Tensile Fracture of the Welded Joints of Austenitic High-Nitrogen 05Kh22AG16N8M Steel with Various Nitrogen Contents

Dynamic recrystallization was studied for the stainless steels with nitrogen contents of 0.56% to 1.08% during hot deformation at temperatures of 900~1200 with strain rates ranging from 0.003 to 42 s-1. It was found that flow stress could increase remarkably with increasing nitrogen content. Flow curves during the deformation by 0.1~42/s at temperatures of 900~1200°C show a single peak, indicating the occurrence of dynamic recrystallization during deformation. The peak strain seems to decrease with increasing N content, suggesting that higher content of N facilitates dynamic recrystallization. The quenched microstructures were analyzed by optical microscopy, EBSD and TEM. The recrystallized grain sizes on the quenched specimens were measured and its dependence on temperature and strain rate was analyzed. At high temperature, continuously dynamically recrystallized microstructures were observed; whilst at low temperature, necklace-like partially recrystallized microstructures were found. Key words: High nitrogen stainless steel; dynamic recrystallization; stress-strain curves

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Effect of hydrogenation on mechanical properties and tensile fracture mechanism of a high-nitrogen austenitic steel

Journal of Materials Science ◽

10.1007/s10853-016-0676-z ◽

2016 ◽

Vol 52 (8) ◽

pp. 4224-4233 ◽

Cited By ~ 4

Author(s):

Elena G. Astafurova ◽

Valentina A. Moskvina ◽

Galina G. Maier ◽

Eugene V. Melnikov ◽

Gennady N. Zakharov ◽

...

Keyword(s):

Mechanical Properties ◽

Austenitic Steel ◽

Fracture Mechanism ◽

Tensile Fracture ◽

High Nitrogen

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La corrosion par piqûres d'aciers inoxydables austéno-ferritiques dans l'eau de mer synthétique

Matériaux & Techniques ◽

10.1051/mattech/199684060023s ◽

1996 ◽

Vol 84 ◽

pp. 23-30

Author(s):

I. Trigui ◽

H. Sidhom ◽

C. Braham ◽

J. Lédion

Keyword(s):

Corrosion Resistance ◽

Pitting Corrosion ◽

Sea Water ◽

Phase Behaviour ◽

High Nitrogen ◽

Electrochemical Tests ◽

Analysis Techniques ◽

Pitting Corrosion Resistance ◽

Nitrogen Contents ◽

Image Analysis Techniques

Duplex stainless steels crevice and pitting corrosion resistance in synthetic sea water is studied. Conventional electrochemical tests and image analysis techniques are used. Three commercial steels are examined. The forged material has the best behaviour, whereas cast materials, in spite of their high nitrogen contents, have a lower corrosion resistance. Micrographic studies show a good correlation between pittings distribution and inclusions distribution and reveal that gamma phase behaviour is more affected by inclusions. The metallurgic purity of products seems to be the most important parameter in this type of corrosion. Consequently, the PREN index is questionable in pitting corrosion grading of these steels because it does not take into acount the inclusions effect.

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Effects of the Addition of High Nitrogen Contents on the Microstructure of 25%Cr- 5%Ni Ferritic-Austenitic Duplex Stainless Steel (DIN Wr. Nr. 1.4460)

Materials Science Forum ◽

10.4028/www.scientific.net/msf.426-432.1213 ◽

2003 ◽

Vol 426-432 ◽

pp. 1213-1218

Author(s):

Izabel Fernanda Machado ◽

Angelo Fernando Padilha

Keyword(s):

Stainless Steel ◽

Duplex Stainless Steel ◽

High Nitrogen ◽

Nitrogen Contents

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Metallurgical and Mechanical Characterization of High-Speed Friction Stir Welded AA 6082-T6 Aluminum Alloy

Materials ◽

10.3390/ma12244211 ◽

2019 ◽

Vol 12 (24) ◽

pp. 4211 ◽

Cited By ~ 1

Author(s):

Anton Naumov ◽

Iuliia Morozova ◽

Evgenii Rylkov ◽

Aleksei Obrosov ◽

Fedor Isupov ◽

...

