scholarly journals Weld Repair of Steam Turbine Rotor with 12 Cr Weld to Mitigate Corrosion Issues

2019 ◽  
Vol 269 ◽  
pp. 03007
Author(s):  
Vamadevan Gowreesan ◽  
Dhimas Ario ◽  
Hepy Hanifa ◽  
Wayne Greaves
Keyword(s):  
Steam Turbine ◽  
Alloy Steel ◽  
Weld Interface ◽  
Turbine Rotor ◽  
Low Alloy Steels ◽  
Low Alloy Steel ◽  
Weld Repair ◽  
Alloy Steels ◽  
Turbine Rotors ◽  
Selection Of

Weld repair of steam turbine rotors has become an acceptable practice to extend the life of rotors. Depending on the type of damage, the extent of weld repair can range from weld build-up of integral discs to stubbing a new forging to replace the damaged portion of an old rotor. Steam turbine rotors made of low alloy steels experience corrosion related damages such as stress corrosion cracking, pitting corrosion, corrosion-erosion etc., Traditional weld repairs have been using low alloy steel welds. While the low alloy welds may have mechanical properties comparable to or even slightly exceeding that of the low alloy steel rotor alloys, the corrosion resistance of the low alloy welds are not great. 12 Chromium weld will provide better resistance to corrosion related damages than typical low alloy welds. However using 12 Chromium weld on low alloy steel rotors provides some additional challenges and limitations. These include selection of optimal combination of weld wire and flux for rotor welding, selection of optimal post weld stress relieve temperature and dealing with abrupt change in chemical composition at the weld interface. This paper discusses development of such a weld procedure and provides some examples where the 12 Chromium weld was successfully applied on steam turbine rotors that experienced corrosion related damages.

Alternative Approach for Qualification of Temperbead Welding in the Nuclear Industry

2012 ◽  
Author(s):  
Steven L. McCracken ◽  
Richard E. Smith
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Alloy Steel ◽  
Nuclear Power ◽  
Post Weld Heat Treatment ◽  
Nuclear Power Industry ◽  
Low Alloy Steels ◽  
Low Alloy Steel ◽  
Alloy Steels ◽  
Weld Heat

Temperbead welding is common practice in the nuclear power industry for in-situ repair of quenched and tempered low alloy steels where post weld heat treatment is impractical. The temperbead process controls the heat input such that the weld heat-affected-zone (HAZ) in the low alloy steel is tempered by the welding heat of subsequent layers. This tempering eliminates the need for post weld heat treatment (PWHT). Unfortunately, repair organizations in the nuclear power industry are experiencing difficulty when attempting to qualify temperbead welding procedures on new quenched and tempered low alloy steel base materials manufactured to modern melting and deoxidation practices. The current ASME Code methodology and protocol for verification of adequate fracture toughness in materials was developed in the early 1970s. This paper reviews typical temperbead qualification results for vintage heats of quenched and tempered low alloy steels and compares them to similar test results obtained with modern materials of the same specification exhibiting superior fracture toughness.

scholarly journals KARAKTERISASI KOROSI BAJA PADUAN RENDAH DI LINGKUNGAN 60% LiBr PADA SUHU DIDIH = CORROSION CHARACTERIZATION OF LOW-ALLOY STEEL UNDER 60% LiBr ENVIRONMENT AT BOILING TERMPERATURE

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Harsisto .
Keyword(s):  
Alloy Steel ◽  
Low Carbon Steel ◽  
Steel Corrosion ◽  
Low Alloy Steels ◽  
Air Conditioner ◽  
Low Carbon ◽  
Low Alloy Steel ◽  
Alloy Steels ◽  
Engine Coolant

