scholarly journals Corrosion Mechanism of MgO–CMA–C Ladle Brick with High Service Life

2019 ◽  
Vol 91 (2) ◽  
pp. 1900436
Author(s):  
Christoph Wöhrmeyer ◽  
Simon Gao ◽  
Zhenfeng Ping ◽  
Christopher Parr ◽  
Christos G. Aneziris ◽  
...  
Keyword(s):  
Service Life ◽  
Corrosion Mechanism ◽  
Ladle Brick ◽  
High Service

scholarly journals Corrosion Mechanism of A Density-Reduced Steel Ladle Lining Containing Porous Spinel-Calcium Aluminate Aggregates

Ceramics ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 155-170 ◽  
Author(s):  
Christoph Wöhrmeyer ◽  
Jianying Gao ◽  
Christopher Parr ◽  
Magali Szepizdyn ◽  
Rose-Marie Mineau ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Service Life ◽  
Calcium Aluminate ◽  
Porous Matrix ◽  
Thermomechanical Properties ◽  
Ladle Lining ◽  
Magnesium Aluminate ◽  
Steel Ladle ◽  
Corrosion Mechanism ◽  
Calcium Magnesium

Refractory monolithics for steel ladle linings are typically products with low porosities and high bulk densities. They achieve high temperature, penetration, and corrosion resistance. Despite the high density of these products, which is due to the low porosity of the aggregates, their matrices still exhibit a high amount of pores. Since calcium magnesium aluminate (CMA) has already proven its resistance to penetration and corrosion as a binder in the matrix, this paper investigated if alumina spinel refractories containing microporous calcium magnesium aluminate aggregates can withstand conditions that occur in a steel ladle wall. The objective was to reduce the castable density with the advantage of a lower material requirement for a ladle lining and reduced heat and energy losses. This was achieved by replacing dense alumina aggregates by up to 38% of porous CMA aggregates (grains with 30 vol% porosity), which resulted in a bulk density reduction from 3.1 g/cm3 for the dense alumina castable to 2.8 g/cm3 for the 38% CMA aggregates containing castable. However, the despite the higher porosity, penetration, and corrosion resistance and thermomechanical properties were not impacted negatively for a model alumina spinel castable. A postmortem investigation was conducted on a newly developed dry-gunning mix that was installed in a steel ladle wall on top of a slag penetrated castable and that achieved a service life of 31 heats versus only 18 heats for the reference mix that contained dense alumina and spinel aggregates. This new repair mix contained the newly designed porous CMA aggregates, which in this case partly replaced the dense alumina and spinel aggregates. These porous aggregates consisted of magnesium aluminate and calcium aluminate micro-crystals. The postmortem study revealed two important phenomena that can explain the improved performance: at the hot face in contact with steel and slag, a thin densified zone was observed that blocked the slag penetration into the porous matrix and the porous aggregates. Iron oxides were almost completely blocked from penetration, and only some manganese oxide was observed in the penetrated zone together with some silica and lime from the slag. Clusters of calcium aluminate (CA6) and magnesium aluminate (MA) spinel build the refractory back-bone on the hot side of the material and gussets filled with mostly glassy calcium aluminum silicates close to the hot face and gehlenite further inside the penetrated zone. Alumina grains had a reaction rim consisting of CA2 or CA6 and a very intimate connection to the surrounding matrix unlike the CMA-free mix that showed micro cracks around the alumina grains. At the colder side, the gunning mix with CMA aggregates showed a very good connection to the substrate, supported by a hercynite formation in the gunning mix resulting from a cross-reaction with remains of iron oxide on the CMA containing repair mix. Furthermore, macroscopic observations of a CMA aggregate containing alumina magnesia castable in the metal zone of a steel ladle revealed that macro cracks developed only very slowly, which resulted in a superior service life.

scholarly journals Corrosion Measurements in Reinforced Fly Ash Concrete Containing Steel Fibres Using Strain Gauge Technique

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
V. M. Sounthararajan ◽  
A. Sivakumar
Keyword(s):  
Reinforced Concrete ◽  
Fly Ash ◽  
Service Life ◽  
Strain Gauge ◽  
Volume Fraction ◽  
Experimental Studies ◽  
Corrosion Process ◽  
Corrosion Mechanism ◽  
Electrical Measurements ◽  
Steel Fibres

Corrosion of steel bars in concrete is a serious problem leading to phenomenal volume expansion and thereby leading to cover concrete spalling. It is well known that the reinforced concrete structures subjected to chloride attack during its service life cause these detrimental effects. The early detection of this damage potential can extend the service life of concrete. This study reports the comprehensive experimental studies conducted on the identification of corrosion mechanism in different types of reinforced concrete containing class-F fly ash and hooked steel fibres. Fly ash replaced concrete mixes were prepared with 25% and 50% fly ash containing steel fibres at 0.5%, 1.0%, and 1.5% by volume fraction. Corrosion process was investigated in an embedded steel bar (8 mm diameter) reinforced in concrete by passing an impressed current in sodium chloride solution. Strain gauge attached to the rebars was monitored for electrical measurements using strain conditioner. Strain gauge readings observed during the corrosion process exhibited the volume changes of the reinforcement embedded inside the concrete. The corrosion potential of different steel fibre reinforced concrete mixes with fly ash addition showed higher resistance towards the corrosion initiation.

