In this work, the toxicity level of nano- and microparticles obtained by underwater welding was assessed. The evaluated on three types marine microalgae: Heterosigma akashiwo (Ochrophyta), Porphyridium purpureum (Rhodophyta), Attheya ussuriensis (Bacillariophyta). aim to study environmental risks associated with ingress micro- nanoparticles metal oxides into environment. Water samples containing suspensions from wet cutting processes were analyzed inductively coupled plasma mass spectrometry...

Underwater wet welding is commonly used in joining pipelines and underwater construction. Harmful hazardous compounds are added to many flux-cored wires for cutting, can have a negative impact on marine life. The specific objective of this study was evaluate the aquatic toxicity two suspension samples obtained using electrode wire microalgae Attheya ussuriensis Porphyridium purpureum. Growth rate inhibition, cell size, biochemical changes were evaluated by flow cytometry. results bioassay...

High susceptibility to cold cracking induced by diffusible hydrogen and embrittlement are major obstacles greater utilization of underwater wet welding for high-strength steels. The aim the research was develop gas–slag systems flux-cored wires that have high metallurgical activity in removal hydroxyl groups. Thermodynamic modeling experimental confirmed a decrease concentration can be achieved reducing partial pressure water vapor vapor–gas bubble increasing capacity slag system reactions...

High-strength steel S960 is one of a number advanced steels able to meet the demands shipbuilding, offshore, and construction industries for favorable good high strength/weight ratio. Gas metal arc welding (GMAW) commonly used in all structural fabrication, developments GMAW have removed previous limitations regarding heat input reduced flaws. One solution controlled while ensuring stable alloying wire. Usage nanoparticles as an element wire shown significant improvements weld properties....

Abstract The paper presents research in the field of underwater wet cutting with use flux-cored wires order to improve quality and performance. has resulted into development gas slag systems for determination of, optimal parameters stability quality. mechanism is a cyclical process formation periodic keyholes metal, it consists operating idle cycles. Efficiency can be determined by analyzing cycle times, welding current, voltage, power number short circuits. To assess efficiency process,...

Investigations were carried out into methods of increasing the productivity automatic MIG/MAG welding steels and improving quality welded joints by investigating effect ultrafine activating fluxes on properties arc formation joints.

It is established that use of activating flux superdispersed powders in laser welding steels allows for improvement the quality welded joints, reducing joint gap width and increasing penetration depth: so doing, process productivity goes up by 7–45%.

The results of investigations the effect ultrafine activating fluxes on variation parameters process penetration S235JR steel and quality welded joints, produced at low laser welding speeds, are presented.

Thermomechanical Controlled Processing (TMCP), the initial microstructure and mechanical properties of rolled products made high-strength steels, have a significant influence on reliability welded structures for low temperature cryogenic service. This paper systematizes advanced research trends in field metallurgy weldability cold-resistant steels. The classification steels are given TMCP diagrams phase transformations considered. Modern methods improving viscoplasticity steel joints...

Abstract The paper describes the results of research about orbital hyperbaric FCA-welding API X70 steel pipes with use gas-shielded flux cored wires TiO 2 -CaF system higher content fluorides in core. As a result research, dependences welding current, arc voltage, metallurgical features and mechanical properties depending pressure chamber are determined. within gas 0,1–0,6 MPa, for provides favourable microstructure welded joint welds according to Class A per ANSI/AWS D3.6M:2010.

For arc welding of high-strength and cold-resistant steels, the author developed an advanced design steel wire with a micro-composite coating nickel matrix nanoparticles LaF3 LaB6, which improves metallurgical influence rare-earth elements (REE) forms refractory sulphides oxides REE, as well boron nitride. The addition 0.1–0.3 wt% La in weld pool leads to increase content compounds La2O3, LaO2, LaS, reduction low-melting brittle SiO2, SiO, MnO, MnS, SiS. use composite LaB6 allows for...

The research results of underwater wet FCA-welding samples from high-strength steel based on the use fluoric flux-cored electrode with metallurgical activity in aquatic environment are adduced. best were achieved welding a TiO2-CaF2 charge system. A favourable structure and mechanical properties joint ensured.

The technology of forced MAG welding steels, based on the application materials in form nanostructured electrode wires with microcomposite coating ultra- and nanodisperse particles halides metallic matrix, is described.

Abstract The paper describes the experimental findings of underwater wet welding and cutting API X70 pipe steel plates with use following flux-cored wires: TiO 2 -CaF ; Fe O 3 -TiO -SiO . For cored wire a diameter mm based on salts iron alkali metals was developed. best weld properties have been achieved during fluoride wires system, which provides suitable micro structure weld, high solidity deposited metal mechanical weld. improves quality thickness up to 8 mm.

Development of welding consumables with fluorides and borides rare earth metals is a promising area for improving the weldability low alloy steels. As lanthanum fluoride boride dissociate, boron dissolve in weld pool arc plasma saturated fluorine. result FeO, MnO, SiO2 deoxidation FeS, MnS desulfurization, refractory sulfides oxides La2O3, La2S3 are formed pool, which can be crystallization nuclei origin acicular ferrite nucleation. The paper proposes model metallurgical processes as well...

This paper considers the metallurgical processes of dissociation, ionization, oxidation, deoxidation, and dissolution oxides during underwater wet cutting. A multiphase mechanism cutting consisting working idle cycles electrical process in a pulsating vapor gas bubble is proposed. model arc penetration into metal due to oxidation stabilization by inner walls narrow kerf For 10 KhSND, 304L steel, CuAl5, AlMg4.5Mn0.7 alloy, we provide principle modeling phase composition mixture based on high...

Achieving a higher quality in wire arc additive manufacturing (WAAM) is result of the development welding metallurgy, filler wires, and control thermophysical properties electric arc. In this paper, authors developed composite wires for WAAM with Ni-LaF3, Ni-LaB6 coating. The addition LaF3, LaB6, SF6 increases specific heat, thermal conductivity, enthalpy, degree plasma ionization, which leads to increase transfer heat from change balance forces during melting. Lorentz electromagnetic force...

The results of investigations the effect ultrafine activating fluxes on properties welding arc and formation welded joints in with direct alternating current to increase productivity automatic argon-shielded steels aluminium alloys improve quality are presented.

Investigations were carried out into the problems of increasing productivity automatic MIG welding aluminium alloys and improving quality droplet transfer electrode metal welded joints by studying effect high-speed processes ultrafine activating fluxes on properties arc formation joint.

The material for our study was collected at the Far Eastern Federal University, Ajax Bay, Sea of Japan and studied St. Petersburg Polytechnic University Peter Great. main indicators genesis marine sediments are complex granulometric composition suspended particles. However, their has not been widely used in oceanology research. purpose this work is to study, using Analysette 22 NanoTec plus (Fritsch) laser particle analyzer, particles formed during underwater welding cutting wire. presence...

The morphometric characteristics of man-made particles underwater welding have been studied, the main types structure and elemental composition nano- micro-particles determined. For first time, process propagation most typical in marine environment was simulated at different current speeds with determination zone potential pollution.

The article describes the study to evaluate emissions atmospheric air of airborne nano- and microparticles generated during underwater welding in seawater from Ajax Bay (Sea Japan) using special wires coated electrodes. most commonly used industrial production processes were selected: semi-automatic (mechanized) with a wire, manual electrodes, cutting wire for cutting. An aerosol particle counter was determine mass concentration fine particles working area above aquarium. highest number...