Heat treatment of wrought iron

• Pages: 475-475

475

Appendix G

Heat treatment of wrought iron

G.1. General provisions

G.1.1. Heat treatment of wrought-iron gear should consist of

heating the gear uniformly in a suitably constructed muffle furnace

until the whole of the metal has attained a temperature between

600˚C (1,100˚F) and 650˚C (1,200˚F), then withdrawing the gear

from the furnace and allowing it to cool uniformly.

G.1.2. If the past history of wrought-iron gear is not known,

or if it is suspected that the gear has been heat-treated at an incor-

rect temperature, before putting it to work it should be given nor-

malizing treatment (950˚-1,000˚C or 1,750˚-1,830˚F) followed by

uniform cooling. Precautions should be taken during the heat

treatment to prevent excessive scaling.

G.1.3. Sling assemblies should be made of materials having

similar properties.

G.1.4. However, if the assembly has some components of

wrought iron and others of mild steel (e.g. mild-steel hooks per-

manently connected to wrought-iron chains), it should be nor-

malized at a temperature between 920˚ and 950˚C (1,700˚ and

1,750˚F), removed from the furnace and cooled uniformly.