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Article

Weishan Huang, Jing-Li Luo, Hani Henein and Josiah Jordan

This paper aims to evaluate the sulfide stress cracking (SSC) resistance of L80 casing steels with different alloying chemistries (e.g. Ti-B and Mn-Cr-Mo) by correlating…

Abstract

Purpose

This paper aims to evaluate the sulfide stress cracking (SSC) resistance of L80 casing steels with different alloying chemistries (e.g. Ti-B and Mn-Cr-Mo) by correlating the reduction in area ratio with the mechanical property, inclusion and carbide.

Design/methodology/approach

SSC tests were conducted in 5.0 Wt.% sodium chloride and 0.5 Wt.% acetic acid solution saturated with H2S using constant load tensile method. The microstructure and fracture morphology of the steel were observed using scanning electron microscope. The inclusion and carbide were identified by energy dispersive spectroscopy and auger electron microscope.

Findings

Among all the testing steels, electric resistance welding (ERW) L80-0.5Mo steel demonstrates the highest SSC resistance because of its appropriate mechanical properties, uniform microstructure and low inclusion content. The SSC resistance of L80 steels generally decreases with the rising yield strength. The fracture mode of steel with low SSC resistance is jointly dominated by transgranular and intergranular cracking, whereas that with high SSC resistance is mainly transgranular cracking. SSC is more sensitive to inclusions than carbides because the cracks are easier to be initiated from the elongated inclusions and oversized oxide inclusions, especially the inclusion clusters. Unlike the elongated carbide, globular carbide in the steel can reduce the negative effect on the SSC resistance. Especially, a uniform microstructure with fine globular carbides favors a significant improvement in SSC resistance through precluding the cracking propagation.

Originality/value

The paper provides the new insights into the improvement in SSC resistance of L80 casing steel for its application in H2S environment through optimizing its alloying compositions and microstructure.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 4
Type: Research Article
ISSN: 0003-5599

Keywords

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Article

Blaoui Mohammed Mossaab, Mokhtar Zemri and Mustapha Arab

The purpose of this paper is to evaluate the effects of medium carbon steel microstructure on the tensile strength and fatigue crack growth (FCG) behavior.

Abstract

Purpose

The purpose of this paper is to evaluate the effects of medium carbon steel microstructure on the tensile strength and fatigue crack growth (FCG) behavior.

Design/methodology/approach

To achieve this aim, four different heat treatment methods (normalizing, quenching, tempering at 300°C and tempering at 600°C) were considered. Microstructural evolution was investigated by scanning electron microscopy. FCG rate tests were conducted on the resultant microstructures with compact tension specimens at room temperature by a standard testing method.

Findings

The results show that the normalized microstructure had the largest number of cycles to failure, indicating a high fatigue resistance, followed by the as received, tempered at 600°C, tempered at 300°C and quenched microstructure.

Originality/value

The paper shows the influence of the microstructure on the fatigue-propagation behavior with the definition of the Paris parameters of each heat treatment condition.

Details

International Journal of Structural Integrity, vol. 10 no. 1
Type: Research Article
ISSN: 1757-9864

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Article

Wangping Wu, Xiang Wang, Qun Wang, Jianwen Liu, Yi Zhang, Tongshu Hua and Peng Jiang

The purpose of this paper is to maraging 18Ni-300 steel fabricate by powder bed based selective laser melting (SLM) process. Microstructure and mechanical properties of…

Abstract

Purpose

The purpose of this paper is to maraging 18Ni-300 steel fabricate by powder bed based selective laser melting (SLM) process. Microstructure and mechanical properties of the maraging steel part before and after heat treatment at a slow cooling rate were investigated.

Design/methodology/approach

The microstructure of the printed part was observed by optical microscopy and scanning electron microscopy. The phases were determined by X-ray diffraction. The surface roughness of the part was recorded by a profilometer. The tensile properties and microhardness of the parts before and after heat treatment were characterized by an electronic universal tensile testing machine and a Vickers hardness tester, respectively.

Findings

Maraging 18Ni-300 steel part comprised of the martensitic phase and a small fraction of austenite phase. After heat treatment, the volume fraction of austenite slightly increased. The surface roughness of the part was about 96 µm. The printed part was dense, but irregular pores were present. The yield strength, ultimate tensile strength (UTS), elongation and Young’s modulus of as-fabricated parts were 554.7 MPa, 1173.1 MPa, 10.9% and 128.9 GPa, respectively. The yield strength, UTS, elongation and Young’s modulus of as-treated parts were 2065 MPa, 2225 MPa, 4.2% and 142.5 GPa, respectively. The microhardness values of surface and cross-section of the as-fabricated part were 407.1 HV and 443.0 HV, respectively. After short-time heat treatment, the microhardness values of the surface and cross-section of the part were 542.7 HV and 567.3 HV, respectively. After long-time heat treatment, the microhardness values of the surface and cross-section of the part were 524.4 HV and 454.8 HV, respectively. The microhardness and tensile strength increased significantly with decreasing elongation due to the changes in phases and microstructure of the parts after heat treatment.

