Nonmetallic Inclusions in 08Kh18N10T Steel as the Cause of Initiation of Defects in Heat-Exchange Tubes of Steam Generators of Nuclear Power Plants

Materials Science - We present the results of investigation of the microstructure of 08Kh18N10T steel in heat-exchange tubes after their long-term operation in steam generators of WWÉR-1000...     

Specific features of the selective dissolution of 12Kh18N10T steel in ozonized sulfuric acid

We study the laws of corrosion-electrochemical behavior and selective dissolution of 12Kh18N10T steel in ozonized aqueous 20, 30, 40, and 70% sulfuric acid solutions. Ozone retards the corrosion rate of the steel only for acid concentrations lower than 40%. In ozonized 30 and 40% H₂SO₄ solutions, the dissolution of nickel and chromium in the course of corrosion of 12Kh18N10T steel becomes slower, but the amount of dissolved chromium is twice as great as that of nickel. We propose a hypothesis on the influence of ozone on the dissolution of components of the steel through the formation of OH⁻ ions, favoring the oxidation of iron and chromium to higher valences, which limits the anodic process. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 41, No. 5, pp. 69–73, September–October, 2005.     

Hydrogen Permeability of Thin-Film Coatings on Nickel and 12Kh18N10T Stainless Steel

We investigate the hydrogen permeability of membranes made of nickel and a stainless steel coated by a thin layer of NiO, carbon, amorphous silicon, and titanium nitride. We present the results of investigation of the morphology, composition, and structure of the coatings. Coatings made of titanium nitride applied by magnetron spraying are the most effective among all the coatings considered.     

12Cr1MOVG过热器管开裂行为分析与控制

12crl MoVG锅炉高温过热器蛇形管弯头,化学成分及力学性能符合国标规定,且使用温度低于580℃但使用不到2 a就发生多处破裂,为此,对其开裂行为进行了理化鉴定.结果表明,管子发生的是应力腐蚀破裂,裂纹的形成与弯管应力状态、内表面质量和介质的腐蚀等有直接的关系.裂纹的出现将严重威胁机组的安全运行,所以,在电站锅炉应用中应对具体的环境条件、选材、设计和工艺进行研究,只要措施得当,开裂问题是可以避免的.     

Low-Cycle Fatigue of the Equipment of Nuclear Power Plants Made of 15Kh2MFA Steel

We summarize experimental data on the low-cycle fatigue resistance of 15Kh2MFA steel, which is widely used in VVER-440 reactors, and its welds. These results were obtained for a fairly great number of melts of the base metal (21 melts) and welds (16 specimens). We compare these experimental data with the reference curve for low-alloy heat-resistant steels according to the Standards PNAE G-7-002-86 currently in force. We show that the values of safety factor n _σ = 2 and n _N = 10 are provided in the assessment of fatigue strength for equipment made of 15Kh2MFA steel, which is very important in connection with the extension of the service life of VVER reactor vessels for 10 – 15 year. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 41, No. 3, pp. 112 – 118, May – June, 2005.     

电站锅炉用TP304H不锈钢管显微组织的老化特征

应用金相、扫描电镜、透射电镜和X射线衍射等分析技术,研究了电站锅炉用TP304H不锈钢管显微组织老化的主要特征,明确了σ析出相含量与管子寿命的定量关系。结果表明：一定的压力条件下,TP304H钢管的显微组织变化与运行温度和时间相关,在设计温度下,随着运行时间的延长,TP304H钢管晶界开始析出呈链状分布的碳化物,继续运行σ相开始沿晶界（特别是三角晶界处）析出;当口相含量达到15％时,爆管几乎不可避免,因此,可以采用定量分析方法通过测定σ相含量来监测TP304H钢管的寿命。     

Evaluation of the Service Life of a Hip Joint Made of 08Kh18N10T Steel by the Methods of Fracture Mechanics

We study the corrosion-fatigue crack-growth resistance of 08H18N10T steel in a RISLT biological solution simulating the medium of human muscular tissues. A procedure of numerical calculation is proposed and the optimal dimensions of an endoprosthesis of a hip joint in the most stressed dangerous section are determined. It is shown that 08H18N10T steel can be used as a material for orthopedic implants. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 41, No. 2, pp. 97–100, March–April, 2005.     

Influence of preliminary plastic deformation of 12Kh18N12T steel on its mechanical properties

We have established that the preliminary plastic deformation of 12Kh18N12T austenitic steel causes cold-work hardening, which depends on the strain rate. With increase in the strain rate of specimens from 8∙10⁻⁴ to 417∙10⁻⁴ sec⁻¹, both strength (ultimate strength) and plasticity (percentage elongation) characteristics of 12Kh18N12T steel decrease. After holding of the preliminarily work-hardened steel at a temperature of 650°C, its strength increases, and its plasticity decreases. At the same time, the isothermal influence for 1 and 10 h does not facilitate intercrystalline corrosion of the steel during its holding in a corrosive medium for 24 h.     

Corrosion cracking and intergranular corrosion of 12Kh18N10T steel weld joints

Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 26, No. 5, pp. 51–56, September–October, 1990.     

Features of work hardening of Kh18N10T steel under conditions of cold electrostimulated drawing

The results of experimental investigation of the evolution of the structure and mechanical properties of Kh18N10T steel wire subjected to normal and electrostimulated drawing at a rate of 1.88 m/sec and a total reduction of up to 75% are given. The change in yield and tensile strengths, elongation, and reduction in electrostimulated drawing characterizing the higher plasticity of the material is analyzed. The structural changes accompanying the process of electrostimulated drawing include a difference in the character of the layer work hardened in drawing, evolution of the substructure, and the appearance of re crystallization twins.Translated from Problemy Prochnosti, No. 6, pp. 49–53, June, 1993.     

Degradation of Welded Joints of Steam Pipelines of Thermal Electric Power Plants in Hydrogenating Media

The mechanical properties of a welded joint of a steam pipeline of live steam after operation for ∼2 · 10⁵ h are compared with the properties of a model (repair) welded joint. In the process of operation, the properties of the metal suffer degradation in all zones of the welded joint. The short-term crack resistance proves to be the most sensitive indicator of degradation. The decrease in the crack resistance is fractographically detected in the form of low-energy intergranular or cleavage fracture. The hardness of the metal is quite sensitive to the changes in the state solely of the weld metal, especially susceptible to degradation in the process of operation. The plasticity of the operating welded joint abruptly decreases as a result of hydrogenation.__________Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 40, No. 6, pp. 105–110, November–December, 2004.