Where would the fracture in a cast iron specimen occur in a compression test?

Where would the fracture in a cast iron specimen occur in a compression test?

Therefore the fracture would be due to slip of planes and is due to the combination of compressive and shear stresses. As cast iron is weak in shear, failure occurs along this inclined plane.

How does a cast iron specimen fail under compression load?

Materials like cast iron are weak in tension because of the presence of sub-microscopic cracks and faults. In compression test the cross sectional area of the specimen increases which tends to increase the compressive strength. Therefore reach much higher ultimate stresses in compression than in tension.

What type of fracture occurs when a brittle material is under torsion?

Case-5: Brittle material in torsion • Since, brittle materials have minimum tensile strength. Hence, brittle materials fails in tension. Hence brittle material subjected to torsion fails at 45° plane (Helicoidal failure). Since, ductile materials are weak in shear.

Why cup and cone formation does not occur in cast iron specimen when tested in tension?

Since ductile material strong in tension, therefore failure is due to shear, the plane of failure is at 45° from the axis of shaft, such failure is known as cup and cone failure.

What is the type of fracture in cast iron?

Cleavage fracture is common in cast irons.

Which is the is code used for compression test on metals?

ASTM E9 describes the compression testing of metals such as steel or metal alloys. This test method determines important mechanical properties such as the yield strength, the yield point, Young’s Modulus, the stress-strain curve, and the compressive strength.

Why is cast iron stronger compression?

Compared to tensile strength cast iron is strong in compressive strength. This is because cast iron is having 2 to 4% carbon in it which makes it brittle in nature and all brittle materials are comparatively stronger in compression than in tension.

Why does brittle material Fail at 45 degrees?

This is due to the reason that the plane of maximum shear stress in case of uniaxial tension is inclined at 45 degrees with the axis. Brittle materials do not undergo significant plastic deformation. They thus fail by breaking of the bonds between atoms, which usually requires a tensile stress along the bond.

How does a brittle fracture occur?

Brittle fracture occurs when an otherwise elastic material fractures without any apparent sign or little evidence of material deformation prior to failure. Fracture occurs instantaneously with little warning and the vessel’s overall structure need not be subject to a high stress at the time.

What is a cone fracture?

A cup and cone fracture is a type of failure observed in ductile metals and plastics that are subjected to a uniaxial force. It is essentially the separation of a body into two separate pieces due to the application of excessive tensile stress.

What is the fracture toughness of cast iron?

11-19 MPa m
The fracture toughness of flake cast iron ranges from 11-19 MPa m1/2 [35].

What causes fracture toughness?

The fracture toughness of metals and other ductile materials is dependent on their thickness. The toughness is highest when plane stress conditions exist at the crack tip, and this occurs when the material is thin (typically less than several millimetres).

What is expected failure for mild steel and cast iron?

Expected failure for Mild Steel and Cast Iron Specimens and reasoning: Fracture in torsion for ductile materials generally occur in the plane of maximum shear stress perpendicular to the axis of bar where as for the brittle material failure occurs along 45° hilux to the axis of bar due to tensile stress across that plane.

What is torsion test on mild steel and cast iron?

Torsion Test on Mild Steel and Cast Iron – Lab Report. Purpose: To study the shear stress ~ shear strain behavior of the material. To study the failure pattern of these materials in torsion. To determine the mechanical properties, e.g, Modulus of elasticity, Modulus of rigidity, Shear strength, shear strain and ductility in torsion.

How do you compare the performance of steel and cast iron?

By simply comparing the two graphs to one another, the traits of each material are clearly displayed. Noticing the domain of each graph, it is shown that the steel test sample rotated nearly ten times more than the cast iron sample. Furthermore, the steel sample experienced nearly two times the torque than the cast iron.

How do you fix a broken cast iron torsion machine?

Tighten the chucks of the attached arm, remembering to tighten them evenly. Start the torsion machine. Observe the material as the torque is applied. Once the cast iron fails stop the machine. Pull the non-attached arm away from the machine. Loosen the chucks of both arms and remove the two pieces of cast iron.