Corrosion Test Data Research Articles

AL 2003TMLDSS (UNS S32003) as a substitute for type 316L

Lean Duplex Stainless Steels (LDSS) have been used or are being considered as substitutes for several well-established materials, in various applications. This paper concentrates on AL 2003 TM LDSS (UNS S32003) as a substitute for Type 316L stainless steel. Comparative data are presented including corrosion test data in various media, mechanical test data, and design strength limits. Examples of applications are given.

A field based study of ferrous metal corrosion in groundwater

There is an increased emphasis on adopting explicit management strategies to ensure the effective use of water wells. This can be achieved through identifying the operational and maintenance needs of water wells and associated infrastructure. The types of material used for this infrastructure will impact upon the life of these assets and their maintenance needs. In groundwater environments there is often little available corrosion rate data from historical records of operating wells upon which to make choices about material selection. Under these conditions it is necessary to rely on corrosion test data to inform design choices. A long term field based immersion test using corrosion coupons was undertaken at 24 sites across Australia. The general corrosion rates of mild steel after 9 months were found to range from 0.018 to 0.624 mm per year while stainless steel was found to have minimal corrosion under the same conditions. Galvanised steel was found to offer minimal protection compared with mild steel when the pH was below 7.

Effect of coating time and heat treatment on structures and corrosion characteristics of electroless Ni–P alloy deposits

Mild steel was electroless coated with nickel–phosphorus alloy from a bath containing sodium hypophosphite and glycin–citrate complexing agents. The effect of coating time on phosphorus content, thickness, structure and hardness of the deposits were analyzed. Corrosion parameters such as current density, corrosion potential and corrosion rate were obtained from tafel polarization curves and immersion corrosion tests in aerated 3.5% NaCl solution. The X-ray diffraction (XRD) patterns, anodic polarization curves and scanning electron microscopy (SEM) of heat-treated specimens obtained in various coating times were also studied. The X-ray diffraction patterns showed that by changing the coating times, amorphous or crystalline structure could be obtained. The coatings containing 11.1–13.1% phosphorous were amorphous, and showed better corrosion resistance than microcrystalline structure. The heat-treated specimens obtained in different coating time had more hardness and corrosion resistance than unheated samples. According to the polarization studies and scanning electron microscopy images, the heat-treated samples with 10.8 and 10.1% phosphorous show the intergranular corrosion, while the coatings with 11.7 and 12.2% of phosphorus have the least corrosion rate. Immersion corrosion test data at the 4-month interval had good agreement with electrochemical polarization results.

実炉試験データの回帰分析による廃棄物発電過熱器材料の腐食速度予測

実炉試験データの回帰分析による廃棄物発電過熱器材料の腐食速度予測

The Hg-Si system (mercury-silicon)

