Effect of Inverter Power Source Characteristics on Welding Stability and Heat Affected Zone Dimensions

The paper presents results the research in the effect of power sources dynamic characteristics on stability of melting and electrode metal transfer to the weld pool shielded metal arc welding. It is proved that when applying inverter-type welding power sources, heat and mass transfer characteristics change, arc gap short-circuit time and drop generation time are reduced. This leads to reduction of weld pool heat content and contraction of the heat-affected zone by 36% in comparison the same parameters obtained using a diode rectifier

Alloying Elements Transition Into the Weld Metal When Using an Inventor Power Source

The temperature distribution over the surface of the welded 12Kh18N10T steel plates using the inventor power source ARC-200 has been calculated. In order to imitate multipass welding when conducting the thermal analysis the initial temperature was changed from 298K up to 798K in 100K increments. It has been determined that alloying elements transition into the weld metal depends on temperature. Using an inventor power source facilitates a uniform distribution of alloying elements along the length and height of the weld seam

Manufacturing Component Parts of Mining Equipment With Application of Hardening Technologies

To ensure highest hardness and wear resistance the authors develop an aggregate technology of manufacturing mining equipment component parts. The aggregate technology of manufacturing faced component parts includes the following operations: plasma-jet hard-facing with high-speed steels; high-temperature tempering after the facing, ultrasonic surface strengthening treatment, additional tempering, reconstructive facing

Traditional Technology of Chromium-Tungsten Steels Facing, its Disadvantages and Suggestions for their Eliminations

To reveal the disadvantages of the traditional technology of facing with chromium-tungsten steels analysis of the given technology was completed. The analysis showed that the main disadvantages of the technology are high-temperature heating and underutilization of high-alloyed metal properties. To eliminate the disadvantages we developed the methods of facing allowing obtaining faced metal which state is close to that of the hardened one without cracks

Real-Time PCR Detection of <i>Bacillus anthracis</i> by Lambda_Ba03 Prophage Genes

The aim of the study was to develop a set of primers and fluorescent probes for the detection of two chromosomal targets of Bacillus anthracis using real-time PCR based on the lambda_Ba03 prophage genes.Materials and methods. BLAST analysis of B. anthracis chromosomal DNA identified two target genes in the region of lambdaBa03 prophage, BA_5358 (AE016879.1: 4852332..4853642) and BA_5361 (AE016879.1: 4855298..4856278). The designed primers and fluorescent hydrolysable TaqMan probes for simultaneous detection of B. anthracis chromosomal DNA by two stated genes were tested in qPCR for sensitivity and specificity.Results and discussion. Studies performed on chromosomal DNA samples of closely related bacteria (B. cereus, B. thuringiensis, B. subtilis, B. clausii) have shown 100 % specificity of the developed sets of primers/probes. The sensitivity of the devised multiplex kit, tested on DNA samples of the m55-VNIIVViM vaccine strain and archival DNA samples of B. anthracis, reached 100 fg of bacterial DNA, which sets the limit of sensitivity at 17 genomes per reaction. The developed multiplex kit can be used as a separate tool for research laboratories studying anthrax