Microstructure and Mechanical Properties of Laser Beam Welds of 15CDV6 Steel

2015 ◽  
Vol 65 (4) ◽  
pp. 339 ◽  
Author(s):  
M.V.L Ramesh ◽  
P. Srinivasa Rao ◽  
V. Venkateswara Rao
Keyword(s):  
Laser Beam ◽  
Fusion Zone ◽  
Carbon Dioxide Laser ◽  
Continuous Wave ◽  
Laser Beam Welding ◽  
Wave Mode ◽  
Maximum Output ◽  
Transverse Tensile ◽  
Temperature Impact ◽  
Continuous Wave Mode

<p>The present study is concerned with laser beam welding of 15CDV6 steel, that is in the hardened (quenched and tempered) condition before welding. Autogenously butt-welded joints are made using carbon dioxide laser with a maximum output of 3.5 kw in the continuous wave mode. Weld microstructure, microhardness measurement across the weldment, transverse tensile properties, and room temperature impact properties of the weldment have been evaluated. The fusion zone exhibits a epitaxial grain growth. The microstrutural features of heat-affected zone and fusion zone vary, due to different thermal cycles for which these were subjected during welding. The average weld metal hardness was 480 Hv. The observed hardness distribution across the welds were correlated with the microstructures. The welds exhibited lower toughness of 50 joules as compared to parent metal of 55 joules and the tensile strength values of the welded specimens are close to that obtained for sheet specimens.</p><p><strong>Defence Science Journal, Vol. 65, No. 4, July 2015, pp. 339-342, DOI: http://dx.doi.org/10.14429/dsj.65.8749</strong></p>

Does a Pulsed Mode Offer Advantages Over a Continuous Wave Mode for Excisional Biopsies Performed Using a Carbon Dioxide Laser?

2012 ◽  
Vol 70 (8) ◽  
pp. 1781-1788 ◽  
Author(s):  
Valerie G.A. Suter ◽  
Hans Jörg Altermatt ◽  
Thomas Dietrich ◽  
Peter A. Reichart ◽  
Michael M. Bornstein
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Laser ◽  
Continuous Wave ◽  
Wave Mode ◽  
Pulsed Mode ◽  
Continuous Wave Mode

Laser Welded Joints of High-Nitrogen Austenitic Steels: Microstructure and Properties

2018 ◽  
Vol 284 ◽  
pp. 344-350 ◽  
Author(s):  
Vera V. Berezovskaya ◽  
A.V. Berezovskiy ◽  
D.H. Hilfi
Keyword(s):  
Welded Joints ◽  
Carbon Dioxide Laser ◽  
Continuous Wave ◽  
High Strength ◽  
Tensile Tests ◽  
Wave Mode ◽  
Austenitic Steels ◽  
Maximum Output ◽  
High Nitrogen ◽  
Corrosion Properties

High nitrogen austenitic steels are used as structural materials required possessing high strength and fracture toughness. The present study is concerned with the characteristic features (shape, size, properties and structure) of the laser welded joints in Cr-Mn-, Cr-Mn-Mo-high nitrogen steels compared to the ones of Cr-Ni-steel joint. Butt welded joints were made using carbon dioxide laser with a maximum output of 5 kW in the continuous wave mode. The hardness and tensile tests of welded joints in the air and 3.5 vol.%-solution of NaCl, as well as the theoretical studies were carried out by optical and transmission electron microscopy (TEM). The results are achieved by testing that the welded joints of HNS had satisfactory weldability, adequately high mechanical and corrosion properties. The austenite of the investigated HNS retains high stability throughout the welding cycle.

Standoff Detection of Oil and Powder Mixtures at 12 Meters Using a Tunable Quantum Cascade Laser-Based System with a Close Focus Telescope and Uncooled Infrared Detector

2021 ◽  
pp. 000370282110603
Author(s):  
J. Chance Carter ◽  
Phillip H. Paul ◽  
Joshua M. Ottaway ◽  
Peter Haugen ◽  
Anastacia M. Manuel
Keyword(s):  
Quantum Cascade Laser ◽  
Continuous Wave ◽  
Infrared Detector ◽  
Wave Mode ◽  
Infrared Source ◽  
Powder Mixtures ◽  
Quantum Cascade ◽  
System A ◽  
Continuous Wave Mode ◽  
Lock In

