Method for internally arranging steel wire without exposure in manufacturing process of long and thin sand core

The invention discloses a method for arranging a steel wire without exposure in the manufacturing process of a long and thin sand core. The method comprises the following steps: step 1, prefabricating three step-shaped hanging needles according to the actual core manufacturing requirement; and 2, the prefabricated hanging needles are sequentially installed in the core box cavity, the hanging needles have certain offset compared with the steel wires, and therefore the steel wires can be extruded more appropriately according to needs, and the positions of the steel wires are controlled. The method has the beneficial effects that the three hanging needles are arranged in the cavity in the static core box of the sand core in advance in an offset manner, so that a steel wire can be arranged in the center of the cavity of the core box in a suspended and limited manner, the steel wire can be completely wrapped after the sand core is formed, and the steel wire is located in the center of the formed sand core; the exposure of the steel wire after the sand core is formed and the excessive deviation of the steel wire relative to the center of the sand core after the sand core is formed are avoided, the forming quality of the sand core is greatly improved, and the rejection rate during casting machining is further reduced.