer composite and steel flat semi-finished product, from which the inventive metal semi-finished products, multilayer composite pipes and multilayer composite profiles are produced by forming, in particular cold forming. The aforementioned features of the flat steel semi-finished product do not change as a result of the aforementioned forming. That is, the metal semi-finished products, multilayer composite pipes and multilayer composite profiles according to the invention have the same features mentioned above after forming as the flat steel half tool. Terms such as thickness and the like refer to the wall thickness of the pipes or profiles.

As an alternative, the flat steel semi-finished product is designed as a strip, plate or sheet-shaped semi-finished product. It is preferably in the form of a coil.

According to one embodiment of the flat steel semifinished product, only a first layer with a second layer connected on one side is provided in the simplest embodiment. The free surface of the second layer can be enamelled (as for example in WO 2019/076717 A) or coated with an anti-corrosion coating based on zinc or aluminum or their derivatives, where in particular, alternatively or additionally, the free surface of the first layer is preferably coated with an anti-corrosion coating Zinc base is coated.

The semifinished product preferably comprises two second, i.e. further layers, which are arranged on both sides of the first layer and are connected to it over the entire surface and with a material fit, so that a sandwich material can be provided which, depending on the application, can have a symmetrical or asymmetrical structure.

Both free surfaces of the second layers can be coated with an anti-corrosion coating, preferably on a zinc basis.

In a further embodiment, the flat steel product has at least one, two, three, four or more further layers, which are arranged one above the other on one or both sides of the first layer and are connected to the layer arranged underneath over the entire surface and with a material fit. An intermediate layer, as described above, is arranged between the layers.

One embodiment relates to a semi-finished metal product, characterized in that the first layer made of a steel alloy has a thickness of at least 50% based on the total thickness. In a further embodiment, in particular with two or more further layers, the first layer made of a steel alloy has the greatest thickness in percentage terms compared to the thickness of the individual further layers based on the total material thickness of the flat steel product. This means that in the case of the alternative with a first layer of a steel alloy and only one further layer, the first layer has a thickness of 50% or more based on the total thickness on. In the case of alternatives with several layers, the first layer has the highest percentage value of the thickness in relation to the total thickness.

In the alternative with only two layers, the first layer made of a steel alloy has a material thickness between 98% and 50.0%, preferably at least 50.01%, 55% 60%, 70%, 80% or 90% and a maximum of 70 %, 80%, 90% based on the total material thickness of the flat steel product.

In general, the material thickness is such that the positive properties of neither the first layer nor the further layer or layers are essentially not negatively influenced by the interaction of the layers with one another. In this regard, a difference between the values of the yield strength of the first and at least one further layer must be observed in order to ensure that the different layers also bring different properties. In this context, a difference in tensile strength must also be considered.

One embodiment is characterized in that there is a difference between the tensile strength values of the first layer and the at least one further layer of at least 20 MPa and a maximum of 2000 MPa, preferably at least 30 MPa, particularly preferably at least 40, in particular at least 50 MPa and preferably a maximum of 1500 MPa, 1000 MPa,

900 MPa, 800 MPa, 700 MPa, particularly preferably 600 MPa, in particular 500 MPa.

By combining two different layers, the wall thickness, inner diameter and material quality of pipes / profiles can vary depending on the application and requirement profile. By using the flat steel semi-finished product, the pipes / profiles can have different physical and chemical properties in the pipe wall layers / profile wall layers, depending on the individual layers of the primary materials used.

In the case of asymmetrical flat steel semi-finished products, the outer or inner pipe wall layer or profile layer can be selected simply by forming.

Asymmetrical relates to a non-symmetrical distribution of the layers in the number of layers on both sides of the first layer and / or layers of different thicknesses on both sides of the first layer. Due to the numerous material combinations, different properties can be combined that cannot be represented from a monolithic material; the following alternatives are only mentioned as examples:

1) Tube / profile with a layer resistant to acid gas on the inside and a high-strength layer on the outside;

2) Pipe / profile with an internally wear-resistant and externally ductile layer;

3) Pipe / profile with an internally high or higher strength and externally ductile and deformable layer;

4) Tube / profile with a layer that can be enamelled on the inside and a layer of standard steel quality on the outside;

5) pipe / profile with an inside ductile and outside a high or higher strength layer;

6) Tube / profile with an internally normalized rolled layer and outside heat-treated steel;

7) Tube / profile with an inner layer made of heat-treated steel and an outer normalizing rolled layer;

8) Tube / profile with a layer of standard quality steel on the inside and a layer that can be melt-dipped or electrolytically coated or coated on the outside;

9) Tube / profile with a layer of stainless steel / stainless steel on the inside and a layer of a standard grade steel on the outside;

10) Tube / profile with a layer of standard grade stainless steel on the inside and a stainless steel / stainless steel layer on the outside.

