Energy Materials 2017: Materials for Oil and Gas and AMREE Oil & Gas III: Materials, Interfaces and Innovations for Hostile Oil and Gas / Energy I
Sponsored by: Chinese Society for Metals
Program Organizers: Indranil Roy, Schlumberger; Chengjia Shang, University of Science and Technology Beijing

Wednesday 8:30 AM
March 1, 2017
Room: 14A
Location: San Diego Convention Ctr

Session Chair: Chengjia Shang, University of Science and Technology Beijing; Samantha McBride, Massachusetts Institute of Technology

8:30 AM  Cancelled
Microstructure and Properties of High Performance Pipeline Steels: Lei Zheng1; 1Baoshan Iron & Steel Co. Ltd.
    Energy demand increasing is the main driving force of high performance pipeline steels development. As pipelines often pass through geological complex and harsh area, recent development of high performance pipeline steels are not only related to high strength, but also more concerned with high deformability for strain-based design, good HIC-resistance for sour environment, high toughness for fracture arrest, and good weldability. Microstructure of pipeline steels can be designed to meet the requirements of high performance pipeline steel. Grain or microstructure refinement is the key point for the metallurgical design of high strength pipeline steel. A dual phase of ferrite and bainite microstructure design can be used for high deformability pipeline steel. Clean steel, no segregation, uniform microstructure and low hardness is the basic requirements for pipeline steel used in sour environment. Microstructure and properties of pipeline steel developed in China recently are introduced in this paper.

9:00 AM  
Advanced Duplex Stainless Steels for Extreme Oil-Gas Environments: Pasi Kangas1; Guocai Chai1; 1Sandvik Materials Technology
    In oil-gas industry, the exploration of new reservoirs will target to those with high pressures and high temperatures or in deep water. This requires that the materials used should have a combination of excellent corrosion resistance and extra high strength that can bear its own weight. In order to meet these challenges, some new advance steels namely hyper duplex stainless steels have recently been developed. These materials have a nitrogen content up to about 0.5% and PRE-values close to 50, and show a combination of highest corrosion resistance or CPT and highest strength among the existing duplex stainless steels. This paper provides an overview on the development and properties of these materials. It will mainly focus the influence of composition and microstructures on the corrosion and mechanical properties. The ratios of properties/cost and strength/weight will be compared with Ni based alloys and other steels. Their applications are also discussed.

9:30 AM  
Development of High-strength and High Corrosion-resistant Ni-Cr-Al Alloy for Drilling Tools: Yoshihiko Koyanagi1; Hiroyuki Takabayashi1; Shigeki Ueta1; 1Daido Steel Co., Ltd./R&D center
    Recently, demand of oil is increasing with the increase in global energy consumption. Materials for drilling tools for the oilfield engineering are required high corrosion resistance, high strength and nonmagnetic characteristics for sensing. Developed DSA760 (Ni-38Cr-3.8Al) alloy can be used in a wide range of drilling tools because DSA760 has not only the high strength and high corrosion resistance also nonmagnetic characteristics. The tensile strength of DSA760 can be obtained more than 2000MPa by aging heat treatment even though the hardness is lower in solution heat treatment. The corrosion resistance of DSA760 is better than typical austenitic stainless steel. DSA760 is expected to contribute as a material for drilling tools in severe environment.

10:00 AM Break

10:20 AM  Invited
Investigation on the Weldability of High-strength Steels Used for Low Temperature Environment: Chengjia Shang1; Xuelin Wang1; 1University of Science and Technology Beijing
    In modern pipeline construction, architectural engineering and offshore engineering steels more often high-strength steels are required to provide higher energy and cost efficiencies. Therefore, in the recent years steel producers developed various high strength base materials and filler metals. These high performance steels are currently produced either by thermo-mechanical controlled process (TMCP) or by traditional quenching-tempering (Q-T) process. However, irrespective of the production method, the weldability is an important aspect of concern, especially low temperature toughness. The requirements to the mechanical properties of the weld increase, the demands on the component safety are becoming increasingly important. Thus, our present works are focused on the development of welding wires used for submerged arc welding (SAW) with excellent low-temperature toughness, the effect of welding process parameters on the microstructure and properties of multi-pass weld metal and the influence of new designed post-weld heat treatment (PWHT) on the comprehensive performance of weld joint.

