| 摘要 |
PURPOSE:To reduce man-hours for sand molding and to economize a material for facing sand by blowing quick-curable system sand formed by kneading refractory particles with a binder and a hardener added with a quick curing accelerator to the surface of a pattern thereby forming quickly a facing sand layer. CONSTITUTION:Zircon sand, chromite sand, etc. having high refractoriness are used for the refractory particles in order to prevent burning after casting. Furan, phenolic, phenol, furan resins are used for the binder and xylene sulfonic acid, paratoluene sulfonic acid, benzensulfonic acid and phosphoric acid curing agent added with a sulfuric acid as a quick curing accelerator are used for the curing agent. The system sand is used by changing the kind of the binder and curing agent and the amt. thereof to be added and the amt. of the curing accelerator to be added for spring, summer and winter in order to adjust the pot life of the system sand. The facing sand layer is formed on the surface of a pattern by a spray molding device.
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