We have designed and demonstrated a quantum cascade laser (QCL) based standoff system that utilizes an uncooled mercury cadmium telluride (MCT) detector with lock-in signal processing for chemical identification at a distance of 12.5 meters in indoor ambient light conditions. In the system, a tunable quad-QCL operating (1 MHz) in quasi-continuous wave mode between 8.45 and 10.03 μm (∼1182 to 1000 cm−1) serves as the active mid-infrared source for remotely interrogating mineral, powder, and thin film oil samples including powder mixtures (6, 12.5, 25, and 50%) of crystalline quartz (SiO2) in KBr. Light as reflected from a given sample is collected using a 10-inch (25.4 cm) Dall Kirkham telescope and coupled with ZnSe optics to an uncooled MCT detector. The mixture dependence of the highly transparent KBr and strongly absorbing quartz was found to fit a modified version of the Schatz reflectance model for compacted powder mixtures. All reflectance spectra reported are relative to an Au-coated diffuse reflector. A NIST traceable polystyrene standard reflector was also used to determine the QCL wavelength tuning range and calibration.

Stable continuous-wave mode-locked laser from a 1645 nm Er:YAG ceramic oscillator

2022 ◽  
Author(s):  
Yangyu Liu ◽  
Xue Cao ◽  
AnHua Xian ◽  
Guangmiao Liu ◽  
Wei zhou ◽  
...  
Keyword(s):  
Solid State ◽  
Pulse Width ◽  
Peak Power ◽  
Continuous Wave ◽  
Modulation Depth ◽  
Average Power ◽  
Mode Locking ◽  
Wave Mode ◽  
Semiconductor Saturable Absorber ◽  
Continuous Wave Mode

Abstract We demonstrate stable continuous-wave mode-locking (CWML) pulses around 1645nm by employing the home-made Er:YAG ceramic. By using a fiber laser and semiconductor saturable absorber mirror (SESAM) with modulation depth of 1.2%, we get ML pulses with the output average power up to 815 mW, the pulse width shortened as ~4 ps, and the peak power of 1.8 kW. With the SESAM of modulation depth of 2.4%, the second-order harmonic ML pulses were also obtained. As far as we know, this is the first report of CWML from Er3+-doped ceramics and also the shortest pulse duration in Er3+-doped solid-state oscillators.

Passively continuous-wave mode-locked Er^3+-doped ZBLAN fiber laser at 28 μm

2012 ◽  
Vol 37 (18) ◽  
pp. 3849 ◽  
Author(s):  
Chen Wei ◽  
Xiushan Zhu ◽  
R. A. Norwood ◽  
N. Peyghambarian
Keyword(s):  
Fiber Laser ◽  
Continuous Wave ◽  
Wave Mode ◽  
Continuous Wave Mode

scholarly journals High-power terahertz quantum cascade lasers with ∼0.23 W in continuous wave mode

AIP Advances ◽  
2016 ◽  
Vol 6 (7) ◽  
pp. 075210 ◽  
Author(s):  
Xuemin Wang ◽  
Changle Shen ◽  
Tao Jiang ◽  
Zhiqiang Zhan ◽  
Qinghua Deng ◽  
...  
Keyword(s):  
High Power ◽  
Continuous Wave ◽  
Quantum Cascade Lasers ◽  
Wave Mode ◽  
Quantum Cascade ◽  
Continuous Wave Mode ◽  
Cascade Lasers

Laser Power Density Dependence in Absorption Measurements

1980 ◽  
Vol 34 (3) ◽  
pp. 311-313
Author(s):  
Peter M. Castle
Keyword(s):  
Power Density ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Continuous Wave ◽  
Strong Dependence ◽  
Wave Mode ◽  
Input Power ◽  
Absorption Cross ◽  
Continuous Wave Mode ◽  
Absorption Measurements

The absorption cross section of CF2Cl2 has been measured as a function of presure and CO2 laser input power at 10.764 μm. The laser was operated in the continuous wave mode providing a continuous energy deposition in the sample. It is shown that the absorption cross section measured has a strong dependence on input power density in the range from 5 to 15 W/cm2 and pressure in the 3 to 50 Torr regime. It is demonstrated that most of these effects can be attributed to the temperature rise in the beam interaction volume.

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