006 - Rocafc Ch 5

Front 1

Mechanical property

Back 1

Property that describes the behavior of metals under applied loads

Front 2

Load

Back 2

An external force applied to an elastic body that causes stress in a material.

Front 3

Stress

Back 3

The effect of an external force applied upon a solid material

Front 4

Tensile stress

Back 4

Stress caused by 2 equal forces acting on the same axial line to pull an object apart. It tends to stretch an object.

Front 5

Proportional limit

Back 5

The maximum stress a material can withstand without permanent deformation

Front 6

What happens to the cross sectional area under excesssive tensile loading?

Back 6

It is reduced while the length is increased.

Front 7

Compressive stress

Back 7

Stress caused by 2 equal forces acting on the same axial line to crush an object. It tends to squeeze them.

Front 8

What happens to the cross sectional area of a material under excessive compressive loading?

Back 8

The deformation causes an increase in cross section and a decrease in overall length

Front 9

Shearing stress

Back 9

Stress caused by 2 equal and parallel forces acting upon a material from opposite directions. It tends to cause one side to slide in relation to the opposing side. Note the stress is placed on the cross sectional area that is parallel to the line of the force

Front 10

Bending stress

Back 10

Stress caused by equal forces acting perpendicular to the horizontal axis of the material. Note bending stress is a combination of both tensile and compressive stresses.

Front 11

Torsional stress

Back 11

Stress caused by 2 forces acting in opposite twisting motions. It tends to twist the material.

Front 12

Torque

Back 12

A twisting force that tends to cause rotation. The product of the applied force times the distance from center of application.

Front 13

Strain

Back 13

Deformation per unit length of a solid under stress. The magnitude is equal to the total amount of deformation divided by the original size of the material.

Front 14

Elastic deformation

Back 14

Ability of a material to return to its original size and shape after being loaded and unloaded

Front 15

Plastic deformation

Back 15

Failure of a material to return to its original shape and size after being loaded and unloaded

Front 16

Elastic limit

Back 16

The yield point, the last point at which a material can be deformed and still return. The transitional area from elastic to plastic deformation.

Front 17

Modulus of elasticity

Back 17

Ratio of stress to strain with the elastic limit. The less a material deforms under a given stress the higher the modulus of elasticity.

Front 18

Ductility

Back 18

The ability of a material to stretch, bend or twist without breaking or cracking.

Front 19

Hardness

Back 19

The ability of a material to resist indentation

Front 20

Brittleness

Back 20

Lack of ductility

Front 21

Toughness

Back 21

Combination of strength and ductility

Front 22

Malleability

Back 22

The ability of a material to be deformed by compressive forces without developing defects

Front 23

Creep

Back 23

Slow progressive strain that causes materials to fail

Front 24

Cryogenic property

Back 24

Ability of the material to resist failure when subjected to very low temperatures

Front 25

Physical property

Back 25

Property of the thermal, electrical, optical, magnetic and general properties of the material

Front 26

Thermal properties

Back 26

Melting point, thermal conductivity and thermal expansion and contraction

Front 27

Thermal conductivity

Back 27

The rate at which the material transmits heat. Metals with high conductivity require more heat input during welding.

Front 28

Thermal expansion

Back 28

Expansion of material when subjected to heat. Coefficient of thermal expansion the unit change in the length of a material caused by changing the temperature 1 degree farenheight

Front 29

Electrical property

Back 29

Ability of a material to conduct or resist electricity or the flow of electrons

Front 30

Optical property

Back 30

Color of the material and how it reflects light

Front 31

Absorptivity

Back 31

Fraction of light absorbed

Front 32

Reflectivity

Back 32

Fraction of light reflected

Front 33

Transmissivity

Back 33

Fraction of light transmitted

Front 34

Chemical properties

Back 34

Properties directly related to molecular composition and pertain to the chemical reactivity of metals and the surrounding environment such as corrosion, oxidation and reduction.

Front 35

Corrosion

Back 35

Combining of materials with elements that leads to the deterioration or wasting away of the metal.

Front 36

Oxidation

Back 36

Combining of metal with oxygen into metal oxides

Front 37

Reduction

Back 37

The loss or removal of oxygen during the welding process. Atmospheric oxygen has the greatest effect on welds and must be controlled to prevent contamination.

Front 38

Structures are designed for strength and rigidity by considering not only the external loading but also what?

Back 38

The internal stresses caused by the external loads and the material required to carry those loads and stresses within the allowable elasticity.

Front 39

What is a no-load weld?

Back 39

Welds subjected to minimal loads, such as just their own weight.

Front 40

What is a fixture?

Back 40

A device used to maintain the correct positional relationship between joint members required by print specs.

Front 41

What is a positioner?

Back 41

A mechanical device that supports and moves joint members for maximum loading, welding and unloading efficiency.

Front 42

True or false:

Equillibrium is a state of balance between opposing forces.

Back 42

True

Front 43

A load that remains constant is considered what?

Back 43

Static

Front 44

What kind of weld joins the joint members at specific points to keep the joint members from moving out of their positions.

Back 44

A tack weld