Methods for the measurement of ferrite content in multipass duplex stainless steel welds

Putz, A.; Althuber, M.; Zelić, Anto; Westin, Elin M.; Willidal, Thomas; Enzinger, Norbert

doi:10.1007/s40194-019-00721-4

Cited by 34 publications

(13 citation statements)

References 18 publications

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“…Images were analyzed using software ImageJ (version 1.52r). Lately, point counting analysis using ferritscopes, which measure ferrite number is more present, but some newest articles suggest image analysis as a more precise and more reliable method [ 48 , 49 ]. This method’s main drawback is its dependency on etching quality.…”

Section: Methodsmentioning

confidence: 99%

Influence of the Interlayer Temperature on Structure and Properties of Wire and Arc Additive Manufactured Duplex Stainless Steel Product

2020

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WAAM (wire and arc additive manufacturing) is becoming an increasingly popular method to produce components from metals, which are usually not so suitable for conventional production methods. One of the good examples is duplex stainless steels (DSSs), which are quite complex for welding and machining. Excessive ferrite amount is a common problem for them and controlling an interlayer temperature could offer a solution. However, using too low interlayer temperature will slow down the whole process and compromise one of the WAAM’s main advantages—the high productivity. The aim of this study is to find the relationship between interlayer temperature and process duration and to determine the influence of the interlayer temperature on product structure and other properties. Three samples (walls) were made using different interlayer temperatures (50 °C, 100 °C and 150 °C) and they were tested to analyze their surface texture, chemical composition, ferrite amount, the appearance of porosity and the hardness. Ferrite amount was higher and there was more porosity on lower interlayer temperatures, while there is no significant difference between surface texture and chemical composition for the samples. Considering the fact that higher interlayer temperatures provide a faster process, they should be preferred to produce duplex stainless steel products.

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Section: Methodsmentioning

confidence: 99%

Influence of the Interlayer Temperature on Structure and Properties of Wire and Arc Additive Manufactured Duplex Stainless Steel Product

2020

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“…Figure 7 shows the ferrite numbers of the specimens measured by magnetic induction using the Feritscope®. The use of the standard filler metal G 22 9 3 N L results in a value of 43 FN, which corresponds to a δ-ferrite content of 39% (FN = 1.1 x δ-ferrite [%] [20,21]). The ferrite content of the specimens increases as the percentage of filler metal GZ 22 5 3 L increases.…”

Section: Mixing Of Electrode and Cold Wirementioning

confidence: 99%

GMAW Cold Wire Technology for Adjusting the Ferrite–Austenite Ratio of Wire and Arc Additive Manufactured Duplex Stainless Steel Components

Stützer

Totzauer

Wittig

et al. 2019

Metals

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The use of commercially available filler metals for wire and arc additive manufacturing (WAAM) of duplex stainless steel components results in a microstructure with a very low ferrite content. The ferrite–austenite ratio in the duplex stainless steel weld metal depends on both the cooling rate and particularly on the chemical composition. However, the research and testing of special filler metals for additive deposition welding using wire and arc processes is time-consuming and expensive. This paper describes a method that uses an additional cold wire feed in the gas metal arc welding (GMAW) process to selectively vary the alloy composition and thus the microstructure of duplex stainless steel weld metal. By mixing different filler metals, a reduction of the nickel equivalent and hence an increase in the ferrite content in additively manufactured duplex stainless steel specimens was achieved. The homogeneous mixing of electrode and cold wire was verified by energy dispersive spectroscopy (EDS). Furthermore, the addition of cold wire resulted in a significant increase in sample height while the sample width remained approximately the same.

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“…In a study conducted by Varbai and Májilinger in 2019, a method to measure the austenite/ferrite (A/F) ratio in the different zones of the welded sample through the analysis of its images using a proper etching attack was studied. Putz et al, in 2019, also studied this topic, focusing on the difference among various methods to measure the A/F ratio on the welds correctly [7,8].…”

Section: Introductionmentioning

confidence: 99%

Maintenance of the Austenite/Ferrite Ratio Balance in GTAW DSS Joints Through Process Parameters Optimization

Rodriguez¹,

Miranda²,

González

et al. 2020

Materials

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The present work describes the influence of the parameters employed in the gas tungsten arc welding process (GTAW) when nickel powder is used as a filler metal in 2304/2507 duplex stainless-steel dissimilar joints. Multi-objective optimization was applied in order to maintain the austenite/ferrite percentage in the welded zone. A microstructural and phase quantification analysis was performed in each sample through optical and scanning electron microscopes. It was found that a nickel powder addition combined with low heat input increased the biphasic ratio across the different zones of the dissimilar welded samples. Although the austenite volume fraction increased in the 2304 heat-affected zone (HAZ) near to 25%, it was not sufficient according to international standards. The obtained results led to the maintenance of the 50/50 phase percentage in the 2507 HAZ welded joint side, as well as to the increment of the austenite percentage in the 2304 HAZ.Materials 2020, 13, 780 2 of 14 temperatures, another phenomenon is observed: ferrite decomposition occurs, causing the formation of harmful secondary phases, such as sigma (σ), chi (χ), carbides, and nitrides phases, which subsequently deteriorate the mechanical and corrosion-resistance properties of the DSS. Santos et al. conducted a study, based on the analysis of thermal history, which showed the temperature measured across the weld and its effect on the microstructural and mechanical behavior, and compared the results with the three-dimensional finite element model built. In addition, Sarlak, Atapour, and collaborators specifically studied the corrosion behavior across the welding in samples obtained by the welding process of a lean duplex stainless steel (LDSS) and its effect on the microstructure [9][10][11].Various joining techniques, such as plasma, laser, tungsten inert gas (TIG), and gas metal arc welding (GMAW) are being developed to meet the requirements demanded by these materials, avoiding distortion. However, ferritization is a problem with these processes. In addition, the effect generated by the entry of heat into these materials is a research topic. Plasma arc welding has beneficial results for DSS, which is situated at a controlled heat input and an acceptable ferrite ratio compared with other processes. Flux-cored arc welding (FCAW) has gradually attracted strong attention in welding DSS due to its higher welding efficiency compared with the gas tungsten arc welding process (GTAW) process. However, studies on the microstructure, mechanical properties, and corrosion resistance of the DSS FCAW joint are limited. Advanced laser hybrid welding has a great advantage for DSS, because it reduces heat input and distortion level compared with SAW and FCAW [12,13]. The GTAW is a welding procedure that has been employed efficiently in past years to weld materials such as stainless steels due to its facility to produce sound joints that meet specific requirements of industries, added to its facility to work when thin materials are required. However, it has be...

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Methods for the measurement of ferrite content in multipass duplex stainless steel welds

Cited by 34 publications

References 18 publications

Influence of the Interlayer Temperature on Structure and Properties of Wire and Arc Additive Manufactured Duplex Stainless Steel Product

Influence of the Interlayer Temperature on Structure and Properties of Wire and Arc Additive Manufactured Duplex Stainless Steel Product

GMAW Cold Wire Technology for Adjusting the Ferrite–Austenite Ratio of Wire and Arc Additive Manufactured Duplex Stainless Steel Components

Maintenance of the Austenite/Ferrite Ratio Balance in GTAW DSS Joints Through Process Parameters Optimization

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