African Fusion AUgust 2016

August 2016

AFRICAN FUSION

Figure 10: Complex structure of graphite inclusion, visible on

an over-etched surface (high resolution SEM image, original

magnification 26 790×).

coupon failed through the graphitised HAZ.

• Prolonged heat treatment at 635°C, at times for up to 1 200

hours, resulted in spheroidisation, but not in noticeable

graphitisation.

• Repair welding on graphitised material can be performed

successfully.

References

[1] Foulds JR and Viswanathan R: “Graphitization of steels

in elevated-temperature service”; Journal of Materials

Engineering and Performance, vol. 10, pp. 483-492,

Aug. 2000.

[2] Meier A, Hammerschmidt DandSkibbe E: “Graphitization

effects on high temperature ductwork”; Energytech, p.5,

2014.

[3] Samuals LE: “Light Microscopy”; pp. 165-183, 1999.

[4] Okada M: “Graphitization of weld heat-affected zone in

carbon steel”; Transaction of the Japan Institute of Met-

als, pp. 353-359, 1982.

[5] Dennis, W: “Heterogeneous Nucleation of Graphite in

Hypo-EutectoidSteel”; Iron andSteel Institute, pp. 59-64,

1952.

[6] Harry E: “Subcritical decomposition of carbide phase in

some low-carbon silicon steels”; The Journal of the Iron

and Steel Institute, pp. 109- 112, 1954.

[7] Brown F: “Nucleation of Graphite in Steel”; Welding

Journal, pp. 257-261, 1954.

[8] He K: “An electron microscopic study of spheroidal

graphite nodules formed in a medium-carbon steel by

annealing”; Acta Materialia, pp. 2919-2927, 2007.

[9] Foulds JRandShingledecker JP: “Anupdatedassessment

of graphitization of steels in elevated temperature ser-

vice”; Journal of Materials Engineering andPerformance,

vol. 24 no. 2, pp. 586-597, Dec. 2014.

[10] Moss C: “Graphitization in type A201 carbon steel in

petro- chemical plate after long term service”; Aus-

tralian Nuclear Science and Technology Organisation,

pp. 351‑359, 1994.

[11] ASME Boiler and Pressure Vessel Code: vol. IX, Welding,

Brazing and Fusing Qualifications, 2013.

[12] Toft L and Marsden R: “The Structure and Properties

of 1%Cr- 0.5%Mo Steel”; The Iron and Steel Institute,

276‑294, 1963.