For the purposes of the invention, a steel alloy is selected as the first layer from the group of steels containing or consisting of: so-called carbon steels, such as case-hardening steels with high toughness in the core and wear-resistant surface; Quenched and tempered steels, unalloyed or alloyed, for hardness and toughness as required or spring steels with high abrasion resistance and rigidity; soft, unalloyed steels, if necessary for cold rolling; high strength and higher strength te steels, especially for cold forming; Hot wide strip for the manufacture of pipes; hot rolled tempered steel; wear-resistant steel; Structural steel, such as normalized fine-grain structural steel; weatherproof structural steel; Structural steel or high-strength structural steel; unalloyed structural steel; IF - steel; high strength IF steels; micro-alloy steel; creep-resistant pressure vessel steels; Stainless steel; Quenched and tempered steels; Manganese-boron steels; Boron-alloyed heat treatable steels; Hot strip, in particular for welded and seamless large pipes (such as: L245, L290, L360, L245, L290, L360, L390, L415, L450, L485, L555, L245MS, L290MS, L360MS, L390MS, L415MS, L450MS, L485XMS, 42N485XMS / M, X 52 N / M, X 56 M, X 60M, X 65 M, X 70 M, X 80 M, H40, J55, K55, N80); Steels as used as a standard in the automotive industry, for example: Deep-drawing steels, for example with the designations DC 01 / DX52D, DX 51 D, DC 03 / DX 53D, DC 04 / DX54D, DX05 / DX56D, DC 06 / DX57D, DD14; Conventional higher and high-strength steels (cold strip, with, for example, HC 260LA / AX260LAD, HC 300 LA / HF 300LAD, HC 340 LA / HX340LAD, HC 380 LA / HX380 LAD, HC 420 LA / HX420 LAD, HX 460 LA / HX460 LAD , HX340 LAD, HX380 LAD, HX460 LAD, HX500 LAD, S315 MC, S355 MC, F420 MC, S460 MC, S500 MC, S 600 MC, S 700 MC, S 235 J, S355 J, HX160YD, HC 180Y / HX180YD, HC 220Y / HX220YD, HX260Y / HX260YD, HC 180B / HX180BD, HC 220B / HF 220 BD, HC 260B / HX260 BD); Multi-phase steels (cold strip, with, for example, HC T 780X, HC T980X, HC T500X, HC T600X, HC T780C, HD T580X, HTC 780C, HC T690T, HD T 450F, HD T 560F, HTC 1200); Surface-refined steels, with, for example, ZF 100, ZF 120, Z100, Z140, Z200, Z275, Z350, Z 600, T7200, AS 080, AS 120, AS 150, ZM 070, ZM 100, ZM 120, ZM 160, Z E25 / 25, ZF 50/50, ZE 75/75, ZE 100/100.

A steel alloy from the group mentioned above is selected as at least one or more additional layers; an aluminum-based alloy is also possible. It is essential to the invention that the first and the at least one further layer differ in the values of their yield strength. Given this condition, each combination is possible within the meaning of the invention. Steel alloys from the group described above are preferably used as the first layer and as at least one further layer.

Preferred alternatives are selected from the above group of Examples 1-10 or from the following group, containing or consisting of:

11.) Combination of two-layer material C60 and S 355 + N for the manufacture of concrete pump pipes. The inner layer of the pipe consists of an abrasion-resistant layer C60, the rest Pipe made of a ductile S355 + N layer, with a thickness ratio of 50:50% to 25:75%.

12.) Combination of two-layer stainless steel material with structural steel for pipeline construction

13.) Combination of two-layer material MnB steel with S355J + N for the production of precision tubes for chassis applications with a thickness ratio of 50:50% to 25: 75%.

14.) Combination of two-layer material 26MnB5 and 34MnB5 for the production of precision tubes for chassis applications in a thickness ratio of 50:50% to 25: 75%.

15.) Combination of three-layer material for longitudinally welded pipes for pipeline construction, e.g. as a substitute for solid stainless steel or pipes made of metallurgically clad primary material with a first layer with a layer thickness of 60% with pipe steel quality X60, on both sides a further layer with a layer thickness of 20%: and austenitic stainless steel grade 1.4404.

