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Article
Publication date: 1 April 2006

Furen Xiao, Bo Liao, Guiying Qiao, Chunling Zhang, Yiyin Shan, Yong Zhong and Ke Yang

As an optimal microstructure of pipeline steels, acicular ferrite is widely found in steels used in oil and gas pipeline transportation because it possesses both high…

Abstract

As an optimal microstructure of pipeline steels, acicular ferrite is widely found in steels used in oil and gas pipeline transportation because it possesses both high strength and good toughness. In this paper, the microstructure of acicular ferrite and its continuous cooling transformation (CCT) diagrams of six steels with different carbon and alloy additions have been studied by using dilatometry, optical metallography. And the effects of different hot deformation processes on the CCT diagrams and microstructures have also been studied. Furthermore, the effects of microalloyed elements and hot deformation on continuous cooling transformation have been discussed. The results show that lower carbon content and alloy additions such as Mn, Nb, Ti, Mo, Ni and/or Cu in steels will promote the formation of acicular ferrite. The hot deformation promotes the acicular ferrite transformation and refines the microstructures of final products.

Details

Multidiscipline Modeling in Materials and Structures, vol. 2 no. 4
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 30 May 2019

Pramod Kumar and Amar Nath Sinha

The present research work aims to study the effect of average beam power (laser process parameters) on the overlapping factor, depth of penetration (DOP), weld bead width…

Abstract

Purpose

The present research work aims to study the effect of average beam power (laser process parameters) on the overlapping factor, depth of penetration (DOP), weld bead width, fusion zone and heat affected zone (HAZ) in laser welding of 304L and st37 steel. Back side and top surface morphology of the welded joints have also been studied for varying average beam power.

Design/methodology/approach

Laser welding of austenitic stainless steel (304L) and carbon steel (st37) was carried out using Nd:YAG laser integrated with ABB IRB 1410 robot in pulse mode. The selection of laser process parameters was based on the specification of available laser welding machine. Dissimilar laser welding of 304L and st37 carbon steel for full depth of penetration have been performed, with varying average beam power (225-510W) and constant welding speed (5mm/s) and pulse width (5ms).

Findings

Recrystallized coarse grains were observed adjacent to the fusion zone and nucleated grains were seen away from the fusion zone towards carbon steel. Overlapping factor and HAZ width st37 side increases with increase in average beam power whereas top weld bead width increases first, attains maximum value and then subsequently decreases. Bottom weld bead width increases with increase in average beam power. The mechanical properties namely microhardness and tensile strength of the welded joints have been investigated with varying average beam power.

Originality/value

In the recent development of the automobile, power generation and petrochemical industries the application of dissimilar laser welding of austenitic stainless steel (304L) and carbon steel (st37) are gaining importance. Very limited work have been reported in pulsed Nd:YAG dissimilar laser welding of austenitic stainless steel (304L) and carbon steel (st37) for investigating the effect of laser process parameters on weld bead geometry, microstructural characterization and mechanical properties of the welded joint.

Details

World Journal of Engineering, vol. 16 no. 3
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 11 June 2018

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

Article
Publication date: 15 June 2012

Ugur Caligulu, Mustafa Taskin, Haluk Kejanli and Ayhan Orhan

The purpose of this paper is to investigate interface characterization of CO2 laser welded AISI 304 austenitic stainless steel and AISI 1010 low carbon steel couple. Laser…

Abstract

Purpose

The purpose of this paper is to investigate interface characterization of CO2 laser welded AISI 304 austenitic stainless steel and AISI 1010 low carbon steel couple. Laser welding experiments were carried under argon and helium atmospheres at 2000, 2250 and 2500 W heat inputs and 200‐300 cm/min welding speeds.

Design/methodology/approach

The microstructures of the welded joints and the heat affected zones (HAZ) were examined by optical microscopy, SEM, EDS and X‐Ray analysis. The tensile strength of the welded joints was measured.

Findings

The result of this study indicated that the width of welding zone and HAZ became much thinner depending on the increased welding speed. On the other hand, this width widened depending on the increased heat input. Tensile strength values also confirmed this result. The best properties were observed at the specimens welded under helium atmosphere, at 2500 W heat input and at 200 cm/min welding speed.

Originality/value

There are many reports which deal with the shape and solidification structure of the fusion zone of laser beam welds in relation to different laser parameters. However, the effect of all influencing factors of laser welding has up to now not been extensively researched. Much work is required for understanding the combined effect of laser parameters on the shape and microstructure of the fusion zone. This paper, therefore, is concerned with laser power, welding speed, defocusing distance and type of shielding gas and their effects on the fusion zone shape and final solidification structure of some stainless steels.

