Page 60 - Ship Construction.DJ Eyres 6Ed

Ch05-H8070.fm Page 49 Wednesday, October 18, 2006 8:02 AM
Steels 49
brittleness. Stern frames, rudder frames, spectacle frames for bossings, and
other structural components may be produced as castings.

Steel Forgings

Forging is simply a method of shaping a metal by heating it to a temperature
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where it becomes more or less plastic and then hammering or squeezing it
to the required form. Forgings are manufactured from killed steel made
by the open hearth, electric furnace, or oxygen process, the steel being in
Construction to Ship Structure. ศูนย์ฝกพาณิชย์นาวี
the form of ingots cast in chill moulds. Adequate top and bottom discards
are made to ensure no harmful segregations in the finished forgings and
the sound ingot is gradually and uniformly hot worked. Where possible
the working of the metal is such that metal flow is in the most favourable
direction with regard to the mode of stressing in service. Subsequent heat
treatment is required, preferably annealing or normalizing and tempering
to remove effects of working and non-uniform cooling.

Further Reading
ึ
Lloyds Register – Rules and Regulations for the Classification of Ships
2004, Part 2 – Rules for the Manufacture, Testing and Certification of
Materials.
งานห้องสมุด
Lloyds Register – Provisional Rules for the Application of Sandwich Panel

Some Useful Web Sites
www.ie-sps.com for more information about SPS systems.