Research of corrosion-resistant welding of NPP equipment performed with a strip electrode by arc and electroslag methods

2021 ◽  
pp. 94-106
Author(s):  
M. N. Timofeev ◽  
I. A. Morozovskaya ◽  
S. N. Galyatkin ◽  
N. I. Zatokovenko ◽  
E. I. Kutsenko ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Carbon Steel ◽  
Corrosion Resistant ◽  
Strip Electrode ◽  
Metallic Inclusions ◽  
Deposited Metal ◽  
Composition Structure

This article presents the results of studies of corrosion-resistant surfacing with a strip electrode under a layer of flux on carbon steel, performed by arc and electroslag methods. The similarity of the chemical composition, structure, mechanical and corrosion characteristics of the deposited metal in both cases is estab- lished. It has been shown that electroslag surfacing provides greater purity for non-metallic inclusions.

Study of Corrosion-Resistant Deposited Metal of NPP Equipment Performed with a Strip Electrode by Arc Welding and Electroslag Welding Methods

2021 ◽  
Vol 12 (6) ◽  
pp. 1597-1605
Author(s):  
M. N. Timofeev ◽  
I. A. Morozovskaya ◽  
S. N. Galyatkin ◽  
N. I. Zatokovenko ◽  
E. I. Kutsenko ◽  
...  
Keyword(s):  
Arc Welding ◽  
Electroslag Welding ◽  
Corrosion Resistant ◽  
Strip Electrode ◽  
Deposited Metal

Effect of plasma treatment on chemical composition, structure and sorption properties of lignocellulosic hemp fibers (Cannabis sativa L.)

2020 ◽  
Vol 236 ◽  
pp. 116000 ◽  
Author(s):  
Biljana M. Pejić ◽  
Ana D. Kramar ◽  
Bratislav M. Obradović ◽  
Milorad M. Kuraica ◽  
Andrijana A. Žekić ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Plasma Treatment ◽  
Cannabis Sativa ◽  
Sorption Properties ◽  
Hemp Fibers ◽  
Composition Structure ◽  
Structure And Sorption Properties

Methods for Defining the Concentration of Nanostructured Powders in Protective Gas and its Effect on the Microstructure of Deposit Metal

2015 ◽  
Vol 770 ◽  
pp. 28-33 ◽  
Author(s):  
M.A. Kuznetsov ◽  
Svetlana A. Barannikova ◽  
Evgeniy A. Zernin ◽  
A.V. Filonov ◽  
D.S. Kartcev
Keyword(s):  
Chemical Composition ◽  
Austenitic Steel ◽  
Arc Welding ◽  
Metal Structure ◽  
Structure Of Metal ◽  
Deposited Metal ◽  
Protective Gas ◽  
Equilibrium Microstructure ◽  
Positive Effect ◽  
Nanostructured Powders

The effect on the deposited metal structure of nanostructured modifiers introduced into the weldpool has been studied. Methods have been developed for determining the concentration of nanostructured powders of tungsten, molybdenum and Al2O3 in protective gas and for defining their optimal concentration. The influence of nanopowders on the structure of deposited metal was examined in consumable electrode arc welding employing the austenitic steel (chemical composition: C – 0,12%, Cr – 18%, Ni – 10%,Ti – 1%) as deposit and 1.2-mm welding wire manufactured from the austenitic steel (chemical composition: C – 0,12%, Cr – 18%, Ni – 9%,Ti – 1%). Addition of nanostructured powders of tungsten, molybdenum and Al2O3 to the weldpool has shown positive effect on the structure of metal in arc welding. It is shown that introducing the powders decreases dendrite size and leads to the formation of a more equilibrium microstructure of the weld.

scholarly journals Modification of Non-Metallic Inclusions by Rare-Earth Elements in Microalloyed Steels

2012 ◽  
Vol 12 (2) ◽  
pp. 129-134 ◽  
Author(s):  
M. Opiela ◽  
A. Grajcar
Keyword(s):  
Rare Earth ◽  
Chemical Composition ◽  
Rare Earth Elements ◽  
Mechanical Treatment ◽  
Induction Furnace ◽  
Microalloyed Steels ◽  
Metallurgical Process ◽  
Metallic Inclusions ◽  
Mean Size ◽  
Thermo Mechanical Treatment

Modification of Non-Metallic Inclusions by Rare-Earth Elements in Microalloyed Steels The modification of the chemical composition of non-metallic inclusions by rare-earth elements in the new-developed microalloyed steels was discussed in the paper. The investigated steels are assigned to production of forged elements by thermo-mechanical treatment. The steels were melted in a vaccum induction furnace and modification of non-metallic inclusions was carried out by the michmetal in the amount of 2.0 g per 1 kg of steel. It was found that using material charge of high purity and a realization of metallurgical process in vacuous conditions result in a low concentration of sulfur (0.004%), phosphorus (from 0.006 to 0.008%) and oxygen (6 ppm). The high metallurgical purity is confirmed by a small fraction of non-metallic inclusions averaging 0.075%. A large majority of non-metallic inclusions are fine, globular oxide-sulfide or sulfide particles with a mean size 17 μm2. The chemical composition and morphology of non-metallic inclusions was modified by Ce, La and Nd, what results a small deformability of non-metallic inclusions during hot-working.

