Pipeline integrity management is evolving rapidly, driven by the need for more accurate, efficient, and comprehensive inspection technologies. Among these, Low-Field Magnetic Flux Leakage (LFM) has emerged as a critical technology for detecting subtle changes in material properties and identifying crack-like anomalies that traditional ILI technologies alone may miss.

LFM is an inline inspection technology that operates at reduced magnetization levels to detect subtle changes in steel microstructure, affecting permeability —especially around sharp features, hard spots, and strain-induced anomalies. Used in combination with traditional high-field MFL technologies, LFM’s sensitivity to metallurgical variations makes it a critical tool for anomaly prioritization and material verification in high-risk pipeline environments.

This paper introduces an advanced inline inspection magnetic based combination tool—and explores the unique value proposition of including LFM technology. Real-world examples demonstrate how LFM enhances detection, classification, and prioritization of pipeline threats, including mechanical damage and circumferential stress corrosion cracking (CSCC).

The paper presents both the LFM technology and relevant field evaluations carried out during the post-ILI dig programs demonstrating LFM value.

Key word: crack-like, gouging, hardness, hard spot, in-line inspection, low field magnetic flux leakage (LFM), mechanical damage, re-rounded dents, stress corrosion cracking (SCC)