scholarly journals Investigation of the Technological Possibility of Laser Hardening of Stainless Steel 14Cr17Ni2 to a Deep Depth of the Surface

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 5
Author(s):  
Vladislav Somonov ◽  
Igor Tsibulskiy ◽  
Ruslan Mendagaliyev ◽  
Alexander Akhmetov

The article presents the results of a research of the process of laser hardening of steel 14Cr17Ni2 (AISI 431) by radiation of a high-power fiber laser LS-16. Assessment of the theoretically possible maximum depth in laser processing without additional beam transformations, the use of additional coatings and devices were shown. The results of experiments on increasing the depth of the hardened layer during laser processing by using scanning of the laser beam and optimally selected mode parameters without scanning are demonstrated. The influence of the number of passes on the depth of the hardened layer is investigated. The microstructure of hardened samples was studied and quantitative estimation of structural components was carried out. The microhardness of hardened samples at different modes of laser hardening was measured.

2018 ◽  
Vol 19 (6) ◽  
pp. 636-639
Author(s):  
Irena Nowotyńska ◽  
Stanisław Kut ◽  
Krzysztof Kogut

The main problem occurring during the laser hardening of tools is the lack of continuity and diversity of surface layer properties as a result of the use of many parallel hardening paths. As a consequence, there may be a forgiven or under-hardened area between successive paths. The paper presents the original method of laser hardening of tools, especially bending, using a laser beam splitter. Such a hardening method enables simultaneous heating and tempering of the tool corner and the surfaces adjoining it at the desired width in one pass with the same parameters. As a consequence, the hardened layer is uniform on the surface of the corner and adjacent surfaces, i.e. without forgiven or unhardened areas. The use of this method requires equipping the hardening laser head with a divider, whose task is to distribute the laser beam to separate parts of the beam with adjustable width by means of appropriately placed mirrors. The new method of hardening not only eliminates the problem of so-called hardening marks created as a result of laser hardening, which directly affects the quality, durability and durability of the tool, but is also much more efficient and also beneficial for economic reasons.


Author(s):  
Rupinder Singh ◽  
Rishab ◽  
Jashanpreet S Sidhu

The martensitic 17-4 precipitation-hardenable stainless steel is one of the commercially established materials for structural engineering applications in aircrafts due to its superior mechanical and corrosion resistance properties. The mechanical processing of this alloy through a conventional manufacturing route is critical from the dimensional accuracy (Δ d) viewpoint for development of innovative structural components such as: slat tracks, wing flap tracks, etc. In past two decades, a number of studies have been reported on challenges being faced while conventional processing of 17-4 precipitation-hardenable stainless steel for maintaining uniform thickness of aircraft structural components. However, hitherto little has been reported on direct metal laser sintering of 17-4 precipitation-hardenable stainless steel for development of innovative functional prototypes with uniform surface hardness (HV), Δ d, and surface roughness ( Ra) in aircraft structural engineering. This paper reports the effect of direct metal laser sintering process parameters on HV, Δ d, and Ra for structural components. The results of study suggest that optimized settings of direct metal laser sintering from multifactor optimization viewpoint are laser power 100 W, scanning speed 1400 mm/s, and layer thickness 0.02 mm. The results have been supported with scanning electron microscopy analysis (for metallurgical changes such as porosity (%), HV, grain size, etc.) and international tolerance grades for ensuring assembly fitment.


Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 372 ◽  
Author(s):  
Samuel Ligon ◽  
Gurdial Blugan ◽  
Jakob Kuebler

Freestanding SiCNO ceramic pieces with sub-mm features were produced by laser crosslinking of carbosilane and silazane polymer precursors followed by pyrolysis in inert atmosphere. Three different pulsed UV laser systems were investigated, and the influence of laser wavelength, operating power and scanning speed were all found to be important. Different photoinitiators were tested for the two lasers operating at 355 nm, while for the 266 nm laser, crosslinking occurred also without photoinitiator. Pre-treatment of glass substrates with fluorinated silanes was found to ease the release of green bodies during solvent development. Polymer crosslinking was observed with all three of the laser systems, as were bubbles, surface charring and in some cases ablation. By focusing the laser beam several millimeters above the surface of the resin, selective polymer crosslinking was observed exclusively.


2015 ◽  
Vol 9 (4) ◽  
pp. 265-269 ◽  
Author(s):  
Wojciech Cieszyński ◽  
Michał Zięba ◽  
Jacek Reiner

Abstract Application of laser welding technology requires that the laser beam is guided through the whole length of the joint with sufficiently high accuracy. This paper describes result of research on development of optomechatronic system that allows for the precise positioning of the laser head’s TCP point on the edge of welded elements during laser processing. The developed system allows for compensation of workpiece’s fixture inaccuracies, precast distortions and workpiece deformations occurring during the process.


Author(s):  
Moo-Keun Song ◽  
Jong-Do Kim ◽  
Dong-Sig Shin ◽  
Su-Jin Lee ◽  
Dae-Won Cho

In this study, the parameters for underwater laser cutting of 50-mm thick stainless steel, which is typically used in nuclear power structures, are investigated. The focal position of laser beam significantly affects the cutting quality. In particular, in the cutting of the thick sample, change in the focal position determines the kerf width and the roughness of the cut surface. Moreover, the effects of the variation of kerf width and the cut surface characteristics on the focal position of the laser beam are investigated. As the focal position moved to the inside of the material, the upper kerf width increased, but the quality of the cut surface was improved.


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