Steel strapping and methods of use

Abstract

Various embodiments of the present disclosure provide a steel strapping and a method of applying the steel strapping around a coil at elevated temperatures. The steel strapping comprises an austenitic stainless steel including an austenite stabilizer.

Description

STEEL STRAPPING AND METHODS OF USEPRIORITY

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application 63 / 695,839, filed September 17, 2024, the entire contents of which is incorporated by reference.FIELD

[0002] The present disclosure relates to steel strapping and methods of using the steel strapping, for example, steel strapping comprising austenitic stainless steels having austenite stabilizers. More particularly, the disclosure relates to applying the steel strapping around coils at elevated temperatures.BACKGROUND

[0003] Steel strapping, due to their good tensile strength and shock resistance at room temperature, are often used to secure articles (e.g., coils) for shipping or storage purposes.For example, cold-rolled, heat-treated steel strapping provides strong mechanical strength and packaging effectiveness for heavy-duty applications (e.g., securing coils) at room temperature. However, steel strapping tends to lose mechanical strength and soften at elevated temperatures.SUMMARY

[0004] Various embodiments of the present disclosure provide steel strapping. The steel strapping as described herein provides desired mechanical strength at both room temperature and elevated temperatures and provides stable elongation and bending properties at elevated temperatures.

[0005] Various embodiments of the present disclose also provide methods of applying the steel strapping as described herein around coils at elevated temperatures. The steel strapping, when applied around coils at such temperatures, retains desired mechanical strength as well as elongation and bending properties, and therefore, are suitable to be used to secure coils at elevated temperatures.

[0006] In one embodiment, the steep strapping comprises an austenitic stainless steel, wherein the austenitic stainless steel comprises carbon in an amount up to 0.6 % by weight, silicon in an amount up to 2 % by weight, chromium in an amount up to 20 % by weight, and an austenite stabilizer. The steel strapping has a tensile strength (Rm) of at least 500 MPa at a temperature between 500 °C and 600 °C, and an elongation at break Aso in a range of 15 % to 20 % at a temperature between 500 °C and 600 °C.

[0007] In one embodiment, a method comprises directing a leading end of a steel strapping drawn from a supply around a coil that is at a temperature between 500 °C and 600 °C, wherein the steel strapping is a steel strapping as described herein, and wherein the steel strapping has a thickness in a range of 0.60 mm to 1.50 mm and a width in a range of 19 mm to 35 mm. The method also comprises attaching the leading end of the steel strapping to a portion of the steel strapping to form the loop of strap.BRIEF DESCRIPTION OF THE FIGURES

[0008] Figure 1 A illustrates the tensile strengths of Steel Strapping and Comparative Steel Strapping A and B, respectively, at room temperature.

[0009] Figure IB illustrates the tensile strengths of Steel Strapping and Comparative SteelStrapping A and B, respectively, at a temperature of 500 °C.

[0010] Figure 1C illustrates the tensile strengths of Steel Strapping and Comparative Steel Strapping A and B, respectively, at a temperature of 600 °C.

[0011] Figure 2A illustrates the elongation at break Aso of Steel Strapping and Comparative Steel Strapping A and B, respectively, at room temperature.

[0012] Figure 2B illustrates the elongation at break Aso of Steel Strapping and Comparative Steel Strapping A and B, respectively, at a temperature of 500 °C.

[0013] Figure 2C illustrates the elongation at break Aso of Steel Strapping and Comparative Steel Strapping A and B, respectively, at a temperature of 600 °C.

[0014] Figure 3 A illustrates the tensile strengths of Steel Strapping when subjected to various performance tests.

[0015] Figure 3B illustrates the elongation at break of Steel Strapping when subjected to various performance tests.DETAILED DESCRIPTION

[0016] Various embodiments of the present disclosure provide steel strapping and methods of using the steel strapping, for example, steel strapping comprising austenitic stainless steels having austenite stabilizers. As shown in the examples below, the steel strapping as described herein provides great mechanical strength at both room temperature and elevated temperatures and provides stable elongation and bending properties at elevated temperatures. The steel strapping of the present disclosure can therefore be used to secure coils at elevated temperatures.

[0017] As used herein, the term “about” is understood to refer to ± 10% of the stated value.For example, “about 3 % by weight” would be understood to refer to a value that is “in the range of 2.7 to 3.3 % by weight.”I. Steel Strapping

[0018] As described herein, the present disclosure relates to steel strapping. In various embodiments, the steel strapping comprises an austenitic stainless steel.

[0019] The amount of carbon (C) in steel plays a major role in the formation of austenite, which can ultimately affect the strength of the steel. A sufficient amount of carbon allows a desired austenitization to occur; however, an excessive amount of carbon can negatively affect the weldability of the steel.

[0020] Accordingly, in various embodiments as otherwise described herein, the austenitic stainless steel comprises carbon in an amount up to 0.6 % by weight, e.g., in an amount up to 0.5 % by weight, or up to 0.4 % by weight, or up to 0.3 % by weight. In various embodiments, the austenitic stainless steel comprises carbon in an amount of at least 0.2 % by weight, e.g., in an amount of at least 0.3 % by weight. For example, the austenitic stainless steel comprises carbon in an amount of about 0.3 % by weight.

[0021] In certain embodiments, steel includes a low amount of silicon (Si) to provide a good surface quality. Accordingly, in various embodiments as otherwise described herein, the austenitic stainless steel comprises silicon in an amount up to 2 % by weight, e.g., in an amount up to 1.5 % by weight, or up to 1 % by weight, or up to 0.5 % by weight. In various embodiments, the austenitic stainless steel comprises silicon in an amount of at least 0.2 % by weight, e.g., in an amount of at least 0.3 % by weight. For example, the austenitic stainless steel comprises silicon in an amount of about 0.3 % by weight.

