Session: 05-02-4: Experimental Testing - Session four

Paper Number: 134591

134591 - Solving the Complexity of Hard Spots by Understanding Their Origin 

Abstract: 

The level of industry knowledge concerning hardness anomalies has increased exponentially over the past years. It is now well understood that hardness anomalies are localized changes in microstructure that can take many physical forms, depending on a combination of variables such as steel chemistry, steel manufacturing processes. They can have a range of microstructures, different morphologies in terms of shape and different hardness profiles, all of which influences the assessment of hardness anomalies using nondestructive methods like in-line inspection (ILI).

 

The first incarnations of ILI for assessment of hardness anomalies were developed using pull tests with artificially produced hardness anomalies. This was because, until recently, there was limited access to real anomalies that had been removed from service. Despite the fact that more hardness anomalies have been removed from service and can be used for development, the need for artificial hardness anomalies for pull testing and development of ILI performance specifications still exists. Recreating hardness anomalies that accurately represent the anomalies that are present in vintage pipe (pre-1970s) remains a challenge.

 

Besides the obvious parameters of a hardness anomaly, such as absolute maximum hardness, length, width and hardening depth, ILI signals are heavily influenced by the volume of martensite (and other microstructures) and grain size present within the anomaly. The increased level of knowledge about the different types of hardness anomalies that now exists has provided a basis for creating representative anomalies. ROSEN developed a laboratory approach to create artificial anomalies that can be used in combination with the continually expanding set of field validation data to improve the assessment capabilities of ILI in terms of POD, POI and sizing. This paper presents the work done in developing artificial hardness anomalies for use in pull testing and laboratory research and the detailed investigation of different ILI measurement techniques (high and low magnetization in combination with eddy currents and geometry channels) to optimize the detection, identification, surface discrimination (internal/external) and sizing of different types of hardness anomalies.

 

The work presented in this paper has led to a significant improvement in the capabilities of ILI to assess hardness anomalies. This represents a reduction in risk and increased level of safety when managing the threat of hard spots in vintage natural gas, liquid and, looking to the future, hydrogen transmission and distribution pipelines.

Presenting Author: Thomas Eiken Rosen Technology and Research GmbH

Presenting Author Biography: Thomas Eiken is the Head of Material Properties Applications. Rosen’s Material Property Applications cover ILI solutions for detection and classification of hardness variations in pipeline steel (RoMat DMG) and determination of pipe grade (RoMat PGS).
Before he joined the ROSEN-GROUP, Thomas worked as a project manager and responsible welding supervisor for a German pipeline construction company until he joined Rosen. During this time, Thomas managed pipeline sites and developed Welding Procedures for pipelines and natural gas pipe storages.
He is experienced in material properties of line pipe steel, European and International pipeline construction and line pipe standards and he is familiar with German and U.S. regulation of pipelines.

Thomas is based at the Rosen Technology and Research Center, Lingen. He joined the Rosen Group in 2013.
He has 29 years’ experience in the European pipeline industry and hold a Diploma in civil engineering and an IIW-Diploma “International Welding Engineer”.

Authors:

Thomas Eiken Rosen Technology and Research GmbH
Daniel Molenda Rosen Technology and Research GmbH
Jason Edwards Rosen Technology and Research Center GmbH