When using a metal-based multi-layer composite, the properties of the pipe / profile wall layers can be combined in the finished pipe / profile according to the large number of individual layers. The individual layer thicknesses can also vary. Preference is given to using hot-rolling material and form-fitting, two-layer and multi-layer composite coils that can be split horizontally or lengthways before processing, for the production of welded or roll-profiled multi-layer composite pipes or profiles. The steel flat semi-finished product can come from a constant as well as a thickness-varying rolling process.

The individual layers of the flat steel product have different mechanical, chemical and tribological material properties and have the same or different material thicknesses. By combining it into a multi-layer composite, local properties that meet the requirements on the pipe / profile outside and inside are achieved in the pipe / profile produced from it than would be achieved by using a monolithic material.

The use of a two-layer and multi-layer composite coil for direct piping or roll profiling eliminates the time-consuming process of making two individually manufactured pipes / profiles with un- different properties have to be merged. In addition, the material and form fit of the invention is significantly better than in the known processes and applications.

According to a further embodiment of the flat steel product, the steel flat product is produced by means of plating, in particular roll cladding or by means of casting. The flat steel semifinished product according to the invention is preferably produced by means of hot roll cladding, as disclosed, for example, in German patent specification DE 10 2005 006 606 B3.

According to a further embodiment of the steel flat semifinished product, the steel flat semifinished product is made with means of package construction see DE 10 2005 006 606 B3 or composite casting see patent

DE 10 2014 116 949 Al with subsequent roll cladding.

The content of all named patent specifications to which reference is made is hereby incorporated into this application.

As an alternative, the two-layer and multi-layer steel flat semi-finished product is produced in which the slabs of the various materials are pre-rolled in a conventional hot strip mill to the thickness that corresponds to their percentage of the respective layer, so that ultimately when the layers are placed on top of one another, a bond is formed again Slab thickness arises. This is held together by welding the edges together and, in the subsequent final hot-rolling process, is made into a form-fitting and material-locking layer composite with a thickness of 1.5 mm to 25 mm.

In a further alternative, the two-layer and multi-layer steel flat semi-finished product is produced in which a slab with a steel alloy of the first layer is encapsulated by a metallic alloy of the at least further layer and is then further processed as described above, i.e. rolled etc.

The semi-finished metal product is then produced directly from the flat steel semi-finished product, preferably by cold forming. In particular, the cold forming is carried out by folding, UO forming or roll profiling to produce a profile and, if necessary, subsequent welding. In an alternative, the subsequent piping or profiling takes place in a continuous process from the broadband or narrowband coil. The cold forming of the flat steel semi-finished product according to the invention, which is provided in sheet or plate form This can be done, for example, in a discontinuous process by folding or RO-forming, preferably in conventional forming tools. Alternatively and preferably, the shaping of, for example, strip-shaped flat steel semi-finished products can be carried out inexpensively by roll profiling on preferably conventional profiling systems. By folding, UO-shaping or roll profiling, open or closed profiles with different cross-sectional geometries can be produced, depending on the requirements. The manufactured profiles can have a longitudinally constant or a longitudinally variable cross-section aufwei sen.

In one embodiment, FIF welding is used. In the finished pipe or closed hollow profile, the individual layers or layers are essentially present in the area of the weld seam despite the welding process. A mixed phase, which can have gradients, is essentially avoided so that the specific properties of the individual layers are retained. In the context of the invention, "essentially" means that a property or feature of a layer or layer can be increased by a maximum of 50%, 40%, 35%, 30%, preferably 25%, 20%, particularly preferably 15%, 12%, 10%, especially 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1% percent or 0%, i.e. not changing at all. One such characteristic is, for example, the concentration of one of the alloying elements. I.e. with regard to the concentration, there are no or only slight gradients in the weld seam, as described above. Other such features would be, for example, the presence of certain phases, lattice structures, etc. In one embodiment, the semi-finished metal product is thus a tube, an open or closed hollow profile.

As a result of the cold forming, the semi-finished metal product has the same properties and features as the flat steel semi-finished product, in particular with regard to the structure of the individual layers, their composition, their chemical and physical properties and the thickness; it only differs in shape due to the deformation and, in the case of a closed profile or pipe, in the presence of a weld seam. Accordingly, other features are only present in the area of the weld seam, but these have no influence on the use of the semi-finished metal product.