Research-based characterization of low alloy steel chrome andmanganese is done because of the problem of corrosion and corrosion limit water evenly on low carbon steel. Based on the findings, the engine coolant is switched on-and off every day so there was influence of outside air and the decrease of the temperature to room temperature. Based on the research and discussion of the characteristics of the five types low alloy steel containing 0.5 wt% manganese in the medium 60% LiBr + 0.2% LiOH at a temperature of (150 ± 2) ° C and exposure to atmospheric air for 50 hours and 110 hours , it showed that the corrosion rate is dependent on the level of content of the chromium. In the addition of the chromium in low alloy steels exposed in the test solution, there is no consistency in the natural corrosion potential value, but in general all test objects were in a corroded state.Keywords : air conditioner, low alloy steel, corrosion, LiBr, LiOH, the boiling temperature and the room temperature.AbstrakPenelitian karakterisasi baja paduan rendah berbasis krom dan mangan ini dilakukan karena adanya masalah korosi merata dan korosi batas air pada baja karbon rendah. Berdasar fakta di lapangan,mesin pendingin tersebut dilakukan “on-Off” setiap hari sehingga ada pengaruh udara luar dan turunnya suhu hingga suhu ruangan. Berdasarkan penelitian dan pembahasan tentang karakteristik 5 jenis baja paduan rendah dengan kandungan 0,5% berat unsur mangan dalam media 60% LiBr + 0,2% LiOH pada suhu(150±2) °C dan ekspos udara atmosfer selama 50 jam dan 110 jam, hasilnya menunjukkan bahwa laju korosi masih tergantung pada kadar kandungan unsur krom. Pada penambahan unsur krom dalam baja paduan rendah yang diekspos dalam larutan uji, tidak menunjukkan adanya konsistensi harga potensial korosi alaminya, tetapi secara umum semua benda uji berada dalam keadaanterkorosi.Kata Kunci : mesin pendingin ruangan, baja paduan rendah, korosi, LiBr,LiOH, suhu didih dan suhu ruangan.AbstrakPenelitian karakterisasi baja paduan rendah berbasis krom dan mangan inidilakukan karena adanya masalah korosi merata dan korosi batas air padabaja karbon rendah.Berdasar fakta di lapangan,mesin pendingin tersebut dilakukan “on-Off” setiaphari sehingga ada pengaruh udara luar dan turunnya suhu hingga suhuruangan. Berdasarkan penelitian dan pembahasan tentang karakteristik 5jenis baja paduan rendah dengan kandungan 0,5% berat unsur mangandalam media 60% LiBr + 0,2% LiOH pada suhu(150±2) °C dan ekspos udaraatmosfer selama 50 jam dan 110 jam, hasilnya menunjukkan bahwa lajukorosi masih tergantung pada kadar kandungan unsur krom. Padapenambahan unsur krom dalam baja paduan rendah yang diekspos dalamlarutan uji, tidak menunjukkan adanya konsistensi harga potensial korosialaminya, tetapi secara umum semua benda uji berada dalam keadaanterkorosi.Kata Kunci : mesin pendingin ruangan, baja paduan rendah, korosi, LiBr,LiOH, suhu didih dan suhu ruangan.

scholarly journals The influence of grain boundaries on the development of deformation in low-carbon low-alloy steels

2021 ◽  
pp. 55-63
Author(s):  
Yu.S. Slupska ◽  
L.M. Dadiverina ◽  
D.Yu. Chashyn ◽  
H.O. Toropchenov ◽  
M.O. Pyko
Keyword(s):  
Plastic Deformation ◽  
Grain Boundaries ◽  
Alloy Steel ◽  
Low Alloy Steels ◽  
Low Carbon ◽  
Low Alloy Steel ◽  
Defective Structure ◽  
Urgent Task ◽  
Alloy Steels ◽  
Kinetics Of

