Cracking of the mixing chamber caused by sigma phase precipitation in austenitic steel welded joints

Abstract This paper describes the technology of welding of finned tubes made of the X5CrNi1810 (1.4301) austenitic steel, developed at Energoinstal SA, allowing one to get high quality joints that meet the requirements of the classification societies (PN-EN 15614), and at the same time to significantly reduce the manufacturing costs. The authors described an automatic technological line equipped with a Trumph disc laser and a tube production technological process. To assess the quality of the joints, one performed metallographic examinations, hardness measurements and a technological attempt to rupture the fin. Analysis of the results proved that the laser-welded finned tubes were performed correctly and that the welded joints had shown no imperfections.

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Effect of sigma phase precipitation on microstructure and properties of cast ZG0Cr26Ni5Mo3Cu3 duplex stainless steel under different heat treatments

China Foundry ◽

10.1007/s41230-018-7226-z ◽

2018 ◽

Vol 15 (3) ◽

pp. 182-188 ◽

Cited By ~ 2

Author(s):

Ze-hua Zhu ◽

Wei-dong Zhang ◽

Xiao-hui Tu ◽

Xiao-jian Wang ◽

Wei Li

Keyword(s):

Stainless Steel ◽

Duplex Stainless Steel ◽

Sigma Phase ◽

Heat Treatments ◽

Phase Precipitation ◽

Microstructure And Properties

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Austenite-ferrite interface crystallography dependence of sigma phase precipitation using the five-parameter characterization approach

Materials Letters ◽

10.1016/j.matlet.2017.03.090 ◽

2017 ◽

Vol 196 ◽

pp. 264-268 ◽

Cited By ~ 21

Author(s):

N. Haghdadi ◽

D. Abou-Ras ◽

P. Cizek ◽

P.D. Hodgson ◽

A.D. Rollett ◽

...

Keyword(s):

Sigma Phase ◽

Phase Precipitation

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Internal Friction Influenced by Hydrogen in Super Duplex Stainless Steels

Materials Science Forum ◽

10.4028/www.scientific.net/msf.502.345 ◽

2005 ◽

Vol 502 ◽

pp. 345-350

Author(s):

Toshio Kuroda ◽

Katsuyuki Nakade ◽

Kenji Ikeuchi

Keyword(s):

Internal Friction ◽

Stainless Steels ◽

Sigma Phase ◽

Peak Height ◽

Phase Precipitation ◽

Internal Friction Peak ◽

Hydrogen Charging ◽

Super Duplex Stainless Steels ◽

Two Peaks ◽

Friction Analysis

The influence of microstructure concerning sigma phase on hydrogen behavior was investigated by means of internal friction analysis. After hydrogen charging, a sharp significant internal friction peak by hydrogen in austenite of as-received specimen was observed at 245K for a frequency of 1.5Hz. However, the peak height in the specimen precipitated significant sigma phase was substantially lower than in as-received specimen since hydrogen in austenite have a concentration lower by sigma phase precipitation. In addition, the broadening and scattering of the internal friction peak was clearly identified by interaction between hydrogen and sigma phase. It means that the two peaks associated with hydrogen in the both sigma phase and austenite were considered to be overlapped. Consequently, it was clearly confirmed that hydrogen entered in the sigma phase lattice and hydrogen was also trapped at sigma/austenite interfaces.

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