Technical Features:
Continuous cast iron bar, also called as dense bar, is an engineered metal product manufactured with advanced technical processes. It is not only the finest cast iron in the world but also a superior alternative to steel, iron castings and aluminum and other materials. Both the cast iron bar process and the unique metallurgical properties inherent to the material can provide many cost saving advantages for the production of your metal components.
Manufacturing this highly machinable material involves a water-cooled graphite die mounted on the base of a refractory lined crucible. Molten iron enters the die and a solid skin begins to form around the perimeter of the bar. As the bar is pulled through the die, the solid skin becomes thick enough to support the molten iron core. The only part of the bar that is solid immediately outside of the die is the rim.
Heat from the molten iron core re-heats the rim above the critical temperature, and the entire bar cools in still air, eventually to room temperature. The reheating of the rim and uniform cooling create a homogenous, consistent structure throughout the cross section. This eliminates the cracking and porosity problems commonly encountered with sand casting.
The die/cooler system is mounted on the bottom of the bar machine. Slag, dross and tool wearing inclusions float to the top of the crucible, well away from the entrance end of the die. The ferrostatic head from the molten metal in the bar machine crucible feeds iron under pressure into the die and eliminates microshrinkage that can have a detrimental effect on fatigue properties in some parts like gear teeth. The clean, fine grain microstructure makes continuous cast iron an excellent starting material for many metal components, and it shares the same optimal noise damping capabilities as other types of cast iron.
High purity;
Excellent machinability;
High dimension precisions, small machining allowance and excellent machined surface finish;
Remarkable improvement in tenacity and fatigue-resistance;
High and uniform density; excellent pressure-tightness;
Heat Treat Response
Thermal Conductivity
Vibration Damping
Wear Resistance
Weight Reduction
Corrosion Resistance
Cost Effective
The continuous casting process enables the material to be lack of shrinkage and porosity, gas holes, sand, slag and other tool-wearing inclusions, etc.
The material's graphite properties and its uniform hardness result in faster machining (as much as 30%) and less scrap than carbon steels. The superior machinability is possible due to the graphite in cast iron bar giving it natural chip breaking abilities and resulting in precision machining at optimal speeds. The material being removed will either come off in long stringers or small chips, commonly known as free machining.
In contrast to normal scrap rates of 10 to 40% with iron castings, users of continuous cast iron bar can virtually eliminate scrap.
High dimension precisions, small machining allowance and excellent machined surface finish
Cast iron bar's fine grained microstructure allows excellent surface finishes after machining. Optimal surface finishes are achieved with fine flake size. Coarse graphite flakes can lead to tearing of the material during machining resulting in a rougher finish. Slight modifications in tooling and machining conditions will correct this condition. Surface finishes to 10 RMS can be achieved without secondary operations such as grinding and honing. Machined finishes of 32 RMS are typical, however single-digit values are readily obtainable.
The need for deburring is virtually eliminated. Parts are free from dross slag and other tool wearing inclusions. The superior finish, free from sand inclusions, results in longer tool life.
Remarkable improvement in tenacity and fatigue-resistance
Fatigue strength is primarily influenced by the graphite size and shape and will also be affected by the matrix structure. Cast iron bar continuous casting process and strict metallurgical controls result in a uniformly dense, fine-grained microstructure essentially free of porosity, sand and other inclusions, that can affect the endurance ratio severely lowering fatigue life. Cast iron bar have optimal strength in tension, compression and fatigue versus sand castings. Ductile irons having nodular graphite will have the highest endurance ratio.
High and uniform density; excellent pressure-tightness
Tests have shown that DaHua continuous cast iron bar will withstand 40 MPa hydraulic pressure across a 1mm thickness in hydraulic cylinder end caps, which is much more than normally operated pressure 23 Mpa.
Cast iron bar have excellent response to heat treatment. An achievable matrix hardness of HRC60 and an average hardness of HRC50 are possible.
Cast iron bar irons have excellent thermal conductivity due to the presence of graphite. This is an advantage in applications such as permanent molds and glass molds. Coarse flake graphite in a ferritic matrix has a thermal conductivity value of approximately 2 times that of low carbon steel.
The graphite composition in Cast iron bar gives it a much higher damping capacity than low carbon steel, cushioning vibrations as they are transmitted through a part. This ability to dampen vibrations results in a quieter product than is possible with a steel product manufactured to the same dimensional tolerances and with similar surface finishes. Gray cast iron bar have at least ten times the damping capacity of low carbon steel and ductile cast iron bar have three times the capacity.
When three "chimes", same size pieces, of gray iron, ductile iron and steel are each struck, the vibration and ringing sound resonate for different lengths of time. Gray iron, which may even be difficult to hear, stops immediately, ductile iron is short while steel resonates for an extended period of time.
The graphite particles in cast iron bar prevent friction welding which causes galling. cast iron bar resist galling and scuffing and will outperform heat treated steel in a standard pin abrasion test when in the quench and tempered or austempered condition. Additionally, localized thermal stresses are reduced because of cast iron bar's high thermal conductivity. Alloy additions, such as chrome, will stabilize carbides and improve wear properties if necessary.
Cast iron bar weigh 10% less than steel resulting in substantial savings in transportation and delivery costs to the manufacturer. This can also be especially important when meeting requirements in applications where weight is a consideration.
Corrosion resistance is not a specific property of a metal but a characteristic that depends on the conditions of exposure and the quality of performance that is required. All cast iron bar have two constituents in their microstructure, graphite and the matrix structure. Graphite will withstand a wide variety of chemical and atmospheric conditions and the matrix structure will behave similar to non-alloyed steel under the same conditions.
Cast iron bar ni-resist, having an austenitic matrix, is the most corrosion resistant grade, although even standard grades of cast iron bar may be suitable depending on the environment.
Continuous iron casting process typically equates to unparalleled value for those needing an engineered metal for their component production. Continuous cast iron bar offer numerous physical and structural advantages over steel, sand castings and aluminum because of the unique manufacturing methods. The ability to combine various graphite structures with different matrix structures (ferritic versus pearlitic) results in a variety of grades with several properties. That means cast iron bar can be tailored in a way that best meets your needs.
With cast iron bar, you can lower your overall costs and improve part performance. Making your parts run quieter, increasing your tool life and saving you money are just a few of the many benefits you can realize by using cast iron bar.