[0022] In certain embodiments, steel includes chromium (Cr) to suppress the formation of perlite and to increase the strength of the steel. Inclusion of an excessive amount of chromium can potentially lead to cracks in the steel. Accordingly, in various embodiments as otherwise desired herein, the austenitic stainless steel comprises chromium in an amount upto 20 % by weight, e.g., in an amount up to 18 % by weight, or up to 16 % by weight, or up to 14 % by weight. In various embodiments, the austenitic stainless steel comprises chromium in an amount of at least 12 % by weight, e.g., in an amount of at least 14 % by weight. For example, the austenitic stainless steel comprises chromium in an amount of about 14 % by weight.

[0023] In various embodiments as otherwise described herein, the austenitic stainless steel comprises an austenite stabilizer to stabilize the austenitic structure of steel. The presence of the austenite stabilizer can enhance the strength and toughness of the steel. In various embodiments, the austenitic stainless steel comprises an austenite stabilizer in an amount up to 18 % by weight, e.g., in an amount up to 16 % by weight. In various embodiments, the austenitic stainless steel comprises an austenite stabilizer in an amount of at least 14 % by weight, e.g., in an amount of at least 16 % by weight. For example, in various embodiments, the austenitic stainless steel comprises an austenite stabilizer in the range of 14 % to 18 % by weight, e.g., in an amount in a range of 14 % to 17 % by weight, or 14 % to 16 % by weight, or 14 % to 15 % by weight, or 15 % to 18 % by weight, or 15 % to 17 % by weight, or 15 % to 16 % by weight, or 16 % to 18 % by weight, or 16 % to 17 % by weight. For example, the austenitic stainless steel comprises an austenite stabilizer in an amount of about 16 % by weight.

[0024] In one embodiment, the austenite stabilizer is manganese (Mn). Addition of manganese can facilitate the addition of other elements (e.g., nitrogen) in the steel, thus strengthening the mechanical properties of the steel. Manganese can also help refine crystal grains in the steel, contributing to the toughness of the steel. Moreover, when there is sulfur in the steel, manganese can react with the sulfur (e.g., to form manganese sulfide), which helps minimize the brittleness of the steel. However, an excessive amount of manganese can adversely impact the elongation and bending properties as well as the weldability of the steel.

[0025] Accordingly, in various embodiments as otherwise described herein, the austenitic stainless steel comprises manganese in an amount in a range of 14 % to 18 % by weight, e.g., in an amount in a range of 14 % to 17 % by weight, or 14 % to 16 % by weight, or 14 % to 15 % by weight, or 15 % to 18 % by weight, or 15 % to 17 % by weight, or 15 % to 16 % by weight, or 16 % to 18 % by weight, or 16 % to 17 % by weight. For example, the austenitic stainless steel comprises manganese in an amount of about 16 % by weight. In this embodiment, the austenitic stainless steel is free of nickel.

[0026] In another embodiment, the austenite stabilizer is nickel (Ni). Nickel, when included in steel, provides similar functions as manganese, but is more expensive than manganese. Accordingly, in various embodiments as otherwise described herein, the austenitic stainless steel comprises either manganese or nickel, but not both.

[0027] In another embodiment, the austenitic stainless steel comprises both manganese and nickel. In various embodiments, the austenitic stainless steel comprises manganese in any of the amounts described herein between 14 % to 18 % by weight and nickel in an amount up to 0.30 % by weight. For example, the austenitic stainless steel comprises manganese in an amount of about 16 % by weight and nickel in an amount of about 0.25 % by weight.

[0028] The steel strapping can include iron (Fe) and some impurities. Accordingly, in various embodiments as otherwise described herein, the steel strapping further comprises iron. Moreover, in various embodiments, the steel strapping comprises impurities, including, but not limited to, phosphorus (P), sulfur (S), nitrogen (N), and / or copper (Cu).

[0029] In various embodiments, the phosphorus is in an amount up to 0.05 % by weight, e.g., in an amount up to 0.04 % by weight, or up to 0.03 % by weight, or up to 0.02 % by weight. In various embodiments, the phosphorus is in an amount of at least 0.01 % by weight,e.g., in an amount of at least 0.02 % by weight. For example, the phosphorus is in an amount of about 0.02 % by weight.

[0030] In various embodiments, the sulfur is in an amount up to 0.015 % by weight, e.g., in an amount up to 0.010 % by weight, or up to 0.005 % by weight, or up to 0.002 % by weight. For example, the sulfur is in an amount of about 0.001 % by weight.

[0031] In various embodiments, the nitrogen is in an amount up to 0.4 % by weight, e.g., in an amount up to 0.3 % by weight, or up to 0.2 % by weight. In various embodiments, the nitrogen is in an amount of at least 0.2 % by weight, e.g., in an amount of at least 0.3 % by weight. For example, the nitrogen is in an amount of about 0.3 % by weight.

[0032] In various embodiments, the copper is in an amount up to 2.0 % by weight, e.g., in an amount up to 1.5 % by weight, or up to 1.0 % by weight, or up to 0.5 % by weight. For example, the copper is in an amount of about 0.5 % by weight.

[0033] As described herein, the steel strapping of the present disclosure provides excellent mechanical strength at both room temperature and elevated temperatures. Accordingly, in various embodiments as otherwise described herein, the steel strapping has a tensile strength (Rm) of at least 750 MPa at a temperature of about 500 °C, as measured by ISO 6892-2. In various embodiments, the steel strapping has a tensile strength (Rm) of at least 650 MPa at a temperature of about 600 °C, as measured by ISO 6892-2. In various embodiments as otherwise described herein, the tensile strength (Rm) of the steel strapping is measured by ASTM E21.

