8/3/2019 Inland Steel Report

1/7

ISPAT INLAND RESEARCH AND DEVELOPMENT

REPORT OF ANALYSIS

Problem Description: Plate Defect

Analytical Request: Optical Metallography and Scanning Electron Microscopy

Sample Numbers: 4-121

Company Origin: Sidex

Submitter: I. Ivan

Date Received: June 21, 2004

Investigation No.: 04_Sx_6

Reported to: D. White

Reported by: Lusito Laus Date Reported: July 19, 2004

Copies: I. Ivan, T. Tsai, W. Heitmann, P. Chaubal, S. Lalam

Library key words: Sidex, Plate defect

SAMPLES/ANALYSISSidex submitted a piece of plate sample to Ispat Inland R&D for metallographic and SEM/EDS analyses.The thickness of the plate is 13.5 mm. We were told that the plate material was intended for a weldedpipe application. We were not given the material composition, the location in the pipe from where thesample was taken, or the reason for its failure.

The sample was polished (as received) on the side face showing a defect. Refer to Figure 1 for lowmagnification side photographs. Inland also polished the top surface of the sample to observe itsmicrostructure. Refer to Figure 2 for low magnification top photographs.

The microstructures of the defect and base materials are shown in Figure 3. The base material displays anormal ferrite-pearlite microstructure that is typical of hot rolled plate. The "defect" appears to be part ofa weld or thermally repaired region of the pipe. It consists of a "filler" material and a heat-affected zone

both of which have a mixed bainite/acicular ferrite microstructure. A top view of the defect (Figure 4)shows the weld pattern and the bainite/acicular ferrite microstructure of the filler material.

SEM/EDS analysis of particles found near the defect area (Figure 5) show high levels of Si, Na, Al, andMg, elements that are typically found in weld fluxes. Bulk analysis of the base and filler regions(Figures 6 and 7) shows no significant difference in their compositions. Analysis of inclusions found inthe heat-affected zone (Figure 8) indicates the presence of rare-earth elements Ce and La. These may havecome from the stabilizers used in the weld flux.

Our impression is that the defect is part of a weld that may have had a weld slag inclusion. There is

8/3/2019 Inland Steel Report

2/7

2nothing unusual about the microstructure of the base material.

DefectSideView

Figure 1. Side view of the plate (as received) showing defect.

38x

DefectTop

View

Figure 2. Top view of the plate showing defect, nital etch.

8/3/2019 Inland Steel Report

3/7

3PLATE SAMPLE MICROSTRUCTURE

Side View

16x

380x

380x

Defect

Base Material

Heat Affected Zone

Microstructurenear the defect

Figure 3. Microstructures of the regions near the defect,heat-affected zone and base material, nital etch.

8/3/2019 Inland Steel Report

4/7

4

Top View

380x

38x

380x

38x

Defect

Figure 4. Microstructure at the defect from the top view, nital etch.

8/3/2019 Inland Steel Report

5/7

5SEM Analyses

16x

Figure 5. SEM analysis of the inclusions found at the defect.

8/3/2019 Inland Steel Report

6/7

6

Figure 6. Chemistry of the base material by SEM analysis.

Figure 7. Chemistry of the defect by SEM analysis.

8/3/2019 Inland Steel Report

7/7

7

Porosity

Defect

Figure 8. SEM analysis of the inclusions at the porosity.