• Annealing softens Ductile Iron by producing a carbide-free, fully ferritic matrix.
  

• The primary purpose of annealing, or ferritizing, Ductile Iron is the production of castings with maximum ductility and toughness, reduced strength and hardness, improved machine-ability and uniform properties. This is a brief description of the service ..

Capabilities:

Table 7.1  Recommended practices for annealing Ductile Iron castings.

Type of Anneal	Purpose	Temperature (a)	Time	Cooling Cycle (b)
Low temperature (Ferritizing)	In absence of carbides.  To obtain Grades 60-45-12, 60-40-18	1325 to 1350F (720 to 730C)	1 hour per inch of cross section	Furnace cool (100F or 55C per hour) to 650F (345C).  Air Cool.
Full (for lower silicon content iron)	In absence of carbides.  To obtain Grade 60-40-18 with max. low temperature impact strength	1600 to 1650F 870 to 900C	only to equalize at control temperature	Furnace cool (100F or 55C per hour) to 650F (345C).  Air Cool.
High temperature (Graphitizing)	In presence of carbides.  To obtain Grades 60-45-12, 60-40-18	1650 to 1700F 900 to 925C	2 hours minimum	Furnace cool @200F (95C) per hour to 1300F (700C). Furnace cool @ 100F (55C) per hour to 650F (345C) Air cool.
Two stage Graphitizing and Ferritixing	In presence of carbides.  To obtain Grades 60-45-12, 60-40-18 where rapid cooling is practical	1600 to 1650F 870 to 900C	1 hour per inch of cross section	Fast cool to 1250 to 1300F (675 to 700C). Reheat to 1350F (730 C).  2 hours per inch of cross section.  Air cool.
(a) Temperature of castings. (b) Slow cooling from 1000 to 650F (540 to 315C) is to minimize residual stresses.

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