[0034] The steel strapping as described herein also provides stable elongation and bending properties at elevated temperatures. Accordingly, in various embodiments as otherwise described herein, the steel strapping has an elongation at break Aso of about 17 % at a temperature of about 500 °C, as measured by ISO 6892-2. In various embodiments, the steelstrapping has an elongation at break Aso of about 18 % at a temperature of about 600 °C, as measured by ISO 6892-2. In various embodiments as otherwise described herein, the elongation at break Aso of the steel strapping is measured by ASTM E21.

[0035] In various embodiments, the steel strapping as described herein has a thickness in a range of 0.60 mm to 1.50 mm, e.g., in a range of 0.60 mm to 1.40 mm, or 0.60 mm to 1.30 mm, or 0.60 mm to 1.20 mm, or 0.60 mm to 1.10 mm, or 0.60 mm to 1.00 mm, or 0.60 mm to 0.90 mm, or 0.60 mm to 0.80 mm, or 0.70 mm to 1.50 mm, or 0.70 mm to 1.40 mm, or 0.70 mm to 1.30 mm, or 0.70 mm to 1.20 mm, or 0.70 mm to 1.10 mm, or 0.70 mm to 1.00 mm, or 0.70 mm to 0.90 mm, or 0.70 mm to 0.80 mm, or 0.80 mm to 1.50 mm, or 0.80 mm to 1.40 mm, or 0.80 mm to 1.30 mm, or 0.80 mm to 1.20 mm, or 0.80 mm to 1.10 mm, or 0.80 mm to 1.00 mm, or 0.80 mm to 0.90 mm. For example, the steel strapping has a thickness of about 0.8 mm.

[0036] In various embodiments, the steel strapping as described herein has a width in a range of 19 mm to 35 mm, e.g., in a range of 19 mm to 30 mm, or 19 mm to 25 mm, or 25 mm to 35 mm, or 25 mm to 30 mm, or 30 mm to 35 mm. For example, the steel strapping has a width of about 32 mm.

[0037] In various embodiments, the steel strapping as described herein has a break load in a range of 29000 N to 35000 N at room temperature, e.g., in a range of 29000 N to 34500 N, or 29000 N to 34000 N, or 29000 N to 33500 N, or 29000 N to 33000 N, or 29000 N to 32500 N, or 29000 N to 32000 N, or 29000 N to 31500 N, or 29000 N to 31000 N, or 29000 N to 30500 N, or 29000 N to 30000N, or 29000 N to 29500 N, or 29500 N to 35000 N, or 29500 N to 34500 N, or 29500 N to 34000 N, or 29500 N to 33500 N, or 29500 N to 33000 N, or 29500 N to 32500 N, or 29500 N to 32000 N, or 29500 N to 31500 N, or 29500 N to 31000 N, or 29500 N to 30500 N, or 29500 N to 30000N, or 30000 N to 35000 N, or 30000 N to34500 N, or 30000 N to 34000 N, or 30000 N to 33500 N, or 30000 N to 33000 N, or 30000 N to 32500 N, or 30000 N to 32000 N, or 30000 N to 31500 N, or 30000 N to 31000 N, or 30000 N to 30500 N, as measured by ISO 6892-1. For example, the steel strapping has a break load in a range of 29440 N to 33280 N at room temperature, as measured by ISO 6892- 1.

[0038] In various embodiments, the steel strapping as described herein has a tensile strength in a range of 1000 MPa to 1500 MPa at room temperature, e.g., in a range of 1000 MPa to 1450 MPa, or 1000 MPa to 1400 MPa, or 1000 MPa to 1350 MPa, or 1000 MPa to 1300 MPa, or 1000 MPa to 1250 MPa, or 1000 MPa to 1200 MPa, or 1000 MPa to 1150 MPa, or 1000 MPa to 1100 MPa, or 1000 MPa to 1050 MPa, or 1050 MPa to 1500 MPa, or 1050 MPa to 1450 MPa, or 1050 MPa to 1400 MPa, or 1050 MPa to 1350 MPa, or 1050 MPa to 1300 MPa, or 1050 MPa to 1250 MPa, or 1050 MPa to 1200 MPa, or 1050 MPa to 1150 MPa, or 1050 MPa to 1100 MPa, or 1100 MPa to 1500 MPa, or 1100 MPa to 1450 MPa, or 1100 MPa to 1400 MPa, or 1100 MPa to 1350 MPa, or 1100 MPa to 1300 MPa, or 1100 MPa to 1250 MPa, or 1100 MPa to 1200 MPa, or 1100 MPa to 1150 MPa, or 1150 MPa to 1500 MPa, or 1150 MPa to 1450 MPa, or 1150 MPa to 1400 MPa, or 1150 MPa to 1350 MPa, or 1150 MPa to 1300 MPa, or 1150 MPa to 1250 MPa, or 1150 MPa to 1200 MPa, or 1200 MPa to 1500 MPa, or 1200 MPa to 1450 MPa, or 1200 MPa to 1400 MPa, or 1200 MPa to 1350 MPa, or 1200 MPa to 1300 MPa, or 1200 MPa to 1250 MPa, as measured by ISO 6892-1.

[0039] In various embodiments, the steel strapping as described herein has a sealed joint efficiency in a range of 50 % to 70 % of an average break strength at room temperature, e.g., in a range of 50 % to 65 %, or 50 % to 60 %, or 50 % to 55 %, or 55 % to 70 %, or 55 % to 65 %, or 55 % to 60 %, or 60 % to 70 %, or 60 % to 65 %, or 65 % to 70 %, as measured byISO 6892-1.

[0040] In various embodiments, the steel strapping as described herein has a sealless joint efficiency in a range of 60 % to 80 % of an average break strength at room temperature, e.g., in a range of 60 % to 75 %, or 60 % to 70 %, or 60 % to 65 %, or 65 % to 80 %, or 65 % to 75 %, or 65 % to 70 %, or 70 % to 80 %, or 70 % to 75 %, or 75 % to 80 %, as measured by ISO 6892-1.

