Chemical, Structural, Mechanical and Intergranular Corrosion Characterization of Welded Pipes Joints Made of TP 347 Steel

Abstract:

The paper presents the experimental results obtained on the pipes welded joints made of TP 347 steel in normal state, NT (welded) and heat-treated state, TT for post-welding stabilization. Heat treatment for stabilization was performed in an electric furnace which provided the process parameters (Theat = 900°C, Vheat = vcooling ≈ 300°C, etc.) and a precision temperature of ±10°C to 1000°C. Chemical compositions of TP 347 steel pipe and of the filler material (ER 347) have values falling within the manufacturing standards (Cr = 17 ... 19% and Ni = 9... 13%). In the specific areas of the welded joints were detected austenitic structures with heterophasic areas of ferrite and complex carbides areas, having the hardness between 162 and 225 HV10. No welding and heat treatment defects were detected, such as cracks and microcracks. The mechanical strength (Rp0,2 and Rm), determined on the base metal and on the welded joints presents high values. Thus, for the base metal were obtained values of Rp0,2 of minimum 212 N/mm2, respectively values of minimum 523 N/mm2 for Rm. For the welded joints, Rm has values between 522 N/mm2 and 527 N/mm2. All the values obtained are higher than those required by ASTM A370standard. The base materials in NT and TT state presents high values of impact energy KV at 20°C, between 72J and 78J, and for the welded joints, the values of KV are between 53J and 60J, with ductile breaking aspect of the specimens’surfaces. The surfaces of the tested specimens for resistance to intergranular corrosion according to ASTM A 262-2010, Method E, presented not specific defects, attesting a corresponding behavior of the intergranular corrosion of TP347 steel and of the welded joints made of the pipes having the dimensions of ø219 x 8.18 mm. The values of the chemical, structural, mechanical and intergranular corrosion characteristics determined on specific samples evidence a high quality of the base material and of the welded joints of TP 347steel pipe, conducted by qualified welding technology, commonly used in the manufacture of components from chemical and petrochemical industries.

• Periodical: Applied Mechanics and Materials (Volumes 291-294)
• Pages: 2594-2604
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.291-294.2594
• Online since: February 2013
• Authors: Romulus Pascu, Roşu Radu Alexandru, Fulga Doru, Duma Iuliana
• Keywords: Mechanical Tests, Microscopic Analysis, Welded Joint

References

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