Practical and theoretical investigations into inert gas cutting of 304 stainless steel using a high brightness fiber laser

In order to fabricate the micro cavity with complex structure on stainless steel, the technology of micro electrochemical machining based on surface modification by fiber laser is adopted. Heating scan on the surface of 304 stainless steel by using fiber laser can realize marking. In the process of laser heating and metal melting on the surface of 304 stainless steel, oxide layer can be formed and phase transformation can also occur, and the corrosion resistance layer with predefined pattern is formed. In the next process of micro electrochemical machining, the laser masking layer severs as the protective layer to realize micro machining of micro cavity. A newly developed device of electrochemical micro machining based on surface modification by fiber laser can meet the micro machining requirement. After laser masking processing through laser scanning on the surface of the 304 stainless steel, the passivation electrolyte and high-frequence-pulse electrochemical machining power supply were adopted, and the samples with typical structures by using electrochemical micromachining with fiber laser masking were fabricated.

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Defect structures induced by inert-gases in rapidly solidified type 304 stainless steel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104856 ◽

1988 ◽

Vol 46 ◽

pp. 558-559

Author(s):

Jung Chan Bae

Keyword(s):

Stainless Steel ◽

Inert Gases ◽

Inert Gas ◽

Water Quenching ◽

304 Stainless Steel ◽

Ingot Metallurgy ◽

Dislocation Loops ◽

Experimental Conditions ◽

Type 304 ◽

Type 304 Stainless Steel

Defects-are formed in most plastically deformed, quenched, and radiation damaged materials, and their type and distribution depend on the experimental conditions. Extensive research on radiation damage has shown that inert gases accumulate in materials and cause significant alterations of the microstructure and mechanical properties. In the centrifugal atomization process, the exposure of Type 304 stainless steel droplets to inert gas environments presents opportunities for their entrapment. The observation of large number density defects such as vacancy type dislocation loops and stacking faults in as-solidified Type 304 stainless steel powder is attributed to the inert gas/vacancy interaction.The purpose of this work is to examine the defect microstructure of extruded powder metallurgy (P/M) Type 304 stainless steel after preconditioning heat treatments at 900, 1000,1100, and 1200C for 1 hour followed by water quenching. Also, ingot metallurgy (l/M) Type 304 stainless steel (remnants of the feed stock for the powders) was heat treated at 1000 and 1100C for 1 hour followed by water quenching for comparison.

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Microstructural evolution and properties of tungsten inert gas and fiber laser welded SUS445 ferritic stainless steel

International Journal of Materials Research (formerly Zeitschrift fuer Metallkunde) ◽

10.1515/ijmr-2020-8043 ◽

2021 ◽

Vol 112 (9) ◽

pp. 687-694

Author(s):

Ching-Wen Lu ◽

Huei-Sen Wang ◽

Chih-Chun Hsieh ◽

Jie-Jyun Wu

Keyword(s):

Mechanical Properties ◽

Stainless Steel ◽

Corrosion Resistance ◽

Fiber Laser ◽

Ferritic Stainless Steel ◽

Heat Affected Zone ◽

Volume Fraction ◽

Inert Gas ◽

Laves Phases ◽

Welding Processes

Abstract To determine the weldability of SUS445 ferritic stainless steel, two welding approaches, tungsten inert gas and fiber laser welding processes, were used and compared. After the welding processes, the microstructure, mechanical properties, and corrosion resistance of the welds were investigated. In the weld fusion zones of these two welding approaches, different morphologies of the grains were obtained. No obvious precipitation formed in these zones. In the heat affected zone of the tungsten inert gas welds, more volume fraction and larger grain sizes of the Laves phase and larger matrix grains were observed, which significantly affected its corrosion resistance and mechanical properties. However, in the heat affected zone of the fiber laser welds, only small amounts Laves phases and a relatively narrow matrix grain growth area were observed, which offers better corrosion resistance and mechanical properties.

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