Sage-Tips

What is the difference between white cast iron and grey cast iron?

Like gray cast iron, white cast iron features many small fractures. The difference is that white cast iron features cementite below its surface, whereas gray cast iron features graphite below its surface. The graphite creates the appearance of a gray color, while the cementite creates the appearance of a white color.

Which is stronger grey cast iron or white cast iron?

Hardness and Strength White cast iron is harder than grey, to the point that it is quite brittle. Grey iron, by contrast, is softer but stronger. The two types are sometimes combined, allowing a piece to be made with a hard outer coating of white iron and a strong core of grey.

What are the advantages of grey cast iron?

Advantages of Gray Cast Iron

• Low Cost.
• Good Vibration/Damping Capability.
• Excellent Compressive Strength.
• Ability to Withstand Thermal Cycling.
• Tensile Strength.
• Deformation Resistance.
• Low Melting Point.
• Oxidation Resistance.

Why is grey cast iron so brittle Why is it resistant to wear?

Gray iron is a common engineering alloy because of its relatively low cost and good machinability, which results from the graphite lubricating the cut and breaking up the chips. It also has good galling and wear resistance because the graphite flakes self lubricate.

What is gray iron vs ductile iron?

While gray iron does not have a measurable yield strength, the range for tensile strength is 20,000 psi – 60,000 psi. Impact – Ductile iron has a greater resistance to impacts, and is able to resist a minimum of 7 foot pounds of impact (versus 2 pounds of impact for gray iron).

What is the hardest that GREY cast iron can be?

Because of their austenitic matrix and with flake graphite, the high-nickel cast irons are the toughest of all cast irons.

Which is more brittle GREY cast iron or white cast iron?

In grey cast iron, most of the carbon is present in the form of graphite flakes, which make the material softer, more machinable and less brittle than white cast iron. As the name suggests, cast iron is very fluid when molten and is therefore suitable for the manufacture of intricate castings.

Is GREY cast iron weldable?

This depends on microstructure and mechanical properties. For example, grey cast iron is inherently brittle and often cannot withstand stresses set up by a cooling weld. As nodular and malleable irons are less likely to form martensite, they are more readily weldable, particularly if the ferrite content is high.

Why GREY iron is brittle and weak in tension?

Gray cast iron possess graphitic microstructure. The matrix contains graphite in the shape of flakes. So, gray cast iron has low tensile strength. Stress concentration occurs at the tip of these graphite flakes and makes them brittle in nature.

What is the reason of toughness of GREY cast iron?

Explanation: Grey cast iron has very poor toughness. Its major reason is notch like an effect of graphite flakes. These flakes increase stress concentration in it lowering toughness.

Why is gray iron brittle and weak in tension?

Gray cast irons are comparatively weak and brittle in tension due to its microstructure; the graphite flakes have tips which serve as points of stress concentration. Strength and ductility are much higher under compression loads.

Is grey cast iron stronger than white cast iron?

Grey cast iron’s strength is comparable to low or medium carbon steel, but it has less tensile strength and shock resistance compared to steel. Common items made from grey cast iron are well caps and well seals. White cast iron was used in both cast iron and malleable iron fittings.

Why is cast iron used as a tip cutting tool?

Cast iron in it pure state is called grey cast or pig iron and in bygon times was used to tip cutting tool because it is one of the hardest metals they had .Normaly cast Iron is very easy to cut and drill as the carbon acts like wax ,but if the iron as been chilled when made or quenched in water it reverts back to gray cast iron.ps this…

Why is cast iron more difficult to machine than steel?

The graphite structure in cast iron breaks away more easily, and in a more uniform manner. Harder irons, such as white iron, are much more difficult to machine due to their brittleness. Steel isn’t as easy to cut with the same consistency, and it causes more tool wear, resulting in higher production costs.

What is the difference between white and malleable cast iron?

Malleable iron starts out as white iron casting but is then treated at a heat of roughly 1,650°F, 900°C. Malleable iron contains more blunt boundaries opposed to flakes, which eliminates the stress concentration problems that grey cast iron can cause.