10 Welding Process & Design Flashcards
Welding method of in which the parts are to be initially heated by placing directly to fire of a forge
Forge welding
The oldest and still most used source of heat for welding based on a chemical reaction is the burning of
Oxyacetylene
Weld quality is improved by
Shielding gas
In welding when the rod is negative the set up is called
Straight polarity
In welding when the rod is positive, the set up is called
Reverse polarity
The most versatile of all welding processes is
Arc welding
A process more closely associated with pressure than fusion methods of welding and used only for making butt joints between the flat ends of work pieces without filler material
Percussive welding
This process is used primarily for attaching threaded fastening devices in applications as shipbuilding
Stud welding
Used to provide a gaseous shield that flushes away atmospheric gases to prevent oxidation and other gases contaminations of molten metal during the transfer from the rod after deposition in the molten pool
Coatings
Coatings of this are commonly used for direct current welding rods
Sodium salt
Coatings of this are commonly use for alternating current welding rods
Potassium salt
Electrodes that are design with coatings that burn off slowly enough to support the rod at a proper distance above the work for good arc length with the less operator skill
Contact electrodes
Welding method used to weld magnesium, titanium, stainless steel, is
Gas tungsten arc welding GTAW
Welding process of this type have in common the use of a filler material in wire form, which is continuously fed into the weld metal pool, and a shielding gas, or mixture of gases, to provide the atmosphere
Gas metal arc welding GMAW
Argon, helium, and carbon dioxide are used for
Welding gas shields
Welding method used primarily for lap joints between flat sheets
Spot welding
Welding method which a series of overlapping spot welds produce a continuous joint use primarily where pressure or liquid tightness is a requirement such as automotive gasoline tanks
Seam welding
Welding process in which a stream of gas is ionized by heat as it passes through an electric arc. Used for metals such as aluminum
Plasma arc
Welding method used to weld refractory metals such as beryllium
Electron beam welding
Cold bonding may be performed with less deformation by applying high frequency mechanical energy in this welding process. And important assembly method for plastics
Ultrasonic welding
The welding process, used most exclusively for making butt welds in heavy round sections, the bars and tubes are brought together with high forces while one is rotated
Friction welding
Welding procedure used for coating or cladding, structural metal with a more expensive but more corrosive resistant metal
Explosion welding
The actual shape of the bonded area or a cross-sectional shape of the filler material, frequently governed by the preparation given the edges of the part to be welded, is known as the type of
Weld
Increased welding difficulty can be excepted as carbon or alloy content is increased in the steel with the exception of this element which reduces hardenability
Vanadium
Post heat treating of stainless steel weldments is always required to restore maximum
Corrosion resistance
The American Welding Society categorizes weld defects in three general classes
Dimensional, structural, and properties
Differential heating and cooling sets up unequal stresses in the weld area that must be absorbed by
Warping, Deformation (plastic flow), or cracking if neither of the other can occur
Pockets and voids that are the result of the same kind of chemical reactions that cause similar defects in castings
Porosity
Slag, metal oxides, and non-metallic solids that are entrapped during welding are
Inclusions
The result of melting base metal and not replacing it with weld metal leaving a notch or a grove is called
Undercut
Usually caused by high stresses set up by localized dimensional changes in welds
Cracks
Cracks in the weld metal are primarily of three types
Transverse, longitudinal, and multiple star shape crater tracks