was certainly below 1023 at.% Si. [1967May] had performed x-ray diffraction analysis of Si powder isolated from heteroEquilibrium Diagram geneous Si amalgam prepared at 450–500 8C and observed that the x-ray patterns showed complete agreement with those No quantitative experimental data concerning the Si-Hg obtained from pure solid Si thus pointing that the solid solusystem have been found. The limited information that is bility of Hg in (Si) is below the detection limit of the method available indicates a simple eutectic with very small terminal used. Further experiments related to this feature were persolid solubilities, and a very low solubility of Si in liquid formed at higher temperatures. [1963Zib] and [1969Leb] Hg is likely. The eutectic composition is likely to be very estimated Hg content of order of 1027 at.% from electric near the melting point of Hg. The provisional Hg-Si phase resistance measurements when Si was saturated with Hg diagram at 0.101 MPa was presented by [1965Pad]. vapors either at 1100 8C for 72 h or at 1250 8C for 30 h, respectively. [1975Ari] investigated influence of P (phosphorus) on apparent solubility of Hg in Si at 1200 8C by measLiquidus urements of Hall coefficient and activation analysis. Hg concentration was found to be practically independent when [1864Win] observed no interaction between Si and Hg at P content in Si was below 1.2 3 1026 at.%. However, the 20 or 300 8C. Electroreduction of SiF4 from ethanol solution solubility level measured by means of activation analysis on a Hg electrode produced heterogenous amalgams was 100 times higher than from the Hall coefficient. Further [1931Kre]. Corrosive resistance studies of Si exposed to Hg extended measurements of the solubility were performed in at and above its boiling point were reported by [1950Eps], the same laboratory. [1993Rak] selected the method of activa[1963Wil] and [1965Nej] with no indication of significant tion analysis of consecutive thin Si layers as the more reliable solubility. [1956Str] stated that the solubility of Si in Hg technique. The experiments were carried out in the temperawas below a detection limit of 7 3 1023 at.% Si at room ture range 1000–1250 8C changing P concentration between temperature. [1989Gum], with a regular solution approxima3.8 3 1028 and 3.8 3 1025 at.%. The values of the Hg tion and with the cellular model of Miedema et al. [1983Nie], solubility determined changed very slightly with P content calculated respective solubilities of 4 3 10211 and 2 3 10214 (see Table 1) and it seems rational (after suggestions of the at.% Si at 25 8C. authors) to assume that the solubility data at the lowest P [1986Gum] used the corrosion test data of [1965Nej] to concentration (3.8 3 1028 at.% P) may be treated as the predict a solubility of ,1025 at.% Si at 482 8C. An enthalpy solubilities of Hg in pure Si. Taking into account the increase of solution for Si (in liquid Hg) at infinite dilution was of the Hg solubility with temperature, [1993Rak] estimated estimated as 75 kJ/mol Si by [1983Nie] with the Miedema enthalpy of dissolution of gaseous Hg in solid Si at about 150 model. Available data support the conclusions of [MassalkJ/mol Hg. It seems that the Hg displays retrogate solubility ski2]: solubility value of 2 3 10225 at.% Si at 25 8C calculated dependence on temperature with its maximum at around 1300 by [1977Koz] seems rather low. 8C by similarity to other elements dissolved in solid Si [1960Tru].

環境評価点を用いた銀の大気腐食に対する寿命評価

Atmospheric corrosion test data for silver were analyzed which were obtained in various sites in Japan. A new corrosion life assessment method was developed. The method took into account the interactive effect of multiple environmental factors on the decrease in metal weight during corrosion tests. The simple and practically useful formula for corrosion life prediction was established in terms of environmental indices and the formula could enable the evaluation of time dependent loss of metal weight based on the environmental assessment.

Electrochemical investigation of the corrosion resistance of a protective tantalum electroplate

The data of corrosion tests of tantalum coatings with various electrochemical techniques in 1 M (9.5), 30, and 38% sulfuric acid at room and heightened temperature are considered. Independently of the substrate (carbon or stainless steel), the electroplated tantalum reliably protect it in a corrosive environment.

Control of corrosion in oil and gas production tubing

Controlling corrosion in production tubing is essential for maintaining production and for preventing loss of well control. Materials for use downhole have to meet criteria for corrosion resistance and also mechanical requirements. The potential corrosion rate can be estimated and the risks of sulphide stress corrosion cracking assessed on the basis of the anticipated environmental conditions and flow regime. Material options for tubing can then be considered on the basis of published corrosion test data and also field experience. Candidate materials may be tested under the precise field conditions expected in order to ensure that overconservative choices are not made. Corrosion inhibitors, coated carbon steel, and fibre reinforced plastic tubing have temperature, flow regime, and mechanical limitations. Specific corrosion resistant alloys (CRAs) have environmental limitations with respect to temperature, hydrogen sulphide, and chloride content. Details of field experience with all of these material options are given. There exists a large amount of experience with CRAs for downhole applications. Correctly selected CRAs have a good track record of service, even for hostile, H2 S containing conditions. There are a few limited examples of CRA clad tubing. This product may be one that needs re-evaluation as it offers potential for economic use of costly but effective CRAs.

