basic asnt review 3rd Flashcards
fracture is the type of material failure. of the following, which is another type of material failure? (fracture mechanics, low frequency dynamic loading, Permanent deformation, elongation within the Elastic range)
Permanent deformation
which of the following statements best differentiates between a defect and a discontinuity (all discontinuities are defects, all defects will lead to failure if detected, discontinuities can propagate and become defects, discontinuities are external natural boundaries only; Defects are internal flaws )
Discontinuities can propagate and become defects
Nondestructive testing is often differentiated from other measurement Or inspection technique In that
Nondestructive testing involves indirect tests related to some other quality or characteristic of the material
Which of the following describes a function of nondestructive testing (identification and sorting of material, identification of material properties, assuring absence of faults or defects that could cause a part to fail)
All of these
An important basis for the success of fracture control design procedures is
The need to assure that unexpected flaws of some critical size are not present when the component enters service
properly used, nondestructive testing can assist in fracture control by
Providing an accurate evaluation of the number and type of discontinuities that exist in the material
a statement that a particular experiment to produce to .9 probability of detection with a 95% of Confidence level means that
There is a 5% probability that the probability of detection is overstated
The most solid metals and plastics that have reasonable strength at room temperature are called
Allotropic materials
Material properties as used in design, are most frequently determined by
Material testing
Even at the early stages of product planning, nondestructive testing should be considered because (may be required by codes and specifications, the design of the part should permit easy access to critical areas for inspection, the materials selected should be compatible with an nondestructive technique that can accurately evaluate the product)
All of these
Which of the following material properties are of most concern if corrosion resistance is essential (Processing Properties, mechanical properties, physical properties, Chemical Properties )
Chemical Properties
Which of the following is true relative to the comparison of the properties of aluminum based alloys and iron base of alloys (iron has a lower melting point than aluminum, iron can exist in different crystalline structures and it can be controlled by heat treatment, iron can be alloyed to increase its strength whereas aluminum is strongest in its pure state, iron is preferred in load carrying designs but should not be used in any deformation type of manufacturing process)
iron can exist in different Crystalline structures, and its properties can be controlled by heat treatment
Tensile tests are conducted on specimens from a newly developed alloy in order to determine the ultimate Tensile strength of that material. Such tests are called
Destructive tests
A bar that is 12 inches long, 2 inches wide, and 1 inch thick is subjected to a Tensile load acting along the length of the bar of 36,000 pounds. What is the tensile stress within the bar
18,000 PSI
The modulus of elasticity, or Young’s modulus, is related to the materials relative
Stiffness or yield strength
Which of the following materials is typically considered when the application only requires High compressed of strength (Low carbon steel, high carbon steel, cast iron, magnesium )
Cast iron
A fatigue failure can often be prevented by using non destructive testing to
Detect surface discontinuities that could be stress risers
Which of the following tests uses a pendulum to break a specimen that is notched and supported on both ends, with the result of measuring energy absorption (creep test, charpy test, fatigue test, transverse rupture test)
Charpy test
Direct hardness tests provide a measure of a materials ability to resist
Surface and near surface penetration
A particular type of steel has an ultimate strength of 80,000 pounds psi, an elastic limit of 60,000 PSI and a yield strength of 62,000 PSI. An allowable design stress of 20,000 PSI is used, what is the factor of safety based on the ultimate strength
Four
Under ordinary usage, metals exist as
Crystalline solids
The terms of body centered cubic, face centered cubic, and hexagonal close packed all refer to the
Lattice structures that make up unit cells in a solid metallic Structure
the process of returning ductility to a cold work low carbon steel is called
Recrystallization
Many metals exhibit an increase in strength caused by plastic flow beyond elastic limit. This effect is called
Work hardening
When used as an in process treatment, recrystallization can
Improve ductility, refine grains
Process is called all Austenitizing, annealing, normalizing, sphereoidizing are
Approximate equilibrium heat treatment processes
the term of precipitation hardening is often used interchangeably with the term
Work hardening
An NDT to method that has the ability to measure changes in electrical conductivity caused by the effects of heat treatment is
Eddy current testing
