Paderborn, Germany
Paderborn, Germany

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Patent
Benteler Steel Tube GmbH | Date: 2015-09-23

The invention relates to a perforating gun used for hydraulic fracturing applications in a wellbore and has an outer tube having several recesses of a second kind. The recesses of a second kind are configured to absorb shock waves from a shape charge in the perforating gun to reduce the numbers of cracks that form on the perforating pun. In some embodiments, the recesses of a second kind have a variety of shapes and sizes to aid in the absorption of shock waves.


Mola J.,TU Bergakademie Freiberg | Ullrich C.,TU Bergakademie Freiberg | Kuang B.,TU Bergakademie Freiberg | Rahimi R.,TU Bergakademie Freiberg | And 3 more authors.
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2017

The high-temperature austenite phase of a high-interstitial Mn- and Ni-free stainless steel was stabilized at room temperature by the full dissolution of precipitates after solution annealing at 1523 K (1250 °C). The austenitic steel was subsequently tensile-tested in the temperature range of 298 K to 503 K (25 °C to 230 °C). Tensile elongation progressively enhanced at higher tensile test temperatures and reached 79 pct at 503 K (230 °C). The enhancement at higher temperatures of tensile ductility was attributed to the increased mechanical stability of austenite and the delayed formation of deformation-induced martensite. Microstructural examinations after tensile deformation at 433 K (160 °C) and 503 K (230 °C) revealed the presence of a high density of planar glide features, most noticeably deformation twins. Furthermore, the deformation twin to deformation-induced martensite transformation was observed at these temperatures. The results confirm that the high tensile ductility of conventional Fe-Cr-Ni and Fe-Cr-Ni-Mn austenitic stainless steels may be similarly reproduced in Ni- and Mn-free high-interstitial stainless steels solution annealed at sufficiently high temperatures. The tensile ductility of the alloy was found to deteriorate with decarburization and denitriding processes during heat treatment which contributed to the formation of martensite in an outermost rim of tensile specimens. © 2017, The Minerals, Metals & Materials Society and ASM International.


According to the present invention, a seamless steel pipe for use in cases where internal pressure is applied is disclosed, the seamless steel pipe having been produced by tempering a tubular steel body at a holding temperature of >450 C., the seamless steel pipe having a length extending between a first end and a second end, the seamless steel pipe having a high burst strength and at least over part of the length having a yield strength Rp0.2 of >1050 MPa, and the seamless steel pipe having a grain structure with an average grain size of <15 m, and the tubular steel body having been manufactured from a steel alloy, which steel alloy comprises, besides iron and inevitable impurities, the following alloying elements in mass-%:


Rusing C.J.,University of Paderborn | Lambers H.-G.,Benteler Steel Tube GmbH | Lackmann J.,Benteler Automotive | Frehn A.,Benteler Automotive | And 4 more authors.
Materials Today: Proceedings | Year: 2015

The current work investigates the impact of pre-deformation temperatures on the microstructure evolution and the subsequent cyclic stress-strain response of high-manganese steel showing twinning-induced plasticity (TWIP) at room temperature (RT). Deformation at low temperatures increases the hardening rate at low to medium degrees of deformation through concurrent martensitic transformation. In contrast, high temperatures promote dislocation slip. Thus, employing pre-treatments at temperatures below and above RT leads to the evolution of considerably different microstructures. Low-cycle fatigue experiments revealed distinct differences for the pre-treated TWIP steels. © 2015 The Authors.


