METHOD FOR COATING INTERNAL PASSAGES OF AN ARTICLE
A method for coating an article includes preheating the article to a first temperature to burn off impurities, cooling the article to a second temperature, coating the article with a coating, drying and heat-treating the article to solidify the coating.
1 . A method for coating an article, comprising the steps of:
preheating the article to a first temperature to burn off impurities;
cooling the article to a second temperature;
coating the article with a coating; and
heat-treating the article to solidify the coating.
2 . The method according to claim 1 , wherein:
the article is a cast iron casting having at least one internal passageway.
3 . The method according to claim 2 , wherein:
the first temperature is approximately 1200° F.
4 . The method according to claim 2 , wherein:
the first temperature is approximately 1650° F.
5 . The method according to claim 2 , wherein:
the second temperature is approximately ambient temperature.
6 . The method according to claim 2 , wherein:
the step of coating the article includes filling the casting with the coating, draining the casting, vibrating the casting and air-drying the casting.
7 . The method according to claim 6 , wherein:
the step of coating the article further includes cleaning excess material from the exterior of the casting.
8 . The method according to claim 2 , wherein:
the step of heat treating the article includes normalizing the casting to drive water from the casting, moving the casting to a preheated oven, and heating the casting to a third temperature just below a melting point of the coating.
9 . The method according to claim 8 , wherein:
the step of heat treating the article further includes increasing the temperature within the oven to a fourth temperature for approximately 25 to 30 minutes, turning off the oven, and removing the casting once the oven the temperature drops below approximately the third temperature.
10 . The method according to claim 9 , wherein:
the third temperature is approximately 1200° F.
11 . The method according to claim 9 , wherein:
the fourth temperature is approximately 1450° F.
12 . A method for coating a cast iron article, comprising the steps of:
preheating a cast iron article to a first temperature to burn off impurities;
cooling said cast iron article to a second temperature;
coating said cast iron article with a solution;
vibrating said cast iron article containing said solution;
heat-treating said cast iron article to solidify the coating.
13 . The method according to claim 12 , wherein:
said cast iron article having at least one internal passageway.
14 . The method according to claim 13 , wherein:
the step of heating-treating includes normalizing said cast iron article to drive water from the casting, moving said cast iron article to a preheated oven, and heating said cast iron article to a third temperature just below a melting point of the coating.
15 . The method according to claim 14 , wherein:
the step of heat treating said cast iron article further includes increasing the temperature within the oven to a fourth temperature for approximately 25 to 30 minutes, turning off the oven, and removing said cast iron article once the oven the temperature drops below approximately said third temperature.
16 . The method according to claim 12 , wherein:
said first temperature is approximately 1650° F.
17 . The method according to claim 12 , wherein:
said second temperature is approximately ambient temperature.
18 . The method according to claim 14 , wherein:
said third temperature is approximately 1200° F.
19 . The method according to claim 15 , wherein:
said fourth temperature is approximately 1450° F.