scholarly journals Application of the Mathar Method to Identify Internal Stress Variation in Steel as a Welding Process Result

2017 ◽  
Vol 25 (2) ◽  
pp. 125-136
Author(s):  
Dariusz Kowalski
Keyword(s):  
Internal Stress ◽  
Welding Process ◽  
Internal Stresses ◽  
Induced Voltage ◽  
Stress Variation ◽  
Steel Members ◽  
Electric Arc Welding ◽  
Destructive Measurement ◽  
Non Destructive ◽  
Excessive Stress

Abstract The paper deals with the method to identify internal stresses in two-dimensional steel members. Steel members were investigated in the delivery stage and after assembly, by means of electric-arc welding. In order to perform the member assessment two methods to identify the stress variation were applied. The first is a non-destructive measurement method employing local external magnetic field and to detecting the induced voltage, including Barkhausen noise The analysis of the latter allows to assess internal stresses in a surface layer of the material. The second method, essential in the paper, is a semi-trepanation Mathar method of tensometric strain variation measurement in the course of a controlled void-making in the material. Variation of internal stress distribution in the material led to the choice of welding technology to join. The assembly process altered the actual stresses and made up new stresses, triggering post-welding stresses as a response for the excessive stress variation.

Internal Stresses in Nanocrystalline Nickel and Nickel-Iron Alloys

2012 ◽  
Vol 706-709 ◽  
pp. 1607-1611 ◽  
Author(s):  
J.D. Giallonardo ◽  
Uwe Erb ◽  
G. Palumbo ◽  
G.A. Botton ◽  
C. Andrei
Keyword(s):  
Grain Size ◽  
Internal Stress ◽  
Structural Difference ◽  
Intrinsic Stress ◽  
Internal Stresses ◽  
Second Phase ◽  
Nickel Iron ◽  
Second Phase Particles ◽  
Second Phases ◽  
Rule Out

Nanocrystalline metals are often produced in a state of stress which can adversely affect certain properties, e.g. corrosion resistance, wear, fatigue strength, etc. This stress is referred to as internal or “intrinsic” stress since it is not directly caused by applied loads. The structural causes of these stresses in nanocrystalline materials are not fully understood and are therefore an area of particular interest. The internal stresses of nanocrystalline Ni and Ni-16wt%Fe were measured and found to increase with the addition of iron. Characterization using HR-TEM revealed no signs of porosity, second phase particles, or a high density of dislocations. Both materials possessed well defined high-angle grain boundaries. The main structural difference between the two materials was found to be grain size and correspondingly, a decrease in grain size resulted in an increase in internal stress which supports the applicability of the coalescence theory. The current study also provides evidence to rule out the effect of voids (or porosity), dislocations, and second phases as possible causes of internal stress.

Method of Non-Destructive Measurement of Natural Radionuclides Concentration in Building Materials

ANRI ◽  
2021 ◽  
Vol 0 (1) ◽  
pp. 31-44
Author(s):  
Aleksey Vasil'ev ◽  
Aleksey Ekidin ◽  
Mariya Pyshkina ◽  
Georgiy Malinovskiy ◽  
Aleksandra Onischenko ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Flux Density ◽  
Building Materials ◽  
Specific Activity ◽  
Natural Radionuclides ◽  
Gamma Spectrometer ◽  
Average Activity ◽  
Destructive Measurement ◽  
Non Destructive ◽  
Calculated Flux

A method for non-destructive monitoring of the content of natural radionuclides in building materials has been developed. Spectrum measurements of gamma radiation are carried out with a pre-calibrated field gamma spectrometer. The calculation of the average specific activity of natural radionuclides in building materials is carried out by comparing the calculated flux density of unscattered gamma quanta normalized to the specific activity, and the experimentally measured count rates in the photopeak. calculated for the geometry of the room under study and the location of the detector. Application of the developed method makes it possible to estimate the average activity of natural radionuclides in building materials without destruction.

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