Determination of the corrosion wear allowance to the wall thickness of vessels and pipelines

This article examines the kinetics of the corrosion rate and of the stresses in a thin-wall cylinder which is subjected to the simultaneous effect of the torque, axial force, and internal and external pressures of the corrosion medium. The corrosion wear allowance of the walls of vessels and pipelines is expressed by means of the product of the standardized service life and the corrosion rate. The corrosion rate is assumed to be constant with time and is determined mainly from the data of corrosion tests carried out on specimens without loading. The derived equations for calculating the endurance of the vessels in the conditions of corrosion and mechanical failure show that the endurance of the vessel depends on the type of vessel, the loading mode, and the initial strength of the metal. It is necessary to take into account the effect of the stress state on the corrosion rate in the proposed method of determining the design wall thickness of the vessels and the corrosion wear allowance.

The cyclic nature of corrosion of zircaloy-4 in 633 K water

Optical and electron microscopic examination of cathodic-vacuum-etched cross-sections of corrosion films on zircaloy-4, produced during 108.86-Ms (1260-day) tests in 633 K water, revealed alternate dense columnar-grained layers and narrow porous layers lying parallel to the metal surface, but no through-thickness openings except at corners. Correlation of layer structures with corrosion test data indicates that the corrosion process consists of repeated cycles of cube-root kinetics. During each cycle, a new protective layer grows at the metal-oxide interface. At a critical thickness, the layer suddenly becomes non-protective, causing transition to the initially rapid corrosion rate of a new cycle. Porous layers mark the location of the interface at the time of each transition. Variations in post-transition corrosion rates are related to variations in the cube-root rate constant, average film density, and critical layer thickness. A stress-controlled corrosion mechanism is proposed.

Fundamentals of Corrosion and Corrosion Control for Residential Subsurface Transformers

The severe and varied environment of residential sub- surface transformers (RST) requires different materials and means of corrosion protection from the pole-top transformer. The galvanic characteristics of mild steel and stainless steels are presented along with corrosion test data on mild steel and ferritic stainless steels in RST environments. Also, field test data on corrosion and cathodic protection of transformers in typical RST installations are given.

The Establishment of A Q Rating Factor for Decorative Chromium Plate by X-Ray Fluorescence

AbstractProcedures and methods employed to develop anX-ray emission spectrometer technique for determining the quality of decorative chromium plate are presented. Individual plate quality factors and their significance are discussed: 1.Plate thickness2.Plate density3.Plate corrosion resistanceGeometric instrumentation changes to the General Electric XRD-5S spectrometer are detailed. These alterations have made it possible to take more complete advantage of the nondestructive nature of the fluorescent method, and have also yielded an increase in useful radiation intensity of 50%.The unsuccessful attempts to employ commercially plated Hull-cell-type test panels as “standards” are described, along with the satisfactory application of fabricated standards of vacuum vapor-deposited high-purity chromium, laminated to spectrographically pure nickel foils. The merits and limitations of the resultant “absolute purity — absolute density” standard curve are shown and are related to other measurement techniques and accelerated corrosion test data.

Correlation of the Results Obtained With Corrosion Inhibitors in the Laboratory and in the Field★

Abstract One of the responsibilities of the oil field corrosion engineer is to correlate laboratory and field test data. With this in mind the principle factors which influence internal corrosion in oil wells (factors which the corrosion engineer must consider) are reviewed here. A laboratory corrosion test method is discussed. Corrosion rate data obtained in the laboratory with three West Texas crude oil and brine systems and the corrosion inhibition obtained in these systems with two organic inhibitors are analyzed and compared. Field corrosion test data for the same three fields are presented. The correlation of laboratory and field test data is discussed in relation to the many variables encountered. It is concluded that the evaluation of the use of inhibitors in some cases may be difficult and may require considerable experience and judgment on the part of the corrosion engineer.