What is Porosity in Welding? Porosity is a type of weld-defect that specifically refers to the entrapment of external gases within a welded joint, most commonly oxygen. As the molten metal of a weld cools and solidifies, the external gas will either enter in a weld and become trapped internally thus creating cavities or it will be forced out of the weld leaving behind visible holes, gas-mark, or pits, or crater pipe on the surface of the weld. The presence of porosity can severely affect the overall integrity and strength of the weld meaning, that a porosity-contaminated weld will nearly always be … Continue reading Weld porosity, herringbone, wormhole, crater pipe

High Temperature Hydrogen Attack (HTHA) is one of the Damage Mechanisms that affects Hydrogen service Steel equipment which exists mainly at Refineries, Methanol and Ammonia plants . HTHA occurs at elevated temperatures with Hydrogen service. HTHA vulnerability for equipment depends on three major factors, namely, Metallurgy type (composition), operating temperature and Hydrogen partial pressure. HTHA is mostly found in equipment made from Carbon Steel as well as Carbon ½ Mo. Damage mechanism· HTHA can occur in hydrogen atmosphere at elevated temperatures (at least 400 °F or 204 °C) and a hydrogen partial pressure of pH2 > 3.45 bar.· Thermal dissociation … Continue reading Nelson curves and HTHA damage

Tempering of steels Tempering is an ancient metallurgical heat treatment technique by this procedure steels are heated below the eutectoid transformation temperature (A1 line) and cooling in the air. Rapid cooling is taking part in the specimen. At 400°F (205°C) epsilon martensite converts into carbide to orthorhombic cementite, low carbon martensite into BCC ferrite, and the retained austenite into lower bainite respectively. At 800°F (427°C) continuous formation of cementite is materialized immaculately. Tempering is necessitated after quenching or hardening to decrease some of the extents of hardness and to undertake better toughness by lessening the hardness of the steel. By … Continue reading What is steel tempering?

Proactive Maintenance in Rotating Asset Whilst the Predictive Maintenance (PdM) are planned based on an assessment. The assessments are usually implemented by accumulating baseline data and tracking trends via measuring the operation condition of the asset. The condition monitoring includes, but not limited to: Preventive Maintenance (PM) in Rotating Asset is usually planned based on the manufacturing maintenance book and the practical lesson learn data. ·       Vibration Monitoring·       Temperature Monitoring·       Lubrication Monitoring·       Process Monitoring·       Visual Monitoring The goal of the proactive maintenance in the rotating equipment asset is:·       To reduce unnecessary maintenance plan based on fit to purpose assessment·       To minimize the overhaul and breakdown likelihood development … Continue reading How to maintenance rotating equipment?

What is importance of Lubricant oil analysis on regular basis? Which are the parameters need to be analyzed? Routine Lubricant oil analysis is the key to a successful maintenance program. Oil testing provides essential information to determine the condition of your equipment. Baseline of normal wear can be established during the first few months of a program. As the program matures, only routinely scheduled testing can indicate when abnormal wear or contamination is occurring. The basic parameters and their significances are: Kinematic Viscosity-Increase may be due to high soot or insoluble contents, water contaminations, admixture with high viscosity fuel or … Continue reading Lubricant oils in engine

What are Additives?What are the roles of Additives in lubricating oils? Additives are substances formulated for improvement of the anti-friction, chemical and physical properties of base oils (mineral, synthetic, vegetable or animal), which results in enhancing the lubricant performance and extending the equipment life. Combination of different additives and their quantities are determined by the lubricant type (Engine oils, Gear oils, Hydraulic oils, cutting fluids, Way lubricants, compressor oils etc.) and the specific operating conditions (temperature, loads, machine parts materials, environment).Amount of additives may reach 30%. Different types of Additives are , 1-Friction modifiers-Friction modifiers reduce coefficient of friction, resulting … Continue reading What are additives?

What the significance of adhesion testing in paints and coatings?What are the different test methods for adhesion testing? Good adhesion is critical to the integrity and long-term performance of a coating. Poor adhesion can result in failure, corrosion and contamination of surfaces or contents. So, it’s vitally important to undertake adhesion testing to assess the quality of the attachment between the dry paint film (coating) and its substrate. Test Methods: Pull-off Test — This procedure is accomplished by sticking a loading fixture perpendicularly to the coating, then slowly increasing tensile load until either the fixture and adhesive layers are removed or … Continue reading What is adhesion test