Effect of modifying non-metallic inclusions with rare earth metals on the structure and properties of weld metal in welding high strength steels

Developments of high strength steels for natural gas pipelines have been in the forefront of steelmaking and rolling technology in the past decades. However, parallel to such developments in steel industry, the welding technology especially with regards to SMAW process which is still widely used in many projects has not evolved accordingly. Decreasing carbon equivalent has shifted the tendency of hydrogen cracking from the HAZ to the weld metal. Hydrogen cracking due to its complex mechanism is affected by a range of interactive parameters. Experience and data gained from field welding of pipeline construction projects indicated that weld metal hydrogen cracking is related to welding position as it occurs more in the 6 o’clock position of pipeline girth welds. In this research an attempt is made to open up the above observation in order to investigate the contributory factors such as welding position and welding progression in terms of diffusible hydrogen and possibly residual stress considerations. It was observed that transverse cracks produced in laboratory condition may not be detected by radiography. But, the higher tendency for cracking at 6 o’clock position was confirmed through bend test. It is shown that more hydrogen can be absorbed by the weld metal in the overhead position. It is shown that welding progression may also have a significant effect on cracking susceptibility and it is proposed that to be due to the way that weld residual stresses are developed. The observations can have an important impact on planning for welding procedure approval regarding prevention of transverse cracking in pipeline girth welds.

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The longitudinal bead-TRC test for cold crack susceptibiity of weld metal for high strength steels

Welding International ◽

10.1080/09507118809447457 ◽

1988 ◽

Vol 2 (2) ◽

pp. 135-139 ◽

Cited By ~ 1

Author(s):

F Matsuda ◽

H Nakagawa ◽

K Shinozaki

Keyword(s):

Weld Metal ◽

High Strength Steels ◽

High Strength

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Physical Properties Of Rare Earth Elements

The American Journal of Applied Sciences ◽

10.37547/tajas/volume03issue01-13 ◽

2021 ◽

Vol 03 (01) ◽

pp. 79-88

Author(s):

Davron Rakhmonovich Djuraev ◽

◽

Mokhigul Madiyorovna Jamilova ◽

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Physical Properties ◽

Phase Transformations ◽

Rare Earth Metals ◽

Economic Effect ◽

Structure And Properties ◽

Structure And Stability ◽

Ongoing Phase

The article studies the physical properties of rare earth metals, pays special attention to their unique properties, studies the main aspects of the application of rare earth metals in industry. Also, the structure and stability of various forms of sesquioxides of rare earth elements, in particular, europium, as well as the effect of the method of oxide preparation on its structure and properties are considered. The analysis of the ongoing phase transformations of rare earth metals is made. The article emphasizes the use of correct choices to achieve a large technical and economic effect when using rare earth metals in industry. The article is intended for teachers working in the field of physics and chemistry, as well as for students of the specialty "physics and chemistry".

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