Keyword(s):

Mechanical Properties ◽

Aluminum Alloy ◽

Welding Speed ◽

Welded Joints ◽

High Speed ◽

Structural Characteristics ◽

Tensile Fracture ◽

Friction Stir ◽

Microhardness Distribution ◽

Aluminum Sheets

The objective of this study was to investigate the effect of the high welding speed on the mechanical properties and their relations to microstructural characteristics of butt friction stir welded joints with the use of 6082-T6 aluminum alloy. The aluminum sheets of 2.0 mm thick were friction stir welded at low (conventional FSW) and high welding speeds (HSFSW) of 200 and 2500 mm/min, respectively. The grain size in the nugget zone (NZ) was decreased; the width of the softened region was narrowed down as well as the lowest microhardness value located in the heat-affected zone (HAZ) was enhanced by HSFSW. The increasing welding speed resulted in the higher ultimate tensile strength and lower elongation, but it had a slight influence on the yield strength. The differences in mechanical properties were explained by analysis of microstructural changes and tensile fracture surfaces of the welded joints, supported by the results of the numerical simulation of the temperature distribution and material flow. The fracture of the conventional FSW joint occurred in the HAZ, the weakest weld region, while all HSFSW joints raptured in the NZ. This demonstrated that both structural characteristics and microhardness distribution influenced the actual fracture locations.

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Research on the properties of TIG welded joints of high nitrogen nickel-free austenitic stainless steel and welding wire

Materials Research Innovations ◽

10.1179/1432891714z.000000000538 ◽

2014 ◽

Vol 18 (sup2) ◽

pp. S2-579-S2-584 ◽

Cited By ~ 1

Author(s):

H. Wang ◽

D-C. Yang ◽

Y-X. Liu ◽

C-T. Ji

Keyword(s):

Stainless Steel ◽

Austenitic Stainless Steel ◽

Welded Joints ◽

High Nitrogen ◽

Welding Wire

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Effect of Heat Treatment on TiNx Film Structure

Materials Science Forum ◽

10.4028/www.scientific.net/msf.480-481.187 ◽

2005 ◽

Vol 480-481 ◽

pp. 187-192

Author(s):

S. Zerkout ◽

M. Benkahoul ◽

H. Sahraoui ◽

S. Achour ◽

A. Mosser

Keyword(s):

Heat Treatment ◽

Nitrogen Content ◽

Thermal Instability ◽

Lattice Parameter ◽

Film Structure ◽

High Nitrogen Content ◽

High Nitrogen ◽

Tin Films ◽

Film Instability ◽

Nitrogen Contents

TiN films with different nitrogen contents were deposited on glass and Si (100) substrates by d. c. magnetron reactive sputtering. The structure of the films was determined by Xray diffraction. It was found that heat treatment at 773 decreased the lattice parameter. A considerable thermal instability of over-stoichiometric films was observed after annealing films in air. This instability enhanced with increasing nitrogen content and is characterized by an abundant appearance of clear and dark disks in Scanning Electron Microscopy (SEM). Also, it was shown that the film instability does not come from an interfacial reaction but was observed when the TiNx layers present a (200) preferred orientation together with high nitrogen content.

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Microstructure and Mechanical Properties of Friction Stir-Welded Dissimilar Joints of ZK60 and Mg-4.6Al-1.2Sn-0.7Zn Alloys

Materials ◽

10.3390/ma15010023 ◽

2021 ◽

Vol 15 (1) ◽

pp. 23

Author(s):

Liangwen Xie ◽

Xianyong Zhu ◽

Yuexiang Fan ◽

Weijia Sun ◽

Peng Wang ◽

...

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Welded Joints ◽

Gradual Increase ◽

Tensile Fracture ◽

Dissimilar Joints ◽

Friction Stir ◽

Base Materials ◽

Transverse Tensile ◽

Better Than

In order to clarify the microstructural evolution and the mechanical property of dissimilar friction stir-welded joints of ZK60 and Mg-4.6Al-1.2Sn-0.7Zn magnesium alloys, two types of arrangement with ZK60 at advancing side (AS) or retreating side (RS) were adopted. The macrostructure and the microstructure of the dissimilar welded joints were discussed, and the microhardness and the transverse tensile properties of the joints were measured. There are three stirring sub-zones with different compositions and two clear interfaces within the joints. Due to the effect of both the original grain size of base materials and the growth of recrystallized grains, in the stir zone (SZ), the grain size of ZK60 increased slightly, while the grain size of Mg-4.6Al-1.2Sn-0.7Zn decreased significantly. The dissolution of precipitates was gradually significant from RS to AS within the SZ due to the gradual increase in strain and heat. The grain refinement led to an increase in hardness, while the dissolution of precipitates resulted in a decrease in hardness. The performance of the joints obtained with ZK60 placed on the RS is slightly better than that of that on the AS. The tensile fracture of both joints occurred at the interface between SZ and the thermos-mechanical affected zone at the AS, and showed a quasi-dissociative fracture.

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