Investigation of service life and corrosion mechanism of tubing in production well on polymer flooding

2020 ◽  
Vol 55 (8) ◽  
pp. 634-644 ◽  
Author(s):  
Dezhi Zeng ◽  
Zhiming Yu ◽  
Baojun Dong ◽  
Haixin Zhang ◽  
Huiyong Yu ◽  
...  
Keyword(s):  
Service Life ◽  
Polymer Flooding ◽  
Corrosion Mechanism ◽  
Production Well

A Possible Basis for Nondestructive Characterization of Ropes of Nylon 6

1997 ◽  
Vol 503 ◽  
Author(s):  
H. Jiang ◽  
M. K. Davis ◽  
R. K. Eby ◽  
P. Arsenovic
Keyword(s):  
Tensile Strength ◽  
Service Life ◽  
Fiber Diameter ◽  
Structural Parameters ◽  
Crystal Form ◽  
Nylon 6 ◽  
Remaining Service Life ◽  
Nondestructive Characterization ◽  
Fractional Content

ABSTRACTPhysical properties and structural parameters have been measured for ropes of nylon 6 as a function of the number of use operations. The fractional content of the α crystal form, sound velocity, birefringence, tensile strength and length all increase systematically and significantly with increasing the number of use operations. The fractional content of the γ crystal form and fiber diameter decrease with use. These trends indicate that the measurement of such properties and structural parameters, especially the length, provide a possible basis for establishing a reliable, rapid, and convenient nondestructive characterization method to predict the remaining service life of nylon 6 ropes.

Development of Approaches to Solving the Problems of Ensuring Strength, Service Life and Safety of the Trunk Oil Transportation

2019 ◽  
pp. 7-14 ◽  
Author(s):  
N.A. Makhutov ◽  
◽  
Ya.M. Fridlyand ◽  
A.A. Raspopov ◽  
M.V. Lisanov ◽  
...  
Keyword(s):  
Service Life ◽  
Oil Transportation

CARBONATION INDUCED CORROSION ANALYSIS OF REINFORCED CONCRETE STRUCTURES BASED ON FULL PROBABILISTIC APPROACH – AN INDONESIAN CASE STUDY

2018 ◽  
Vol 4 (1) ◽  
pp. 165
Author(s):  
Herry Prabowo ◽  
Mochamad Hilmy
Keyword(s):  
Service Life ◽  
Probabilistic Approach ◽  
Concrete Structures ◽  
Weather Condition ◽  
Analysis Data ◽  
National Standard ◽  
Concrete Carbonation ◽  
Durability Design ◽  
Starting Point ◽  
Real Performance

The assessment of the service life of concrete structures using the durability design approach is widely accepted nowadays. It is really encouraged that a simulation model can resemble the real performance of concrete during the service life. This paper investigates the concrete carbonation through probabilistic analysis. Data regarding Indonesian construction practice were taken from Indonesian National Standard (SNI). Meanwhile, data related to Indonesian weather condition for instance humidity and temperature are taken from local Meteorological, Climatological, and Geophysical Agency from 2004 until 2016. Hopefully the results can be a starting point for durability of concrete research in Indonesia.

Functional and operational risk as a criterion for assessing the durability of an autonomous energy system

2019 ◽  
Vol 12 (1) ◽  
pp. 56-62 ◽  
Author(s):  
A. O. Nedosekin ◽  
A. V. Smirnov ◽  
D. P. Makarenko ◽  
Z. I. Abdoulaeva
Keyword(s):  
Service Life ◽  
Structural Reliability ◽  
Residual Life ◽  
Fuzzy Random Variable ◽  
Operational Risk ◽  
Energy System ◽  
Technical System ◽  
Residual Service Life ◽  
Technological Parameters ◽  
Residual Service

The article presents new models and methods for estimating the residual service life of an autonomous energy system, using the functional operational risk criterion (FOR). The purpose of the article is to demonstrate a new method of durability evaluation using the fuzzy logic and soft computing framework. Durability in the article is understood as a complex property directly adjacent to the complex property of system resilience, as understood in the Western practice of assessing and ensuring the reliability of technical systems. Due to the lack of reliable homogeneous statistics on system equipment failures and recoveries, triangular fuzzy estimates of failure and recovery intensities are used as fuzzy functions of time based on incomplete data and expert estimates. The FOR in the model is the possibility for the system availability ratio to be below the standard level. An example of the evaluation of the FOR and the residual service life of a redundant cold supply system of a special facility is considered. The transition from the paradigm of structural reliability to the paradigm of functional reliability based on the continuous degradation of the technological parameters of an autonomous energy system is considered. In this case, the FOR can no longer be evaluated by the criterion of a sudden failure, nor is it possible to build a Markov’s chain on discrete states of the technical system. Assuming this, it is appropriate to predict the defi ning functional parameters of a technical system as fuzzy functions of a general form and to estimate the residual service life of the technical system as a fuzzy random variable. Then the FOR is estimated as the possibility for the residual life of the technical system to be below its warranty period, as determined by the supplier of the equipment.

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