scholarly journals Post Underwater Wet Welding Heat Treatment by Underwater Wet Induction Heating

2021 ◽  
Vol 100 (7) ◽  
pp. 229-238
Author(s):  
Ezequiel Caires Pereira Pessoa ◽  
◽  
Alexandre Queiroz Bracarense ◽  
Valter Rocha Dos Santos ◽  
Ricardo Reppold Marinho ◽  
...  
Keyword(s):  
Induction Heating ◽  
High Hardness ◽  
Exploratory Research ◽  
Low Carbon ◽  
Maximum Hardness ◽  
Heated Zone ◽  
Class A ◽  
Electromagnetic Induction Heating ◽  
Steel Welds ◽  
Filling Passes

Wet welding procedures of Class A structural ship steels frequently fail to comply with the American Welding Society (AWS) D3.6M, Underwater Welding Code, in the maximum hardness criterion for the heat-affected zone (HAZ). The maximum hardness accepted in a welded joint is 325 HV for higher-strength steel (yield strength > 350 MPa). In multi-pass welds, this problem occurs frequently and is restricted to the HAZ of the capping passes. The HAZ of the root and filling passes are softened by the reheating promoted by their respective subsequent passes. This paper presents the results of exploratory research into postweld underwater electromagnetic induction heating. The objective of the research was to evaluate the ability of induction heating to soften the specific high-hardness HAZs in underwater conditions. The results showed that this technique could reduce the maximum HAZ hardness of low-carbon structural ship steel welds to values below 325 HV, which is the maximum accepted by AWS for Class A welds. The induction-heated zone reached a maximum depth of about 10 mm, which is considered adequate to treat the HAZ of cap-ping passes in underwater wet welds.

Dimensionamiento de un horno de fundición por inducción electromagnética y cálculo de los parámetros eléctricos

2019 ◽  
pp. 1-15
Author(s):  
Arnulfo Pérez-Pérez ◽  
Jorge Sergio Téllez-Martínez ◽  
Gregorio Hortelano-Capetillo ◽  
Jesús Israel Barraza-Fierro
Keyword(s):  
Induction Heating ◽  
Power Supply ◽  
Electromagnetic Induction ◽  
Cast Steel ◽  
Electrical Power ◽  
Heating System ◽  
Heating Time ◽  
Ferrous Alloys ◽  
Electromagnetic Induction Heating ◽  
Induction Heating System

In this work, the dimensions of a furnace for melting of ferrous alloys were determined. The furnace has an electromagnetic induction heating system. In addition, the parameters of electrical power supply such as frequency and power were calculated. A 5kg cast steel mass with a density of 7.81 kg / dm3 was proposed. This corresponds to a crucible volume of 0.641 dm3. The frequency was obtained from tables, which take into account the diameter of the crucible, and its value was 1 KHz. The energy consumption was determined with the heat required to bring the steel to the temperature of 1740 K, the energy losses through the walls, bottom and top of the crucible. This value was divided between the heating time (30 minutes) and resulted in a power of 4.5 KW. The development of the calculations shows that the induction heating is an efficient process and allows a fast melting of ferrous alloys.

Laser Assisted High Entropy Alloy Coating on Low Carbon Steel

2019 ◽  
Vol 813 ◽  
pp. 159-164
Author(s):  
Carlos Alberto Souto ◽  
Gustavo Faria Melo da Silva ◽  
Laura Angelica Ardila Rodriguez ◽  
Aline C. de Oliveira ◽  
Kátia Regina Cardoso
Keyword(s):  
Wear Resistance ◽  
Carbon Steel ◽  
Low Carbon Steel ◽  
High Hardness ◽  
Alloy Coating ◽  
High Entropy Alloy ◽  
Nominal Composition ◽  
Low Carbon ◽  
High Entropy ◽  
Scan Speed

Coatings with high entropy alloys of the AlCoCrFeNiV system were obtained by selective laser melting on low carbon steel substrates. The effect of the variation of the Fe and V contents as well as the laser processing parameters in the development of the coating were evaluated. The coatings were obtained from the simple powder mixtures of the high purity elemental components in a planetary ball mill. The coatings were obtained by using CO2 laser with a power of 100 W, diameter of 0.16 mm, and scan speed varying from 3 to 12 mm/s. Phase constituents, microstructure and hardness were investigated by XRD, SEM, and microhardness tester, respectively. Wear resistance measurements were carried out by the micro-abrasion method using ball-cratering tests. The coatings presented good adhesion to the substrate and high hardness, of the order of 480 to 650 HV. Most homogeneous coating with nominal composition was obtained by using the higher scan speed, 12 mm/s. Vanadium addition increased hardness and gave rise to a high entropy alloy coating composed by BCC solid solutions. Ball cratering tests conducted on HEA layer showing improvement of material wear resistance, when compared to base substrate, decreasing up to 88% its wear rate, from 1.91x10-6 mm3/Nmm to 0.23x10-6 mm3/Nmm.