10:50 AM  
Novel Cu-bearing Antibacterial Pipeline Steels for Microbiologically Induced Corrosion Control: Xianbo Shi1; Yiyin Shan1; Wei Yan1; Wei Wang1; Zhenguo Yang1; Ke Yang1; 1Institute of Metal Research, Chinese Academy of Sciences
    Novel Cu-bearing pipeline steels were fabricated by making proper Cu alloying designs. Antibacterial performance and MIC behavior were carried out by antibacterial tests, electrochemistrical monitor, corrosion product analyses and confocal laser scanning microscope (CLSM). Cu-bearing pipeline steels had strong antibacterial performance against E. coli and S.aureus compared with X80 steel. 1.0Cu steel showed excellent resistance to SRB with remarkable strength enhancement by nano-scale Cu-rich precipitates and good impact toughness compared with X80 steel. Cu-rich precipitates were found to be responsible for the antibacterial capability. The linear polarization resistances of both X80 and 1.0Cu steels in the soil-extract solution with SRB were dramatically decreased after 2 days, leading to the corrosion current density value of X80 steel was much higher than that of 1.0Cu steel. The corrosion product analysis revealed that much biofilm produced by SRB was the reason that many pits and larger pit depth on X80 steel.

11:20 AM  
Development of Cr-based Duplex Alloy for Corrosive Environments I: Evaluation of Mechanical Properties and Pitting Potential: Masafumi Nojima1; Tomonori Kimura1; Makoto Ogata1; Naoya Toko1; Kosuke Kuwabara1; 1Hitachi, Ltd. Research & Developmant Group
    Cr based duplex alloys (CrDA) as materials for instruments operating in Oil&Gas harsh environments have been developed. CrDA is characterized by the duplex structure composed of hard and corrosion-resistant α phase and ductile γ phase. We performed mechanical and electrochemical tests to optimize the microstructure of CrDA and to exhibit the superiority as the corrosion-resistant structural material. Nine alloys with different  phase fractions and Cr contents were formed with vacuum melting and casting. CrDA with γ phase areal fraction less than 47 % exhibited 0.2 % proof stress over 733 MPa and fracture elongation over 10.9% regardless of Cr content in the γ phase. No alloys experienced pitting corrosion under the potential less than 1000 mV v.s. SHE standard electrode in artificial sea water at 30℃.

11:45 AM  
Development of Cr-based Duplex Alloy for Corrosive Environments II: Evaluation of Corrosion Resistance in Boiling Sulfuric Acid: Tomonori Kimura1; Masahumi Nojima1; Makoto Ogata1; Naoya Tokoo1; Kosuke Kuwabara1; 1HITACHI, Ltd
    Cr based duplex alloys (CrDA) with high wear and corrosion resistance have been developed as alternative alloys to bearing cladding alloys such as stellite 6. The developed alloys contain over 37 wt.% of Cr to form passivation film and to have duplex microstructure composed of α phase and γ phase. In order to evaluate their corrosion resistance necessary for cladding alloys in Oil&Gas instruments, corrosion tests in boiling 5% sulfuric acid were performed for the 9 alloys having different compositions as shown in the former presentation. The corrosion rates of developed alloys were lower than that of stellite 6. The corrosion behavior of CrDA was classified into the selective corrosion of α phase, that could be suppressed when α phase contained over 51 wt.% of Cr.

12:10 PM  
Effect of Residual Stress on Aging Precipitation Behavior of Oil-grade Alloy 718: Zhongnan Bi1; Hailong Qin1; Jinhui Du1; Ji Zhang1; 1Central Iron and Steel Research Institute, China
    In the present study, the effect of residual stress on aging precipitation behavior of oil-grade alloy 718 has been investigated. The external stresses, from -300MPa to 300MPa, is applied to solid solution specimens for simulating the effect of residual stress at the aging temperature of 790℃ for 8h. Furthermore, a φ220mm forging, containing quenched-in residual stress, is subjected to an 790℃ aging treatment. Microstructure observation, tensile test and hardness test are used for the investigation. The results show that the precipitation of the γ’’ phase is promoted by residual stress (tensile or compressive stress), and δ phase can also be observed when the stress is big enough after standard heat treatment. The strength and hardness of the material are affected by residual stress due to their influence on precipitations.