Originality/value

This work studied the effect of heat treatment at 550°C combined with a subsequent slow cooling rate on microstructure and mechanical properties of maraging 18Ni-300 steel obtained by the powder bed based SLM process.

Details

Rapid Prototyping Journal, vol. 26 no. 8
Type: Research Article
ISSN: 1355-2546

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Article

Luis Ricardo Jacobo, Rafael Garcia, Victor Hugo Lopez and Antonio Contreras

The purpose of this paper is to study the effect of heat treatment (HT) applied to an API X60 steel in corrosion resistance and stress corrosion cracking (SCC…

Abstract

Purpose

The purpose of this paper is to study the effect of heat treatment (HT) applied to an API X60 steel in corrosion resistance and stress corrosion cracking (SCC) susceptibility through slow strain rate tests (SSRT) in NS4 solution and congenital water (CW) to assess external and internal SCC, respectively.

Design/methodology/approach

API X60 steel was heat treated at a temperature of 1,200°C for 30 min followed by water quenching. Specimens from this steel were machined according to NACE TM 198. SSRT were performed in a constant extension rate tests (CERT) machine at room temperature at a strain rate of 1 × 10–6 s–1. For this purpose, a glass cell was used. Corrosion behavior was evaluated through polarization curves (PCs).

Findings

The SCC index obtained from SSRT indicates that the steel heat treated could be susceptible to SCC in CW and NS4 solution; the mechanism of SCC was hydrogen embrittlement. Thus, CW may promote the SCC phenomenon in pipelines. HT improves the steel corrosion resistance. Higher corrosion rate (CR) was observed when the steel is exposed to CW. The corrosion process in X60 steel shows that the oxidation reaction in the anodic branch corresponds to an activation process, and the cathode branches reveal a diffusion process.

Originality/value

The purpose of the heat treatment applied to X60 steel was to generate a microstructure of acicular ferrite to improve the corrosion resistance and SCC behavior.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 3
Type: Research Article
ISSN: 0003-5599

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Article

Paulraj Sathiya, M.Y. Abdul Jaleel and B. Shanmugarajan

Laser welding under high power, high degree of automation and high production rate is extremely advantageous in automotive application. Super austenitic stainless steel is…

Abstract

Purpose

Laser welding under high power, high degree of automation and high production rate is extremely advantageous in automotive application. Super austenitic stainless steel is the preferable material for high corrosion resistance requirements. These steels are relatively cheaper than austenitic stainless steel and it is expensive than nickel base super alloys for such applications. The main purpose of this paper is to present the investigations of the microstructure and mechanical properties of super austenitic stainless steel butt joints made by 3.5 kW cooled slab CO2 laser welding using different shielding gases such as argon, nitrogen and helium.

Design/methodology/approach

The tensile and impact tests were performed and the fractured surfaces were analyzed by scanning electron microscope. The hardness across the joint zone was measured. The X‐ray diffraction technique was used to analyze the phase composition. The microstructure of the laser welds were analyzed through optical microscopy.

Findings

The tensile sample fractures indicate that the specimen fails in a ductile manner under the action of tensile loading. The impact fracture surfaces of the different shielding gas laser welded joints show mixed mode fractures, that is, ductile and cleavage fractures. The hardness values of the Helium shielded laser joints in the weld metal regions are much higher than the others.

Research limitations/implications

There is no limitation, except for the availability of the high beam power laser welding machine.

Practical implications

The only practical implication is the laser welding shop hazard during the experiment.

Social implications

Social implication is limited. The only hazard during the laser welding is that it may affect human body tissues.

Originality/value

The research work described in the paper is original.

Details

Journal of Engineering, Design and Technology, vol. 10 no. 1
Type: Research Article
ISSN: 1726-0531

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Article

C. Miranda‐Herrera, I. Sauceda, J. González‐Sánchez and N. Acuña

The purpose of this paper is to evaluate the electrochemical behaviour of two carbon steels exposed to acidic geothermal solutions and their resistance to hydrogen induced…

Abstract

Purpose

The purpose of this paper is to evaluate the electrochemical behaviour of two carbon steels exposed to acidic geothermal solutions and their resistance to hydrogen induced cracking (HIC), in order to determine the effect of hydrogen damage on the failure process of the steels used for line pipe and casings at a geothermal plant.