Another object of the invention relates to a method for producing a metal semifinished product, as described above, by cold forming a flat steel semifinished product, also as described above. In one embodiment, the flat steel product is manufactured by means of plating or by means of casting. The present invention also relates to a tube and / or profile produced by cutting, joining, coating or reshaping the semi-finished metal product as described above or produced in a method according to the invention.

The invention also relates to the use of a tube and / or profile according to the invention in vehicle, railway, shipbuilding or aerospace, in automobi len applications, for example in chassis, steering and drive systems and structural components, as well as in OCTG (Oil Country Tubular Goods) and industrial applications, such as media transport, liquid and gaseous media, for example hydrogen, water, petroleum, natural gas, biogas, concrete, with a flat steel product according to the invention being formed cold or warm.

The objects of the invention have a number of advantages, such as:

• The combination of two or more metallic materials can produce chemical and / or physical properties that are not possible with a monolithic material;

• a positive connection is established;

• There are lower manufacturing tolerances compared to prior art methods;

• The possibility of continuous production from a coil is made available, which is not possible with the prior art. As a result, any pipe / profile length can be produced, circular welds are avoided;

• There are cost advantages due to a more stable and faster process compared to the state of the art; In particular, cost savings compared to monolithic material, through any distribution of the layer thicknesses within the material composite. As a result, e.g. a stainless steel wear layer can be reduced to a minimum.

Claims

1. Cold or hot-formed semi-finished metal product made from a hot-rolled or cold-rolled multi-layer composite steel flat product with the following features: a) a thickness of at least 0.8 mm to a maximum of 25.0 mm, b) comprising a first layer made of a steel alloy and at least a further metallic layer, which is fully and cohesively connected to the first layer, c) a difference between the values of the yield strength of the first layer and the at least one further layer of at least 10 MPa and a maximum of 2000 MPa; d) an intermediate layer is arranged between the first layer and the at least one further layer, e) the intermediate layer and / or the transition from one layer to the intermediate layer has a concentration gradient containing at least one of the elements from the group: C, AI , Si, Mn, P, S, N, Ti, B, Cu, Sn, Sb, Ca, As, Cr, Ni, Mo, V, Nb.

2. Semi-finished metal product according to claim 1, characterized in that the flat steel half product comprises two further layers which are arranged on both sides of the first layer and are connected to it over the entire surface and with a material fit.

3. Semi-finished metal product according to claim 2, characterized in that the flat steel product comprises at least one, two, three, four or more further layers, which are arranged one above the other on both sides of the first layer and are connected to the layer underneath over the entire surface and materially and an intermediate layer according to claim 1 is arranged between the layers.

4. Semi-finished metal product according to one of the preceding claims, characterized in that the first layer made of a steel alloy has a material thickness between 98% and 50% based on the total material thickness of the flat steel semi-finished product.

5. Semi-finished metal product according to one of the preceding claims, characterized in that the first layer made of a steel alloy has the greatest percentage thickness compared to the thickness of the individual further layers based on the total material thickness of the steel flat semi-finished product.

6. Semi-finished metal product according to one of the preceding claims, characterized in that there is a difference between the values of the tensile strength of the first layer and the min least one further layer of at least 20 MPa and a maximum of 2000 MPa.

7. Semi-finished metal product according to one of the preceding claims, characterized in that the flat steel semi-finished product is produced by means of plating or by means of casting.

8. Semi-finished metal product according to one of the preceding claims, characterized in that it is produced from the flat steel semi-finished product by cold forming.

9. Semi-finished metal product according to claim 8, characterized in that cold forming is carried out by folding, U-O forming or roll profiling to produce a profile and, if appropriate, subsequent welding.

10. Semi-finished metal product according to one of the preceding claims, characterized in that it is a tube, an open or closed hollow profile.

11. Metal semifinished product according to one of the preceding claims, characterized in that it differs from the flat steel semifinished product only in the shape and possibly in the presence of a weld seam.

12. A method for producing a metal semifinished product according to any one of claims 1-11 by cold forming a flat steel semifinished product as described in claims 1-6.

13. The method for producing a metal semi-finished product according to claim 12, characterized in that the flat steel semi-finished product is produced by means of plating or by means of casting.

14. Pipe and / or profile, produced by cutting, joining, coating or reshaping the semi-finished metal product according to one of claims 1-11 or produced in a method according to one of claims 12 or 13.

15. Use of a tube and / or profile according to claim 14 in vehicle, railway, shipbuilding or aerospace, in automotive applications, for example in chassis, steering and drive systems and structural components, as well as in OCTG and in industrial Applications such as media transport.