Detection of macrosegregation in a large metallic specimen using XRF

Abstract

The characterisation of macroscopic chemical segregation in engineering components over length scales of many metres can be an arduous task. This report investigates the implentation of a technique that is capable of mapping long-range variations in the chemical composition of metal components, without the need for extensive sample preparation. The capability of the method is optimised for large production components, in a setting where process parameters such as measurement time and minimal surface preparation are of importance. Hence, a readily-available hand-held X-ray fluorescence instrument and analysis software are used to map macrosegregation in a low-alloy steel slab.

A Comprehensive Case Study of Macrosegregation in a Steel Ingot

“…Maps for Mn and Ni are not presented here due to the excessive noise found in their results-this can be attributed to their relatively low concentrations and the intensity of the background around their Ka peaks (the background was essential zero at the Mo Ka energy). [12] A comparison of the results of chemistry measurements with porosity measurements demonstrated clearly that the vertical strings of porosity (not the chevrons) observed in the ingot were associated with A-segregate channels. [11] The results of OES measurements made on material trepanned from the ingot, including highly enriched material from the very top, are shown in Figure 10.…”

“…Face A was then subject to chemical mapping using an automated macroscale XRF technique; the use of which was examined in another article. [12] An Olympus Innov-X Delta Dynamic hand held XRF analyser was employed, with robotics designed and constructed by Geotek Ltd. [13] The beam energy used was 40 kV, with a beam of current 52 lA. The step size used was 5 mm in both orthogonal directions of movement, and the dwell time was 10 seconds.…”

Atomic spectrometry update. Review of advances in the analysis of metals, chemicals and functional materials

“…The importance of element segregation in steels is also highlighted by Pickering and Holland. 25 A portable XRF analyser was used to provide a rapid and quantitative analysis of segregation with respect to Cr, Mn, Mo and Ni with Si proving problematic. The authors proposed this approach for the detection of longrange variations in composition and in cast products from the steel plant.…”

“…Calibration for the XANES was accomplished by pressing pellets of plastic, methyl cellulose binder and lead chromate and/or chromium acetylacetonate. The last two components could have their proportions changed to obtain 0, 5,10,15,20,25,30,50,75,90,95 and 100% Cr VI . The absorption of the pre-edge peak of Cr K-edge XANES spectra were summed and normalized and yielded straight calibrations, even though measurements were conducted at different beam time and beam line.…”

Mechanism of Dry Molten Slag Granulation Using a Rotating Multi‐Nozzle Cup Atomizer

“…As a typical process for granulating, [9,10] the rotary cup atomizer (RCA) is widely used in various industries to reduce the particle size to suitable size for the intended usage, such as chemical, powder metallurgy, pharmaceutical, food, agriculture, etc. Also, RCA can be used to granulate the molten slag, which was first introduced by Pickering et al [11] In Japan, Australia, and China, RCA has been studied extensively in dry molten slag granulation by many researchers, such as, Yagi and Kasai, [4,12,13] Akiyama and Hadi, [14][15][16] Xie and Pan, [17] Qi and Yu. [18,19] However, the slippage between the molten slag and the disk or cup is still a main drawback associated with rotary atomizers.…”