HT 3 advancement exam, chapter 6, metallurgy

What are two of the detrimental impurities sometimes found in steels?
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What are two of the detrimental impurities sometimes found in steels?
phosphorus and sulfur
During welding, what do sulfur or phosphorus sometimes produce?
forms gas which creates pockets. this causes brittleness
What is Load and how is it measured?
external force applied to a material
Newton's Third Law
For every action there is an equal and opposite reaction
What is stress?
the equal and opposite reaction to externally applied pressure
How is stress measured?
Pounds (for load) per square inch (for area)
What is strain?
deformation or change in shape caused by a load
How is strain measured?
Strain is measured in inches per inch or in percentage
What are the three basic forms of stress?
Tension, compression, and shearing
What are complex stresses?
Any combination of basic stresses i.e. bending/torsional
What is Tension stress?stress that pulls a material apart <----[]---->What is Compression stress?compression stress develops within a material to oppose the forces that then to compress or crush the material ----->[]<-----What is shearing stress?stress that develops when opposite external forces are applied along parallel lines in such a way as to tend to cut the material. ||[]^ v |What is bending stress?What is Torsional stress?External stress that tends to produce rotationHow are atoms arranged in solid metals?in a definite geometric (or crystallographic) patternWhat is the smallest grouping of atoms called?a unit cellWhat is a regular arrangement of unit cells called?a Space LatticeWhat is it called when metal crystalizes in a way that is not perfectly formed?Each unit that is not formed correctly is known as a grain rather than a crystalWhat does Grain Structure refer to?the crystalline structure of the metal, often in reference to the shape and size of the grainsT/F: the quicker a metal solidifies, the smaller the grains will beTrueWhat two solid solutions are important constituents of steels?Ferrite and AusteniteWhat is Ferrite?solid solution of alpha iron and carbonWhat is Austenite?solid solution of gamma iron and carbonWhat are intermetallic compounds?compounds formed BETWEEN a metal and some other substanceWhat is the most important thing to remember about intermetallic compounds?loss of identity and change in propertiesWhat is Iron Carbon/Cementite?extremely brittle compound formed by the combination of iron and carbonWhat is the formula for Iron Carbide/Cementite?Fe3C shows that three atoms of iron combine with one atom of carbon to produce Iron CarbideWhat is a Mechanical Mixture?the structure of an alloy when two or more structural forms are mixed together but are still separately distinguishableWhat is Pearlite?an intimate mechanical mixture of ferrite and Cementite in alternating plates or layersHow is Peralite formed?when steel that contains just about 0.85% carbon is heated to a certain temp and then cooled slowlyWhat is Eutectoid composition?when the entire structure is in the form of Pearlitewhat is the completely pearlitic structure called?Eutectoid or Eutectoid StructureWhat is a physical property?a characteristic of a metal that can be observed it measuredWhat effects the physical properties of steel?Carbon content, impurities, addition of various alloying metals, heat treatmentDefine elasticitythe ability of a material to return to it's original size and shape after strainWhat is the elastic limit?The maximum amount a material can be stretched by a force without permanently deforming (and still return to its original length when the load is removed)What happens when the elastic limit is exceeded through an axial load?permanent deformation in the form of elongation or compressionWhat happens when the elastic limit is exceeded through a non-axial load such as Torsion or shear?a permanent angular deformationExplain the Modulus of Elasticityratio of stress obtained by dividing the stress by the strain Stress (psi) E= ------------ Elongation (inch per inch)What is the Yield Point?stress at which deformation of the material first increases markedly without any increase in applied load.Define Ultimate Strengththe maximum stress that a material is capable of withstanding in tension, compression, or shearWhat is Compressive strength?how much squeezing force metal can withstand before it failsWhat is Tensile Strength?ability of a metal to resist being pulled apartDefine fatiguetendency of a material to fail after repeated stressing at the same pointwhat is metal fatigue?the tendency for a metal to break under the action of repeated cyclic stressesforms of stressHardnessability of a material to resist penetrationToughnessthe property that enables a material to withstand shock, endure Tensile stresses, and to be deformed without breakingPlasticityMaterials that can withstand extensive permanent deformation without breaking or rupturing the opposite of brittlenessWhat is ductility?the property that enables a material to withstand extensive permanent deformation from tensionWhat is a malleable material?one that can withstand extensive permanent deformation from compressionWhat does the term "creep" refer to?describes a special kind of plastic deformation that occurs very slowly at high temperatures when the material is under constant stressExplain BrittlenessThe opposite of ductility. A material that will fracture before exhibiting any noticable permanent deformation e.g. cast ironExplain corrosion resistanceProperty that enables a material to resist entering into a chemical combination with other substancesWhat are the two major types of metal?Ferrous and non-ferrousFerrous metalsmetals containing ironNon-ferrous metalany metal which is not formed from ironWhat is known as Ingot Iron?commercially pure iron (99.85% iron)What is wrought iron?a mixture of very pure iron and slagHow is cast iron made?produced by resmelting a charge of pig iron and scrap ironWhat are the four kinds of cast iron?white cast iron, grey cast, malleable cast, and nodular castDescribe white cast ironan alloy of iron, carbon, and silicon. is hard, brittle, wear resistant, and unmachinable due to its carbon (Cementite)Describe grey cast ironAlways contains iron, carbon, and silicon and generally contains more carbon (graphite flakes) and silicon than white cast.Three types of grey cast ironcommon, high strength, alloyDescribe malleable cast ironstrong, machinable, and ductile. made by hearing white castings to 1700°F for about 50 hrs then slowly cooled to room temp.Describe Nodular Cast IronProduced the same way as grey but with more control of inoculating agents. contains spherical graphite rather than flake. good machinablity, dampening capacity. ductility is about half that of cast steelHow are steels classified?on the basis of manufacturing method, method of shaping, method of heat treatment, properties, intended use, and chemical compositionWhen classified by manufacturing method what are steels known as?1. basic, open hearth 2. basic, electric 3. acid, Bessemer 4. acid, electric 5. acid, open hearth 6. basic, oxygen furnaceWhen steel is classified by it's method of shaping how are they referred?cold rolled steel, forged steel, drawn steel, and cast steelClassifying steel by heat treatmentAnnealed steel and casehardened steelClassifying steel by propertiesCorrosion-Resistant Steels (CRES) Heat resistant steels low-expansion steels free-machining casehardening High Tensile Steel (HTS) Special Treatment Steel (STS)plain carbon steelA ferrous alloy in which carbon is the prime alloying element.Different types of plain Carbon steel(in increasing order of the amount of carbon present) 1. mild steel 2. low-carbon steel 3. medium-carbon steel 4. high-carbon steel 5. very-high-carbon steelAlloy Steelcreated by adding other elements to plain Carbon steeleutectic pointlowest temperature at which a metal/alloy will meltHow many classifications of alloy steels and what are they2 low-alloy and high-alloyHow does Chromium improve steel?increases resistance to corrosion, improves hardness/toughness/wear resistance/strength/responsiveness to heat treatmentHow does manganese improve steel?increases strength and responsiveness to heat treatmentHow does Molybdenum (molly-b) improve steel?increases toughness and improves strength of steel at higher temperaturesHow does nickel improve steel?increases strength, ductility, and toughnessHow does tungsten improve steel?produces dense, fine grains; helps steel to retain it's hardness and strength at high temperaturesHow does silicon improve steel?improves the electrical quality of steelHow does vanadium improve steel?retards grain growth and improves toughness