Final
Low-carbon (mild) steel is
0.02-0.30% carbon, tough and ductile, most commonly used type of carbon steel, mostly produced as rolled steel
Medium carbon steel
0.30-0.45% carbon content, strong and hard but less ductile, not easily welded
High carbon steel
0.45-0.75% carbon, very hard and strong
Never use acetylene at pressures in excess of ________.
15 psi! 5 psi is enough
stainless steel
A metal alloy of steel, contains sufficient chromium to form a passive film of chromium oxide on the surface; noted for its ability to resist rust.
lead angle
Angle between torch or welding rod and the work, parallel to the direction of the weld (45 Deg.)
work angle
Angle between torch or welding rod and the work, perpendicular to the direction of the weld
thermal spray
COATING PROCESSES IN WHICH MELTED (OR HEATED) MATERIALS ARE SPRAYED ONTO A SURFACE
Iron, Carbon (2.1 to 4%) and Silicon (1 to 3%); what metal is this?
Cast Iron
Which metal is the softest?
Cesium
Which metal is the hardest?
Chromium
metalloids
Elements that have properties of both metals and nonmetals.
AC stands for Direct Current
False
I can change the welding current and switch polarity while making a weld
False
I can wear welding gloves while operating the belt/disk sanders
False
I do not have to wear a welding jacket if I am just doing a tack-weld
False
If I start gas welding, I turn on the main valve of the oxygen tank FIRST
False
It is okay to arc weld on coated material
False
The ground clamp does not need to be attached to the welding table or work piece
False
The letter "E" on the electrode denotes "electricity"
False
When operating sheet metal shear, I can cut 2 pieces at a time
False
Steel is the most widely used of all metals, accounting for 95% of worldwide metal production.
False: Iron
If I see pinholes in surface of my weld, this is called undercut
False: it's porosity
FCAW
Flux Core Arc Welding
FCAW:
Flux Cored Arc Welding; a wire consisting of a steel electrode surrounding a powder fill material
MIG Welding
GMAW (gas metal arc welding): pool of solid-steel wire is fed from the machine through a liner; heat, filler rod, shielding gas
Brinell Hardness Test
Indicated the diametric area of impression as the Hardness Number
non metals
Low conductivity, not ductile, not malleable, brittle, dull, gas at room temp
tensile strength
MEASURE WHICH INDICATES THE ABILITY OF A MATERIAL TO WITHSTAND A LONGITUDINAL STRESS
box and pan brake
Machine used for bending sheet metal
soldering
Process of finding two pieces of metal I'm means of the filler materialHaving a lower melting point than the metals to be joined
malleability
REFERS TO A MATERIAL'S ABILITY TO DEFORM UNDER COMPRESSIVE STRESS.
SMAW
Shielded Metal Arc Welding (Stick); requires filler rod, and shielding
hot rolled steel
Steel formed into its final shape by passing it between rollers while it is very hot. Blue scale on surface when cooled
galvanized steel
Steel that has been coated with a protective layer of zinc to prevent rusting
extractive metallurgy
The practice of removing valuable metals from an ore and refining the extracted raw metals into a purer form.
A dirty tip torch can cause backfiring.
True
Aluminum has about 1/3 the density and stiffness of steel
True
Copper is probably the oldest known metal
True
Galvanized steel is widely used in applications where RUST RESISTANCE is needed
True
In Arc welders, the amperage is adjustable and the voltage is constant
True
It is NEVER okay to dip electrode holder into water buckets.
True
Low carbon "Mild" steel has about 0.3% carbon
True
The electrode forms a slag coating over a bead
True
The first two digits on an electrode represent tensile strength
True
Weld speed determines width of bead
True
You have to remove slag before cooling it off with water
True
Iron and Carbon (less than 0.03%); what metal is this?
Wrought Iron
metal
a generally solid substance with: HIGH ELECTRICAL AND HEAT CONDUCTIVITY, LUSTER, HARDNESS, high tensile strength, ductility & malleability
plating
a process in which a metal is deposited on a conductive surface
deep drawing
a process in which sheet metal blank is radically drawn into a forming die by the mechanical action of a punch
lead
a soft heavy, highly malleable metallic element; poor conductor of electricity, very resistant to corrosion
shear strength
ability of a material to resist forces that attempt to cause the internal structure of the material to slide against itself
zinc
bluish-white, lustrous, diamagnetic metal; 3rd most used nonferrous metal
very high carbon steel
carbon content higher than 0.75%, super hard and strong, seldom welded
bronze
copper and tin
brass
copper and zinc
neutral flame
equal amount of oxygen and acetylene
carburizing flame
excess acetylene
oxidizing flame
excess oxygen
rolling
fabricating process in which metal is passed through a pair of adjustable rolls
annealing
heat (metal or glass) and allow it to cool slowly, in order to remove internal stresses and toughen it.
strength
its ability to withstand AN APPLIED STRESS without failure
The Rockwell R Hardness Test
measure the resistance to/ penetration of: a steel ball or a diamond cone; depth of impression is measured
ferrous
metals which contain iron, generally magnetic
nonferrous
metals which do not contain any iron; not magnetic, more resistant to corrosion
The periodic table is divided into three sections:
metals, non-metals, and metalloids
spinning
metalworking process by which a disc or tube of metal is rotated at high speed and formed into an axially symmetric part
flashback
popping and hissing noise; explosion at the tip of the nozzle and a squealing sound and smoke issuing from the nozzle tip
backfire
popping noise; explosion at the tip of the nozzle
case hardening
process of hardening the surface of a metal, often a low carbon steel, by infusing elements into the surface; resulting surface is harder than base material
punching
process of using a press to push a punch through the material and into a die to create a hole in the workpiece
hardness
property of a metal, which gives it the ability to being PERMANENTLY DEFORMED under load;
Quenching
refers to heating and a rapid subsequent cooling; heating to 1500F and rapidly cooling with air =, bring, oil, or water
porosity
refers to the pinholes in the surface of the weld bead
Tempering
relieve the internal stresses and reduce brittleness, slowly heat up the piece below its hardening temperature and a blue line of heat will appear and allow it cool slowly with air
cold rolled steel
sheet steel that has been formed using heavy rollers at room temperature, to improve its surface finish, hardness, and strength
The best metallic conductor of electricity is:
silver
nickel
silvery-white lustrous metal with a slight golden tinge
aluminum
soft, lightweight, ductile, durable metal; good thermal and electrical conductor
ductility
the ability of a substance to be drawn, pulled, or extruded through a small opening to produce a wire
compressive strength
the maximum compressive stress that a material can withstand w/o being crushed
ironing
the process of uniformly thinning the workpiece in a specific area
luster
the way light interacts with the surface of metal; radience, shine
sheet metal
thickness <1/4
plate
thickness >1/4
metal finishing
to improve the appearance of the product, to prevent corrosion, cover the surface of a less expensive metal with a more expensive one
perforating
to puncturing of a material with a harder (usually sharp) object to create a hole or aperture
radioactive metals
uranium and plutonium
press brake forming
uses an open-frame single action press to bend, corrugate, curl, notch, perforate, pierce, or punch a sheet metal or plate`
MIG Welding
welding that uses an inert gas or gas mixture for shielding; buzzing sound