Design/methodology/approach

Samples of two different steels: ASTM A‐53 Grade B (line pipe) and API L‐80 (casing) were immersed for a duration of 96 h in the electrolyte proposed by NACE to evaluate susceptibility to HIC. Samples of the two steels embedded in non‐conducting Bakelite were subjected to potentiodynamic polarisation scans at room temperature using as the electrolyte brines obtained from different wells at the Cerro Prieto geothermal plant. Hardness tests were performed on the samples before and after the HIC tests in order to determine hardness changes induced by hydrogen penetration as field results indicated embrittlement of the steels after four months of service.

Findings

The steels, ASTM A‐53 Grade B and API L‐80 did not exhibit crack sensitivity as no cracks are observed in the tests specimens, though they showed an increase in hardness. The steels exhibited high‐corrosion rates in the brine media at room temperature (3.3 mm/yr), which is expected to increase at higher temperatures.

Originality/value

The work revealed that carbon steels used for line pipes and casings at geothermal plants can exhibit high resistance to HIC, however they corrode at high rates and may show embrittlement. It is suggested that due to the high‐operation temperature, the damage induced by hydrogen resulted in hardness increase but was not sufficient to develop cracks.

Details

Anti-Corrosion Methods and Materials, vol. 57 no. 4
Type: Research Article
ISSN: 0003-5599

Keywords

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Article

Halil Ibrahim Ünal, Hakan Atapek, Baran Gürkan Beleli, Seyda Polat, Serap Gümüs and Ersoy Erisir

The purpose of this paper is to investigate the fracture of grade X42 microalloyed steel used as pipe material after tensile test at room temperature and impact tests at…

Abstract

Purpose

The purpose of this paper is to investigate the fracture of grade X42 microalloyed steel used as pipe material after tensile test at room temperature and impact tests at 0, −20 and −40°C, respectively.

Design/methodology/approach

In the first stage of the study, X42 steels in the form of sheet and pipe materials were selected and etched samples were characterized using light microscope. In the second stage, mechanical properties of steels were obtained by microhardness measurements, static tensile and impact tests and all the broken surfaces were examined by scanning electron microscope to determine the fracture type as a function of both microstructure and loading.

Findings

The examinations revealed that: first, the sheet material had a typical ferritic-pearlitic matrix, second, the transverse section of the sheet steel exhibited a matrix consisting of polygonal ferrite-aligned pearlite colonies and the longitudinal one had elongated ferrite phase and pearlite colonies in the direction of rolling, third, ferrite and pearlite distribution was different from the sheet material due to multiaxial deformation in the pipe material, fourth, tensile fracture surfaces of the steels had typical dimple fracture induced by microvoid coalescence, fifth, impact fracture surfaces of the steels changed as a function of the test temperature and cleavage fracture mode of ferritic-pearlitic matrix became more dominant as the temperature decreased, and sixth, grain morphology had an effect on the fracture behavior of the steels.

Originality/value

The paper explains the fracture behaviour of X42 microalloyed pipeline steel and its fractographical analysis.

Details

International Journal of Structural Integrity, vol. 6 no. 5
Type: Research Article
ISSN: 1757-9864

Keywords

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Article

L.M. Quej-Ake, A. Contreras, H.B Liu, J.L. Alamilla and E. Sosa

The purpose of this paper is to study the susceptibility to corrosion processes of X60, X65 and X70 steels immersed in sand-clay soil with pH 3.0, using electrochemical…

Abstract

Purpose

The purpose of this paper is to study the susceptibility to corrosion processes of X60, X65 and X70 steels immersed in sand-clay soil with pH 3.0, using electrochemical techniques, scanning electron microscopy (SEM), energy dispersive spectroscopy and X-ray diffraction (XRD).

Design/methodology/approach

Natural acidic soil sample was collected as close as possible to buried pipes (1.2 m in depth) in a Right of Way from south of Mexico. Both steels and soil were characterized through SEM and XRD. Then, open circuit potential was recorded for all steels exposed to soil at different exposure times. Thus, the electrochemical impedance spectroscopy (EIS) was traced, and anodic polarization curves were obtained.