[0041] In various embodiments, the steel strapping as described herein has a welded joint efficiency in a range of 80 % to 100 % of an average break strength at room temperature, e.g., in a range of 80 % to 95 %, or 80 % to 90 %, or 80 % to 85 %, or 85 % to 100 %, or 85 % to 95 %, or 85 % to 90 %, or 90 % to 100 %, or 90 % to 95 %, or 95 % to 100 %, as measured by ISO 6892-1.

[0042] In various embodiments, the steel strapping as described herein the steel strapping has an elongation at break Aso in a range of 10 % to 20 % at room temperature, e.g., in a range of 10 % to 18 %, or 10 % to 16 %, or 10 % to 14 %, or 10 % to 12 %, or 12 % to 20 %, or 12 % to 18 %, or 12 % to 16 %, or 12 % to 14 %, or 14 % to 20 %, or 14 % to 18 %, or 14 % to 16 %, or 16 % to 20 %, or 16 % to 18 %, or 18 % to 20 %, as measured by ISO 6892-2. For example, the steel strapping has an elongation at break Aso of about 13 % at room temperature.

[0043] As described herein, the present disclosure also relates to methods of applying the steel strapping around coils heated to elevated temperatures, such as temperatures between 500 °C and 600 °C. The coils can include coils of hot-rolled material, such as steel, aluminum, or other metals.

[0044] In various embodiments as otherwise described herein, the method comprises directing a leading end of a steel strapping drawn from a supply around a coil that is at anelevated temperature, e.g., between 500 °C and 600 °C, and attaching the leading end of the steel strapping to a portion of the steel strapping to form the loop of strap.

[0045] In various embodiments, the steel strapping is a steel strapping as described herein.

[0046] In various embodiments, the supply is a roll of steel strapping that is mounted to a strapping dispenser. In various such embodiments, directing the leading end of the steel strapping drawn from the supply around the coil involves drawing the steel strapping from the roll of steel strapping.

[0047] In various embodiments, the method is carried out by an automated strapping machine. The strapping machine forms a loop of the steel strapping around the coil. The strapping machine includes a strap chute that encircles the coil, a strapping head that forms the strap loop using steel strapping drawn from the roll, a controller that controls the strapping head to strap the coil, and a frame that supports these components. A typical strapping head includes a strap-feeding assembly, a strap-tensioning assembly, and a strapsealing assembly. The strap-feeding assembly is configured to feed steel strapping from the roll into and around the strap chute and to retract the steel strapping so it exits the strap chute and moves radially inwardly into engagement with the coil. The strap-tensioning assembly is configured to tension the steel strapping around the coil. The strap-sealing assembly is configured to hold the leading end of the steel strapping, to attach two portions of the steel strapping together to form the tensioned strap loop, and to cut the tensioned strap loop from the remaining steel strapping.

[0048] To strap the coil, the strapping machine carries out a strapping process including a strap-feeding cycle, a strap-retraction cycle, a strap-tensioning cycle, and a strap-sealing cycle. The strapping machine first carries out the strap-feeding cycle during which the strapfeeding assembly feeds steel strapping (with the leading end first) through the strap-sealingassembly and into and around the strap chute until the leading strap end returns to the strapsealing assembly. The strapping machine then carries out the strap-retraction cycle during which the strap-sealing assembly holds the leading end while the strap-feeding assembly retracts the steel strapping to pull the steel strapping out of the strap chute and onto and around the coil. The strapping machine then carries out the strap-tensioning cycle during which the strap-tensioning assembly tensions the steel strapping to a designated strap tension. The strapping machine then carries out the strap-sealing cycle during which the strap-sealing assembly attaches the leading end to another portion of the steel strapping to form a strap joint, thereby forming a tensioned strap loop around the load, and cuts the tensioned strap loop from the remaining strap. In some embodiments, the remaining strap is a trailing end of the steel strapping.

[0049] The manner of attaching the two portions of the steel strapping to one another depends on the type of strapping machine. Some strapping machines include strapping heads with jaws that mechanically deform (referred to as “crimping” in the industry) or cut notches into (referred to as “notching” in the industry) a seal element positioned around the two portions of the steel strapping to attach them to one another. Other strapping machines include strapping heads with punches and dies configured to form a set of mechanically interlocking cuts in the two portions of the steel strapping to attach them to one another (referred to in the strapping industry as a “sealless” attachment). Still other strapping machines configured for metal strap include strapping heads with spot, inert-gas, or other welders configured to weld the two portions of the steel strapping to one another. In some embodiments, the other welder is a friction welder or an ultrasonic welder.

[0050] Accordingly, by incorporating austenite stabilizers in an austenitic stainless steel, the steel strapping as described herein provides great mechanical strength at both room temperature and elevated temperatures and provides stable elongation and bending propertiesat elevated temperatures. In particular, the present inventors have determined that including a certain amount of austenite stabilizers (e.g., manganese) in the austenitic stainless steel can not only retain the stability of the austenitic structure of the steel strapping but also contribute to the mechanical strength as well as the elongation and bending properties of the steel strapping at elevated temperatures. Furthermore, the steel strapping as described herein, when applied around coils, especially at elevated temperatures, do not stick to the coils, provides high strength resistance to the coils, and exhibit great corrosion resistance and weldability. The steel strapping as described herein therefore is suitable for a wide range of heavy-duty applications in various industries.II. Examples

[0051] Testing was performed on exemplary steel strapping as described herein. Table 1 lists the compositions of one such exemplary steel strapping — Steel Strapping — and two comparative steel strapping — Comparative Steel Strapping A and B. Comparative Steel Strapping A is a commercially available steel strapping by Signode, which is a cold-rolled, heat-treated steel strapping. Comparative Steel Strapping B is another commercially available steel strapping by Signode, which is a cold-rolled steel strapping without heat treatment. For each, the amount of each element is provided as % by weight, and each has a thickness of about 0.80 mm and a width of about 32 mm.TABLE 1. Compositions of Steel Strapping and Comparative Steel Strapping A and B1. _ Tensile Strength

[0052] Tensile strength tests are to measure the maximum amount of stress a material can withstand before breaking when the material is stretched or pulled. To evaluate the tensile strength of the steel strapping as described herein, the present inventors have performed the tests on Steel Strapping in line with ISO 6892-2. For comparison, the present inventors have also performed the tests on Comparative Steel Strapping A and B under similar conditions.

