scholarly journals Influence of Ultrasound on Pore and Crack Formation in Laser Beam Welding of Nickel-Base Alloy Round Bars

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1299
Author(s):  
Jan Grajczak ◽  
Christian Nowroth ◽  
Sarah Nothdurft ◽  
Jörg Hermsdorf ◽  
Jens Twiefel ◽  
...  
Keyword(s):  
Laser Beam ◽  
Cross Sections ◽  
Crack Formation ◽  
Base Alloy ◽  
Laser Beam Welding ◽  
Beam Power ◽  
Weld Shape ◽  
Laser Beam Power ◽  
Nickel Base ◽  
Node Position

Welding by laser beam is a method for creating deep and narrow welds with low influence on the surrounding material. Nevertheless, the microstructure and mechanical properties change, and highly alloyed materials are prone to segregation. A new promising approach for minimizing segregation and its effects like hot cracks is introducing ultrasonic excitation into the specimen. The following investigations are about the effects of different ultrasonic amplitudes (2/4/6 µm) and different positions of the weld pool in the resonant vibration distribution (antinode, centered, and node position) for bead on plate welds on 2.4856 nickel alloy round bars (30 mm diameter) with a laser beam power of 6 kW. The weld is evaluated by visual inspection and metallographic cross sections. The experiments reveal specific mechanisms of interaction between melt and different positions regarding to the vibration shape, which influence weld shape, microstructure, segregation, cracks and pores. Welding with ultrasonic excitation in antinode position improves the welding results.

Fiber Laser Beam Welding of Ti-6242 - Effect of Processing Parameters on Microstructural and Mechanical Properties

2016 ◽  
Vol 879 ◽  
pp. 903-908 ◽  
Author(s):  
Nikolai Kashaev ◽  
Dmitry Pugachev ◽  
Stefan Riekehr ◽  
Volker Ventzke
Keyword(s):  
Mechanical Properties ◽  
Laser Beam ◽  
Fiber Laser ◽  
Laser Beam Welding ◽  
Base Material ◽  
Butt Joint ◽  
Beam Power ◽  
Focus Position ◽  
Laser Beam Power ◽  
Advance Speed

The present work investigates the effects of laser beam power, focus position and advance speed on the geometry, microstructure and mechanical properties of fiber laser beam welded Ti-6Al-2Sn-4Zr-2Mo (denoted as Ti-6242) butt joints used for high temperature applications. Detailed microstructural and mechanical studies were performed on welds produced using optimized parameters (a laser beam power of 5 kW, a focus position of 0.0 mm and an advance speed of 6.2 m/min). The Ti-6242 base material is characterized by a globular (α+β) microstructure. The heat input during laser beam welding led to the formation of a martensitic α’-phase fusion zone. The heat affected zone consisted of globular grains and acicular crystallites. These local transformations were connected with a change in the micro-texture, average grain size and β-phase content. Furthermore, the microhardness increased from 330 HV 0.3 to 450 HV 0.3 due to the martensitic transformation. The mechanical behavior of the laser beam welded Ti-6242 butt joint loaded in tension was determined by the properties of the Ti-6242 base material. The local increase in hardness provided a shielding effect that protected the Ti-6242 butt joint against mechanical damage.

scholarly journals Hybrid laser-arc welding of laser- and plasma-cut 20-mm-thick structural steels

2022 ◽  
Author(s):  
Ömer Üstündağ ◽  
Nasim Bakir ◽  
Sergej Gook ◽  
Andrey Gumenyuk ◽  
Michael Rethmeier
Keyword(s):  
Laser Beam ◽  
Arc Welding ◽  
Laser Beam Welding ◽  
Digital Camera ◽  
Welding Process ◽  
Beam Power ◽  
Beam Diameter ◽  
Hybrid Laser Arc Welding ◽  
Single Pass ◽  
New Findings

AbstractIt is already known that the laser beam welding (LBW) or hybrid laser-arc welding (HLAW) processes are sensitive to manufacturing tolerances such as gaps and misalignment of the edges, especially at welding of thick-walled steels due to its narrow beam diameter. Therefore, the joining parts preferably have to be milled. The study deals with the influence of the edge quality, the gap and the misalignment of edges on the weld seam quality of hybrid laser-arc welded 20-mm-thick structural steel plates which were prepared by laser and plasma cutting. Single-pass welds were conducted in butt joint configuration. An AC magnet was used as a contactless backing. It was positioned under the workpiece during the welding process to prevent sagging. The profile of the edges and the gap between the workpieces were measured before welding by a profile scanner or a digital camera, respectively. With a laser beam power of just 13.7 kW, the single-pass welds could be performed. A gap bridgeability up to 1 mm at laser-cut and 2 mm at plasma-cut samples could be reached respectively. Furthermore, a misalignment of the edges up to 2 mm could be welded in a single pass. The new findings may eliminate the need for cost and time-consuming preparation of the edges.

scholarly journals The influence of laser re-melting on microstructure and hardness of gas-nitrided steel

2016 ◽  
Vol 36 (1) ◽  
pp. 18-22 ◽  
Author(s):  
Dominika Panfil ◽  
Piotr Wach ◽  
Michał Kulka ◽  
Jerzy Michalski
Keyword(s):  
Laser Beam ◽  
Laser Treatment ◽  
Diffusion Zone ◽  
Nitrided Layer ◽  
Nitriding Process ◽  
Beam Power ◽  
Gas Nitriding ◽  
Nitrided Steel ◽  
Laser Beam Power ◽  
And Diffusion

Abstract In this paper, modification of nitrided layer by laser re-melting was presented. The nitriding process has many advantageous properties. Controlled gas nitriding was carried out on 42CrMo4 steel. As a consequence of this process, ε+γ’ compound zone and diffusion zone were produced at the surface. Next, the nitrided layer was laser remelted using TRUMPF TLF 2600 Turbo CO2 laser. Laser tracks were arranged as single tracks with the use of various laser beam powers (P), ranging from 0.39 to 1.04 kW. The effects of laser beam power on the microstructure, dimensions of laser tracks and hardness profiles were analyzed. Laser treatment caused the decomposition of continuous compound zone at the surface and an increase in hardness of previously nitrided layer because of the appearance of martensite in re-melted and heat-affected zones

Laser beam power fade induced by system and atmospheric effects

1982 ◽  
Vol 21 (13) ◽  
pp. 2432 ◽  
Author(s):  
U. Halavee ◽  
M. Tamir ◽  
E. Azoulay
Keyword(s):  
Laser Beam ◽  
Beam Power ◽  
Atmospheric Effects ◽  
Laser Beam Power ◽  
Power Fade

Modern fiber laser beam welding of the newly-designed precipitation-strengthened nickel-base superalloys

2014 ◽  
Vol 57 ◽  
pp. 12-20 ◽  
Author(s):  
Homam Naffakh Moosavy ◽  
Mohammad-Reza Aboutalebi ◽  
Seyed Hossein Seyedein ◽  
Massoud Goodarzi ◽  
Meisam Khodabakhshi ◽  
...  
Keyword(s):  
Laser Beam ◽  
Fiber Laser ◽  
Laser Beam Welding ◽  
Nickel Base Superalloys ◽  
Nickel Base
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