Method for producing cast-iron, and in particular cast-iron which contains vermicular graphite

US4667725A · kind A · utility

Assignee

• SINTERCAST AB · SE

Inventor

• Stig L. B/a/ ckerud · Mariestad, SE

Key dates

• Filing date: May 7, 1986
• Grant date: May 26, 1987
• Expiry date: May 7, 2006

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C21C1/10
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Method for producing castings from cast-iron containing structure-modifying additives. A sample from a bath of molten iron is permitted to solidify during 0.5 to 10 minutes. The temperature is recorded simultaneously by two temperature responsive means, one of which is placed in the center of the sample and the other in the immediate vicinity of the vessel wall. The dispersion degree of the graphite phase is assessed in relation to known reference values by aid of recorded values of supercooling at the vessel wall, the recalescence at the vessel wall, the difference between the temperature at the vessel wall and at the centrum of the vessel and the derivative of the temperature decrease at the vessel wall during the time of constant eutectic growth temperature at the center. When necessary a graphite nucleating agent is added to the molten bath or the dispersion is lowered by implementing a holding time prior to casting. The morphology of the graphite precipitation is also determined by aid of recorded values and possibly corrected by changing the amount of structure-modifying agents present.