2 results about "Shrinkage porosity" patented technology

The invention discloses a mould for producing a double-screw plastic extruding machine barrel lining, and belongs to the field of ferrous metallurgy. The mould comprises an upper box body and a lowerbox body, a forming cavity for producing the double-screw plastic extruding machine barrel lining is defined by the upper box body and the lower box body, a mud core for forming a double-screw installation hole is arranged in the middle of the forming cavity, an exothermic riser is formed in the position, in the upper box body, of the middle of the top of the forming cavity, and graphite chill isarranged at the position, in the lower box body, of the middle of the bottom of the forming cavity; and inner gates are symmetrically formed in the positions, close to the end, of one side of the forming cavity, and an outer gate and a pouring channel which communicate with the inner gates are formed in the upper box body at the same time. According to the mould, feeding is conducted when pouringis conducted on the upper and lower thick walls of the forming cavity through the exothermic riser and the graphite chill, meanwhile heat of molten metal is dispersed by adopting the inner gates and the outer gate, the lining quality can be improved, surface cracking is reduced, and generation of a shrinkage cavity and a shrinkage porosity can be effectively prevented.

The invention provides a bearing cap sand mold structure, which includes a sand mold main body, which is provided with four casting cavities that are inclinedly arranged in two groups. Each casting cavity is connected to a riser and an ingate, the risers are in top casting connected, and the ingate communicates with a sprue, which is connected to a sprue cup. In the sand mold structure, each sandmold main body is provided with a riser. In the precondition that risers are adopted as less as possible, the requirement of interior shrinkage porosity of a casting is met, and the technical yield rises. The cavities are directly connected to the ingate, so that the sand washing risk is reduced, the rejection rate is reduced, and the production efficiency is improved.