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Gray cast iron and gray cast iron applications
The surface of the fracture surface of gray cast iron in gray cast iron, is characteristic of ferrite and graphite-free. During the freeze, so slow speed radiator in sand molds, People to dissolve the amount of graphite in the liquid iron have enough time to release the small plates, free shapes (usually plates) .
The chemical composition of gray cast includes mainly: iron (more than 95% by weight), and the main alloying elements carbon and silicon 2.5-4% 1-3%.
Characterization of gray cast iron
Gray cast iron has a low cost and relatively easy smelting, have low melting temperature (1350 ° C) and not demanding on impurities. Gray iron castings have good properties and high ability to mute, so the organization is also the advantage of porous material for containing lubrication oil. However, brittle cast iron, resistant to bending, can not be forged. When quenching in mold, white cast iron was difficult turning machining mechanical engineering.
Classification of gray cast iron according to ASTM A48
Classify | Tensile strength [KSI] | Compressive strength [KSI] | Modulus (E) [106 psi] |
20 | 22 | 33 | 10 |
30 | 31 | 109 | 14 |
40 | 57 | 140 | 18 |
60 | 62.5 | 187.5 | 21 |
The properties of the SAE J431 grade gray cast iron under
Marx cast | Brinell hardness | t/h | Describe |
G1800 | 120–187 | 135 | Ferritic-pearlitic |
G2500 | 170–229 | 135 | Pearlitic-ferritic |
G3000 | 187–241 | 150 | Pearlitic |
G3500 | 207–255 | 165 | Pearlitic |
G4000 | 217–269 | 175 | Pearlitic |
t/h = Tensile strength / stiffness |
Comparing the damping of some metals
Material | Ability dampers |
Gray cast (carbon equivalent high) | 100–500 |
Gray cast (low carbon equivalent) | 20–100 |
Cast globe | 5–20 |
Malleable cast iron | 8–15 |
Cast iron white | 2–4 |
Steel | 4 |
Aluminum | 0.465654 |
Application of gray cast
Due to the characteristics of the gray cast iron on so people use them a lot in the engineering industry, casting large ice machine, with high complexity, the details do not bear the big bend, but need good compression strength . Having the equipment and materials used gray cast iron to> 70% of the total weight. The ice machine tools (turning, milling, planing, ...), the body of an internal combustion engine ... and are manufactured from gray cast iron.