Measures to eliminate surface slag and pores of carbon steel precision castings

   Carbon steel precision casting In production, carbon steel precision castings have high carbon content During the pouring process, the inhalation and oxidation are serious, and the surface of the casting is prone to slag and pores, mainly concentrated on the upper part of the casting in the group tree scheme. Affect the appearance and quality of the casting. In the case that the conventional method cannot be completely solved, the sand mold casting process design method is introduced. By adding the sprue, the molten steel is injected into the shell from the external sprue, so that the molten steel rises smoothly in the shell, and the generated gas and slag accompany the molten steel. The castings are smoothly floated through the inner runner to avoid slag holes on the upper surface of the casting in the group tree scheme, improve the surface quality of the castings, and reduce the repair cost of the castings later.

   Our company is engaged in the production of carbon steel precision casting group tree material, the material is carbon steel A4, in the dense slag, pores, the main reason is the thick casting, molten steel During the process of injecting the shell, when the molten steel level reaches the uppermost plane of the casting, the generated slag and gas are about to float out of the casting, and the molten steel continues to be injected, and the inner gate is pressed, and the slag and gas in the shaped shell cannot be filled. The floating through the inner runner causes the accumulation, and the conventional method of solving the slag and the pores can not be solved. The slag pores on the surface of the casting add a lot of work to the later repair, and increase the cost.

  After casting a cup opening in the original sprue cup mouth (see Figure 2), the molten steel is directly injected into the lowermost end of the shell from the newly added cup to reach the molten steel in the shell. As the stagnation rises steadily, the generated slag gas can smoothly float out of the gate runner, and the slag pores are completely solved.

  By adding a cup mouth, the slag hole on the upper surface of the casting in the group tree scheme is solved, but the increased cup mouth can not be removed by being clamped in the die, and it is difficult to add sand to the die, and the sand is introduced by changing the group tree scheme. The die casting process, plus a sprue (see Figure 3), the molten steel is injected into the shell through the added sprue, which avoids the slag hole and avoids the problem of difficult sand cleaning.