Findings

The steel corrosion processes started when the active sites were exposed to natural acidic soil. However, corrosion rates decreased for three steels as immersion time increased, obtaining the highest corrosion rate for X60 steel (0.46 mm/year for 5 h). This behavior could be attributed to corrosion products obtained at different exposure times. While, 5 h after removing corrosion products, X65 steel was more susceptible to corrosion (1.29 mm/year), which was corroborated with EIS analysis. Thus, corrosion products for the three steels exposed to natural acidic soil depended on different microstructures, percentage of pearlite and ferrite phases, in which different corrosion processes could occur. Therefore, the active sites for carbon steel surfaces could be passivated with corrosion products.

Practical implications

The paper identifies the any implication for the research.

Originality/value

Some anodic peaks could be caused by metallic dissolution and was recorded using high positive polarization (high field of perturbation). In addition, the inductive effects and diffusion process were interpreted at low frequency ranges using EIS. According to X-ray diffraction (XRD), acidic soil had Muscovite containing aluminum and iron phases that were able to generate hydrogen proton at the presence of water; it might be promoted at the beginning of deterioration on low carbon steels. Steel surface cleaning after removing corrosion products was considered to study the possible diffusion phenomena on damaged steel surfaces using EIS.

Details

Anti-Corrosion Methods and Materials, vol. 65 no. 3
Type: Research Article
ISSN: 0003-5599

Keywords

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Article

Grzegorz Lesiuk, Monika Maria Duda, José Correia, Abilio M.P. de Jesus and Rui Calçada

For nowadays construction purposes, it is necessary to define the life cycle of elements with defects. As steels 42CrMo4 and 41Cr4 are typical materials used for elements…

Abstract

Purpose

For nowadays construction purposes, it is necessary to define the life cycle of elements with defects. As steels 42CrMo4 and 41Cr4 are typical materials used for elements working under fatigue loading conditions, it is worth to know how they will behave after different heat treatment. Additionally, typical mechanical properties of material (hardness, tensile strength, etc.) are not defining material’s fatigue resistance. Therefore, it is worth to compare, except mechanical properties, microstructure of the samples after heat treatment as well. The paper aims to discuss these issues.

Design/methodology/approach

Samples of normalized 42CrMo4 (and 41Cr4) steel were heat treated under three different conditions. All heat treatments were designed in order to change microstructural properties of the material. Fatigue tests were carried out according to ASTM E647-15 standard using compact tension specimens. Later on, based on obtained results, coefficients C and m of Paris’ Law for all specimens were estimated. Similar procedure was performed for 41Cr4 steel after quenching and tempering in different temperatures.

Findings

The influence of heat treatment on the fatigue crack growth rates (42CrMo4, 41Cr4 steel) has been confirmed. The higher fatigue crack growth rates were observed for lower tempering temperatures.

Originality/value

This study is associated with influence of microstructural properties of the material on its’ fatigue fracture. The kinetic fatigue fracture diagrams have been constructed. For each type of material (and its heat treatment), the Paris law constants were determined.

Details

International Journal of Structural Integrity, vol. 9 no. 3
Type: Research Article
ISSN: 1757-9864

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Article

Sabah Khammass Hussein, Isam Tareq Abdullah and Abbas Khammas Hussein

The purpose of this paper is to join AA5052 to AISI 1006 steel sheets using the spot friction forming technique.

Abstract

Purpose

The purpose of this paper is to join AA5052 to AISI 1006 steel sheets using the spot friction forming technique.

Design/methodology/approach

A steel sheet was pre-holed with a diameter of 4.8 mm and pre-threaded with a single internal M6 thread. Lap joint configuration was used so that the aluminium specimen was put over steel. A rotating tool with a 10 mm diameter was used for the joining process. A Taguchi method was used to design three process parameters (plunging tool depth, rotating speed and preheating time), with three levels for each parameter. The effect of the process parameters on the joint shear strength was analysed. The macrostructure, microstructure and scanning electron microscope of the joint were investigated. The temperature distribution during the joining process was recorded.

Findings

The formed aluminium was extruded through the steel hole and penetrated through the thread slot. A mechanical interlock was achieved between the extruded aluminium and the steel. The plunging depth of the tool exhibited a significant effect on the joint shear strength. The joint efficiency increased gradually as the plunging depth increased. Two modes of failure were found shear and pull-out. The maximum temperature during the process reached 50 per cent of aluminium’s melting point.

Originality/value

For the first time, AA5052 was joined with AISI 1006 steel using a friction spot forming technique with an excellent joint efficiency.

Details

Multidiscipline Modeling in Materials and Structures, vol. 15 no. 6
Type: Research Article
ISSN: 1573-6105

Keywords

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