1.Cast iron can be divided into
Grey iron cast. Carbon content is high (2.7%-4.0%), melting point is low (1145-1250℃), shrinkage is small during solidification, compressive strength and hardness are close to carbon steel, and shock absorption is good. Casting and cutting performance is better. It is used to manufacture machine tool bed, cylinder, box and other structural parts.
White iron cast. The content of carbon and silicon is low, the shrinkage is large during solidification, and the shrinkage and crack are easy to occur. High hardness and brittleness, unable to bear impact load. It is mostly used as the blank of malleable iron cast and the wear-resistant parts.
Malleable iron cast. It is obtained from white iron cast by annealing, with uniform structure and properties, good wear resistance, plasticity and toughness. It is used to manufacture parts with complex shape and can withstand strong dynamic loads.
Ductile iron cast. The hot metal of gray iron cast obtained by spheroidizing treatment has higher strength, better toughness and plasticity than common gray iron cast. It is used to manufacture internal combustion engines, automotive parts and agricultural machinery, etc.
Vermicular graphite iron cast. The mechanical properties of grey iron cast obtained by vermicularizing treatment are similar to that of nodular iron cast, and the casting properties are between that of grey iron cast and nodular iron cast. Parts used to make automobiles.
Alloy iron cast. Ordinary iron cast was obtained by adding appropriate alloying elements (such as silicon, manganese, phosphorus, nickel, chromium, molybdenum, copper, aluminium, boron, vanadium, tin, etc.). Alloy elements change the matrix structure of iron cast, which has the corresponding characteristics of heat resistance, wear resistance, corrosion resistance, low temperature resistance or no magnetism. It is used to manufacture parts and components of mines, chemical machinery, instruments and meters.
Quality of Injection pressure
Including appearance quality, internal quality and use quality. Appearance quality refers to surface roughness, surface defects, size deviation, shape deviation and weight deviation of castings. Internal quality mainly refers to the metallographic structure, as well as the hole, crack, inclusion and segregation existing in the casting. Service quality refers to the durability of iron castings under different conditions, including wear resistance, corrosion resistance, cold and heat resistance, fatigue resistance, shock absorption and other properties, as well as the cutting ability, weldability and other technological properties.
Factors affecting quality
The first is the design technicality of iron castings. In order to avoid or reduce the defects such as component segregation, deformation and cracking, the rationality of design must be considered from the angle of casting alloy and casting process characteristics, namely obvious size effect and solidification, shrinkage and stress, besides determining the geometry shape and size of iron castings according to working conditions and properties of metal materials.
Secondly, reasonable foundry technology should be adopted. That is to say, according to the structure, weight and size of iron castings, casting alloy characteristics and production conditions, proper parting surface, moulding and core-making methods are selected, and casting bars, chills, risers and gating systems are reasonably set up.
The third is the quality of raw materials for foundry. Metal furnace charge, refractory material, fuel, flux, modifier, casting sand, moulding sand binder, paint and other materials are not up to standard, which will cause defects such as porosity, pinholes, slag inclusion, sand bonding, and affect the appearance quality and internal quality of cast iron.
Fourthly, the process operation should be formulated to improve the technical level of workers so that the process regulations can be implemented correctly.
Calculating Casting Price
We need to check whether we can use sand casting process to produce blank castings, some may use wet sand, some may use resin sand, or shell casting, or automatic forming process. Wet sand is cheaper and shell casting is the most expensive. Relevant factors include dimension tolerance, surface quality, structural complexity, annual demand, weight and size. These factors will affect the cost of the blank casting.
For normal work, most of the cast iron factories with processing capacity will be able to process in-house. Otherwise, they will have to entrust other professional processing workshops for processing. Because cooperation between foundry and processing workshops may cause more difficulties and delay delivery, this is not a good choice.
Consider other costs.
Other costs include packaging costs, surface treatment, painting, inland and sea freight, and, of course, exchange rates. These costs will be related to the specific needs of customers.
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