Increasing Hardness of Surface Layer of Low-Carbon Steel by Account of Plasma Treatment of Coating Modification

2021 ◽  
Vol 316 ◽  
pp. 794-802
Author(s):  
Andrey E. Balanovsky ◽  
Van Trieu Nguyen
Keyword(s):  
Surface Layer ◽  
Thermal Treatment ◽  
Plasma Treatment ◽  
Plasma Heating ◽  
High Surface ◽  
Surface Hardness ◽  
High Hardness ◽  
Diffusion Region ◽  
Low Carbon ◽  
Wide Range

The Purpose of paper is to conduct studies to assess the possibility of increasing the hardness of the surface layer of steel St3 grade by plasma heating of the applied surface coating containing powder alloy PR-N80X13S2R. Mixtures of pasta were divided into 2 groups: for furnace chemical-thermal treatment and plasma surface melting. The study of the microstructure showed a difference in the depth of the saturated layer, depending on the processing method, during chemical-thermal treatment-1 mm, plasma fusion - 2 mm. The results of measuring the surface micro-hardness showed that, the obtained coating from a mixture of PR-N80X13S2R + Cr2O3 + NH4Cl has a uniform high surface hardness (31-64 HRC), from a mixture of only PR-N80X13S2R - the surface hardness varies in a wide range (15-60 HRC). The study of the microhardness of the cross section of the surface layer showed that, the diffusion region: from a mixture of powder PR-N80X13S2R + Cr2O3 + NH4Cl has uniform hardness (450-490 HV); from a mixture of PR-N80X13S2R - hardness increases in the depth of the molten region (from 300 to 600 HV), and sharply decreases in the heat affected zone (210-170 HV). The use of PR-N80X13S2R alloy powder as the main component in the composition of the paste deposited on the St3 surface during plasma treatment leads to the formation of a doped surface layer with high hardness.

scholarly journals A Novel Shape Memory Plate Osteosynthesis for Noninvasive Modulation of Fixation Stiffness in a Rabbit Tibia Osteotomy Model

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Christian W. Müller ◽  
Ronny Pfeifer ◽  
Karen Meier ◽  
Sebastian Decker ◽  
Janin Reifenrath ◽  
...  
Keyword(s):  
Shape Memory ◽  
Induction Heating ◽  
Electromagnetic Induction ◽  
Plate Osteosynthesis ◽  
Bending Stiffness ◽  
Niti Sma ◽  
Additional Surgery ◽  
Rabbit Tibia ◽  
Electromagnetic Induction Heating

Nickel-titanium shape memory alloy (NiTi-SMA) implants might allow modulating fracture healing, changing their stiffness through alteration of both elastic modulus and cross-sectional shape by employing the shape memory effect (SME). Hypotheses: a novel NiTi-SMA plate stabilizes tibia osteotomies in rabbits. After noninvasive electromagnetic induction heating the alloy exhibits the SME and the plate changes towards higher stiffness (inverse dynamization) resulting in increased fixation stiffness and equal or better bony healing. In 14 rabbits, 1.0 mm tibia osteotomies were fixed with our experimental plate. Animals were randomised for control or induction heating at three weeks postoperatively. Repetitive X-ray imaging and in vivo measurements of bending stiffness were performed. After sacrifice at 8 weeks, macroscopic evaluation,µCT, and post mortem bending tests of the tibiae were carried out. One death and one early implant dislocation occurred. Following electromagnetic induction heating, radiographic and macroscopic changes of the implant proved successful SME activation. All osteotomies healed. In the treatment group, bending stiffness increased over time. Differences between groups were not significant. In conclusion, we demonstrated successful healing of rabbit tibia osteotomies using our novel NiTi-SMA plate. We demonstrated shape-changing SME in-vivo through transcutaneous electromagnetic induction heating. Thus, future orthopaedic implants could be modified without additional surgery.

Susceptibility to Stress Corrosion Cracking for Low-Carbon Steel Welds in Carbonate-Bicarbonate Solution

CORROSION ◽  
2008 ◽  
Vol 64 (12) ◽  
pp. 939-948 ◽  
Author(s):  
H. Mitsui ◽  
R. Takahashi ◽  
H. Asano ◽  
N. Taniguchi ◽  
M. Yui
Keyword(s):  
Carbon Steel ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Low Carbon Steel ◽  
Corrosion Cracking ◽  
Low Carbon ◽  
Steel Welds

Sintering and Crystallization of Al2O3-La2O3-ZrO2 Eutectic Glass

2018 ◽  
Vol 281 ◽  
pp. 261-265
Author(s):  
Gang He ◽  
Jia Xi Liu ◽  
Nan Lu ◽  
Guang Hua Liu ◽  
Jiang Tao Li
Keyword(s):  
Mechanical Properties ◽  
Crystallization Temperature ◽  
Eutectic Composition ◽  
High Hardness ◽  
Flame Spraying ◽  
Maximum Hardness ◽  
Glass Microspheres ◽  
Densification Mechanism ◽  
Controlled Crystallization ◽  
Crystallization Of Glass

High hardness nanoceramics with a Al2O3-La2O3-ZrO2 eutectic composition were fabricated by sintering and crystallization of glass microspheres. Glass microspheres prepared by the flame spraying-water quenching technique were hot pressing sintered and converted to nanoceramics by controlled crystallization. The sintering densification mechanism of the glass microspheres and the effect of crystallization temperature on microstructure and mechanical properties of the prepared nanoceramics were investigated. The phases of the nanoceramics composed of LaAlO3, ZrO2 and LaAl11O18 at crystallization temperature above 1100°C. It was found that the nanoceramic obtained at 1300°C have a maximum hardness of 18.4 GPa, fracture toughness of 3.3 MPa m1/2.

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