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http://dx.doi.org/10.3365/KJMM.2010.48.04.297

Microstructures and Hardness of CO2 Laser Welds in 409L Ferritic Stainless Steel  

Kong, Jong Pan (Dept. of Material Science and Engineering, Pusan National University)
Park, Tae Jun (Dept. of Material Science and Engineering, Pusan National University)
Na, Hye Sung (Dept. of Material Science and Engineering, Pusan National University)
Uhm, Sang Ho (POSCO Technical Research Laboratories)
Kim, Jeong Kil (POSCO Technical Research Laboratories)
Woo, In Su (POSCO Technical Research Laboratories)
Lee, Jong Sub (POSCO Technical Research Laboratories)
Kang, Chung Yun (Dept. of Material Science and Engineering, Pusan National University)
Publication Information
Korean Journal of Metals and Materials / v.48, no.4, 2010 , pp. 297-304 More about this Journal
Abstract
The microstructure and hardness of $CO_2$ laser welds were investigated in the Ti-stabilized ferritic stainless steel 409L. The observed specimen was welded in a fully penetrated condition in which the power was 5 kW and the welding speed 5 m/min. The grain structure near the bond line of the laser welds was produced by epitaxial growth. The grain size was the largest in the fusion zone, and HAZ showed nearly the same grain size as that of the base metal. The HAZ microstructure consisted of subgrains and precipitates that were less than 100 nm in size and that were located along the subgrain boundaries. On the other hand, the hardness was the highest in the fusion zone due to the large amount of small precipitates present. These were composed of TiN, Ti(C,N) and $TiO_2$+Ti(C,N). The hardness decreased continuously from the fusion zone of the base metal. The HAZ hardness was slightly greater than that of the base metal due to the existence of subgrains and precipitates in the subgrain boundary.
Keywords
alloys; welding; microstructure; scanning/transmission electron microscopy (STEM); hardness;
Citations & Related Records
Times Cited By KSCI : 2  (Citation Analysis)
Times Cited By SCOPUS : 3
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