The study of corrosion behaviour api 5l steel in sea water using immersion test method

Abstract

API 5L steel, a low carbon steel with a high alloy content, is often used as an underwater construction material or oil and gas pipeline. Banten has a wide sea area and has a long coastline where part of the coastline is used for petrochemical industries. There are three coast areas of Banten, namely Bayah Rangkasbitung, Anyer and Merak, that are used for petrochemical industries. Most of those industries use API 5L steel for underwater construction materials and pipes to channel seawater, chemical compounds, gas and oil. Whereas, seawater will greatly affect the lifetime of API 5L construction steel because it can cause corrosion. The purpose of this study is to analyze the corrosion characteristics of API 5L steel affected by the environment of seawater media and the temperature of seawater in accordance with its natural conditions. The samples of API 5L steel were immersed in seawater media with variation of immersion time of 5, 10, 15 Days and variation of immersion temperature of 20°C, 40°C, and 60°C. In this study, a series of tests were carried out, namely immersion test, weight loss test, and SEM test (Scanning Electron Microscopy). The highest corrosion rate on API 5L steel is 0.39 mmpy which belongs to Merak's seawater media in the immersion time of 15 Days and the temperature of 60°C, while the lowest corrosion rate on the API 5L steel is 0.013 mmpy which belongs to Bayah's seawater media with a time of immersion of 10 Days and a temperature of 20°C.