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25 Cards in this Set
- Front
- Back
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How does a brinell tester work |
Hydraulic force impresses onto the sample. The diameter of the impression relates to the hardness. 3000kg for steel 500 kg for non ferrous |
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How does a Rockwell tester work |
Same as brinell but measures depth of impression. |
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What is the procedure for using a Rockwell |
Clean Opposite surface ground flat Scratches polished out Minor load 10kg applied to zero Major load applied on dial Depth is indicated on a scale on Rockwell. |
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What are the shapes of the points in a Rockwell |
1/16 ball 1/8 ball Conical diamond |
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What is the shape if the point in a brinell |
Spherical |
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What is ultimate tensile strength |
maximum stress that a material can withstand while being stretched or pulled before breaking. In brittle materials the ultimate tensile strength is close to the yield point, whereas in ductile materials the ultimate tensile strength can be higher. |
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What is Youngs modulus of elasticity |
used to describe the elastic properties of objects like wires, rods or columns when they are stretched or compressed.defined as the"ratio of stress (force per unit area) along an axis to strain (ratio of deformation over initial length) along that axis"It can be used to predict the elongation or compression of an object as long as the stress is less than the yield strength of the material. |
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What is yield strength |
Yield Strength is the stress a material can withstand without permanent deformation or a point at which it will no longer return to its original dimensions (by 0.2% in length). |
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What is % elongation |
Elongation is a measure of the ductility of a material as determined by a tension test. It is the increase in the gauge-length of a test specimen after fracture divided by its original gauge-length. Higher elongation means higher ductility. |
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What is the difference between tensile strength and yield point |
The yield is when the material starts to give; the UTS or ultimate tensile strength is when it snaps. |
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What is the formula for tensile strength |
The formula is: s = P/a Where, s is the tensile strength P is the force required to break a is the cross-sectional area |
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How is the brinell hardness number derived |
Dividing the applied load by the surface area of the indentation |
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How is the Rockwell number derived |
Rockwell hardness value is derived from the difference in the baseline (minor) and final depth (major) measurements. |
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What is hardness |
Resistance to cuts penetration and abrasion |
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What is malleability |
Able to be bent formed or shaped without cracking |
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What is ductility |
Be able to be drawn into wire stock or extruded in rods |
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What is elasticity |
Tendency to return to original shape. Leaf springs |
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What is toughness |
Resistance to tearing or breaking when bent or stretched |
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What is density |
Mass per unit volume |
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What is brittleness |
Tendency to break or shatter when exposed to stress. Cast iron. |
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What is fusibility |
Ability to be joined by heating. Welding |
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What is conductivity |
Ability to carry heat or electricity |
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What is contraction |
When a metal is cooled it shrivels |
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What is thermal expansion |
Expanding when hot. Contracting when cooled. The amount is predictable which is called coefficient of expansion |
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What is metal cladding |
used to improve mechanical properties or increase corrosion resistance, repair worn out parts. |
