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MATERIALS OF CONSTRUCTION
WEISERT, E. D. (1952b) Chem. Eng., NY 59 (July) 314. Hastelloy alloy B.
WELLS, A. A. (1968) British Welding Journal 15, 221. Fracture control of thick steels for pressure vessels.
WIGLEY, D. A. (1978) Materials for Low Temperatures, Engineering Design Guide No. 28 (Oxford U.P.).
Bibliography
Further reading on materials, materials selection and equipment fabrication.
CALLISTER,W. D. Materials Science and Engineering, an Introduction (Wiley, 1991).
CRANE, F.A.A. and CHARLES,J. A. Selection and Use of Engineering Materials, 2nd edn (Butterworths, 1989).
EWALDS,H.L. Fracture Mechanics (Arnold, 1984).
FLINN,R. A.and TROJAN,P.K. Engineering Materials and Their Applications, 4th edn (Houghton Mifflin,
1990).
RAY,M. S. The Technology and Application of Engineering Materials (Prentice Hall, 1987).
ROLFE,S. T. Fracture Mechanics and Fatigue Control in Structures, 2nd edn (Prentice Hall, 1987).

7.15. NOMENCLATURE
Dimensions
in MLT£
A Area L 2
C Cost of material £/M
t Time T
w Mass loss M
Density ML 3
d Design stress ML 1 T 2

7.16. PROBLEMS
7.1. A pipeline constructed of carbon steel failed after 3 years operation. On exami-
nation it was found that the wall thickness had been reduced by corrosion to
about half the original value. The pipeline was constructed of nominal 100 mm
(4 in) schedule 40, pipe, inside diameter 102.3 mm (4.026 in), outside diameter
114.3 mm (4.5 in). Estimate the rate of corrosion in ipy and mm per year.
7.2. The pipeline described in question 7.1 was used to carry wastewater to a hold-up
tank. The effluent is not hazardous. A decision has to be made on what material
to use to replace the pipe. Three suggestion have been made:

1. Replace with the same schedule carbon steel pipe and accept renewal at 3-year
intervals.
2. Replace with a thicker pipe, schedule 80, outside diameter 114.3 mm (4.5 in),
inside diameter 97.2 mm (3.826 in).
3. Use stainless steel pipe, which will not corrode.

The estimated cost of the pipes, per unit length is: schedule 40 carbon steel £3 ($5),
schedule 80 carbon steel £5 ($8.3), stainless steel (304) schedule 40 £15 ($24.8).
Installation and fittings for all the materials adds £10 ($16.5) per unit length.
The downtime required to replace the pipe does not result in a loss of production.
If the expected future life of the plant is 7 years, recommend which pipe to use.