Parametric Study of the Effect of Feed Speed and Power on Laser Cut Quality of 4130 Steel
Samples of 4130 steel were cut by a CO2 laser and the effects of power and feed rate on kerf width, surface roughness, striation frequency and the size of heat affected zone (HAZ) were studied. It was observed that power had a major effect on kerf width and size of HAZ, while feed rate affects were secondary. In the other hand, surface roughness and striation frequency were affected most by feed rate. At low power levels the smallest kerf width and HAZ are obtained and the effect of feed rate is moderate. Low feed rates gave good surface roughness and low striation frequency. For optimum cut quality, kerf width, HAZ and surface roughness are kept minimum. However operating conditions that satisfy these requirements while maintaining high productivity could not be identified.
Laser Surface Modification — A Focus on the Wear Degradation of Titanium Alloy
Over the years, engineering materials are being developed due to the need for better service performance. Wear, a common phenomenon in applications requiring surface interaction, leads to catastrophic failure of materials in the industry. Hence, prevent‐ ing this form of degradation requires the selection of an appropriate surface modifica‐ tion technique. Laser surface modification techniques have been established by researchers to improve mechanical and tribological properties of materials. In this chapter, adequate knowledge about laser surface cladding and its processing parame‐ ters coupled with the oxidation, wear and corrosion performances of laser-modified ti‐ tanium has been reviewed.
A device for uranium series leaching from glass fiber in HEPA filter
For the disposal of a high efficiency particulate air (HEPA) glass filter into the environment, the glass fiber should be leached to lower its radioactive concentration to the clearance level. To derive an optimum method for the removal of uranium series from a HEPA glass fiber, five methods were applied in this study. That is, chemical leaching by a 4.0 M HNO3–0.1 M Ce(IV) solution, chemical leaching by a 5 wt% NaOH solution, chemical leaching by a 0.5 M H2O2–1.0 M Na2CO3 solution, chemical consecutive chemical leaching by a 4.0 M HNO3 solution, and repeated chemical leaching by a 4.0 M HNO3 solution were used to remove the uranium series. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after leaching for 5 h by the 4.0 M HNO3–0.1 M Ce(IV) solution were 2.1, 0.3, 1.1, and 1.2 Bq/g. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after leaching for 36 h by 4.0 M HNO3–0.1 M Ce(IV) solution were 76.9, 3.4, 63.7, and 71.9 Bq/g. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after leaching for 8 h by a 0.5 M H2O2–1.0 M Na2CO3 solution were 8.9, 0.0, 1.91, and 6.4 Bq/g. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after consecutive leaching for 8 h by the 4.0 M HNO3 solution were 2.08, 0.12, 1.55, and 2.0 Bq/g. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after three repetitions of leaching for 3 h by the 4.0 M HNO3 solution were 0.02, 0.02, 0.29, and 0.26 Bq/g. Meanwhile, the removal efficiencies of 238U, 235U, 226Ra, and 234Th from the waste solution after its precipitation–filtration treatment with NaOH and alum for reuse of the 4.0 M HNO3 waste solution were 100, 100, 93.3, and 100%.