Non-alloyed P355NH steel according to EN 10028-3:2003 belongs to a group of fine-grained steels for pressure vessels being used in welded construction at decompression chamber for divers. Values of the chemical, structural and mechanical characteristics and steel toughness experimentally determined fit the analyzed steel in P355NH steel group according to EN 10028-3:2003. The toughness of the analyzed steel at the test temperature of -30°C is characterized by high values of fracture energy KV in longitudinal direction between 48 and 86 J and on transverse direction between 17 and 34J. Steel toughness at the test temperature of -30°C required by ABS standard (in Section 4/5.3 and Table 1) provides for breaking energy KV of min. 35J, with ductile fracture surfaces, value that is not respected at some lots of the three batches (A, B, C) of steel. Finally, based on the direct correlation established between HV10 hardness of the fine structure and the toughness it was made a selection of the lots of non-alloy steel P355NH which correspond to ABS norm for welded construction of the decompression chamber for divers
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.
The paper presents a vibroacoustic method to determining the stiffness of coated steel with various materials such as metal oxides, metallic paints, polymers etc and Young's modulus for coating materials. The method consists in measuring the dynamic response of the steel in the form of a rectangular bar subjected to external impulse. One of the latest non-destructive experimental techniques in this field is based on the analysis of vibrating signal response recorded with a condenser microphone. A Fast Fourier Transform algorithm is used for processing the sampled signals. Knowing the mechanical properties of steel plates prior to coating with metal oxides, and determining the same properties after coating, can be obtained the mechanical properties of metal oxides and their influence on the properties of the ensemble.
CMT weld brazing process (Cold Metal Transfer) knows a higher applicability in various industries (aeronautic, automobile) due its advantages compared with other welding processes. The paper presents the experimental results obtained on sheets joints using austenitic stainless steel mark 304 of 1 mm thick in butt and overlap variants using CuSi3 filler alloy of 1.2 mm diameter. The macroscopic analysis shows that were not presented welding defects and the microscopic examination did not showed welding defects such as microcracks. After the mechanical tests it was observed that al the tested specimens the fracture occurred in the base metal except the sample 1 where the fracture occurred in the welding zones. The bending test showed that all the samples were bent to 180° without cracks which assure good mechanical resistance to deformation. ΔHV1 estimator values determined in the characteristic areas of the joints shows that at sample 2 there are structural hardening tendencies in the zones BM1-WELD and BM2-WELD with values of 36% respectively 28.5% attesting moderate structural hardening (ΔHV1<50%), the brittle-type fracture risk in these areas is considered low.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.