[0053] Figure 1 A illustrates the tensile strengths of Steel Strapping and Comparative Steel Strapping A and B, respectively, at room temperature. As shown in Figure 1 A, all of Steel Strapping and Comparative Steel Strapping A and B exhibit a relatively high tensile strength in a range of 1000 MPa to 1200 MPa.

[0054] However, when the tests are performed at elevated temperatures, especially at a temperature of 500 °C or 600 °C, the tensile strengths of Comparative Steel Strapping A and B drop below 500 MPa, as shown in Figures IB and 1C. In particular, Figure IB shows that at 500 °C, the tensile strength of Steel Strapping nearly doubles that of either Comparative Steel Strapping A or B, with each of Comparative Steel Strapping A and B having a tensile strength below 500 MPa.

[0055] Similar results are shown in Figure 1C, where each of Comparative Steel Strapping A and B exhibits a tensile strength below 250 MPa at 600 °C, about 80 % lower than their tensile strengths at room temperature, respectively. In great contrast, the tensile strength of Steel Strapping remains high at 600 °C, about three times higher than that of ComparativeSteel Strapping A or B. Surprisingly, Steel Strapping retains about two thirds of its tensile strength at room temperature at 600 °C.

[0056] Collectively, the data above shows that while Comparative Steel Strapping A and B have good tensile strengths at room temperature, they lose strengths significantly at elevated temperatures. On the other hand, Steel Strapping not only demonstrates great tensile strength at room temperature, but exhibits remarkably high tensile strength at elevated temperatures. Without intending to be bound by theory, the present inventors believe that the considerable loss of the tensile strength for either of Comparative Steel Strapping A and B is likely due to their microstructural changes at elevated temperatures, whereas the addition of austenite stabilizers such as manganese stabilizes the austenitic structure of Steel Strapping and therefore retains the strength and toughness of Steel Strapping even at elevated temperatures.2, Elongation

[0057] Elongation tests are to measure the ductility of a material. The measurement indicates how much a material can be stretched before it eventually snaps or breaks. To evaluate the elongation of the steel strapping as described herein, the present inventors have performed the tests on Steel Strapping in line with ISO 6892-2. For comparison, the present inventors have also performed the tests on Comparative Steel Strapping A and B under similar conditions.

[0058] Figure 2A illustrates the elongation at break Aso of Steel Strapping and Comparative Steel Strapping A and B, respectively, at room temperature. As shown in Figure 2A, all of Steel Strapping and Comparative Steel Strapping A and B exhibit an elongation at break Aso in a range of 10 % to 16 %.

[0059] However, when the tests are performed at elevated temperatures, especially at a temperature of 500 °C or 600 °C, the elongation of either Comparative Steel Strapping A or B changes markedly. As shown in Figure 2B, at a temperature of 500 °C, Comparative SteelStrapping A exhibits an elongation at break Aso lower than that at room temperature, and Comparative Steel Strapping B exhibits an elongation at break Aso more than double of that at room temperature. Furthermore, Figure 2C shows that at a temperature of 600 °C, both Comparative Steel Strapping A and B soften dramatically, with an elongation at break Aso about three or four times higher than that at room temperature and more than double of that at 500 °C. The data indicates that neither Comparative Steel Strapping A nor B is stable in elongation at elevated temperatures, with Comparative Steel Strapping B becoming much softer and thus much weaker in strength at elevated temperatures.

[0060] On the other hand, Figures 2B and 2C show that Steel Strapping maintains stable in elongation at 500 °C and 600 °C, with an elongation at break Aso comparable to that at room temperature. Unlike Comparative Steel Strapping A or B, Steel Strapping does not soften or lose strength at elevated temperatures.3. Performance under Combined Thermal and Tensile Stress

[0061] To simulate real-world operating conditions, Steel Strapping was exposed to high temperatures of 500, 600, 700, or 800 °C for 20 minutes, then subjected to sustained tension equivalent to 50% of its breaking strength for 12 hours. These tests were performed using a tensile testing machine according to ASTM E21.

[0062] The conditions and results of this test are depicted in Figures 3 A and 3B, and summarized in Table 2 below.TABLE 2. Performance Tests of Steel Strapping

[0063] After soaking at 500 °C for 20 minutes, Steel Strapping exhibited a tensile strength of 831 MPa and an elongation of 19.8 % after 1.98 kN of sustained tension was applied for 12 hours. After soaking at 600 °C for 20 minutes, Steel Strapping exhibited a tensile strength of 706 MPa and an elongation of 16.2 % after 1.98 kN of sustained tension was applied for 12 hours. After soaking at 700 °C for 20 minutes, Steel Strapping exhibited a tensile strength of 412 MPa and an elongation of 10.1 % after 1.98 kN of sustained tension was applied for 12 hours. After soaking at 800 °C for 20 minutes, Steel Strapping exhibited a tensile strength of 196 MPa and an elongation of 12.3 % after 0.55 kN of sustained tension was applied for 12 hours. In each of the tests above, Steel Strapping maintained its integrity and did not fail under the applied load.