Problem statement. Most modern materials have a polycrystalline structure. Their most important property − mechanical strength − is determined by the defective structure of the crystals. Under the defective structure should be understood not only the concentration and distribution of point defects, dislocations, packaging defects, but also the grain boundaries. The development of such processes as diffusion, recrystallization, plasticity, creep, fragility, cracking and corrosion resistance depends on the grain boundaries. The degree of this influence is directly related to the peculiarities of the atomic structure of boundaries and their interaction with other defects. Therefore, the study of the influence of interfacial and intraphase boundaries on the development of plastic deformation in modern materials is an urgent task. Purpose of the article. Investigation of the influence of the type of polycrystalline boundaries on the kinetics of propagation of plastic deformation in low-carbon low-alloy steel 06Х1. Conclusion. Investigation of the influence of the type of polycrystalline boundaries on the kinetics of propagation of plastic deformation in low-carbon low-alloy steel 06Х1. Conclusion. For low-carbon low-alloy steel 06Х1 the influence of the type of polycrystalline boundaries on the kinetics of plastic deformation propagation is investigated. The relationship between the propagation of plastic deformation and the type of interfacial and intraphase boundaries is established. The proposed physical model takes into account the ability of structural components to block plastic deformation. Keywords: propagation of plastic deformation; boundaries of a special type; boundaries of a general type

Hydrogen stress cracking resistance and hydrogen transport properties of ASTM A508 grade 4N

CORROSION ◽  
10.5006/3949 ◽  
2021 ◽  
Author(s):  
Esteban Rodoni ◽  
Andreas Viereckl ◽  
Zakaria Quadir ◽  
Aaron Dodd ◽  
Kim Verbeken ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Yield Strength ◽  
Alloy Steel ◽  
Hydrogen Diffusion ◽  
Low Alloy Steels ◽  
Low Alloy Steel ◽  
Cracking Resistance ◽  
Stress Cracking ◽  
High Nickel ◽  
Alloy Steels

Low alloy steels combine relatively low cost with exceptional mechanical properties, making them commonplace in oil and gas equipment. However, their strength and hardness are restricted for sour environments to prevent different forms of hydrogen embrittlement. Materials used in sour services are regulated by the ISO 15156-2 standard, which imposes a maximum hardness of 250 HV (22 HRC) and allows up to 1.0 wt% Ni additions due to hydrogen embrittlement concerns. Low alloy steels that exceed the ISO 15156-2 limit have to be qualified for service, lowering their commercial appeal. As a result, high-performing, usually high-nickel, low alloy steels used successfully in other industries are rarely considered for sour service. In this work, the hydrogen stress cracking resistance of the high-nickel (3.41 wt%), quenched and tempered, nuclear-grade ASTM A508 Gr.4N low alloy steel was investigated using slow strain rate testing as a function of applied cathodic potential. Results showed that the yield strength and ultimate tensile strength were unaffected by hydrogen, even at a high negative potential of -2.00 V<sub>Ag/AgCl</sub>. Hydrogen embrittlement effects were observed once the material started necking, manifested by a loss in ductility with increasing applied cathodic potentials. Indeed, A508 Gr.4N was less affected by hydrogen at high cathodic potentials than a low-strength (yield strength = 340 MPa) ferritic-pearlitic low alloy steel of similar nickel content. Additionally, hydrogen diffusivity was measured using the hydrogen permeation test. The calculated hydrogen diffusion coefficient of the ASTM A508 Gr.4N was two orders of magnitude smaller when compared to that of ferritic-pearlitic steels. Hydrogen embrittlement and diffusion results were linked to the microstructure features. The microstructure consisted in a bainitic/martensitic matrix with the presence of Cr<sub>23</sub>C<sub>6</sub> carbides as well as Mo and V-rich precipitates, which might have played a role in retarding hydrogen diffusion, kept responsible for the improved HE resistance.

On the Materials Requirements for a Solar Solid-Expansion Machine

2000 ◽  
Vol 122 (3) ◽  
pp. 154-157
Author(s):  
B. J. Brinkworth
Keyword(s):  
Figure Of Merit ◽  
High Strength ◽  
Solar Thermal ◽  
Low Alloy Steels ◽  
Expansion Engine ◽  
Alloy Steels ◽  
Thermal Histories ◽  
Engineering Alloys ◽  
Selection Of

An outline is given of the mechanical and thermal histories of the working substance for a generic stand-alone solar thermal solid-expansion engine. A Figure-of-merit for the selection of materials is devised and evaluated, showing that high-strength engineering alloys figure best for this duty, with the carbon and low-alloy steels a practical choice. [S0199-6231(00)00403-2]

Sign in / Sign up

Export Citation Format

Share Document