Hydrodynamic Physical Modeling of Laser Drilling

2002 ◽  
Vol 124 (4) ◽  
pp. 852-862 ◽  
Author(s):  
D. K. Y. Low ◽  
L. Li ◽  
P. J. Byrd
Keyword(s):  
Material Removal ◽  
Laser Intensity ◽  
Low Carbon Steel ◽  
Laser Drilling ◽  
Low Carbon ◽  
Additional Energy ◽  
Complex Process ◽  
Threshold Time ◽  
Drilling Conditions ◽  
Melt Ejection

Laser drilling is a complex process that involves material removal through both vaporization and hydrodynamic melt ejection. The process is further complicated when an assist gas is incorporated, which is often the case under most practical drilling conditions. It is the intent of this article to investigate these effects through both experiments and theoretical analysis. The analysis accounts for conduction in the solid, vaporization, vaporization-induced recoil pressure melt ejection, convection due to the melt flow as well as the effects of using an O2 assist gas, which includes the effective assist gas pressure exerted on the melt surface, the forced convection cooling and the additional energy generated due to the oxidation of the melt surface by O2. The effects of the absorbed laser intensity on the melt surface temperature, melt ejection velocity and drilling velocity were studied for both cases of laser drilling with and without O2 assist gas and compared to experimental results obtained for EN3 low carbon steel. The dependence of threshold time on the absorbed laser intensity for either vaporization-dominated or melt ejection-dominated (hydrodynamic-dominated) material removal was studied and subsequently related to the threshold conditions for spatter formation. The model was subsequently optimized by examining the significance of the O2 effects considered.

scholarly journals The Mechanism of Corrosion–Erosion in Steam Extraction Lines of Power Stations

1988 ◽  
Vol 110 (2) ◽  
pp. 180-184 ◽  
Author(s):  
L. E. Sanchez-Caldera ◽  
P. Griffith ◽  
E. Rabinowicz
Keyword(s):  
Material Removal ◽  
Metal Removal ◽  
Removal Rate ◽  
Low Carbon Steel ◽  
Mass Transfer Process ◽  
Diffusion Resistance ◽  
Low Carbon ◽  
Wear Rates ◽  
Power Stations ◽  
Steam Extraction

Corrosion-erosion occurs in steam extraction piping made of low carbon steel that conveys wet steam. The rate of metal removal peaks at 150°C and is most severe on the inside and outside of bends and in the vicinity of fittings. A theory is presented by which three processes are shown to give rise to the observed peak in the metal removal rate: (1) the oxidation reaction, (2) the mass transfer process, which governs at 150°C, and (3) the diffusion resistance of the oxide layer, which governs at higher temperatures. The results of the derived model agree well with the available experimental data in predicting wear rates and in establishing the temperature and the location of maximum material removal.

S.E.M.-T.E.M. Image Comparison

1971 ◽  
Vol 29 ◽  
pp. 132-133
Author(s):  
G. M. Greene ◽  
J. W. Sprys
Keyword(s):  
Electron Microscope ◽  
Low Carbon Steel ◽  
Secondary Emission ◽  
Low Carbon ◽  
Preparation Time ◽  
Actual Surface ◽  
Fine Detail ◽  
Transmission Electron ◽  
Transmission Study ◽  
Large Sections

The present study demonstrates that fracture surfaces appear strikingly different when observed in the transmission electron microscope by replication and in the scanning electron microscope by backscattering and secondary emission. It is important to know what form these differences take because of the limitations of each instrument. Replication is useful for study of surfaces too large for insertion into the S.E.M. and for resolution of fine detail at high magnification with the T.E.M. Scanning microscopy reduces sample preparation time and allows large sections of the actual surface to be viewed.In the present investigation various modes of the S.E.M. along with the transmission mode in the T.E.M. were used to study one area of a fatigue surface of a low carbon steel. Following transmission study of a platinum carbon replica in the T.E.M. and S.E.M. the replica was coated with a gold layer approximately 200A° in thickness to improve electron emission.

Development of trimming technology for hot rolled ultra-low carbon steel

1993 ◽  
Vol 90 (7-8) ◽  
pp. 917-922
Author(s):  
Y. Matsuda ◽  
M. Nishino ◽  
J. Ikeda
Keyword(s):  
Carbon Steel ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Ultra Low Carbon Steel ◽  
Hot Rolled

Study of operating properties of aanticorrosion packing papers

2020 ◽  
Vol 76 (10) ◽  
pp. 1021-1027
Author(s):  
A. P. Ponomarev ◽  
L. G. Kolyada ◽  
E. V. Tarasyuk
Keyword(s):  
Steel Strip ◽  
Low Carbon Steel ◽  
Strength Characteristics ◽  
Low Carbon ◽  
Operating Characteristics ◽  
Packing Materials ◽  
Accelerated Corrosion ◽  
Operating Properties ◽  
Deformation And Strength Characteristics ◽  
Anticorrosion Properties

Metal products are subjected to atmospheric corrosion during transportation and storing. An important way to prevent this negative phenomenon is application of special packing materials, in particular materials, containing volatile inhibitors of corrosion, which protect metal against various corrosion agents. To protect metal effectively it is necessary to provide a definite level of operating characteristics of packing materials. The purpose of the work was the study of operating properties of inhibited crepe, inhibited and laminated polyethylene film, inhibited crepe and reinforced by polypropylene web papers, manufactured by OJSC “PP TechnoKhim”, Magnitogorsk, used for packing of metals. Structural and dimensional, sorption, deformation and strength characteristics, of the studied anticorrosion papers are presented, the characteristics being calculated based on the results of measurements. To determine their physical-mechanical and anticorrosion properties, standard methods and methodologies were used. To evaluate impact of moisture and transportation conditions, indices of water adsorption and wear of the studied papers were determined. Inhibitor content in these materials was determined by thermogravimetric analysis method. Their protective ability was studied on samples of low carbon steel strip. For accelerated corrosion tests the strip samples were degreased by alcohol, dried in air and packed in the studied anticorrosion papers, after that they were exposed under increased temperatures and moisture conditions. It was determined, that among the materials under the study, the inhibited crepe paper, reinforced by polypropylene web, hhas the best complex of physical-mechanical and anticorrosion properties. It provides a higher level of prevention corrosion of metal l and surpasses other materials in a number of deformation and strength characteristics. Recommendations were proposed to improve qquality of produced anticorrosion papers.

The Effect of Small Defects on Fatigue Life of a Low Carbon Steel

2019 ◽  
Author(s):  
Natalia Gonçalves Torres ◽  
Vinícius Rodrigues ◽  
Edgar Mamiya
Keyword(s):  
Fatigue Life ◽  
Carbon Steel ◽  
Low Carbon Steel ◽  
Low Carbon
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