Wuxi Dongao Nonferrous Casting Co., Ltd.
Home > News > Content
Spheroidizing Process Of Ductile Iron Valve Clack Casting
- Jun 06, 2018 -

In the process of production, nodular cast iron disc requires its chemical composition to have a higher content of carbon-silicon than that of gray cast iron for its original iron liquid, and to reduce the content of manganese, phosphorus and sulfur in nodular cast iron. During the production process, the molten iron temperature will be higher than that of its gray cast iron to compensate for the spheroidization and the temperature loss of the molten iron during inoculation.

In the process of spheroidizing, the nodular cast iron valve flap is effective to add a nodularizer in the molten iron, and when it is operated, it is added with its inoculant to inoculate. In general, its ductile iron has poor fluidity, so that the shrinkage is relatively large. Therefore, a higher pouring temperature and a larger size of a gating system are required. In the operation, a reasonable application of a riser and a cold iron are adopted for the sequential solidification principle.

Heat Treatment of Ductile Cast Iron Valves

1. Annealing: The ferrite matrix is obtained to a certain extent, so that it can effectively improve its plasticity, toughness, eliminate its stress, so that it can effectively improve its cutting performance.

2. Normally. The pearlite matrix is obtained to increase strength and wear resistance.

3. Conditioning. Obtains the tempered sorbite matrix, as well as good comprehensive mechanical properties such as spindle, crankshaft, connecting rod and so on.

4. Austempering. During the operation, parts with complex shapes and high overall performance requirements can be obtained to a certain extent to obtain a bainite matrix structure and comprehensive mechanical properties such as high strength, high hardness, and high toughness, so as to avoid cracking during heat treatment, such as a spindle , crankshafts, gears, etc.

The energy-saving requirements of spheroidal graphite cast iron flaps, to a certain extent, lead to the fact that they basically redesign parts so that they can achieve light weight and high efficiency to a certain extent. This will inevitably remind their designers to pay attention to materials.

Ductile iron is increasingly considered to provide high strength-weight characteristics and can be produced at relatively low cost. When the tonnage of the ductile iron increases and the market penetration is staggering, this material must not be seen to reach its full potential. Based on this, a cast iron plant that does not produce ductile iron suggests good reconsideration of this possibility.