Technology of welding of products made of steel 15Kh5M with control of thermal cycles

1993 ◽  
Vol 29 (9) ◽  
pp. 444-448
Author(s):  
A. G. Khalimov ◽  
N. M. Korolev ◽  
�. R. Gallyamov
Keyword(s):  
Thermal Cycles ◽  
Steel 15Kh5m

Laboratory Ageing Thermal Cycles of MV Cable Joints: results of different diagnostic techniques

2020 ◽  
Author(s):  
Johnny Borghetto ◽  
Alfredo Contin ◽  
Andrea Morotti ◽  
Andrea Pegoiani ◽  
Giovanni Pirovano ◽  
...  
Keyword(s):  
Diagnostic Techniques ◽  
Thermal Cycles

Study of the structural degradation of steel 15Kh5M upon continuous duty

2020 ◽  
Vol 86 (1) ◽  
pp. 38-43
Author(s):  
Vladimir A. Kim ◽  
Valeriya V. Lysenko ◽  
Anna A. Afanaseva ◽  
Khasan I. Turkmenov
Keyword(s):  
Grain Boundaries ◽  
Structural Changes ◽  
Structural Transformations ◽  
Structural Degradation ◽  
Structural Arrangement ◽  
Dispersed Particles ◽  
Complex Process ◽  
Multifractal Spectra ◽  
Steel 15Kh5m ◽  
Complex Indicators

Structural degradation of the material upon long-term thermal and force impacts is a complex process which includes migration of the grain boundaries, diffusion of the active elements of the external and technological environment, hydrogen embrittlement, aging, grain boundary corrosion and other mechanisms. Application of the fractal and multifractal formalism to the description of microstructures opens up wide opportunities for quantitative assessment of the structural arrangement of the material, clarifies and reveals new aspects of the known mechanisms of structural transformations. Multifractal parameterization allows us to study the processes of structural degradation from the images of microstructures and identify structural changes that are hardly distinguishable visually. Any quantitative structural indicator can be used to calculate the multifractal spectra of the microstructure, but the most preferable is that provides the maximum range of variation in the numerical values of the multifractal components. The results of studying structural degradation of steel 15Kh5M upon continuous duty are presented. It is shown that structural degradation of steel during operation under high temperatures and stresses is accompanied by enlargement of the microstructural objects, broadening of the grain boundaries and allocation of the dispersed particles which are represented as point objects in the images. The processes of structural degradation lead to an increase in the range of changes in the components of the multifractal spectra. High values of complex indicators of structural arrangement indicate to an increase in heterogeneity and randomness at the micro-scale level, but at the same time, to manifestation of the ordered combinations of individual submicrostructures. Those structural transformations adapt the material to external impacts and provide the highest reliability and fracture resistance of the material.

scholarly journals Contactless temperature measurement in wire-based electron beam additive manufacturing Ti-6Al-4V

2021 ◽  
Author(s):  
F. Pixner ◽  
R. Buzolin ◽  
S. Schönfelder ◽  
D. Theuermann ◽  
F. Warchomicka ◽  
...  
Keyword(s):  
Electron Beam ◽  
Additive Manufacturing ◽  
Thermal Imaging ◽  
Temperature Profiles ◽  
Layer By Layer ◽  
Thermal Cycles ◽  
Cooling Rates ◽  
Geometric Boundary ◽  
Microstructural Characterisation ◽  
Local Misorientation

AbstractThe complex thermal cycles and temperature distributions observed in additive manufacturing (AM) are of particular interest as these define the microstructure and the associated properties of the part being built. Due to the intrinsic, layer-by-layer material stacking performed, contact methods to measure temperature are not suitable, and contactless methods need to be considered. Contactless infrared irradiation techniques were applied by carrying out thermal imaging and point measurement methods using pyrometers to determine the spatial and temporal temperature distribution in wire-based electron beam AM. Due to the vacuum, additional challenges such as element evaporation must be overcome and additional shielding measures were taken to avoid interference with the contactless techniques. The emissivities were calibrated by thermocouple readings and geometric boundary conditions. Thermal cycles and temperature profiles were recorded during deposition; the temperature gradients are described and the associated temperature transients are derived. In the temperature range of the α+β field, the cooling rates fall within the range of 180 to 350 °C/s, and the microstructural characterisation indicates an associated expected transformation of β→α'+α with corresponding cooling rates. Fine acicular α and α’ formed and local misorientation was observed within α as a result of the temperature gradient and the formation of the α’.

Thermal cycles and their effects during friction stir welding of AA7075 thicker plates with and without in‐process cooling

2021 ◽  
Vol 52 (3) ◽  
pp. 308-319
Author(s):  
T. Srinivasa Rao ◽  
M. Selvaraj ◽  
S.R. Koteswara Rao ◽  
T. Ramakrishna
Keyword(s):  
Friction Stir Welding ◽  
Thermal Cycles ◽  
Friction Stir

Electrical Conductivity Behaviour of Ferritic Steel Interconnect in Function of Spinel Composition, Electrode Material and Thermal Cycles

2019 ◽  
Vol 91 (1) ◽  
pp. 2189-2200
Author(s):  
Pierre Coquoz ◽  
Noelia Coton ◽  
Fabien Morand ◽  
Stephane Frund ◽  
Raphaël Ihringer
Keyword(s):  
Electrical Conductivity ◽  
Electrode Material ◽  
Ferritic Steel ◽  
Thermal Cycles ◽  
Spinel Composition ◽  
Conductivity Behaviour

scholarly journals The Interface Microstructure and Shear Strength of Sn2.5Ag0.7Cu0.1RExNi/Cu Solder Joints under Thermal-Cycle Loading

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 518 ◽  
Author(s):  
Congcong Cao ◽  
Keke Zhang ◽  
Baojin Shi ◽  
Huigai Wang ◽  
Di Zhao ◽  
...  
Keyword(s):  
Shear Strength ◽  
Fracture Mechanism ◽  
Thermal Cycle ◽  
Solder Joints ◽  
Joint Interface ◽  
Interface Microstructure ◽  
Average Thickness ◽  
Thermal Cycles ◽  
Initial State ◽  
Cycle Loading

The interface microstructure and shear strength of Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints under thermal-cycle loading were investigated with scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and physical and chemical tests. The results show that an intermetallic compound (IMC) layer of Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints evolved gradually from the scalloped into larger wavy forms with increasing number of thermal cycles. The roughness and average thickness of IMC increased with thermal-cycle loading. However, at longer thermal-cycle loading, the shear strength of the joints was reduced by about 40%. The fracture pathway of solder joints was initiated in the solder seam with ductile fracture mechanism and propagated to the solder seam/IMC layer with ductile-brittle mixed-type fracture mechanism, when the number of thermal cycles increased from 100 to 500 cycles. By adding 0.05 wt.% Ni, the growth of the joint interface IMC could be controlled, and the roughness and average thickness of the interfacial IMC layer reduced. As a result, the shear strength of joints is higher than those without Ni. When compared to joint without Ni, the roughness and average thickness of 0.05 wt.% Ni solder joint interface IMC layer reached the minimum after 500 thermal cycles. The shear strength of that joint was reduced to a minimum of 36.4% of the initial state, to a value of 18.2 MPa.

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