Effect of laser heat treatment on bending property of laser welded joints of low-alloy ultra-high strength steel

2019 ◽  
Vol 31 (3) ◽  
pp. 032011
Author(s):  
Chong Luo ◽  
Yue Zhao ◽  
Yang Cao ◽  
Lin Zhao ◽  
Jiguo Shan
Keyword(s):  
Heat Treatment ◽  
Welded Joints ◽  
High Strength Steel ◽  
High Strength ◽  
Laser Heat Treatment ◽  
Bending Property ◽  
Laser Heat ◽  
Ultra High Strength Steel

scholarly journals Crack Initiation and Propagation Fatigue Life of Ultra High-Strength Steel Butt Joints

2019 ◽  
Vol 9 (21) ◽  
pp. 4590 ◽  
Author(s):  
Markus J. Ottersböck ◽  
Martin Leitner ◽  
Michael Stoschka ◽  
Wilhelm Maurer
Keyword(s):  
Fatigue Life ◽  
Crack Initiation ◽  
Welded Joints ◽  
High Strength Steel ◽  
High Strength ◽  
Crack Initiation And Propagation ◽  
Butt Joints ◽  
Fatigue Assessment ◽  
Initiation And Propagation ◽  
Ultra High Strength Steel

The division of the total fatigue life into different stages such as crack initiation and propagation is an important issue in regard to an improved fatigue assessment especially for high-strength welded joints. The transition between these stages is fluent, whereas the threshold between the two phases is referred to as technical crack initiation. This work presents a procedure to track crack initiation and propagation during fatigue tests of ultra high-strength steel welded joints. The method utilizes digital image correlation to calculate a distortion field of the specimens’ surface enabling the identification and measurement of cracks along the weld toe arising during the fatigue test. Hence, technical crack initiation of each specimen can be derived. An evaluation for ten ultra high-strength steel butt joints reveals, that for this superior strength steel grade more than 50% of fatigue life is spent up to a crack depth of 0.5 mm, which can be defined as initial crack. Furthermore, a notch-stress based fatigue assessment of these specimens considering the actual weld topography and crack initiation and propagation phase is performed. The results point out that two phase models considering both phases enable an increased accuracy of service life assessment.

Local laser heat treatment of ultra high strength steels to improve formability

2009 ◽  
Vol 3 (4-5) ◽  
pp. 347-351 ◽  
Author(s):  
Reimund Neugebauer ◽  
Sören Scheffler ◽  
Reinhart Poprawe ◽  
Andreas Weisheit
Keyword(s):  
Heat Treatment ◽  
High Strength Steels ◽  
High Strength ◽  
Laser Heat Treatment ◽  
Laser Heat ◽  
Ultra High Strength Steels
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