Running and feeding system on DISA line for producing annular thin-wall gray iron castings and design method of running and feeding system

Abstract

The invention relates to a running and feeding system on a DISA line for producing annular thin-wall gray iron castings and a design method of the running and feeding system. The running and feeding system comprises feeder heads and a pouring system, wherein the pouring system adopts a bottom pouring mode and comprises inner runners, a straight runner and transverse runners; two castings are distributed in each template; the two castings are symmetrically distributed by using the straight runner as an axis; the inner runners are arranged under each casting; the running and feeding is characterized in that the number of the runner under each casting is one, and the connecting position of the straight runner and the transverse runners is provided with a first buffer zone; the two inner runners are respectively communicated with the two transverse runners; a second buffer zone is arranged at one end, which is far away from the first buffer zone, of each transverse runner; the feeder heads are respectively arranged right above each casting.

Description

technical field [0001] The invention relates to the technical field of casting technology, in particular to an annular thin-walled gray iron casting riser system and a design method thereof. The gating and riser system is applied to the DISA line for the production of annular thin-walled gray iron castings, which can greatly improve the process yield of annular thin-walled gray iron castings on the DISA line, and can eliminate frequent castings under the current production conditions defect problem. Background technique [0002] Various casting defects often occur in iron castings, especially some thin-walled parts. The thin-walled parts are mushy and solidify at the same time. The feeding channel of the riser on the top of the casting is easily blocked by these areas, so shrinkage, Shrinkage cavity is a casting defect that often occurs in such castings. Shrinkage porosity is an important casting defect. Due to the reduction of the area of ​​the bearing surface, its prese...

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Problems solved by technology

[0004] At present, foundry enterprises adopting the DISA line generally design the gating system according to the design method given by DISA company, and design the riser by adopting an experience method similar to that of cast iron riser design, which lacks strict scientificity, such as image 3 As shown, the casting process diagram of producing this type of casting in the prior art is shown. It can be seen that the gating system and riser used to produce this type of casting on the current DISA line have the following disadvantages: 1. The riser is placed on the casting If it is inclined upward, it will cause the reduction of the feeding pressure above the casting, which will easily lead to insufficient feeding; 2. The gating system adopts the bottom injection type, and two inner runners are set. Cracks occur in the middle of the sprue, which leads to an increase in the reject rate; 3. In the design of the sprue, in order to provide a buffer for the molten metal entering from the sprue cup, the designer makes a buffer on the sprue and the sprue and sprue A large buffer area is designed at the junction of the runners. These two buffer areas will continuously dissipate heat to the surroundings during the solidification process, causing thermal knots in certain areas of the casting, and eventually causing defects such as shrinkage and shrinkage cavities.

Due to the thin wall thickness of such ring-shaped gray iron castings, there are some small protrusions distributed on the ring-shaped thin wall. These small protrusions will become hot spots of the casting during the solidification process, and the preferential solidification of the thin-walled parts will cut off the heat. The feeding channel of the joint, these small protrusions will form shrinkage porosity after solidification is completed; 4. The large riser and the thick sprue cause the process yield to decrease, and cannot solve the fundamental problem of shrinkage porosity

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