[0064] Accordingly, the data above demonstrate that Steel Strapping provides stable elongation and bending properties not only at room temperature but at elevated temperatures. However, Comparative Steel Strapping A and B do not maintain their elongation but soften at elevated temperatures. Without intending to be bound by theory, the present inventors believe that the presence of austenite stabilizers strengthens the microstructure of Steel Strapping, making it remarkably stable in elongation even at elevated temperatures.III. CONCLUSION

[0065] Thus, in various embodiments, the present disclosure provides a steel strapping. The steel strapping comprises an austenitic stainless steel, wherein the austenitic stainless steel comprises carbon in an amount up to 0.6 % by weight, silicon in an amount up to 2 % by weight, chromium in an amount up to 20 % by weight, and an austenite stabilizer, and wherein the steel strapping has a tensile strength (Rm) of at least 500 MPa at a temperature between 500 °C and 600 °C, and an elongation at break Aso in a range of 15 % to 20 % at a temperature between 500 °C and 600 °C.

[0066] In various such embodiments of the steel strapping, the austenitic stainless steel comprises carbon in an amount of at least 0.2 % by weight.

[0067] In various such embodiments of the steel strapping, the austenitic stainless steel comprises carbon in an amount of about 0.3 % by weight.

[0068] In various such embodiments of the steel strapping, the austenitic stainless steel comprises silicon in an amount of at least 0.2 % by weight.

[0069] In various such embodiments of the steel strapping, the austenitic stainless steel comprises silicon in an amount of about 0.3 % by weight.

[0070] In various such embodiments of the steel strapping, the austenitic stainless steel comprises chromium in an amount of at least 12 % by weight.

[0071] In various such embodiments of the steel strapping, the austenitic stainless steel comprises chromium in an amount of about 14 % by weight.

[0072] In various such embodiments of the steel strapping, the austenitic stainless steel comprises the austenite stabilizer in an amount up to 18 % by weight.

[0073] In various such embodiments of the steel strapping, the austenitic stainless steel comprises the austenite stabilizer in an amount of at least 14 % by weight.

[0074] In various such embodiments of the steel strapping, the austenitic stainless steel comprises the austenite stabilizer in an amount of about 16 % by weight.

[0075] In various such embodiments of the steel strapping, the austenite stabilizer is manganese.

[0076] In various such embodiments of the steel strapping, the austenitic stainless steel comprises nickel in an amount up to 0.30 % by weight.

[0077] In various such embodiments of the steel strapping, the austenitic stainless steel comprises nickel in an amount of about 0.25 % by weight.

[0078] In various such embodiments of the steel strapping, the austenitic stainless steel is free of nickel.

[0079] In various such embodiments of the steel strapping, the austenitic stabilizer is nickel.

[0080] In various such embodiments of the steel strapping, the steel strapping further comprises iron.

[0081] In various such embodiments of the steel strapping, the steel strapping further comprises impurities.

[0082] In various such embodiments of the steel strapping, the impurities comprise phosphorus, sulfur, nitrogen, and / or copper.

[0083] In various such embodiments of the steel strapping, the phosphorus is in an amount up to 0.05 % by weight.

[0084] In various such embodiments of the steel strapping, the phosphorus is in an amount of at least 0.01 % by weight.

[0085] In various such embodiments of the steel strapping, the phosphorus is in an amount of about 0.02 % by weight.

[0086] In various such embodiments of the steel strapping, the sulfur is in an amount up to 0.015 % by weight.

[0087] In various such embodiments of the steel strapping, the sulfur is in an amount of about 0.001 % by weight.

[0088] In various such embodiments of the steel strapping, the nitrogen is in an amount up to 0.4 % by weight.

[0089] In various such embodiments of the steel strapping, the nitrogen is in an amount of at least 0.2 % by weight.

[0090] In various such embodiments of the steel strapping, the nitrogen is in an amount of about 0.3 % by weight.

[0091] In various such embodiments of the steel strapping, the copper is in an amount up to 2.0 % by weight.

[0092] In various such embodiments of the steel strapping, the copper is in an amount of about 0.5 % by weight.

[0093] In various such embodiments of the steel strapping, the steel strapping has a tensile strength (Rm) of at least 750 MPa at a temperature of about 500 °C.

[0094] In various such embodiments of the steel strapping, the steel strapping has a tensile strength (Rm) of at least 650 MPa at a temperature of about 600 °C.

[0095] In various such embodiments of the steel strapping, the steel strapping has an elongation at break Aso of about 17 % at a temperature of about 500 °C.

[0096] In various such embodiments of the steel strapping, the steel strapping has an elongation at break Aso of about 18 % at a temperature of about 600 °C.

[0097] In various such embodiments of the steel strapping, the steel strapping has a thickness in a range of 0.60 mm to 1.50 mm.

[0098] In various such embodiments of the steel strapping, the steel strapping has a thickness in a range of 0.70 mm to 0.90 mm.

[0099] In various such embodiments of the steel strapping, the steel strapping has a thickness of about 0.80 mm.

[0100] In various such embodiments of the steel strapping, the steel strapping has a width in a range of 19 mm to 35 mm.

[0101] In various such embodiments of the steel strapping, the steel strapping has a width in a range of 30 mm to 35 mm.

[0102] In various such embodiments of the steel strapping, the steel strapping has a width of about 32 mm.

[0103] In various such embodiments of the steel strapping, the steel strapping has a break load in a range of 29000 N to 35000 N at room temperature as measured by ISO 6892-1.

[0104] In various such embodiments of the steel strapping, the steel strapping has a break load in a range of 29440 N to 33280 N at room temperature as measured by ISO 6892-1.