Spheroidizing and normalizing have the effect of
Increasing ductility
When Steel has been Quench hardened and then reheated to some point below the lower transformation temperature for the purpose of reducing brittleness, this is called
Tempering
Annealing is usually performed to
Decrease hardness, increase ductility, relieve stresses
Attacks on metals by direct chemical action or electrolysis are called
Corrosion
Metal corrosion that is accelerated when the metal is under loads is called
Stress corrosion
Which of the following may be performed to help prevent corrosion (Stress relieving, anodizing, dipping in molten metal, electroplating )
All of these
factors of safety are often in the range of 2 to 4 because
Provide allowances for unexpected loads or conditions, present problems and assigning effective aircraft, could be reduced with the assurance of NDT techniques that the material was free of discontinuities
the reduction of iron ore, by mixing with coke, limestone, and oxygen for combustion of the coke, is accomplished in
A blast furnace
In the iron and steel making process of, the term pig iron refers to
A high a carbon, low ductility metal that is produced in the blast furnace which can be used to make subsequent types of iron and steel
Which of the following techniques is often used to speed up the steelmaking process (adding large amounts of carbon to the molten metal, reducing the amount of scrap steel that is often added to the molten metal, adding oxygen to the molten metal, converting the old open hearth furnaces into electric furnace )
Adding oxygen to the molten metal
Typically, the highest quality of steel has produced in
An electric furnace
What percentage of carbon is found in steel
Less than 2%
By Which of the following processes is most of the world steel produced
Basic oxygen
An undesirable byproduct of steelmaking process is
Slag
A steel with 40 points of carbon contains
0.4% carbon
Low carbon steel contains approximately
0.06 to 0.25% carbon
Corrosion resistance steels having relatively high percentages of nickel and chromium
Stainless steels
Austenitic stainless steels are paramagnetic; this means that
non magnetic
Which of the following is an advantage of cast steel over wrought steel (Cast steel usually have More mechanical properties than wrought steel, cast steel have more Is tropic properties Then wrought steel, cast steel are more corrosion resistant than Wrought steel , cast steel cannot be heat treated and are thus less expensive to produce )
Cast steel have more isotropic properties then wrought steel
which of the following nonferrous metals is the most important structural material (Copper alloys, nickel alloys, zinc alloys, aluminum alloys)
Aluminum alloys
The heat treatment of aluminum for the purpose of hardening and strengthening
Can produce tensile strengths equivalent to some carbon steels
Which of the following metals has low strength, hi corrosion resistance, and is used largely and die casting operation (Aluminum, magnesium, zinc, manganese)
Zinc
Which of the following metal alloys has a density approximately 2/3 that of aluminum (Magnesium, beryllium, copper, nickel)
Magnesium
monel and inconel are
Nickel alloys
Which of the following metals can be typically used in an as cast state (Aluminum, zinc, steel, iron)
All of these
A high strength, low density, corrosion resistance metal alloy of significance in the aircraft, marine and Chemical Processing industries is
Titanium
Which of the following statements is true concerning plastics following their initial polymerization (Thermoplastics re soften when reheated, thermosetting plastics do not soften, but char and deteriorate when reheated, all plastics are synthetic and contain no natural materials)
Thermoplastic RE soften and an thermosetting plastics do not soften but deteriorate when reheated
based on the strength to weight ratio: plastics and stele
Some plastics, including nylon, may have strengths greater steel
regarding solidification of molten metal in a casting mold, how does cooling take place
In phases having different rates of that produce different types of grain structure in different sections of the casting
In a casting, shrinkage occurs
Before, during, and after the transformation from a liquid to solid
Large voids or porosity in the casting result from
Gas evolution before and during solidification
During the solidification of a casting the shrinkage that occurs
May cause cavities that are enlarged by the evolution of gases
The design of the casting is important because the quality of the finished product can be adversely affected by the
Lack of molten metal to compensate for contraction, location of the gate with reference to either progressive solidification or directional solidification, the location of hotspots in areas of the casting that are isolated by thin sections
That term used to describe the discontinuity in a casting that occurs when molten metal interfaces with already solidified metal with failure to fuse at that interface
Cold shut
The part of the casting where the gate or riser was attached
May provide a concentration point for discontinuities
Risers, feeders, or feed heads in castings serve to provide sources of molten metal to compensate for
Shrinkage
Green sand casting molds include
Sand, clay and water