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This paper discusses the use of materials with shape memory in various industries, including the oil and gas industry. The advantages and disadvantages of metallic and non-metallic materials with shape memory are presented. The possibilities of using composite materials with shape memory in the oil and gas industry are considered. The use of composite materials for the manufacture of diaphragms in diaphragm pumps to increase the energy efficiency of equipment is proposed.

Questions are considered of the reliability of assembled welded joints of valve fittings. It is proposed to use impact strength as a criterion of welded metal durability for welded joints. The effect of welding heating cycle on the structure and phase composition, and properties of metal around the joint (MAJ) of the heataffected zone (HAZ) of welded joints made from steel of strength categories K42 and K52 is studied. The effect of strain ageing on impact strength characteristics of the MAJ of the HAZ is analyzed for steel 17GS with different structure and phase compositions. It is shown that metal of the MAJ of the HAZ with a predominantly bainitic structure is most resistant to strain ageing. Dependences are plotted for evaluating welded joint material endurance and determination of the duration of the operating period, during which there is no critical fall in impact strength, and rational welding regimes are also established that make it possible to prolong safe operation of valve equipment to 30-35 years.Valve fittings are one of the most important elements of a gas pipeline system, and therefore in assembly of the valve fittings high specifications are laid down both for the material used, and also the production process. In welding, the welded joint metal structure and properties change considerably compared with its original condition, and therefore in order to provide a service life of an assembly with welded joints, comparable with the standard service life of a gas pipeline (40 years), it is necessary to consider both the production factors in performing welding operations, and also the operating parameters.Most critical for the operating capacity of a welded joint is embrittlement of the heat affected zone (HAZ) metal, in particular metal around the joint (MAJ). In view of this impact strength may be adopted as a criterion for metal endurance of welded joints.In order to estimate the effect of welding technology on the loss of ductility properties for MAJ of the HAZ immediately after welding in the standard of Gazprom 2-4.1-212-2008, impact strength of welded metal is regulated with a test temperature of -40°C, that should not be less than 25 J/cm 2 . Alongside this in the standard of Gazprom 2-2.3-137-2007 specifications are regulated for metal hardness of a welded joint HAZ that should be not more than 300 HV 10 . A significant part of an assembled welded joint of valve fittings, used in main gas pipelines, is made in steels of the strength category K42 and K52, that have a ferrite-pearlite structure. The chemical composition of steels of these strength categories is given in Table 1.

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