Effect of Duration of High-Temperature Tempering on the Texture and Grains of Superheated Rotor Steel

Borisov, I. A.; Dub, A. V.

doi:10.1007/s11041-013-9590-z

Cited by 3 publications

(9 citation statements)

References 1 publication

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“…The combined rotor is made of alloy steels that meet the special operating conditions of high-pressure (HP), medium-pressure (IP) and low-pressure (LP) cylinders. For the stages of the rotor, which operates in low temperatures at JSC "Turboatom", the steels 25H2NMFA and 20H3NMFA were proposed [10][11][12][13][14][15].…”

Section: Formulation Of the Problem: Materials And Methodsmentioning

confidence: 99%

“…The welding of the 25H2NMFA and 20H3NMFA steels (Table 1) is an extremely difficult task [10][11][12][13][14], which is associated with the formation of defective structures in the alloying area, as well as in the area of incomplete recrystallization of the heat-affected zone (HAZ) of the 20H3NMFA steel welded joint. An urgent requirement is also to ensure the necessary resistance against the formation of cold cracks.…”

Section: Formulation Of the Problem: Materials And Methodsmentioning

confidence: 99%

“…Impact toughness of samples with a V-notch along the HAZ (fusion and overheating areas) (Figure 4). The metallographic analysis of the structure of combined welded joints showed that the metal of HAZ sections has a mainly sorbitol and bainitic-ferritic structure on the 25H2NMFA side, as well as a bainitic martensite structure on the 20H3NMFA side [10][11][12][13]20].…”

Section: Investigated Objectmentioning

confidence: 99%

“…The hydrogen content in the metal of the ingots should not exceed 2.23 ppm [10][11][12][13][14][15], and the decrease in its value in steel and weldments has led to the improvement of the mechanical characteristics, hydrogen resistance and durability of steam turbine rotor steels welded joints. The initial steel structure is tempered bainite (Figure 4).…”

Section: Investigated Object Impact Toughness Kcv J/cmmentioning

confidence: 99%

“…(b1, b2)-schematic of a built-up stream turbine rotor with shrunk-on discs; (c)-schematic of a welded stream turbine rotor. The welds connect the discs (ABB Power Generation, Baden, Switzerland) [2,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Rotor body with detailed drawing of gaps for wedges and winding (d) [5].…”

Section: Introductionmentioning

confidence: 99%

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Improvement of the Mechanical Characteristics, Hydrogen Crack Resistance and Durability of Turbine Rotor Steels Welded Joints

et al. 2022

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This article is devoted to the following issues: calculating the values of temperatures obtained by simulating welding heating and the subsequent implementation of the welding process at the given mode parameters made it possible to obtain a welded joint of the rotor with an improved initial structure and increased mechanical properties, hydrogen resistance and durability by up to 10–15%; simulating welding heating in the areas of fusion, the overheating and normalization of the HAZ and the formation of austenite grains; specified welding heating creates the conditions for the formation of new products of austenite decomposition in the form of sorbitol in the area of the incomplete recrystallization of the HAZ. In air and gaseous hydrogen, the destruction of the combined joints took place on the weld metal, as well as on the fusion areas, the overheating and the incomplete recrystallization of the HAZ of 20H3NMFA steel as the base metal. Structural materials have a relatively low strength and high fracture toughness in air. This is manifested in a significant reduction in the elongation (δ), the area (ψ) and critical stress intensity factor (KIc) of welded joints and the endurance limit of cylindrical smooth rotor steel specimens, which were cut from transverse templates. Welded joints in the whole range of load amplitudes are sensitive to the action of hydrogen.

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Section: Formulation Of the Problem: Materials And Methodsmentioning

confidence: 99%

Section: Formulation Of the Problem: Materials And Methodsmentioning

confidence: 99%

Section: Investigated Objectmentioning

confidence: 99%

Section: Investigated Object Impact Toughness Kcv J/cmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Improvement of the Mechanical Characteristics, Hydrogen Crack Resistance and Durability of Turbine Rotor Steels Welded Joints

et al. 2022

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Improving the Quality Condition of the Structure of Welded Joints Made of Rotor Steel

Dmytryk¹,

Skulsky²,

Kasyanenko³

et al. 2022

Problems of Atomic Science and Technology

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The solution to the problem of increasing the reliability and service life of the welded joint of the rotor involved obtaining its original structure with improved quality characteristics. Obtaining was achieved by improving the technology of automatic welding. This improvement was based on the performing the welding process on the optimized parameters of the mode, which provided the appropriate temperature regime of the one-piece connection that is made. Thus, the welding heat provided the formation of the original structure with higher quality characteristics in comparison with a similar structure obtained by the normal mode of welding. It was found that austenitic grains in the structure of the heat affected zone of the welded joint, which is heated above АС3, are smaller in size compared to similar grains in the structure of the standard technology. Accordingly, the new decay products of austenite in the area of heat affected zone, which is heated to the temperature range AC1–AC3, were sorbitol and troostite. In general, by obtaining a better structure allowed to increase the reliability and increase the service life of the rotor by 10…15%.

show abstract

Improving the Quality Condition of the Structure of Welded Joints Made of Rotor Steel

Dmytryk¹,

Skulsky²,

Kasyanenko³

et al. 2022

Problems of Atomic Science and Technology

View full text Add to dashboard Cite

The solution to the problem of increasing the reliability and service life of the welded joint of the rotor involved obtaining its original structure with improved quality characteristics. Obtaining was achieved by improving the technology of automatic welding. This improvement was based on the performing the welding process on the optimized parameters of the mode, which provided the appropriate temperature regime of the one-piece connection that is made. Thus, the welding heat provided the formation of the original structure with higher quality characteristics in comparison with a similar structure obtained by the normal mode of welding. It was found that austenitic grains in the structure of the heat affected zone of the welded joint, which is heated above АС3, are smaller in size compared to similar grains in the structure of the standard technology. Accordingly, the new decay products of austenite in the area of heat affected zone, which is heated to the temperature range AC1 – AC3, were sorbitol and troostite. Thus, the proposed mode of automatic welding has increased reliability and increased by 10…15% of the life of the rotor.

show abstract

Effect of Duration of High-Temperature Tempering on the Texture and Grains of Superheated Rotor Steel

Cited by 3 publications

References 1 publication

Improvement of the Mechanical Characteristics, Hydrogen Crack Resistance and Durability of Turbine Rotor Steels Welded Joints

Improvement of the Mechanical Characteristics, Hydrogen Crack Resistance and Durability of Turbine Rotor Steels Welded Joints

Improving the Quality Condition of the Structure of Welded Joints Made of Rotor Steel

Improving the Quality Condition of the Structure of Welded Joints Made of Rotor Steel

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