Heat Affected Zone Induced by Laser Forming

Volume 1 ◽  
2004 ◽  
Author(s):  
L. Casamichele ◽  
A. Gisario ◽  
V. Tagliaferri
Keyword(s):  
Mechanical Properties ◽  
Heat Affected Zone ◽  
Laser Scanning ◽  
Standard Condition ◽  
Laser Forming ◽  
Hole Drilling ◽  
Flexible Tool ◽  
Indentation Tests ◽  
Testing Complex ◽  
Scanning Path

Laser forming induces mechanical and structural modifications around the Laser Scanning Path. Various conventional methods are currently available to estimate properties of materials like X-ray and neutron diffraction, strain/curvature measurement, hole drilling, layer removal, chemical etching, etc. but their use is severely restricted due to measurement accuracy, applicability to different materials and geometrical configurations. An application of an experimental method to estimate mechanical properties associated with laser forming of metallic sheets is proposed. This method is based on an instrumented indentation technique which offers a more flexible tool to measure mechanical properties of Heat Affected Zone. The main advantage of this technique consists of testing complex geometric forms with a cheap system able to be used for on-line implementation. The experimental validation of the method was performed calibrating the procedure by using several indentation tests in standard condition. A full map of mechanical properties was subsequently traced employing systematic investigations focused on specimens zone closer to the laser heated scanning path.

Analysis and Prediction of Edge Effects in Laser Bending

2000 ◽  
Vol 123 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Jiangcheng Bao ◽  
Y. Lawrence Yao
Keyword(s):  
Residual Stress ◽  
Edge Effects ◽  
Laser Scanning ◽  
Laser Forming ◽  
Stress Distributions ◽  
Rate Dependency ◽  
Laser Bending ◽  
Numerical Investigations ◽  
Wide Range ◽  
Scanning Path

Laser forming of sheet metal offers the advantages of requiring no hard tooling and thus reduced cost and increased flexibility. It also enables forming of some materials and shapes that are not possible now. In single-axis laser bending of plates, the bending edge is found to be somewhat curved and the bending angle varies along the laser-scanning path. These phenomena are termed edge effects, which adversely affect the accuracy of the bending and result in undue residual stress. Numerical investigations are carried out to study the process transiency and the mechanism of the edge effects. Temperature dependency of material properties and strain-rate dependency of flow stress are considered in the numerical simulation to improve prediction accuracy. Numerical results are validated in experiments. Patterns of edge effects and resultant residual stress distributions are examined under a wide range of conditions. A more complete explanation for the mechanism of the edge effects is given.

Investigation of the Effect of Heating-Lines on Tensional Mechanical Properties of Sheet Metal after Laser Forming

2011 ◽  
Vol 117-119 ◽  
pp. 1666-1671
Author(s):  
Ai Hui Luo ◽  
Wen Jiao Dan ◽  
Wei Gang Zhang
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Sheet Metal ◽  
Heat Affected Zone ◽  
Total Elongation ◽  
Laser Forming ◽  
Strain Hardening Exponent ◽  
Elongation Index ◽  
Hardening Coefficient

In this study，tensional mechanical properties of sheet metal with different heating-lines after laser forming are investigated. The basic mechanical properties of material (such as elastic modulus, yield strength, ultimate strength, TEI (total elongation index) and EIU (elongation index of uniform)) with different spacing between neighbored heating-lines and different heating-lines number are presented. The stress-strain curves are complied with a modified Swift law, where the hardening coefficient and strain hardening exponent of material are controlled by strain. The influence of heating-lines number on tensional mechanical properties of material is greater than that of the spacing between neighbored heating-lines. The results show that all mechanical properties are related to the distribution of microstructure in heat-affected zone after laser forming.

scholarly journals Influence of Post Weld Heat Treatment on the Grain Size, and Mechanical Properties of the Alloy-800H Rotary Friction Weld Joints

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4366
Author(s):  
Saqib Anwar ◽  
Ateekh Ur Rehman ◽  
Yusuf Usmani ◽  
Ali M. Al-Samhan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Heat Affected Zone ◽  
Tensile Testing ◽  
Weld Zone ◽  
Alloy 800H ◽  
Weld Joints ◽  
Heat Treated ◽  
Friction Weld

This study evaluated the microstructure, grain size, and mechanical properties of the alloy 800H rotary friction welds in as-welded and post-weld heat-treated conditions. The standards for the alloy 800H not only specify the composition and mechanical properties but also the minimum grain sizes. This is because these alloys are mostly used in creep resisting applications. The dynamic recrystallization of the highly strained and plasticized material during friction welding resulted in the fine grain structure (20 ± 2 µm) in the weld zone. However, a small increase in grain size was observed in the heat-affected zone of the weldment with a slight decrease in hardness compared to the base metal. Post-weld solution heat treatment (PWHT) of the friction weld joints increased the grain size (42 ± 4 µm) in the weld zone. Both as-welded and post-weld solution heat-treated friction weld joints failed in the heat-affected zone during the room temperature tensile testing and showed a lower yield strength and ultimate tensile strength than the base metal. A fracture analysis of the failed tensile samples revealed ductile fracture features. However, in high-temperature tensile testing, post-weld solution heat-treated joints exhibited superior elongation and strength compared to the as-welded joints due to the increase in the grain size of the weld metal. It was demonstrated in this study that the minimum grain size requirement of the alloy 800H friction weld joints could be successfully met by PWHT with improved strength and elongation, especially at high temperatures.

