scholarly journals Effect of corrosion degree on mechanical properties of reinforcements buried for 60 years

2018 ◽  
Vol 11 (3) ◽  
pp. 474-498
Author(s):  
C. E. T. BALESTRA ◽  
M. G. LIMA ◽  
A. Z. MENDES ◽  
R. A. MEDEIROS-JUNIOR
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Yield Strength ◽  
Mass Loss ◽  
Cross Sections ◽  
Pitting Corrosion ◽  
Corrosion Process ◽  
Corrosion Rates ◽  
Corrosion Pits

Abstract This paper studies the influence of the corrosion degree calculated by the mass loss and by the smaller diameters on the yield strength, ultimate strength and final elongation. Reinforcements buried and naturally corroded for 60 years were studied. The mechanical properties of the protruding reinforcing steel were compared to reference bars, which also remained buried for 60 years, but without going through the corrosion process. Micrographs, besides the chemical composition and the characterization of the aggressiveness of the soil were realized. The micrographs and the chemical composition show the presence of pits in the reinforcements and sulfur contents for steel above the prescriptions of the time when the foundations were initially implement, respectively. The results also show that the effects of pitting corrosion on the mechanical properties of the naturally corroded bars may not be adequately expressed by the mass loss. This type of corrosion (pits) produces geometric variations in the cross sections along the length of the test specimens, generating stress gradients between successive sections. This has a noticeable impact on the mechanical properties of the reinforcements. In general, the effects of corrosion are more pronounced on the ductility of the reinforcement. Regarding the aggressiveness of the soil, high corrosion rates were identified in the reinforcement, even with the soil being classified as essentially non-corrosive.

Thermal Stability of Mechanical Properties of Copper after Equal-Channel Angular Pressing

2008 ◽  
Vol 584-586 ◽  
pp. 960-965 ◽  
Author(s):  
Tamara Kravchenko ◽  
Alexander Korshunov ◽  
Natalia Zhdanova ◽  
Lev Polyakov ◽  
Irina Kaganova
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Chemical Composition ◽  
Yield Strength ◽  
Equal Channel Angular Pressing ◽  
Angular Pressing ◽  
Different Temperatures ◽  
Thermal Stability Of

Annealed oxygen-free and tough-pitch copper samples have been processed by equalchannel angular pressing (ECAP) by route BC. The samples included 8 x 8 mm section pieces and a 40 mm diameter bar. Thermal stability was assessed based on the changes in the standard mechanical properties (conventional yield strength, tensile strength, elongation, proportional elongation and contraction) after annealing at different temperatures for 1 hour. Thermal stability of the same grade of material has been found to be different for different batches and to depend on the structural conditions of deformed material. The zone of thermal stability for copper of the two grades of interest does not depend on the material’s chemical composition.

Characterization of glass-ceramics microstructure, chemical composition and mechanical properties

2011 ◽  
Vol 25 ◽  
pp. 012015 ◽  
Author(s):  
E Lodins ◽  
I Rozenstrauha ◽  
L Krage ◽  
L Lindina ◽  
M Drille ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Glass Ceramics

Microstructural and Mechanical Characterization of Nitinol GTAW and FB Welds of Titanium

2006 ◽  
Vol 509 ◽  
pp. 165-170 ◽  
Author(s):  
Alla Kabatskaia Ivanovna ◽  
Victor M. López-Hirata ◽  
Eduardo Oliva López ◽  
Ricardo Rodríguez Figueroa ◽  
Jorge Rodríguez Miramontes
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Mechanical Characterization ◽  
Dendritic Structure ◽  
Intermetallic Phases ◽  
Atomic Diffusion ◽  
Rich Phase ◽  
Gas Tungsten Arc ◽  
Gtaw Process

Microstructural and mechanical characterization of Nitinol gas tungsten arc weld (GTAW) and furnace brazing (FB) welds for grade 1 titanium plates are carried out in order to study the microstructure developed after welding and its effect on the mechanical properties of welds. The GTAW process yields the highest hardness weld. The constituents for this weld consist of a dendritic structure of NiTi and NiTi2 intermetallic phases. The FB process promotes a change of the welds chemical composition due to atomic diffusion of Ti. The weld microconstituents consist of a mixture of a Ti-rich and NiTi2 eutectic and a proeutectic Ti-rich phase.

scholarly journals Influence of the Cooling Rate on the Morphology of Spheroidic Graphite Obtained by the CO2 Process

2013 ◽  
Vol 8 (22) ◽  
pp. 37
Author(s):  
Mauro Carlos Souza ◽  
Antonio Carlos de Araújo Santos ◽  
Wilma Clemente de Lima Pinto ◽  
Mila Rosendal Avelino
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Chemical Analysis ◽  
Cooling Rate ◽  
Processing Parameters ◽  
Mechanical Resistance ◽  
Metallic Materials ◽  
Metallurgical Processing ◽  
Resistance Tests

