PENGARUH LINGKUNGAN KOROSIF TERHADAP LAJU KOROSI PADA PIPA MINYAK DAN GAS

Metal join with weld system use often. In weldment, have save cost, relatively fast work, more light, and variety construct. Weldment have weakness is appear of strain that big cause of differences microstructur on weld zone that metal strength down and cause residual stress, and crack\ud cause weldment.\ud The point of this experience worked is want to know influence of corrosive environment that give at corrosion rate in experiment specimen. And to know forms of exposure corrosion that happen from rate corrosion that result. Then to know micro corrosion that happen in specimen that weld (weld metal, heat affected zone, and base metal). Endly can be recommendation in coating process or corrosion resistant plant because this experiment is diagnose corrosion attack that susceptible in speciment.\ud In this experiment, have experiment methode, that each specimens group exposed in environment that digerences is NaCl 10%, H 2 SO 4 10%, and moist environtment, until hour 168.\ud Then test measure rate corrosion, then test micro corrosion dan macro corrosion that happen as influence environments its in speciment IRON API5L-X52 that weld.\ud The results, forms of corrosion that happen on specimen is in moist environment is uniform corrosion that thin (corrosion rate = 0), on expose environment NaCl 10% liquid is uniform corrosion that thick and pitting corrosion (corrosion rate = 2,036 Mpy), then on expose environment\ud H2 SO 4 10% is happen uniform corrosion and pitting corrosion that more thick (corrosion rate = 53,041 Mpy).\ud Form of micro corrosion that happen is selective leaching corrosion (in Base Metal, Weld Metal, and Heat Affected Zone). Zone that more corrosion attack is HAZ (10,797 %) as result thermal strain from weld thermal influence, then BM zone (8,978 %) result oxidation on exposure cause lost of shield elements and on corrosion resitant reduce, then WM zone (5,94 %) is influence of weld process, and because chemistry property that more better in shield of corrosion and compensation from residual stress

FeS corrosion products formation and hydrogen uptake in a sour environment for quenched & tempered steel

Surface corrosion product formation is one of the important factors affecting the corrosion rate and hydrogen uptake in a H2S environment. However, it is still unclear how the base material composition will affect the corrosion products that are generated, and consequently their impact on the corrosion rate. In this paper, corrosion product formation and the impact of the Mo content of the base material on the composition of the corrosion products and hydrogen absorption in a sour environment was investigated. The corrosion layer was composed of a double layered mackinawite (FeS1−x) structure, which was enriched with molybdenum and chromium. The layers were formed via two different mechanisms, i.e., the inner layer was created via a general oxide film formation corrosion mechanism, whereas the upper layer was formed by a precipitation mechanism. The presence of this double corrosion layer had a large influence on the amount of diffusible hydrogen in the materials. This amount decreased as a function of contact time with the H2S saturated solution, while the corrosion rate of the materials shows no significant reduction. Therefore, the corrosion products are assumed to act as a physical barrier against hydrogen uptake. Mo addition caused a decrease in the maximal amount of diffusible hydrogen

Quantitative measures of corrosion and prevention: application to corrosion in agriculture

The corrosion protection factor (c.p.f.) and the corrosion condition (c.c.) are simple instruments for the study and evaluation of the contribution and efficiency of several methods of corrosion prevention and control. The application of c.p.f. and c.c. to corrosion and prevention in agriculture in The Netherlands is considered in detail. Attention is paid to relations between c.p.f. and c.c., the corrosion costs, possible cost savings and the applied corrosion protection scheme on farms. It is shown that the c.p.f. and the c.c. are useful expedients in a preliminary analysis of corrosion costs and possible cost savings on farms in relation to the corrosion protection methods applied.\ud \ud It is concluded that significant cost savings on arable farms can be derived by improving corrosion protection. No statistically significant cost savings are possible by improving corrosion protection on the dairy farms considered in this research

Prevention of Corrosion Rate by Natural Inhibitor Papaya Leaf Extract

Corrosion is an event of damage or deterioration of a metal caused by reaction with the environtment. Corrosion process can be prevented by the addition of corrosion inhibitor. Papaya leaf extract is an organic material that could potentially be used as a corrosion inhibitor because it contains N-acetyl- glukosamida and amino acid. The purpose of this study is to determine the effects of brine concentration and surface area on the rate of corrosion of a metal plate that can be used as reference incorrosion control on metal plate. Determination of corrosion rate use weight loss methods, with medium marinade variation 3.5%, 5% and 6.5% salt water and a sample of the iron plates of different sizes. Each concentration of the medium contained four samples with different sizes of iron plates immersed for 30 days. The results showed the highest corrosion rate found on a metal plate without inhibitor with a value of 0.1331 mm/ year . The greater concentration of the medium the corrosion rate will be higher. The smaller surface area of iron plate the corrosion rate will be higher

The effect of fluorine-containing inhibitors of corrosion of copper in atmospheric conditions

The effect of fluorine-containing inhibitors of corrosion of copper in atmospheric conditions was studied by method of removing anodic polarization curves and corrosion of full-scale tests. The introduction of the inhibiting compositions as corrosion inhibitor of copper polyfluorinated amines leads to a decrease of the peak current of active dissolution of copper, which increases the corrosion resistance of copper wire rod during transportation in various climate conditions

Erosion-corrosion maps for carbon steel in crude oil/water slurries : impact angle and applied potential effects

In studies of erosion-corrosion, there have been few investigations into the effect of tribological issues, such as particle impact and impact angle, on erosion-corrosion of materials in oil field production. Despite this fact, erosion-corrosion in such environments is a major issue. In such conditions, it is important to define regimes where the effect of lubricating oil may modify the erosion properties of the materials. In this study, the combined effects of erosion and corrosion were investigated in three environments, crude oil (high API gravity 52), reservoir water, and 20% reservoir water with crude oil at a range of applied potentials. Erosion-corrosion maps were constructed, based on the results, showing the change in mechanisms and wastage rates as a function of impact angle and applied potential. Regimes of erosion-corrosion were described on such maps using such an approach. From this work, it can be seen that the corrosion contribution was increased with an increase in the percentage of reservoir water. In the crude oil environment, it was shown that the erosion contribution (Ke) was generally higher than that for corrosion suggesting that corrosion was reduced in crude oil. The results are interpreted in terms of the effect of the crude oil environment in modifying the impact properties of the particles therefore providing surprising resistance to particle impacts in nominally aggressive corrosion environments