scholarly journals INVESTIGATION OF THE CAUSES OF UNSATISFACTORY RESULTS OF ULTRASOUND CONTROL OF EXPERIMENTAL FORGES FROM AUSTENITE HIGH-ALLOY STEEL

2021 ◽  
pp. 26-35
Author(s):  
L.M. DEINEKO ◽  
H.D. SUKHOMLYN ◽  
Т. О. DERHACH ◽  
A.Yu. BORYSENKO
Keyword(s):  
Austenitic Steel ◽  
Intergranular Corrosion ◽  
Austenitic Steels ◽  
Practical Significance ◽  
Boundary Structure ◽  
Temperature Deformation ◽  
Electron Microscopic ◽  
High Alloy ◽  
Steel 08Kh18n10t ◽  
Metallic Inclusions

The purpose of the work is to establish the main causes of defects by ultrasonic testing (UST) of experimental forgings made of high-alloyed austenitic steel 08Kh18N10T on the basis of comprehensive comparative studies of samples of defective and suitable forgings. Techniques. Chemical analysis of forgings was performed on a high-sensitivity spectrometer "SPECTROMAX" company "SPECTRO", Germany; studies of macro- and microstructure (liquation heterogeneity, grain boundary structure, non-metallic inclusions, excess phases, etc.) were carried by the methods: metallographic and electron microscopic with micro-X-ray spectral analysis; tests of forgings for durability against intergranular corrosion (IGC) were carried out by the methods of AMU, GOST 6032. Results. It was established that experimental forgings rejected by UZK, in contrast to suitable forgings, were characterized by: the presence of areas of liquation inhomogeneity of steel, including high content of δ-ferrite; local defects of the macrostructure in the form of flocs; areas with anomalous multi-grained microstructure with a grain size of –2 to 8 points according to GOST 5639; release of chromium carbides at the boundaries of austenitic grains; susceptibility to intergranular corrosion (ICC). All forgings contained non-metallic inclusions within the permissible limits according to GOST 1778, as well as titanium carbides. Scientific novelty. For the first time on the basis of complex researches it is proved that the main reason of unsatisfactory results of UZK of experimental forgings from high-alloyed austenitic steel, is the anomalous multigrain structure connected with the unstable temperature-deformation mode of forging of ingots. Practical significance. Recommendations for improving the structure and improving the quality characteristics of industrial forgings made of high-alloy austenitic steels in terms of industrial production have been developed.

Evaluation of Degradation Causes of the Forged Rotors Made of NiCrMo Steel Grade

2014 ◽  
Vol 782 ◽  
pp. 227-230
Author(s):  
Petr Jonšta ◽  
Roman Heide ◽  
Irena Vlčková ◽  
Miriam Gabčová ◽  
Zdenĕk Jonšta ◽  
...  
Keyword(s):  
Steel Grade ◽  
Excessive Amount ◽  
Steam Turbines ◽  
Electron Microscopic ◽  
X Ray ◽  
Metallic Inclusions ◽  
Casting Ladle ◽  
Nicrmov Steel

Contamination of steel by excessive amount of non metallic inclusions leads tosignificant deterioration of its quality and consequent degradation. Cause of degradation of forgedrotors for steam turbines made of NiCrMoV steel grade is examined in this paper. Metallographicand electron-microscopic analyses were performed, including X-ray microanalysis for detecting thepurity of the forging being examinated. Concurrently, the consequence of failed technologicalproduction process, namely the influence of broken brick for argon blowing at the casting ladle, wasalso examined.

scholarly journals Laser Welding Of Finned Tubes Made Of Austenitic Steels

2015 ◽  
Vol 60 (3) ◽  
pp. 1807-1812
Author(s):  
M. Stolecki ◽  
H. Bijok ◽  
Ł. Kowal ◽  
J. Adamiec
Keyword(s):  
Laser Welding ◽  
Austenitic Steel ◽  
Technological Process ◽  
Welded Joints ◽  
Austenitic Steels ◽  
Tube Production ◽  
High Quality ◽  
Manufacturing Costs ◽  
Finned Tubes

Abstract This paper describes the technology of welding of finned tubes made of the X5CrNi1810 (1.4301) austenitic steel, developed at Energoinstal SA, allowing one to get high quality joints that meet the requirements of the classification societies (PN-EN 15614), and at the same time to significantly reduce the manufacturing costs. The authors described an automatic technological line equipped with a Trumph disc laser and a tube production technological process. To assess the quality of the joints, one performed metallographic examinations, hardness measurements and a technological attempt to rupture the fin. Analysis of the results proved that the laser-welded finned tubes were performed correctly and that the welded joints had shown no imperfections.