The mechanical properties of cast metallic materials are strongly influenced by processing parameters, such as percentage of silicate, sand granulometry, and metallurgical processing. The ductile iron cast produced by the CO2 process depends on variables that determine the behavior of the material in service, such as the cooling rate and chemical composition. This study evaluated the influence of the cooling rate on the spheroidic graphite. In order to determine this effect, a simulation was performed in specimens with 20, 25, and 30 mm in thickness, through the characterization of type, measurement of nodule size, and distribution of nodules. Chemical analysis and mechanical resistance tests were performed. The 25 mm thick specimen showed the best behavior among the three thicknesses evaluated, presenting the formation of many small nodules and a small amount of larger nodules in the center.

Characterization of the Naked Mole Rat Incisors: Chemical Composition, Microstructure and Mechanical Properties

2021 ◽  
pp. 1-10
Author(s):  
Hongyan Qi ◽  
Guixiong Gao ◽  
Huixin Wang ◽  
Yunhai Ma ◽  
Hubiao Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Lamellar Structure ◽  
Three Dimensional ◽  
Microstructure And Mechanical Properties ◽  
Inorganic Matter ◽  
Mole Rat ◽  
Naked Mole Rat ◽  
Reticular Structure

The naked mole rat incisors (NMRI) exhibit excellent mechanical properties, which makes it a good prototype for design and fabrication of bionic mechanical systems and materials. In this work, we characterized the chemical composition, microstructure and mechanical properties of NMRI, and further compared these properties with the laboratory rat incisors (LRI). We found that (1) Enamel and dentin are composed of organic matter, inorganic matter and water. The ratio of Ca/P in NMRI enamel is higher than that of LRI enamel. (2) The dentin has a porous structure. The enamel has a three-dimensional reticular structure, which is more complex, regular and denser than the lamellar structure of LRI enamel. (3) Enamel has anisotropy. Its longitudinal nano-hardness is greater than that of transverse nano-hardness, and both of them are higher than that of LRI enamel. Their nano-hardness and elastic modulus increase with the increment of distance from the enamel-dentin boundary. The nano-hardness of dentin is smaller than that of enamel. The chemical composition and microstructure are considered to be the reasons for the excellent properties of NMRI. The chemical composition and unique microstructure can provide inspiration and guidelines for the design of bionic machinery and materials.

Integrating Automated Ball Indentation With ASME B31G Code to Assess Integrity of Corroded Pipelines

2004 ◽  
Author(s):  
Fahmy M. Haggag ◽  
Larry D. Phillips
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Yield Strength ◽  
Maximum Depth ◽  
Operating Pressure ◽  
Test Technique ◽  
Efficient Operation ◽  
Ball Indentation ◽  
Corrosion Pits ◽  
Safe Operating

In order to provide deterministic structural integrity assessment for safe and efficient operation of corroded pipelines, the following information is required: (a) the actual key mechanical properties (yield and ultimate strength, and fracture toughness) of the pipeline materials, (b) the present thickness and diameter of the pipeline, and (c) the profile of the maximum depth of corrosion pits over the pipeline axial length, and the size of sharp cracks. Both items (b) & (c) can be determined by conventional techniques. A patented in-situ Stress-Strain Microprobe (SSM) system was used to provide item (a), the required key mechanical properties (tensile and fracture toughness), in a nondestructive and localized fashion without any interruption of the pipeline transmission using its novel Automated Ball Indentation (ABI) test technique. The SSM system was used on a short segment of a 356-mm (14-inch) diameter Kerosene pipeline. Although there was no documentation of the pipeline steel grade, the minimum ABI-measured yield strength at four locations was 277 MPa (40.2 ksi) and the minimum ultimate tensile strength was 378 MPa (54.8 ksi) indicating that the steel met the requirements of Grade “A”. Both the Rstreng software and the ASME B31G code were used to calculate the maximum safe operating pressure for the corroded pipeline. The calculations showed that a profile with a few corrosion pits [3–6 mm (0.075–0.236 inch) maximum depth spaced over 483 mm (19 inches) length] reduced the maximum safe pressure significantly from 4.24 MPa (615 psi) to 0.74 MPa (107 psi). The operator of the pipeline limited the maximum operating pressure to 0.69 MPa (100 psi). Furthermore, it was recommended that the ABI measurements be performed on at least 10% of the 7-km Kerosene pipeline and on all patches and welds in order to provide the minimum yield strength values required for determining the remaining strength of the pipeline. This work proves that the integration of the ABI measurements with the corrosion pitting profile allows calculation of the maximum safe operating pressure in order to make the appropriate decision of replacement or repair of certain pipeline sections.

