Term
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Definition
| commonly used to evaluate corrosion rates of welded materials and the usage of these materials in corrosive environments. (could not find a good definition in the book so I googled it.) |
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Term
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Definition
| A base metal is a common or at least inexpensive metal . Frequently, the term is used to refer to those that oxidize or corrode relatively easily, and react variably with dilute hydrochloric acid . (also could not find in book so I googled it) |
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Term
| Bead Weld (or surfacing Weld) |
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Definition
| or surface welds, are made directly onto a flat surface and therefore require no edge preparation. (Degarmo 922) |
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Term
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Definition
| induced by a combination of temperature, pressure, and metallurgical conditions; coalescence between two metals requires sufficient proximity and activity between the atoms of the pieces being joined to cause the formation of common crystals (page 920) |
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Term
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Definition
| process developed to facilitate the joining or assembly; examples include welding, brazing, soldering, and the use of discrete fasteners, such as nuts, bolts, screws, and rivets (page 920) |
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Definition
| warping of the assembly (page 929) |
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Definition
| used for tee, lap, and corner joints, and require no special edge preparation (page 923) |
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Definition
| four basic types, including bead welds, groove welds, fillet welds, and plug welds (page 922-23) |
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Term
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Definition
| (also weld pool) zone where the two materials are fussed together ( pg. 926). |
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Term
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Definition
| type of weld used when full-thickness strength is desired on thicker material (pg. 922). |
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Definition
| the zone adjacent to the fusion zone and wholly within the base material. In this, region the parent metal is not melted, but is subjected to elevated temperatures for a brief period of time (pg. 926). |
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Term
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Definition
| (pg. 922)-the weld and base metal did not come together completely |
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Term
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Definition
| (pg. 922)-insufficient weld depth |
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Term
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Definition
| (pg. 928)-in small amounts they can enhance bonding and provide strength reinforcement, however, they are quite brittle and too much can result in loss of both strength and ductility |
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Term
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Definition
| (pg. 923)-5 basic types of joints (butt, lap, tee, corner, and edge) |
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Term
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Definition
| (pg. 924): one piece structures produced by welding |
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Term
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Definition
| (pg 929): reduces warping, metal is hammered with a peening tool and flattened |
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Term
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Definition
| (pg 923): attach one part on top of another and are often used to replace rivets or bolts |
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Term
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Definition
| (pg 928): a special postwelding heat cycle required when welding higher carbon and alloy steels |
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Term
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Definition
| an alternative technique to reduce the variation in microstructure or at least the sharpness of the variation is to preheat either the entire base metal or the segments adjacent to the joint just prior to welding. (page 927) |
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Term
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Definition
| speed with which a welding process imparts heat. Processes with low heat input tend to produce high total heat content with in the metal, slow cooling rates, large heat affected zones and result in structures with lower strength and hardness, but higher ductility. High heat input processes tend to have low total heats, fast cooling rates and small heat affected zones. (page 927) |
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Term
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Definition
| residual stresses created in welds that are either performed on a nearly complete structure or repair welds where the welded plates are restrained from horizontal movements. (page 929) |
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Term
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Definition
| (928) – the result of restraint to thermal expansion and contraction offered by the pieces being welded |
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Term
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Definition
| (930) – heat treatment given to welded assemblies that sustain additional warpage when machining removes metal and upsets the stress equilibrium balance |
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Term
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Definition
| (921) – using a high temperature flame to cut a work piece |
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Term
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Definition
| the permanent joining of two metals which is induced by a combination of temperature, pressure, and metalurgic conditions. (921) |
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Term
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Definition
| a materials ability to be welded.(930) |
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Term
| Weld Metal (or Weld Pool) |
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Definition
| a mixture of a parent metal and electrode or filler metal, wich the ratio depending upon the process used, the type of joint, and the edge preparartion. (926) |
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Term
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Definition
| (C2H2) is the principle fuel gas used in a welding torch. |
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Term
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Definition
| one of the three types of flames that can be produced by varying the oxygen/acetylene ratio. It contains excess fuel that decomposes to carbon and hydrogen; also called reducing flames; metal is well protected from oxidation with this flame. Used to weld Monel, high-carbon steels, and alloy steels (934). |