Microstructure and local strains in GH3535 alloy heat affected zone and their influence on the mechanical properties

2017 ◽  
Vol 699 ◽  
pp. 48-54 ◽  
Author(s):  
Shuangjian Chen ◽  
D.K.L. Tsang ◽  
Li Jiang ◽  
Kun Yu ◽  
Chaowen Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Affected Zone ◽  
Local Strains ◽  
Alloy Heat

scholarly journals A Review on Microstructural Features and Mechanical Properties of Wheels/Rails Cladded by Laser Cladding

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 152
Author(s):  
Xinlin Wang ◽  
Lei Lei ◽  
Han Yu
Keyword(s):  
Mechanical Properties ◽  
Service Life ◽  
Process Optimization ◽  
Laser Cladding ◽  
Future Development ◽  
Heat Affected Zone ◽  
Small Deformation ◽  
Microstructural Characteristics ◽  
Low Input ◽  
Recent Developments

The service life of rails would be remarkably reduced owing to the increase of axle load, which can induce the occurrence of damages such as cracks, collapse, fat edges, etc. Laser cladding, which can enhance the mechanical properties of the rail by creating a coating, has received great attention in the area of the rails due to the attractive advantages such as low input heat, small heat-affected zone, and small deformation. In this paper, recent developments in the microstructural characteristics and mechanical properties of a cladded layer on the rail are reviewed. The method of process optimization for enhancing the properties of a cladded layer are discussed. Finally, the trend of future development is forecasted.

scholarly journals Microstructure and Mechanical Properties of Heat-Affected Zone of Repeated Welding AISI 304N Austenitic Stainless Steel by Gleeble Simulator

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 773
Author(s):  
Y.H. Guo ◽  
Li Lin ◽  
Donghui Zhang ◽  
Lili Liu ◽  
M.K. Lei
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Impact Energy ◽  
Heat Affected Zone ◽  
Ferrite Content ◽  
Equipment Safety ◽  
Microstructure And Mechanical Properties ◽  
Δ Ferrite ◽  
The Impact

Heat-affected zone (HAZ) of welding joints critical to the equipment safety service are commonly repeatedly welded in industries. Thus, the effects of repeated welding up to six times on the microstructure and mechanical properties of HAZ for AISI 304N austenitic stainless steel specimens were investigated by a Gleeble simulator. The temperature field of HAZ was measured by in situ thermocouples. The as-welded and one to five times repeated welding were assigned as-welded (AW) and repeated welding 1–5 times (RW1–RW5), respectively. The austenitic matrices with the δ-ferrite were observed in all specimens by the metallography. The δ-ferrite content was also determined using magnetic and metallography methods. The δ-ferrite had a lathy structure with a content of 0.69–3.13 vol.%. The austenitic grains were equiaxial with an average size of 41.4–47.3 μm. The ultimate tensile strength (UTS) and yield strength (YS) mainly depended on the δ-ferrite content; otherwise, the impact energy mainly depended on both the austenitic grain size and the δ-ferrite content. The UTS of the RW1–RW3 specimens was above 550 MPa following the American Society of Mechanical Engineers (ASME) standard. The impact energy of all specimens was higher than that in ASME standard at about 56 J. The repeated welding up to three times could still meet the requirements for strength and toughness of welding specifications.

Comparison of mechanical properties of thermally modified wood at growth ring and cell wall level by means of instrumented indentation tests

Holzforschung ◽  
2009 ◽  
Vol 63 (4) ◽  
Author(s):  
Stefanie Stanzl-Tschegg ◽  
Wilfried Beikircher ◽  
Dieter Loidl
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Thermal Treatment ◽  
Mechanical Performance ◽  
Growth Ring ◽  
Beech Wood ◽  
Thermal Modification ◽  
Wood Structure ◽  
Instrumented Indentation ◽  
Indentation Tests

Abstract Thermal modification is a well established method to improve the dimensional stability and the durability for outdoor use of wood. Unfortunately, these improvements are usually accompanied with a deterioration of mechanical performance (e.g., reduced strength or higher brittleness). In contrast, our investigations of the hardness properties in the longitudinal direction of beech wood revealed a significant improvement with thermal modification. Furthermore, we applied instrumented indentation tests on different hierarchical levels of wood structure (growth ring and cell wall level) to gain closer insights on the mechanisms of thermal treatment of wood on mechanical properties. This approach provides a variety of mechanical data (e.g., elastic parameters, hardness parameters, and viscoelastic properties) from one single experiment. Investigations on the influence of thermal treatment on the mechanical properties of beech revealed similar trends on the growth ring as well as the on the cell wall level of the wood structure.

scholarly journals Characterization of mechanical properties by indentation tests and FE analysis – validation by application to a weld zone of DP590 steel

2009 ◽  
Vol 46 (2) ◽  
pp. 344-363 ◽  
Author(s):  
Kyung-Hwan Chung ◽  
Wonoh Lee ◽  
Ji Hoon Kim ◽  
Chongmin Kim ◽  
Sung Ho Park ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Weld Zone ◽  
Fe Analysis ◽  
Indentation Tests
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