Corrosion Rates and Mechanical Properties of Rebar HRB400

2014 ◽  
Vol 953-954 ◽  
pp. 1492-1495
Author(s):  
Ping Li
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Corrosion Rate ◽  
Nacl Solution ◽  
Corrosion Rates ◽  
Before And After ◽  
Corrosion Time

The corrosion rates of rebar HRB400 in 0.5 wt.% NaCl solution were measured, and the mechanical properties before and after corrosion were tested. The results showed that, with the increase of corrosion time, the corrosion rate of rebar HRB400 increases and the corrosion becomes heavier. Meanwhile, the yield strength and tensile strength decrease, but the elongation decreases at first and then increases.

scholarly journals The Influence of Hot-Dip Galvanizing on the Mechanical Properties of High-Strength Steels

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5219
Author(s):  
Milan Šmak ◽  
Jaroslav Kubíček ◽  
Jiří Kala ◽  
Kamil Podaný ◽  
Jan Vaněrek
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Chemical Composition ◽  
Yield Strength ◽  
High Strength Steel ◽  
High Strength Steels ◽  
High Strength ◽  
Steel Members ◽  
Different Types ◽  
Standard Quality

Modern high-strength steels achieve their strength exclusively through the manufacturing process, as the chemical composition of these steels is very similar to the composition of standard-quality steels. Typically, hot-dip galvanizing is used to form a protective zinc layer on the steel parts of structures; nonetheless, the material is exposed to high temperatures during the process. With high-strength steels, this can lead to deterioration of the mechanical properties. This study aims to experimentally examine and evaluate the extent of deterioration of the mechanical properties of high-strength-steel members. The effect was studied on specimens made of three different types of steel with the yield strength ranging from 460 to 1250 MPa. For each type of steel, selected mechanical properties—yield strength, tensile strength, and hardness—were determined on specimens with and without hot-dip galvanization, and the obtained results were mutually compared. Our study shows a significant impact of the hot-dip galvanization process on the mechanical properties of some high-strength steels. With the studied types of steel, the yield strength decreased by up to 18%, the tensile strength by up to 13%, and the hardness by up to 55%.

Characterization of Nickel Based Alloys (Hard Facing Alloys) with Additions of Ti and Mo

2011 ◽  
Vol 312-315 ◽  
pp. 199-204
Author(s):  
K. Khenfer ◽  
S. Lebaili ◽  
S. Hamar-Thibault
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Chemical Composition ◽  
Abrasive Wear ◽  
Mechanical Engineering ◽  
Significant Proportion ◽  
Heterogeneous Materials ◽  
Engineering Industry ◽  
Wear And Corrosion

The mechanical engineering industry is always in the search of new hardfacing alloys which nowadays make it possible to solve considerable delicate problems of abrasive wear and corrosion. These alloys are heterogeneous materials and are generally composed of a ductile matrix and a significant proportion in hard phases (carbides, borides or silicides), which give a good wear resistance and corrosion. The following studies made on alloys containing Ni, rich in Silicon and tungsten. We noted that addition of these elements (Si and W) got interesting mechanical properties. The alloys that we chose for this study contain the elements C, B, Si, Cr and W with additions in Ti and Mo. The aim of this work is the characterisation of the various phases formed during solidification, to study chemical affinities in this system poly-constitutes and to make a correlation between the chemical composition, the conditions of development and the microstructures obtained.

Pitting Corrosion of a Low Carbon Steel in Corrosive Environments: Experiments and Models

2015 ◽  
Vol 1132 ◽  
pp. 349-365 ◽  
Author(s):  
S.K. Kolawole ◽  
F.O. Kolawole ◽  
O.P. Enegela ◽  
O.O. Adewoye ◽  
A.B.O. Soboyejo ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Pitting Corrosion ◽  
Low Carbon Steel ◽  
Carbon Steels ◽  
Low Carbon ◽  
Corrosive Media ◽  
Corrosion Rates ◽  
Effects Of Ph ◽  
Corrosion Pits ◽  
Corrosive Environments

This paper presents the results of the combined study of experiments and modeling of the pitting corrosion behavior of low carbon steel. The effects of pH are elucidated via experiments on low carbon steel exposed to various corrosive media. The corrosion rates for the steel samples immersed in various corrosive media were determined by polarization experiments via a gamry potentiostat. The microscopic observations of the surfaces reveal clear evidence of corrosion pits that increase in size with increasing exposure duration. The observed pit size distribution and the evolution of pit size are modeled using statistical models. The implications of the results are used for the application of low carbon steels in corrosive environment.

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