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Term
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Definition
| filler metal is used to join slight gaps between two materials during welding (935). |
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Term
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Definition
| (pg. 939, 940) is basically the use of controlled, localized upsetting as a means of straightening warped or buckled plates |
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Term
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Definition
| (pg. 921, 935, 943,944, 946) is to promote the formation of a better bond and may be used to clean the surfaces and remove contaminating oxide. It can be added as a powder, the welding rod can be dipped in flux paste or they can be recoated |
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Term
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Definition
| (pg. 921, 925, 935, 941) almost all oxyful gas welding which can produce good quality welds. The metals to be joined are simply melted where a weld is desired and no pressure is required |
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Term
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Definition
| A gap caused by an oxyfuel gas torch flame melting away the metal. (p936) |
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Term
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Definition
| Alternative fuel gasses such as propane and propylene. Lower flame temperature but they can be safely stored in normal pressure tanks. (p935) |
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Term
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Definition
Created when all reactions are carried to completion. (p934)
ratio is 1:1 or 1.5:1 Most welding done with this. |
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Term
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Definition
| Uses a higher ratio 1.5:1. Hotter than the other flame. (p934) |
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Term
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Definition
| the most common thermal cutting, commonly called flame cutting. In some cases the metal is merely melted by the flame of the Oxyfuel gas torch and blown away to form a gap, or kerf. Pg 936 |
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Term
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Definition
| refers to a group of welding processes that use as their heat source the flame produced by the combustion of a fuel gas and oxygen. Pg 933 |
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Term
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Definition
| If the workpiece is already hot from other processing, such as solidification or hot working, no supplemental heating is required, and a supply of oxygen through a small pipe is all that is needed to initiate and continue a cut. Pg 937 |
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Term
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Definition
| the most common is Oxyfuel gas cutting. Look at Ch 35 definition |
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Term
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Definition
| Device that burns acetylene and oxygen and is used for oxy-fuel gas welding as well as cutting. The cutting torch has a tip with a circular array of small holes through which the gas mixture is supplied to form the heating flame. (p.933,937) |
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Term
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Definition
| Locally used in flame straightening in order to straighten warped of buckled plates; shorten the upper surface of the plate and bring it back to a straight or flat configuration; this can be used to correct structures that have been bent accidentally (p.939) |
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Term
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Definition
| a concentrated heat source between two electrodes that can approach 4000*C ; used in arc welding and arc cutting (p.941) |
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Term
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Definition
| a metal cutting process in which the metal is melted by the intense heat of the arc and then force to flow away from the region of the slit or notch; commonly thought of as an adaptation of arc welding; there are several techniques including air-carbon, oxygen, gas metal, gas tungsten and plasma. (p.936-937) |
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Term
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Definition
| all _______ processes employ a basic circuit where electron are attached to the positive workpiece while ionized atoms in are arc column are accelerated toward the negative electrode. Because the ions are much more massive than the electrons, the heat arc is more contrasted at the electrode, by which the metal is melted. Page 941 |
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Term
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Definition
| an electric current that reverses direction in a circuit at regular intervals (not found in Degarmo) |
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Term
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Definition
| iron powder is first deposited into the joint as a means of increasing deposition rate; a single weld pass can then produce enough filler metal to be equivalent to seven or eight conventional submerged are passes. Page 494 |
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Term
| Consumable Electrode Process |
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Definition
| (p. 942) - the group of arc welding processes where the electrode is consumed and supplies the metal needed to fill the joint. |
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Term
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Definition
| (p. 941) - direct-current electrode-negative, also known as straight polarity as the direct current is used and the electrode is made negative. Electrons are attracted to the positive workpiece while ionized atoms in the arc column are accelerated toward the negative electrode. These processes are characterized by fast melting of the electrode (high metal deposition rates) and shallow molten poolon the workpiece (weld penetration). |
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Term
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Definition
| (p. 942) - when the work is made negative and the electrode positive, this is known as direct-current electrode-positive, or reverse polarity. The positive ions impinge on the workpiece, breaking up any oxide films and giving deeper penetration. However, metal deposition rate is lower. |
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Term
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Definition
| A conductor used to make contact with a nonmetallic part of a circuit |
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Term
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Definition
| A metal added in the making of a joint through welding, brazing, or soldering |
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Term
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Definition
