摘要:
A mold for a prototype metal casting or the like may advantageously be made by forming a casting pattern of adhesively bonded aggregate particles using a binder containing a principle constituent that is soluble in supercritical carbon dioxide; forming a rigid shell mold about the pattern of materials that are unaffected by supercritical carbon dioxide; thereafter exposing the pattern and mold combination to supercritical carbon dioxide to remove the pattern binder adhesive and leave unbonded aggregate particles in the mold and removing the aggregate particles from the mold to leave a mold cavity that faithfully defines the pattern shape.
摘要:
Coating foundry sand with a thin layer of an oxidation-promoting catalyst. Preferred catalysts comprise ferric and cupric oxides. The catalysts promote the oxidation of any polymeric binder or residues admixed with the sand. The sand is coated by wetting the grains with a solution of a catalyst precursor, drying the sand and baking the sand in air to convert the precursor to the catalyst.
摘要:
Sand mold for shaping molten metal cast into the mold. The mold includes sand, a thermally oxidizable polymer amongst the grains of the sand, and a catalyst coating on the gains for promoting the thermal oxidation and breakdown of the polymer in the course of removing the sand from the casting and/or reclaiming the sand for reuse. The catalyst coating adheres so tenaciously to the grains of sand that the sand can withstand repeated casting and sand reclamation cycles without the need to replenish the catalyst.
摘要:
In the lost foam casting of aluminum, coating a fugitive pattern with a refractory coating containing a thermally stable, water-insoluble, acid-gasifiable (e.g. CaCO3) compound, and contacting the casting, with the coating thereon, with an acid to dissociate and gasify the compound and rupture the coating. Preferably, any thermal degradation products from the pattern residing in the coating are neutralized to promote wetting of the coating.
摘要:
Coating foundry sand with a thin layer of an oxidation-promoting catalyst. Preferred catalysts comprise ferric and cupric oxides. The catalysts promote the oxidation of any polymeric binder or residues admixed with the sand. The sand is coated by wetting the grains with a solution of a catalyst precursor, drying the sand and baking the sand in air to convert the precursor to the catalyst.
摘要:
A method for making sand particle foundry mold members. Sand particles are coated with an aqueous dispersion of a suitable binder material such as a gelatin gel. The moist gelatin coated particles are gravity fed into a pattern box for the mold member and subjected to multi-axis vibration to pack the sand in the pattern box. The moist sand is then heated with radio frequency energy to promote binder flow to the corners of the particles, and air flow is initiated to transport water from the mass of particles to harden the mass of particles into the mold member.
摘要:
A foundry mold member made from a plurality of sand particles bound together with a binder which is concentrated at the contact points between contiguous sand particles and consists essentially of gelatins having a Bloom rating less than about 175 Bloom grams. The sand particles are first coated with a sol of the gelatin, cooled to ambient temperature and conditioned to a prescribed water content necessary to effect migration of the gelatin to the interparticle contact points upon heating of the coated particles in a pattern mold.
摘要:
Apparatus for the gravity-cast, “lost-foam” casting of metal castings, including a fugitive, pyrolizable foam pattern forming a casting cavity in a bed of loose sand, and a hollow sprue for supplying melt to the casting cavity, wherein the sprue consists essentially of the same metal as is being cast. A high-temperature, porous vent is provided adjacent the discharge end of the metal sprue to expel air from the sprue that would otherwise be trapped therein.
摘要:
Apparatus for the gravity-cast, bottom-fill, “lost foam” casting of metal castings, including a fugitive, pyrolizable pattern (for forming a casting cavity), and a hollow sprue (for conducting melt to the casting cavity) embedded in a bed of loose sand. The sprue is free from pyrolyzable foam and conducts melt from above the pattern to a gating system supplying melt to the pattern. The sprue is constructed so as to cause the melt to approach the gating system from beneath and keep any pyrolysis products from entering the sprue.
摘要:
A foundry mold member made from a plurality of sand particles bound together with a binder which is concentrated at the contact points between contiguous sand particles and consists essentially of gelatins having a Bloom rating less than about 175 Bloom grams. The sand particles are first coated with a sol of the gelatin, cooled to ambient temperature and conditioned to a prescribed water content necessary to effect migration of the gelatin to the interparticle contact points upon heating of the coated particles in a pattern mold.