Corrosion behaviors of iron, chromium, nickel, low-carbon steel and four types of stainless steels in liquid antimony-tin alloy

CORROSION ◽  
10.5006/3820 ◽  
2021 ◽  
Author(s):  
Wei Liu ◽  
Huayi Yin ◽  
Kaifa Du ◽  
Bing Yang ◽  
Dihua Wang
Keyword(s):  
Carbon Steel ◽  
Corrosion Rate ◽  
Stainless Steels ◽  
Liquid Metals ◽  
Low Carbon Steel ◽  
Solid Substrate ◽  
Low Carbon ◽  
Corrosion Resistant ◽  
Corrosion Behaviors ◽  
Iron Chromium

Corrosion-resistant metals and alloys towards liquid metals determine the service performances and lifetime of the devices employing liquid metals. This paper studies the static corrosion behaviors of iron, chromium, nickel, low carbon steel, and four types of stainless steels (SS410, SS430, SS304, SS316L) in liquid Sb-Sn at 500 oC, aiming to screen corrosion-resistant SS for Li||Sb-Sn liquid metal batteries (LMBs). The corrosion rates of Fe and Ni are 0.94 μm h-1 and 6.03 μm h-1 after 160 h’s measurement, respectively. Cr shows a low corrosion rate of < 0.05μm h-1, which is due to the formation of a relatively stable Cr-Sb layer that may be able to prevent the interdiffusion between the solid substrate and liquid Sb-Sn. Ni has a high corrosion rate because the formed Ni-Sb and Ni-Sn compounds are soluble in the liquid Sb-Sn. The corrosion products of both pure metals and SS can be predicted by thermodynamic and phase diagram analysis. Among the four types of SS, SS430 shows the best corrosion resistance towards liquid Sb-Sb with a corrosion rate of 0.19 μm h-1. Therefore, a liquid Sb-Sn resistant material should have a high Cr content and a low Ni content, and this principle is applicable to design metallic materials not only for LMBs but also for other devices employing liquid Sb- and Sn-containing liquid metals.

Influence of High-Calcium Ash Composition on the Composite Binders’ Properties

2021 ◽  
Vol 316 ◽  
pp. 1019-1024
Author(s):  
O. A. Ignatova ◽  
A. A. Dyatchina
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Cement Stone ◽  
Normal Density ◽  
Fine Aggregate ◽  
Equivalent Amount ◽  
High Calcium ◽  
Composition Structure ◽  
Kinetics Of ◽  
Positive Effect

The paper presents the studies’ results of chemical composition, structure, and physico-mechanical properties of high-calcium ashes from the Kansk-Achinsk coals (2017-2019 selection). It was found that ash has a complex poly-mineral composition and contains hydraulically active minerals and oxides of СаОfr, β-C2S, CA, C3A, C4AF, C2F, CaSO4. According to the content of CaOfr, MgO does not meet standards’ requirements. The uniformity of the volume change is maintained by the composition with 50% of cement. The structure and hardening kinetics of ash and ash-cement stone compositions, obtained from the test of normal density, were analyzed. It was established that the hardening of compositions with ash from the Kansk-Achinsk coals was largely influenced by ash minerals. An equivalent amount of cement in composite binders cannot be replaced. In order to obtain a positive effect, compositions with ash instead cement of no more than 30% and a part of fine aggregate, without exceeding the ratio of ash: cement = 1: 1, should be used.

Integrity of Weld Overlay of Flexible Joints and Lined Pipe

2015 ◽  
Author(s):  
Petrônio Zumpano ◽  
Alexandre G. Garmbis ◽  
Eduardo V. Oazen ◽  
Luis Guilherme T. S. Leite ◽  
Rafael N. Silva
Keyword(s):  
Carbon Steel ◽  
Ultrasonic Inspection ◽  
Base Material ◽  
Probability Of Detection ◽  
Internal Layers ◽  
Flexible Joints ◽  
Weld Overlay ◽  
Corrosion Resistant ◽  
Alloy 625 ◽  
Sulfide Stress

This paper describes different alternatives to be adopted to assess the integrity of weld overlays of flexible joints and lined pipes in offshore pipeline and riser projects. Protective layers are adopted as an interesting alternative to full thickness corrosion resistant alloys due to the possibility to adopt carbon steel as base material in order to reduce overall material costs. UNS N06625 (alloy 625) is generally selected for internal layers, such as weld overlay steels, lined pipes or clad pipes because of its sulfide stress cracking (SSC) resistance and outstanding weldability. However, unless the long-term integrity of the cladding or overlay as a protective layer can be demonstrated under the intended service conditions, the base material shall also be resistant against sulfide stress corrosion cracking. Due to low resistance of carbon steel to corrosion fatigue in the presence of contaminants in fluid content, the rupture of thickness of CRA (Corrosion Resistant Alloy) layer becomes a failure mode. An Engineering Critical Assessment (ECA) shall be performed in order to assess if circumferential planar flaws in weld overlay regions will not propagate through the CRA layer, thus exposing the base material, when submitted to critical cyclic loads during the service life. Such analysis would involve fatigue crack growth simulation and surface interaction of full circumferential embedded defects to determine the maximum weld overlay pass height to be limited by machining. This limited height of machined layers should guarantee that a full circumferential flaw will withstand the operational fatigue life. However, this is a very time consuming manufacturing process and would implicate additional concerns for long extensions due to out of straightness and out of roundness. Alternatively, the ECA results may be used to determine the flaw acceptance criteria and required probability of detection of volumetric non-destructive testing. Recent developments in ultrasonic inspection were successfully adopted and represent a better solution for alloy 625 weld overlay in terms of project scheduling and manufacturing costs. Radiographic testing may also be used provided it meets the required sensitivity, in terms of image quality indicators (IQI). Anyway, validation tests shall be performed to demonstrate adequate reliability to detect the minimum required flaw height.

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