[0105] In various such embodiments of the steel strapping, the steel strapping has a tensile strength in a range of 1000 MPa to 1500 MPa at room temperature as measured by ISO 6892- 1.

[0106] In various such embodiments of the steel strapping, the steel strapping has a tensile strength in a range of 1150 MPa to 1300 MPa at room temperature as measured by ISO 6892- 1.

[0107] In various such embodiments of the steel strapping, the steel strapping has a sealed joint efficiency in a range of 50 % to 70 % of an average break strength at room temperature as measured by ISO 6892-1.

[0108] In various such embodiments of the steel strapping, the steel strapping has a sealed joint efficiency in a range of 60 % to 65 % of an average break strength at room temperature as measured by ISO 6892-1.

[0109] In various such embodiments of the steel strapping, the steel strapping has a sealless joint efficiency in a range of 60 % to 80 % of an average break strength at room temperature as measured by ISO 6892-1.

[0110] In various such embodiments of the steel strapping, the steel strapping has a sealless joint efficiency in a range of 70 % to 75 % of an average break strength at room temperature as measured by ISO 6892-1.[OHl] In various such embodiments of the steel strapping, the steel strapping has a welded joint efficiency in a range of 80 % to 100 % of an average break strength at room temperature as measured by ISO 6892-1.

[0112] In various such embodiments of the steel strapping, the steel strapping has a welded joint efficiency in a range of 90 % to 95 % of an average break strength at room temperature as measured by ISO 6892-1.

[0113] In various such embodiments of the steel strapping, the steel strapping has an elongation at break Aso in a range of 10 % to 20 % at room temperature.

[0114] In various such embodiments of the steel strapping, the steel strapping has an elongation at break Aso of about 13 % at room temperature.

[0115] In various other embodiments, the present disclosure provides a method of applying a loop of strap around a coil. The method comprises directing a leading end of a steel strapping drawn from a supply around a coil that is at a temperature between 500 °C and 600 °C, wherein the steel strapping is a steel strapping as described herein, and wherein the steelstrapping has a thickness in a range of 0.60 mm to 1.50 mm and a width in a range of 19 mm to 35 mm. The method also comprises attaching the leading end of the steel strapping to a portion of the steel strapping to form the loop of strap.

[0116] In various such embodiments of the method, attaching the leading end of the steel strapping to the portion of the steel strapping other than the leading end thereof comprises welding the leading end of the steel strapping to the portion of the steel strapping.

[0117] In various such embodiments of the method, further comprising cutting the steel strapping to form a trailing end of the steel strapping, wherein the portion of the steel strapping other than the leading end thereof comprises the trailing end of the steel strapping.

[0118] In various such embodiments of the method, the steel strapping has a thickness in a range of 0.70 mm to 0.90 mm.

[0119] In various such embodiments of the method, the steel strapping has a thickness of about 0.80 mm.

[0120] In various such embodiments of the method, the steel strapping has a width in a range of 30 mm to 35 mm.

[0121] In various such embodiments of the method, the steel strapping has a width of about 32 mm.

[0122] Various changes and modifications to the above-described embodiments described herein will be apparent to those skilled in the art. These changes and modifications can be made without departing from the spirit and scope of this present subject matter and without diminishing its intended advantages. Not all of the depicted components described in this disclosure may be required, and some implementations may include additional, different, or fewer components from those expressly described in this disclosure. Variations in the typesand amounts of the components may be made without departing from the spirit or scope of the claims as set forth herein. Also, unless otherwise indicated, any directions referred to herein reflect the orientations of the components shown in the corresponding drawings and do not limit the scope of the present disclosure. This specification is intended to be taken as a whole and interpreted in accordance with the principles of the invention as taught herein and understood by one of ordinary skill in the art.

Claims

CLAIMS1. A steel strapping comprising an austenitic stainless steel, wherein: the austenitic stainless steel comprises: carbon in an amount up to 0.6 % by weight, silicon in an amount up to 2 % by weight, chromium in an amount up to 20 % by weight, and an austenite stabilizer; and the steel strapping has a tensile strength (Rm) of at least 500 MPa at a temperature between 500 °C and 600 °C, and an elongation at break Aso in a range of 15 % to 20 % at a temperature between 500 °C and 600 °C.

2. The steel strapping of claim 1, wherein the austenitic stainless steel comprises carbon in an amount of at least 0.2 % by weight.

3. The steel strapping of claim 2, wherein the austenitic stainless steel comprises carbon in an amount of about 0.3 % by weight.

4. The steel strapping of claim 1, wherein the austenitic stainless steel comprises silicon in an amount of at least 0.2 % by weight.

5. The steel strapping of claim 4, wherein the austenitic stainless steel comprises silicon in an amount of about 0.3 % by weight.

6. The steel strapping of claim 1, wherein the austenitic stainless steel comprises chromium in an amount of at least 12 % by weight.

7. The steel strapping of claim 6, wherein the austenitic stainless steel comprises chromium in an amount of about 14 % by weight.

8. The steel strapping of claim 1, wherein the austenitic stainless steel comprises the austenite stabilizer in an amount up to 18 % by weight.

9. The steel strapping of claim 8, wherein the austenitic stainless steel comprises the austenite stabilizer in an amount of at least 14 % by weight.

10. The steel strapping of claim 9, wherein the austenitic stainless steel comprises the austenite stabilizer in an amount of about 16 % by weight.