| A material that acts as a catalyst for smelting and soldering. It assists the flow of the molten metal |
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Term
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Definition
| (pg 945)- (FCAW)- overcomes some of the shielded metal arc limitations by moving the powdered flux to the interior of a continuous tubular electrode. |
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Term
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Definition
| (pg 946)- (GMAW)-formerly referred to as metal inert-gas welding. Refers to if the supplemental shielding gas flowing through the torch becomes the primary protection for the arc and molten metal, there is no longer a need for the volatilizing flux, and the electrode can now become a continuous, solid, uncoated metal wire. |
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Term
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Definition
| (pg 951)- (GTAW)- formerly known as tungsten inert-gas welding, or Heliarc welding when helium was the shielding gas. A non-consumable tungsten electrode provides the arc but not the filler metal. The pointed electrode is positioned in a special holder through which inert gas flows to provide a protective shield around the electrode, the arc, the pool of molten metal, and the adjacent heated areas |
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Term
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Definition
| 947) – electrode melts from the heat of the arc, and metal drops form with a diameter approximately equal to that of the electrode wire. Gravity and electromagnetic forces then transfer the drops to the work piece at a rate of several per second. |
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Term
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Definition
| 958) – because of the low rate of heat input, oxyacetylene cutting will produce the zone |
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Term
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Definition
| (956) – region of a slit or notch |
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Term
| Nonconsumable Electrode Process |
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Definition
| (942) – in the second group of arc welding processes employs a tungsten electrode, which is not consumed by the arc, except by relatively slow vaporization |
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Term
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Definition
| It is the welding gun that maintains the arc between a nonconsumable electrode and the workpiece. Pg. 953 |
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Term
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Definition
| The flow of inert gas usually arogon though a constricted arc where it is heated to a high temperature forming hot fast moving plasma. Pg 953 |
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Term
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Definition
| The depth of melting in a workpiece. p(943) |
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Term
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Definition
| When gas is heated to a high temperature it forms a hot fast moving substance called plasma. Pg 953. |
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Term
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Definition
| the arc is maintained between a nonconsumable electrode and either the welding gun or the workpiece. (p953) |
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Term
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Definition
| Both DC and AC are available and generally employ the "drooping voltage" characteristics. (p955) |
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Term
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Definition
| can be used in all positions, has a medium rate of heat input and produces wilds where the depth is approximately equal to the width. (p952) |
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Term
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Definition
| All thermal cutting processes produce some residual stresses (958). The stress which exists in an elastic solid body in the absence of, or in addition to, the stresses caused by an external load (web definition). |
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Term
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Definition
| The work is made negative and the electrode positive, the condition is known as this. Also know as DCEP (p942) |
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Term
| Shielded Metal Arc Welding |
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Definition
| aka stick welding, the most common of the arc welding processes because of its wide versatility and because it requires only low-cost equipment (943). |
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Term
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Definition
| The lowest currents and voltages and the use of CO2 shield gas promote this. The advancing electrode makes direct contact with the weld pool, and the short circuit causes a rapid rise in current. (p947) |
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Term
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Definition
| a coating to accumulate impurities, prevent oxidation, and slow the cooling of the weld metal. (p943) |
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Term
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Definition
| (page 966) – a fast, economical means of joining metals that happens when two pieces of metal are joined together in just one spot not all along a line |
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Term
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Definition
| (page 947) – is a mode of metal transfer that happens during welding that involves small droplets of metal that emerge from a pointed electrode at a rate of hundreds per minute and are easily propelled across the arc in any direction |
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Term
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Definition
| (p.941) -if direct current is used and the electrode is made negative, the condition is known as this |
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Term
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Definition
| (p. 949) - an arc-welding process used to attach studs, screws, pins, or other fasteners to a metal surface |
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Term
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Definition
(p. 948) - no shielding gas is used in this process.
- A thick layer of granular flux is deposited just ahead of a solid bare-wire consumable electrode, and an arc is maintained beneath the blanket of flux with only a few small flames being visible |
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Term
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Definition
| arc between the electrode and the workpiece. (p953) |
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Term
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Definition
| Power supplies that alternate between DCEP and DCEN conditions, but use rectangular waveforms to vary the fraction of time in each mode, as well as the frequency of switching. (p942) |
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