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作者: -1    发布时间: 2018-07-26    次浏览
The clay sand casting process of ductile iron pipe fittings is commonly used

Clay sand is a type (core) sand with clay (clay) as binder. Clay sand modeling is still a production method of ductile iron pipe because of its low production cost.

 (1) advantages: low production cost, high production flexibility, high productivity and short production cycle.

 (2) disadvantages: it is easy to produce casting defects such as sand clamping, scarring, rat tail, air hole, sand hole and sand swelling; It is not suitable for manufacturing medium and large caliber ductile iron pipe parts. The best caliber is less than or equal to DN300.

Ductile iron pipe fittings commonly used production process characteristics of the film - coated sand casting process

Using thermoplastic phenolic resin with latent curing agent (such as methenamine) and lubricant, such as calcium stearate) through a certain mixture of precoated sand coated technology, coated sand coated on the surface of the sand, resin melt when heated, in methenamine decomposition of methylene, under the action of molten resin by linear structure rapidly into not melt body structure, so that the solidification of precoated sand forming.

 (1) advantages: high precision and smooth surface; High production efficiency; Less of choose and employ persons; It covers a small area.

 (2) disadvantages: high production cost; Large investment in molds; It is not suitable for manufacturing medium and large caliber ductile iron pipe parts. The best caliber is less than or equal to DN200.

The resin sand casting process of ductile iron pipe fittings is commonly used

Resin sand casting is to evenly mix the sand and resin, curing agent into the sand box, shape modelling core making, casting box after on, is now widely used in a casting way, although the dimensional accuracy than some modelling of precoated sand is poor, but it is suitable for many varieties of small batch casting, are widely used in pipe fitting enterprise.

 (1) advantages: high dimensional precision of casting, clear outline, smooth surface of casting, good appearance quality, wide adaptability, suitable for all caliber pipe fittings.

 (2) disadvantages: the molding hardening reaction takes a certain time, and its production efficiency is low; The surface of the ductile iron pipe may be badly spheroidized due to the sulfur percolation. Compared with clay sand, the cost is higher.

Ductile iron pipe parts commonly used in the production process characteristics of the disappearing mold casting process

Epc is coated with refractory coating of the foam plastic shape into the sand box, look around with dry sand filling, the micro vibration and negative pressure tight, in the absence of core pouring liquid metal, in the process of casting and solidification to keep certain negative pressure, make foam gasification and then replaced by metal casting method of a new type of casting process.

 (1) advantages: high casting precision and even wall thickness; Flexible design, through the combination of foam plastic die casting a variety of variable diameter pipe pieces; The machining allowance is small, even directly casting the flange water ring and flange hole.

 (2) disadvantages: not all spheroidal pipe fittings are suitable for the epc process; The surface of pipe fittings is prone to wrinkle, corrugation, droplet, cold septum, slag and air entrainment. Long process flow; There are many control points, high technical requirements, high management difficulties, and high quality requirements for managers and operators. It is only suitable for the production of medium and large caliber ductile iron pipe fittings.

Ductile iron pipe fittings commonly used production process characteristics of V - method casting process

The vacuum seal molding (V method modeling) is very different from the traditional sand casting method. It is a physical modeling method. It combines vacuum technology and sand mold casting, do not add water and caking agent the original sand molding, by the plastic film will sand mold cavity surface and sealed on the back, with the help of vacuum pump suction to produce negative pressure, caused by sand mould sand fastening with internal and external pressure forming, under the core, box, casting, casting solidification, remove or stop the smoke gas, negative pressure casting sand then to pieces.

 (1) advantages: smooth surface, clear outline and accurate size of pipe fitting; Short process and low production cost; High utilization rate of metal, high production rate of process; Less investment; Low operating cost; Wide range of adaptation; Suitable for small batch of all caliber pipe fittings.

 (2) disadvantages: large investment in molds; The modeling efficiency is not high.