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Kendrick V.,Gallatin Steel Company | Frye B.,Gallatin Steel Company | McClure J.,Gallatin Steel Company | Holtman M.,Gallatin Steel Company | Stalheim D.G.,DGS Metallurgical Solutions , Inc.
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2014

Oil and gas exploration around the world continues at a rapid pace. This rapid pace of oil and gas exploration in North America has been fueled primarily thorough the development of horizontal drilling and the "fracking" process of underground shale formations. The demand for various grades and dimensions of API casing and pipe has and will continue to increase in the foreseeable future as these shale formations are exploited. To support this demand in North America, Gallatin Steel has embarked on a program to develop API casing and pipe coil skelp via their Compact Strip Plant (CSP). A key characteristic of API grade pipeline steels is excellent fracture toughness. This is one area where historically CSP facilities have struggled, especially in gauges greater than 8.8 mm (0.350") due to overall lack of reduction from the thin slab design of a CSP facility. In addition, utilizing the typical Thermomechanical Control Processing (TMCP) separating recrystallized and non-recrystallized rolling used in API coil skelp production for strength and toughness of a traditional HSM or plate mill is difficult to achieve in the continuous CSP facility. Gallatin Steel has successfully developed, through a controlled combination of slab quality, alloy design, process modifications and process control, excellent toughness in both charpy and DWTT performance from a 65 mm (2.56") slab in final coil thicknesses up to 12.7 mm (0.500"). This paper will describe the results achieved to date on various thicknesses from 7.6 mm to 12.7 mm API skelp development at Gallatin Steel. Mechanical property performance along with microstructures/grain size will be presented. In addition, future work that Gallatin Steel will undertake to further improve the capability to produce quality API coil skelp will be discussed. Copyright © 2014 by ASME. Source

Slifka A.J.,Applied Materials | Drexler E.S.,Applied Materials | Stalheim D.G.,DGS Metallurgical Solutions , Inc. | Amaro R.L.,Applied Materials | And 3 more authors.
American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP | Year: 2013

Tests on the fatigue crack growth rate were conducted on four pipeline steels, two of grade API 5L-X52 and two API 5L-X70. One X52 material was manufactured in the mid-1960s and the other was manufactured in 2011. The two X70 materials had a similar vintage and chemistry, but the microstructure differs. The fatigue tests were performed in 5.5 and 34 MPa pressurized hydrogen gas, at 1 Hz and (load ratio) R=0.5. At high pressures of hydrogen and high values of the stress intensity factor range (ΔK) there is no difference in the fatigue crack growth rates (da/dN), regardless of strength or microstructure. At low values of ΔK, however, significant differences in the da/dN are observed. The older X52 material has a ferrite-pearlite microstructure; whereas, the modern X52 has a mixture of polygonal and acicular ferrites. The X70 materials are both predominantly polygonal ferrite, but one has small amounts (∼5%) of upper bainite, and the other has small amounts of pearlite (<2%) and acicular ferrite (∼5%). We discuss the fatigue test results with respect to the different microstructures, with particular emphasis on the low ΔK regime. Copyright © 2013 by ASME. Source

Zhang G.,Qinhuangdao Shouqin Metal Materials Co Ltd | Bai X.,Qinhuangdao Shouqin Metal Materials Co Ltd | Stalheim D.,DGS Metallurgical Solutions , Inc. | Li S.,Shougang Institute of Technology | Ding W.,Shougang Institute of Technology
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2014

