High-pressure operation through high strength linepipe reduces long distance transportation cost of natural gas. In order to maximize the cost reduction, X120 UOE pipe has been developed. Low C-Mo-B steel with fine-grained lower bainite (LB) microstructure realizes high strength, excellent low temperature toughness and good weldability. The technology was verified in small-scale commercial production or “mini-rolls”. Suitability for use as linepipe was demonstrated through an extensive development program that covers burst test, fracture toughness evaluation, girth welding technology, etc. A demonstration line was successfully constructed using the pipes manufactured in the “mini-rolls”.
Novel polymeric prodrugs were synthesized by mechanochemical solid-state copolymerization of hydroxyethylcellulose and the methacryloyloxy derivative of 5-fluorouracil (5-FU). Copolymerization was about 94% complete after 4 h, and the polymeric prodrug was quantitatively obtained after 14 h of reaction. The number average molecular weight (Mn) and polydispersity (H) of the polymeric prodrug were 39000 g/mol and 6.20, respectively. Mechanical fracturing of the polymer in a stainless steel twin-shell blender improved these properties (Mn=16000 g/mol and H=1.94). 5-FU was sustainably released from the polymeric prodrugs, and the rate was not affected by the molecular weight or molecular weight distribution of the prodrug under the experimental conditions used. These results suggest that novel polymeric prodrugs composed of a polysaccharide and a synthetic polymer can be fabricated by mechanochemical solid-state copolymerization under anaerobic conditions.
The platinum on carbon (Pt/C)-catalyzed deuteration of acrylic and methacrylic acid derivatives in deuterium oxide (D 2 O) efficiently proceeded to give the corresponding acrylic acid-d 3 and methacrylic acid-d 5 derivatives. The olefinic functionality, as well as the methyl group on the unsaturated functionality of the substrate, were satisfactorily deuterated via the hydrogen (H)deuterium (D) exchange reaction. The obtained deuterated compounds are useful building blocks and efficiently converted to the corresponding desired products including a polymer without the degradation of the original deuterium contents.
New X80 UOE pipe manufacturing technology has been developed to attain excellent CTOD properties in HAZ. In the new steel pipe, the HAZ microstructure near the weld fusion line is refined by utilizing the strong suppression of austenite grain growth as well as the formation of intragranular ferrite (IGF). The IGF grows radially from oxides in the same way as in Ti-O steel. The suppression of austenite grain growth is due to the pinning effect by fine particles including ultra fine oxides. As these oxides dispersed in the steels are chemically stable even near the fusion line, the microstructure can be refined. In addition, it is also necessary to suppress the formation of coarse grain boundary ferrite (GBF) near the weld fusion line in order to obtain excellent CTOD properties. So, it was found that the increase of boron addition in weld metal is effective to suppress the formation of coarse GBF near the weld fusion line because boron atoms diffuse into prior austenite grain boundaries near the fusion line from the molten pool during welding. This paper describes new technology for improving CTOD properties in HAZ. The X80 UOE pipe manufactured on a large scale and exhibited excellent CTOD properties at −30°.
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