Details

Industrial Lubrication and Tribology, vol. 64 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 August 1986

Yao‐Nan Chang

Sulphur dew‐point corrosion occurs in the low temperature parts (<200°C) of heavy oil fired boilers such as economisers, air preheaters, and chimneys. Its mechanis…

Abstract

Sulphur dew‐point corrosion occurs in the low temperature parts (<200°C) of heavy oil fired boilers such as economisers, air preheaters, and chimneys. Its mechanis proposed by Kowaka et al suggests that corrosion proceeds in three steps as shown in Figure 1. The first step is corrosion in sulphuric acid at low temperature and concentration, the second step is in sulphuric acid at high temperature and concentration, and the third step is in boiler deposits containing sufficient amounts of unburned carbon and sulphuric acid at high temperature and concentration. The overall corrosion rate was suggested to be mainly determined by the third step due to its much longer time compared with those of first and second steps. Kowaka et al also proposed a test method in the mixture of concentrated sulphuric acid and activated carbon for developing sulphur dew‐point corrosion resistant low alloy steels, and the results were well correlated with the actual field tests. This report extensively covers the corrosion behaviours of austenitic stainless steels which might have practical applications in high temperature environments.

Details

Anti-Corrosion Methods and Materials, vol. 33 no. 8
Type: Research Article
ISSN: 0003-5599

Article
Publication date: 7 September 2015

Solhan Yahya, Norinsan Kamil Othman, Abdul Razak Daud, Azman Jalar and Roslina Ismail

– This paper aims to investigate the influence of temperature and lignin concentration on the inhibition of carbon steel corrosion in 1 M HCl.

Abstract

Purpose

This paper aims to investigate the influence of temperature and lignin concentration on the inhibition of carbon steel corrosion in 1 M HCl.

Design/methodology/approach

Weight loss corrosion tests were performed at different temperatures in the range of 30-70°C (303-343 K).

Findings

It was found that the corrosion inhibition efficiency (IE) of lignin on the carbon steel decreased when the temperature was increased from 60 to 70°C. However, at lower temperatures ranging from 30 to 50°C, the IE improved, due to occurrence of lignin adsorption on the surface of metal specimens. The IE was higher with increasing lignin concentration, thus reducing the weight loss of the carbon steel. The adsorption phenomenon involved exothermic processes because the value of enthalpy of adsorption (ΔH°ads) < 0 and Gibbs free energy of adsorption (ΔG°ads) were less negative with increase in temperature. The entropy of adsorption (ΔS°ads) had negative values, representing the decrease in disorder of adsorption. The adsorption of lignin on the carbon steel surface in 1 M HCl was comprehensive, as deduced from kinetic and thermodynamic parameters. However, physisorption was the major contributor in the inhibition mechanism. The inhibitive features of carbon steel surfaces showed less damage once the steel was treated in lignin, as evident from macroscopy images.

Practical implications

The use of lignin as an acid corrosion inhibitor at high temperature is practical in metal surface treatment process.

Social implications

The use of organic compounds gives an advantage to the environment, universal health and save cost, as the compounds can be found in nature.

Originality/value

Lignin can act as a flexible corrosion inhibitor within the temperature range of 30-70°C in 1 M HCl because it exhibits comprehensive adsorption (i.e. a combination of both physisorption and chemisorption) at specific concentrations.

Details

Anti-Corrosion Methods and Materials, vol. 62 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 28 June 2019

Subramanian Chitra, Ill-Min Chung, Seung-Hyun Kim and Mayakrishnan Prabakaran

The study aims to find new anticorrosive components from a plant source, namely, Pachysandra terminalis Sieb. et Zucc. (P. terminalis), a traditional medicinal shrub…

Abstract

Purpose

The study aims to find new anticorrosive components from a plant source, namely, Pachysandra terminalis Sieb. et Zucc. (P. terminalis), a traditional medicinal shrub predominantly used by Tujia people.

Design/methodology/approach

Because phenolic components from plants are known for its numerous values in several fields, the corrosion inhibitive ability of P. terminalis extract was analyzed by electrochemical studies (polarization, electrochemical impedance spectroscopy) and surface examination (by scanning electron microscopy [SEM], energy-dispersive X-ray spectroscopy [EDX] and atomic force microscopy [AFM]).