Engel W.,Benteler Steel Tube GmbH | Balun J.,Benteler Steel Tube GmbH
Archives of Materials Science and Engineering | Year: 2014

Purpose: This paper presents results of investigates the formation of scales in the temperature range from 1000°C to 1300°C in the oxidation atmosphere without deformation process. Design/methodology/approach: Oxidized samples were examined by means of EDX Analysis using SEM. Findings: It was found that the oxidation temperature influences the occurrence of the Si-rich phase (Fayalite). Fayalite formed only in the samples oxidized at 1300°C and 1250°C. Oxidation temperatures of 1000°C led to formation of scale enriched with chromium, silicon and nickel in the metal/oxide interface without formation of a new phase. Research limitations/implications: In this study the oxidation behavior in a rotary hearth furnace, which has low oxygen content, is investigated. Furthermore, the formation of scale in high oxygen content (dry air) was explored. Originality/value: The descaling process during the hot rolling of steel alloyed with Si is difficult due to pockmark type surface. Therefore the surfaces quality of the hot rolled products depends on the formation and removal of scales during the production process. © by International OCSCO World Press. All rights reserved. 2014.


Hauger A.,Benteler Steel Tube GmbH | Vietoris T.,Benteler Steel Tube GmbH | Bentfeld V.,Benteler Steel Tube GmbH
Stahl und Eisen | Year: 2015

High-grade materials with consistent quality, efficiently and cost-effectively produced, including the customer's needs at the best - these challenges have to he faced by the steel industry and the steel processing industry.


Kittner K.,TU Bergakademie Freiberg | Wiesner J.,Benteler Steel Tube GmbH | Kawalla R.,TU Bergakademie Freiberg
Key Engineering Materials | Year: 2016

At present, the discussion about pores/ voids in large ingots is still actual. Researchers investigated the closing behavior during the open die forging process. Mostly, the approaches take the account into void closure with artificial pores. But artificial pores do not reflect the real closing behavior. This is caused in the surface/ structure of inner voids. During drilling and heating, the voids get a smooth surface and have contact to the atmosphere. Therefore, the material oxidizes on surface and the closing behavior is not similar to the real process. Real pores show a fractal surface with dendrites. And the inner of voids contains a vacuum. In the framework of a new approach, for void closure cast ingots with pores were generated and the structure and the closing behavior were investigated. The final goal is to find out a global closing function "Z". This closing function should improve the understanding of void behavior and in the future the industrial process. The function depends on different parameters, like yield strength of material (Pkf), the pore size (AEq), the pore structure (Pstruct) and process parameters, such as stroke until closure (Pstroke), tool geometry (Ptools) or bite ratio (Pbite ratio). Finally, there is a parameter Pdisturb. This parameter works against the final closure and is important for the understanding of the process, because it represents the influence of dendrites. Furthermore the closing behavior is not comprehensible without the consideration of recrystallization. © 2016 Trans Tech Publications, Switzerland.


In a method for the production of a seamless, multilayered tubular product, a further layer is applied through hardfacing on a base layer of a round or polygonal block, with the further layer made of a metallic material which is different than a metallic material of the base layer. The round or polygonal block with hardfaced further layer is hot formed to produce a tubular product with reduced wall thickness and outer perimeter in one or more stages. A diffusion layer is established between the base layer and the further layer through heat treatment before hot forming and/or after hot forming, thereby producing a thickness of the diffusion layer of at least 5 m with the proviso that the thickness of the diffusion layer is 0.1% to 50% of a thickness of the further layer, with the thickness of the further layer being equal to or greater than 100 m.


Patent
Benteler Steel Tube GmbH | Date: 2016-07-08

The present invention relates to a, comprising a tubular element (10) with at least one heat-affected zone (14), characterized by a yield strength Rp_(0.2 )in the heat-affected zone (14) of at least 640 MPa and a tensile strength Rm in the heat-affected zone of at least 850 MPa and by at least the tubular element (10) consisting of a steel alloy consisting, in weight percent: balance iron and impurities resulting from smelting.


Patent
Benteler Steel Tube GmbH | Date: 2016-07-15

The present invention relates to a gas generator, comprising a comprising a tubular element (10) with high low-temperature toughness. The gas generator is characterized in that the tubular element (10) has a ductile fracture behavior at temperature to at least 196 C., the tubular element (10) has a minimal tensile strength of 650 MPa, the tubular element (10) has a cubic face-centered austenitic structure with at least 90 area percentage and the tubular element (10) consists of a steel alloy which has a manganese content of at least 14.0 wt %

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