Along with the increasing demand of oil and natural gas by various world economies, the operating pressure of the pipeline is also increasing. Large diameter heavy wall X80 pipeline steel is widely used in the long distance high pressure oil and gas transportation in China today. In addition, development of X90/X100 has begun in earnest to support the growing energy needs of China. With the wide use of X80 steels, the production technology of this grade has become technically mature in the industry. Shougang Group Qinhuangdao Shouqin Metal Materials Co., Ltd. (SQS) since 2008 has been steadily developing heavier thicknesses and wider plate widths over the years. This development has resulted in stable mass production of X80 pipeline steel plate in heavy wall thicknesses for larger pipe OD applications. The technical specifications of X80 heavy wall thickness and X90/X100 14.8-19.6 mm wall thicknesses, large OD (48") requiring wide steel plates for the 3rd West-to-East Natural Gas Transmission Pipeline Project and the third line of Kazakhstan-China Main Gas Pipeline (The Middle Asia C Line) and the demonstration X90/X100 line (part of the 3rd West-East Project) in China required changes to the SQS plate mill process design. Considering the technology capability of steelmaking and the plate mill in SQS, a TMCP+OCP (Optimized Cooling Process) was developed to achieve stable X80 and X90/X100 mechanical properties in the steel plates while reducing alloy content. This paper will describe the chemistry, rolling process, microstructure and mechanical properties of X80 pipeline steel plates produced by SQS for 52,000 mT of for the 3rd West-to- East Natural Gas Transmission Pipeline Project and 5,000 mT for the Middle Asia C Line Project along with 1000 tons of 16.3 mm X90/X100 for the 3rd West-East demonstration pipeline. The importance of the slab reheating process and rolling schedule will be discussed in the paper. In addition, the per pass reductions logic used during recrystallized rough rolling, and special emphasis on the reduction of the final roughing pass prior to the intermediate holding (transfer bar) resulting in a fine uniform prior austenite microstructure will be discussed. The optimized cooling (two phase cooling) application after finish rolling guarantees the steady control of the final bainitic microstructure with optimum MA phase for both grades. The plates produced by this process achieved good surface quality, had excellent flatness and mechanical properties. The pipes were produced via the JCOE pipe production process and had favorable forming properties and good weldability. Plate mechanical properties successfully transferred into the required final pipe mechanical properties. The paper will show that the TMCP+OCP produced X80 heavy wall and 16.3 mm X90 wide plates completely meet the technical requirements of the three pipeline projects. Copyright © 2014 by ASME. Source

Stalheim D.,DGS Metallurgical Solutions , Inc. | Jansto S.,CBMM Co.
Proceedings of the 10th International Conference on Steel Rolling | Year: 2010

The hot rolling of steel slabs produced from thin slab casters or billet casters and long products from bar and beam mills is the critical steelmaking step that adds the most value to the final hot roll product. Although hot rolling processes vary from continuous hot strip/sheet rolling mills to plate mills to Steckel mills to bar and beam mills, in many product sectors, all mill configurations are used in the production of similar finished product. This paper presents the universal heating, mechanical metallurgy, operational metallurgy and rolling mill practices that are essential in successfully producing high quality, value-added mieroalloyed steels. Differences in the importance of critical operational parameters are made comparing straight carbon-manganese steel versus mieroalloyed low carbon steels. More disciplined operational practices are reviewed that contribute to the successful rolling of these value added mieroalloyed steels. Reviews of the importance of a uniform cross sectional grain size and more importantly how to successfully produce it will be discussed. In many cases, optimization of metallurgy and mill capability are often overlooked or misunderstood. Optimization of the mill capability not only benefits productivity, but if done correctly can often result in overall improved metallurgy and hence optimization of the alloy design and final mechanical properties and in some cases shape. Regardless of the product sector, the end user demands steels exhibiting higher strength with improved toughness, better weldability, better formability, improved dimensional control, shape, profile and flatness. This can only be achieved through a thorough understanding of the metallurgy and more importantly how to get the most out of given mill's capability and configuration. Many of the newer mills and even some of the older ones have Level 2 automation models that generate the rolling schedule. Unfortunately, these models seldom incorporate metallurgical principals into the rolling logic and hence do not result in optimum rolling schedules for metallurgy or for that fact productivity. This paper will discuss issues with Level 2 models and what a mill owner should consider to get the most from the operation. Source

Slifka A.J.,Applied Materials | Drexler E.S.,Applied Materials | Amaro R.L.,Applied Materials | Lauria D.S.,Applied Materials | And 3 more authors.
American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP | Year: 2014

The National Institute of Standards and Technology has been testing pipeline steels for about 3 years to determine the fatigue crack growth rate in pressurized hydrogen gas; the project was sponsored by the Department of Transportation, and was conducted in close collaboration with ASME B31.12 Committee on Hydrogen Piping and Pipelines. Four steels were selected, two X52 and two X70 alloys. Other variables included hydrogen gas pressures of 5.5 MPa and 34 MPa, a load ratio, R, of 0.5, and cyclic loading frequencies of 1 Hz, 0.1 Hz, and a few tests at 0.01 Hz. Of particular interest to ASME and DOT was whether the X70 materials would exhibit higher fatigue crack growth rates than the X52 materials. API steels are designated based on yield strength and monotonic tensile tests have historically shown that loss of ductility correlates with increase in yield strength. The X70 materials performed on par with the X52 materials in fatigue. The test matrix, the overall set of data, implications for the future, and lessons learned during the 3-year extensive test program will be discussed. Copyright © 2014 by ASME. Source

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