Findings

The examination of total phenolic content (TPC), total flavonoids content (TFC) and individual phenols (UHPLC) showed the presence of 85.21 mg/g (TPC), 25.38 mg/g (TFC), protocatechuic acid (62.10 µg/g), gentisic acid (60.21µg/g), rutin (50.12 µg/g), kaempferol (46.58 µg/g) and p-Coumaric acid (42.35µg/g) . The polarization study shows that the maximum shift is (16 mV), imposing a mixed mode of inhibition, dominantly anodic. The surface morphology studies by SEM, EDX and AFM confirmed the adsorption of phytochemical components on the low carbon steel surface blocking the active sites.

Originality/value

The study unveils the inhibitive nature of P. terminalis, preventing aggressive attack by 0.5 M HCl on low carbon steel. This also exhibits few phenols present in methanolic leaf extract which may be the role player of corrosion inhibition.

Details

Pigment & Resin Technology, vol. 48 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 31 December 2015

Fortunate Moyo and Josias Willem Van der Merwe

– This paper aims to determine the effect of water on the SCC of low carbon steel in ethanol in the absence of supporting salts.

Abstract

Purpose

This paper aims to determine the effect of water on the SCC of low carbon steel in ethanol in the absence of supporting salts.

Design/methodology/approach

Slow strain rate test was done to determine SCC susceptibility. Fractured samples were examined using optical microscopy and scanning electron microscopy.

Findings

While the results demonstrated that water alone had no effect on the SCC susceptibility of low carbon steel in ethanol, 2.5 volume per cent moisture gave indications of cracking tendencies.

Originality/value

With South Africa and the world over turning to bioethanol and ethanol blended fuels as a means of reducing its carbon foot print, there are concerns over the corrosive nature of ethanol on common engineering metals like low carbon steels.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 1
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 6 September 2013

Bruno Souza Fernandes, Kleber Gustavo da Silva Souza, Idalina Vieira Aoki and Franco Dani Rico Amado

The application of coatings on metal substrates can provide an increase in corrosion resistance in the environment where the material is employed. The use of silane causes…

Abstract

Purpose

The application of coatings on metal substrates can provide an increase in corrosion resistance in the environment where the material is employed. The use of silane causes low environmental impact and may represent an alternative to replace chromates and phosphates applied as a pretreatment prior to surface painting. The objective of this study was to evaluate experimental parameters for the investigation of the formation of a vinyltrimethoxysilane (VTMOS) monolayer on 1010 carbon steel applying electrochemical techniques.

Design/methodology/approach

A total of 24 types of coated samples were obtained, following three 23 factorial design of experiments (DOE), and one uncoated. The VTMOS monolayer was formed by hand dip process, followed by curing in a stove, using substrates of sanded, pickled and degreased 1010 carbon steel and hydrolyzed silane.

Findings

The results of coated samples were satisfactory as compared to those of uncoated carbon steel, as the former were better protected against corrosion.

Originality/value

This paper shows an evaluation of experimental parameters that influence the formation of a film of silane VTMOS on 1010 carbon steel by means of electrochemical techniques. The results indicated that the silane monolayer VTMOS promotes enhanced properties that prevent corrosion of 1010 carbon steel and the method of film formation directly influences the properties of such protection.

Details

Anti-Corrosion Methods and Materials, vol. 60 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 4 March 2014

De-Xing Peng and Yuan Kang

Thick composite claddings of carbides on a metal matrix are ideal for use in components that are subject to severe abrasive wear. It is a metal matrix composite (MMC) that…

Abstract

Purpose

Thick composite claddings of carbides on a metal matrix are ideal for use in components that are subject to severe abrasive wear. It is a metal matrix composite (MMC) that is reinforced by an appropriate ceramic phase and nano-diamond cladding to reduce friction and to protect the opposing surface. The paper aims to discuss these issues.

Design/methodology/approach

This work evaluated the wear performance of carbon steel cladded with TiC/nano-diamond powders by gas tungsten arc welding (GTAW) method. The microstructures, chemical compositions, and wear characteristics of cladded surfaces were analyzed by scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX).

Findings

The cladding was uniform, continuous, and almost defect-free, and particles were evenly distributed throughout the cladding layer. The results of wear test indicate that the friction coefficient of the TiC+1.5% nano-diamond cladding is lower than that of AISI 1020 carbon steel. Thus, the wear scar area of the TiC+1.5% nano-diamond cladding is only one-tenth of the AISI 1020 carbon steel.

Originality/value

The experiments in this study confirm that, by reducing friction and anti-wear, the cladding layer prepared using the proposed methods can prolong machinery operating life.

Details

Industrial Lubrication and Tribology, vol. 66 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

1 – 10 of over 6000