Study on Fiber Laser Welding for DP780 High Strength Steel

2011 ◽  
Vol 328-330 ◽  
pp. 48-53
Author(s):  
Tao Huang ◽  
Li Jun Xin ◽  
Zhi Yong Wang

Welding experiments of DP780 high strength steel plate produced by Baosteel with IPG YLR-6000-ST2 fiber laser have been processed. The influence of welding parameters on welding quality has been investigated. As well as microstructure and mechanical character of welding seam have been analyzed. The results show that the joint appearance of DP780 high strength steel welded with IPG YLR-6000-ST2 fiber laser has good performance and the mechanics property is good without fit-up gap. The microstructure of weld bead is columnar crystals, mainly lath-shaped ferrite, needle-like lower bainite and a small amount of martensite. Heat-affected zone is narrow and the grain grows with little size. The measured micro-hardness values of the sample decrease smoothly from weld center to base metal and there does not have softened zone.

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 626
Author(s):  
Riccardo Scazzosi ◽  
Marco Giglio ◽  
Andrea Manes

In the case of protection of transportation systems, the optimization of the shield is of practical interest to reduce the weight of such components and thus increase the payload or reduce the fuel consumption. As far as metal shields are concerned, some investigations based on numerical simulations showed that a multi-layered configuration made of layers of different metals could be a promising solution to reduce the weight of the shield. However, only a few experimental studies on this subject are available. The aim of this study is therefore to discuss whether or not a monolithic shield can be substituted by a double-layered configuration manufactured from two different metals and if such a configuration can guarantee the same perforation resistance at a lower weight. In order to answer this question, the performance of a ballistic shield constituted of a layer of high-strength steel and a layer of an aluminum alloy impacted by an armor piercing projectile was investigated in experimental tests. Furthermore, an axisymmetric finite element model was developed. The effect of the strain rate hardening parameter C and the thermal softening parameter m of the Johnson–Cook constitutive model was investigated. The numerical model was used to understand the perforation process and the energy dissipation mechanism inside the target. It was found that if the high-strength steel plate is used as a front layer, the specific ballistic energy increases by 54% with respect to the monolithic high-strength steel plate. On the other hand, the specific ballistic energy decreases if the aluminum plate is used as the front layer.


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