Session: 05-04-01 Fittings and Testing Methods

Paper Number: 87189

87189 - Hard Stamp, Paint or Chemical Dna, How to Link the Steel Product to the Material Test Report. 

The mill test report (MTR) is proof of  the mechanical properties and required tests of the steel product are performed and meet the requirements. For this purpose representative test pieces representing the product are destructively tested and the results are given on the MTR. The MTR is essential as one cannot determine the mechanical properties non-destructively. The standard way of coupling the MTR and the product is done by specific marking on the product which is given in the MTR. But what if there is no confidence the MTR belongs to the steel product? At that very moment the steel product has no value. In our experience from testing the chemical composition from over 4000 fittings, in around 30% these the MTR could not be of the supposed to be related item.

This testing journey was started by a 16” equal tee that failed during hydrostatic testing. In the subsequent failure investigation it was found to be made from welded pipe whereas the MTR stated it was made from seamless pipe. The actual chemical composition of the tee also deviated significantly from the heat analysis as given in the related MTR. With that it was clear the relation between paper and steel for this Tee was nonexistent. In a second case we have found a large manufacturing defect in a 12” reducer after  the non-destructive testing of the girth weld. Also in this case the actual chemical composition deviates significantly.

In both cases questions were raised on the integrity of the other products delivered that were either installed or in the warehouse. To discriminate between ‘good’ and ‘bad’ products a test program was conducted on all fittings (» 4000). The program consisted of magnetic particle testing of all accessible surfaces and chemical analysis using mobile optical emission spectrometry (OES). Only fittings in which no indications were found and of which the chemical composition corresponds to the  heat analysis of the MTR were acceptable. We found that a significant amount of fittings were not acceptable due to large deviations of the chemical composition. A program of mechanical testing of the deviating products revealed about 5% of the products where not meeting the minimum mechanical requirements.

Within EPRG the background and use of OES, more specifically mobile OES, was researched in two subsequent projects. the first was a literature study titled: Determination of pipe chemical composition by mobile optical emission spectrometry for various applications. The second study was on the practical application and the use of proper tolerance bands for establishing the relation, titled: Mobile optical emission spectrometry validation regarding inspection certificate verification, CEV determination and material characterization.

The paper will review/discuss the EPRG reports and further explain with examples from daily use the use of the mobile OES as a reliable method to establish a better relation between paper and steel based on a relevant test instead of paint or stamped markings.

Presenting Author: Alfons Krom N.V. Nederlandse Gasunie

Presenting Author Biography: Otto Jan Huising joined N.V. Nederlandse Gasunie in 2006 as a specialist for welding and NDE. He holds qualifications as International Welding Engineer, BSc inspection techniques and BSc metallurgy.<br/>In his function he is involved in fit for service evaluations, material verification, application of welding and NDE techniques in gas transmission pipelines. He was the lead for the revision of EN 12732:2021, Gas infrastructure, welding steel pipework, functional requirements. Professionally he is a member of the European Pipeline Research Group design committee and involved in various Hydrogen research projects of the EPRG Hydrogen task group. Further he is a member of the Design Materials and Construction section of the Pipeline Research Council International.<br/>His previous experience is 10 years as senior inspector with Lloyd’s Register in the field of pressure equipment including ASME authorized inspector and 7 years as maritime engineer at ships and power plants.