Analysis of Damage of Solder Joint of Heat Exchanger

2017 ◽  
Vol 270 ◽  
pp. 63-67
Author(s):  
Pavel Gejdoš ◽  
Lenka Klakurková ◽  
Martin Juliš ◽  
Miroslava Horynová ◽  
Lucie Páleníková ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Solder Joint ◽  
Austenitic Steel ◽  
Metallographic Analysis ◽  
High Alloy ◽  
Pressure Test ◽  
The Subject ◽  
Microstructure Of The Material ◽  
Soldered Joint ◽  
Eds Microanalysis

The paper focus on the metallographic analysis of damaged heat exchanger made of high‑alloy austenitic steel by soldering. The object in question is a soldered joint of main mounting plate of the heat exchanger and first heat exchanging plate of it. In this part of the heat exchanger after the vibration and pressure test crack appeared. The subject of the analysis is the evaluation of the microstructure of the solder joint (high-alloy austenitic steel and copper), and evaluation of the appeared crack. The problematic is solved with aid of metallographic analysis of the microstructure of the material, using light microscopy and scanning electron microscopy and the EDS microanalysis of chemical composition.

Ultrasonic monitoring of welded joints of nickel-free high-alloy austenitic steels

1985 ◽  
Vol 21 (4) ◽  
pp. 204-206
Author(s):  
N. V. Khimchenko ◽  
V. A. Bobrov ◽  
A. M. Sel'din ◽  
V. I. Logvinov
Keyword(s):  
Welded Joints ◽  
Austenitic Steels ◽  
Ultrasonic Monitoring ◽  
High Alloy

scholarly journals THE LEVEL OF PLASTICITY OF THE PHASES IN NON-METALLIC INCLUSIONS WITH A COMPLEX STRUCTURE

2021 ◽  
pp. 19-25
Author(s):  
S.I. GUBENKO
Keyword(s):  
Complex Structure ◽  
Cold Deformation ◽  
Inhibitory Effect ◽  
Practical Significance ◽  
Plastic Behavior ◽  
Metallic Inclusions ◽  
Wide Range ◽  
Different Types ◽  
Deformation Ability ◽  
Composition Structure

Purpose. It is necessary to study of the effect of heterophase inclusions on the technological ductility of steels for various purposes. The goal of the work was to study of the nature and level of plasticity of multiphase inclusions in steels under conditions of hot and cold deformation. Methods. Comprehensive methods for the study of heterophase non-metallic inclusions (metallographic, petrographic, X-ray microanalysis methods) were used. Results. Plastic phases in multiphase inclusions of different types under conditions of hot and cold deformation of steels were investigated. It is shown that each type of multiphase inclusions, which are microcomposite formations in steels, is characterized by its laws of development of deformation processes, which are determined by their chemical and phase composition, structure, deformation ability of the phases of inclusions. Scientific novelty. Peculiarities of plastic behavior of multiphase inclusions of different types are established. The inhibitory effect of non-deformable phases of inclusions on the deformability of plastic phases in a wide range of steel deformation temperatures is established. Peculiarities of the nature of plasticity of multiphase inclusions having different compositions and structure are discussed. Practical significance. Using the results obtained will allow developing technologies for producing steels with regulated content and types of multiphase non-metallic inclusions, which will significantly increase their technological plasticity, as well as prevent the formation of various kinds of defects during the processing of steels by pressure.

scholarly journals Nitriding of steels of various structural classes manufactured by laser additive technologies

2020 ◽  
Vol 63 (1) ◽  
pp. 63-70
Author(s):  
E. V. Tsvetkova ◽  
K. O. Bazaleeva ◽  
I. S. Chekin ◽  
O. G. Klimova-Korsmik ◽  
A. S. Zhidkov
Keyword(s):  
Heat Treatment ◽  
Austenitic Steel ◽  
Powder Material ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Austenitic Steels ◽  
Bainitic Steel ◽  
Laser Remelting ◽  
Diffusion Layers ◽  
Structural Classes

The authors have conducted a comparative analysis of diffusion layers of steels of various structural classes manufactured by complex technology including laser remelting of powder material and plasma nitriding. Parameters of diffusion layers of bainitic steel (Fe – 0.09 % C – 1 % Cr – 2 % Ni – 1 % Mo – 1 % Cu) and martensitic steel (Fe – 0.25 % C – 13 % Cr – 2 % Ni) manufactured by direct laser deposition (DLD) and austenitic steel (Fe – 0.03 % C – 17 % Cr – – 14 % Ni – 3 % Mo) manufactured by selective laser melting (SLM) were investigated. During plasma nitriding at 540 °C for 24 h of martensitic and austenitic steels, diffusion layer of 140 – 160 μm was formed, additionally maximum microhardness of surface layer was 800 HV0.1 and 1050 HV0.1 and it is almost constant on thickness of 100 μm. Diffusing layer of bainitic steel is 900 μm and its microhardness monotonously decreases from the surface. Reinforcing phases of nitrided layer were determined by X-ray analysis: γ′ (Fe4N) is fixed in the bainitic steel, γ′ and CrN are fixed in martensitic and austenitic steels. Moreover on the surface of austenitic steel solid nitrided layer is formed. The influence of heat treatment after laser remelting of powder material was also studied. It was determined, that despite decreasing of crystal structure defects after heat treatment, the thickness of nitrided layer changes slightly. Also the authors have investigated the influence of porosity of austenitic steel on the thickness of nitrided layer. It was shown, that porosity of 0.5 – 2.0 % doesn’t result in changing of diffusion layer’s thickness.

Sign in / Sign up

Export Citation Format

Share Document