Development of a novel optical measurement technique to investigate the hot cracking susceptibility during laser beam welding

Bakir, Nasim; Pavlov, V. I.; Zavjalov, Sergey V.; Volvenko, Sergey V.; Gumenyuk, Andrey; Rethmeier, Michael

doi:10.1007/s40194-018-0665-8

Cited by 19 publications

(8 citation statements)

References 15 publications

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“…Another advantage is also the possibility of increasing the welding speed compared to other conventional processes, but solidification cracking occurs easily at a high welding speed. Bakir et al [27] and Kadoi et al [9] demonstrated an on-line/in situ monitoring system of the susceptibility to hot cracking during welding, applicable to laser beam welding. It is possible to make both longitudinal and circumferential joints ensuring the tightness of the joint [28], which is needed at the container.…”

Section: Requirements For the Ferrofluid Containermentioning

confidence: 99%

Laser welding of austenitic ferrofluid container for the KRAKsat satellite

Janiczak

Pańcikiewicz

2021

Weld World

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The production of a ferrofluid container, intended for use in the KRAKsat (CubeSat type) satellite in space conditions, is presented. Mechanized laser beam welding for AISI 316L stainless steel test joint and container prototype was developed and tested. The welded test joints were examined by non-destructive visual, penetration and radiographic testing and destructive testing by macro- and microscopic examination, static tensile test, static bending test, and hardness measurements. The welded container prototype was examined by leak test, temperature-vacuum test and vibration test. Test joints’ evaluation showed a proper selection of welding parameters and expected quality of joints. Austenitic microstructure with small δ-ferrite content in base materials, heat-affected zones, and welds guarantees sufficient mechanical properties for this part geometry. The tensile strength range of test joints was 687–729 MPa, hardness range was 140–200 HV3, and the bending angle was 180°. Welding of the prototype container and testing of tightness, resistance to temperature changes, and vibration were successful. Compliance with flywheel design and manufacturing requirements will enable the launch of a research satellite into orbit with such a wheel.

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Section: Requirements For the Ferrofluid Containermentioning

confidence: 99%

Laser welding of austenitic ferrofluid container for the KRAKsat satellite

Janiczak

Pańcikiewicz

2021

Weld World

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“…Of particular interest are the digital image correlation (DIC) methods that enable the contactless measurements of strain fields behind the weld pool [54]. These measurements quantify the position of crack tip and the strain conditions to form a crack moreover to the thermal stress fields surrounding the weldment and their evolution with welding parameters [42,55,56]. These measurements are useful experimental data to implement both inherent condition for cracking and thermo-field change with welding speed into 3D Multiphysics modeling [57].…”

Section: Figure 12mentioning

confidence: 99%

“…Measuring crack length metrics or crack-no crack macro-conditions [15,43,59,62,63] will provide an overall point of view of the interaction between microstructure and process-induced thermo-mechanical fields. However, if local measurements are applied [31,55,56,64], then thermal-induced strains are not accounted for and only the inherent susceptibility of a microstructure to cracking are evaluated. Therefore, increasing welding speed may lead to a more susceptible microstructure (e.g.…”

Section: Measuring Cracking Susceptibilitymentioning

confidence: 99%

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Effect of weld travel speed on solidification cracking behavior. Part 2: testing conditions and metrics

Coniglio

Cross

2020

Int J Adv Manuf Technol

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Solidification cracking is a weld defect common to certain susceptible alloys rendering many of them unweldable. It forms and grows continuously behind a moving weld pool within the twophase mushy zone and involves a complex interaction between thermal, metallurgical and mechanical factors. Research has demonstrated the ability to minimize solidification cracking occurrence by using appropriate welding parameters. Despite decade's long efforts to investigate weld solidification cracking, there remains a lack of understanding regarding the particular effect of travel speed. While the use of the fastest welding speed is usually recommended, this rule has not always been confirmed on site. Varying welding speed has many consequences both on stress cells surrounding the weld pool, grain structure, and mushy zone extent. Experimental data and models are compiled to highlight the importance of welding speed on solidification cracking. This review is partitioned into three parts: Part I focuses on the effects of welding speed on weld metal characteristics, Part II reviews the data of the literature to discuss the importance of selecting properly the metrics, and Part III details the different methods to model the effect of welding speed on solidification cracking occurrence.

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“…[25,26] The local strains in the vicinity of the weld pool can only be recorded with considerable effort, e. g. using digital image correlation (DIC). [18,[27][28][29][30] Therefore, mostly the "global" augmented strain is used as a simplified parameter for externally loaded hot crack tests. Some test methods instead consider a critical strain rate as a measure of the hot cracking susceptibility.…”

Section: Introductionmentioning

confidence: 99%

Assessment of the Solidification Cracking Susceptibility of Welding Consumables in the Varestraint Test by Means of an Extended Evaluation Methodology

et al. 2022

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Various test methods are available for assessing the susceptibility of materials to solidification cracking during welding. In the widely used Varestraint test, the crack length is selected as a criterion as a function of the applied bending strain. Unfortunately, the crack length does not characterize the material behavior alone but depends to varying degrees on the individual test parameters used, which makes the interpretation of the results difficult. In addition, the crack length is not comparable under different test conditions. To overcome these disadvantages, we have developed a novel evaluation methodology that decouples the machine influence from the material behavior. The measured crack length is related to the maximum possible value specified by welding speed and deformation time. This relative crack length is calculated numerically, considering the orientation of the cracks. Experiments on two high‐alloy martensitic welding consumables show that, in contrast to the conventional evaluation, a comparison of different welding parameters becomes possible. Furthermore, the strain rate proved to be a suitable crack criterion in agreement with Prokhorov's hot cracking model.

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Development of a novel optical measurement technique to investigate the hot cracking susceptibility during laser beam welding

Cited by 19 publications

References 15 publications

Laser welding of austenitic ferrofluid container for the KRAKsat satellite

Laser welding of austenitic ferrofluid container for the KRAKsat satellite

Effect of weld travel speed on solidification cracking behavior. Part 2: testing conditions and metrics

Assessment of the Solidification Cracking Susceptibility of Welding Consumables in the Varestraint Test by Means of an Extended Evaluation Methodology

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