11. The steel strapping of any of claims 1 to 10, wherein the austenite stabilizer is manganese.

12. The steel strapping of any of claims 1 to 11, wherein the austenitic stainless steel is free of nickel.

13. The steel strapping of any of claims 1 to 10, wherein the austenitic stabilizer is nickel.

14. The steel strapping of any of claims 1 to 13, wherein the steel strapping further comprises iron.

15. The steel strapping of any of claims 1 to 14, wherein the steel strapping further comprises impurities.

16. The steel strapping of claim 15, wherein the impurities comprise phosphorus, sulfur, nitrogen, and / or copper.

17. The steel strapping of claim 16, wherein the phosphorus is in an amount up to0.05 % by weight.

18. The steel strapping of claim 17, wherein the phosphorus is in an amount of at least 0.01 % by weight.

19. The steel strapping of claim 18, wherein the phosphorus is in an amount of about 0.02 % by weight.

20. The steel strapping of claim 16, wherein the sulfur is in an amount up to 0.015 % by weight.

21. The steel strapping of claim 20, wherein the sulfur is in an amount of about 0.001 % by weight.

22. The steel strapping of claim 16, wherein the nitrogen is in an amount up to 0.4 % by weight.

23. The steel strapping of claim 22, wherein the nitrogen is in an amount of at least 0.2 % by weight.

24. The steel strapping of claim 23, wherein the nitrogen is in an amount of about 0.3 % by weight.

25. The steel strapping of claim 16, wherein the copper is in an amount up to 2.0 % by weight.

26. The steel strapping of claim 25, wherein the copper is in an amount of about 0.5 % by weight.

27. The steel strapping of any of claims 1 to 26, wherein the steel strapping has a tensile strength (Rm) of at least 750 MPa at a temperature of about 500 °C.

28. The steel strapping of any of claims 1 to 27, wherein the steel strapping has a tensile strength (Rm) of at least 650 MPa at a temperature of about 600 °C.

29. The steel strapping of any of claims 1 to 28, wherein the steel strapping has an elongation at break Aso of about 17 % at a temperature of about 500 °C.

30. The steel strapping of any of claims 1 to 29, wherein the steel strapping has an elongation at break Aso of about 18 % at a temperature of about 600 °C.

31. The steel strapping of any of claims 1 to 30, wherein the steel strapping has a thickness in a range of 0.60 mm to 1.50 mm.

32. The steel strapping of claim 31, wherein the steel strapping has a thickness in a range of 0.70 mm to 0.90 mm.

33. The steel strapping of claim 32, wherein the steel strapping has a thickness of about 0.80 mm.

34. The steel strapping of any of claims 1 to 33, wherein the steel strapping has a width in a range of 19 mm to 35 mm.

35. The steel strapping of claim 34, wherein the steel strapping has a width in a range of 30 mm to 35 mm.

36. The steel strapping of claim 35, wherein the steel strapping has a width of about 32 mm.

37. The steel strapping of any of claims 1 to 36, wherein the steel strapping has a break load in a range of 29000 N to 35000 N at room temperature as measured by ISO 6892-1.

38. The steel strapping of claim 37, wherein the steel strapping has a break load in a range of 29440 N to 33280 N at room temperature as measured by ISO 6892-1.

39. The steel strapping of any of claims 1 to 38, wherein the steel strapping has a tensile strength in a range of 1000 MPa to 1500 MPa at room temperature as measured by ISO 6892-1.

40. The steel strapping of claim 39, wherein the steel strapping has a tensile strength in a range of 1150 MPa to 1300 MPa at room temperature as measured by ISO 6892- 1.

41. The steel strapping of any of claims 1 to 40, wherein the steel strapping has a sealed joint efficiency in a range of 50 % to 70 % of an average break strength at room temperature as measured by ISO 6892-1.

42. The steel strapping of claim 41, wherein the steel strapping has a sealed joint efficiency in a range of 60 % to 65 % of an average break strength at room temperature as measured by ISO 6892-1.

43. The steel strapping of any of claims 1 to 42, wherein the steel strapping has a sealless joint efficiency in a range of 60 % to 80 % of an average break strength at room temperature as measured by ISO 6892-1.

44. The steel strapping of claim 43, wherein the steel strapping has a sealless joint efficiency in a range of 70 % to 75 % of an average break strength at room temperature as measured by ISO 6892-1.

45. The steel strapping of any of claims 1 to 44, wherein the steel strapping has a welded joint efficiency in a range of 80 % to 100 % of an average break strength at room temperature as measured by ISO 6892-1.

46. The steel strapping of claim 45, wherein the steel strapping has a welded joint efficiency in a range of 90 % to 95 % of an average break strength at room temperature as measured by ISO 6892-1.

47. The steel strapping of any of claims 1 to 46, wherein the steel strapping has an elongation at break Aso in a range of 10 % to 20 % at room temperature.

48. The steel strapping of claim 47, wherein the steel strapping has an elongation at break Aso of about 13 % at room temperature.

49. A method of applying a loop of strap around a coil, the method comprising: directing a leading end of a steel strapping drawn from a supply around a coil that is at a temperature between 500 °C and 600 °C, wherein the steel strapping comprises the steel strapping of claim 1, and wherein the steel strapping has a thickness in a range of 0.60 mm to 1.50 mm and a width in a range of 19 mm to 35 mm; and attaching the leading end of the steel strapping to a portion of the steel strapping to form the loop of strap.

50. The method of claim 49, wherein attaching the leading end of the steel strapping to the portion of the steel strapping other than the leading end thereof comprises welding the leading end of the steel strapping to the portion of the steel strapping.

51. The method of claim 50, further comprising cutting the steel strapping to form a trailing end of the steel strapping, wherein the portion of the steel strapping other than the leading end thereof comprises the trailing end of the steel strapping.

52. The method of any of claims 49-51, wherein the steel strapping has a thickness in a range of 0.70 mm to 0.90 mm.

53. The method of claim 52, wherein the steel strapping has a thickness of about 0.80 mm.

54. The method of any of claims 49-53, wherein the steel strapping has a width in a range of 30 mm to 35 mm.

55. The method of claim 54, wherein the steel strapping has a width of about 32 mm.

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