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Showing papers on "Welding published in 1984"


Journal ArticleDOI
TL;DR: In this article, a double ellipsoidal geometry is proposed to model both shallow penetration arc welding processes and the deeper penetration laser and electron beam processes, which can be easily changed to handle non-axisymmetric cases such as strip electrodes or dissimilar metal joining.
Abstract: A mathematical model for weld heat sources based on a Gaussian distribution of power density in space is presented. In particular a double ellipsoidal geometry is proposed so that the size and shape of the heat source can be easily changed to model both the shallow penetration arc welding processes and the deeper penetration laser and electron beam processes. In addition, it has the versatility and flexibility to handle non-axisymmetric cases such as strip electrodes or dissimilar metal joining. Previous models assumed circular or spherical symmetry. The computations are performed with ASGARD, a nonlinear transient finite element (FEM) heat flow program developed for the thermal stress analysis of welds.* Computed temperature distributions for submerged arc welds in thick workpieces are compared to the measured values reported by Christensen1 and the FEM calculated values (surface heat source model) of Krutz and Segerlind.2 In addition the computed thermal history of deep penetration electron beam welds are compared to measured values reported by Chong.3 The agreement between the computed and measured values is shown to be excellent.

2,476 citations


Book
01 Jan 1984
TL;DR: In this paper, the authors describe electric arc welding, high energy density welding, and future developments of welding processes, and discuss the benefits of better understanding of the physics of welding.
Abstract: Greater understanding of the physics of welding is leading to improved application and control of welding processes. Further gains in welding productivity could follow. Electric arc welding, high energy density welding and future developments are described

656 citations


Journal ArticleDOI
TL;DR: Theoretical models of fusion welding are developed and calibrated by using experimental data in this paper, where simple kinetic models for grain growth and particle dissolution are used to construct diagrams which described these processes in the heat-affected zone of a weld as a function of process variables (input energy, weld speed, preheat etc.).

220 citations


Book
01 Jan 1984
TL;DR: The welding principles and applications 6th edition answer key pdf as mentioned in this paper were downloaded from Amazon Mechanical Turk and were used to download a malicious download of a good book with a cup of tea in the afternoon, instead they cope with some harmful bugs inside their laptop.
Abstract: Thank you for downloading welding principles and applications 6th edition answer key pdf. As you may know, people have look numerous times for their chosen novels like this welding principles and applications 6th edition answer key pdf, but end up in malicious downloads. Rather than enjoying a good book with a cup of tea in the afternoon, instead they cope with some harmful bugs inside their laptop.

164 citations


Patent
23 Apr 1984
TL;DR: In this paper, the weld line can be tracked either by bouncing a beam of light off the welding electrode so as to form an illuminated area and detecting the resulting irregularity where the illuminated area crosses the welding line, or by detecting the deformation in the surface of the weld pool as the pool flows into the gap between the metal portions being joined.
Abstract: Video data generated at a high rate by a camera observing a welding operation is selectively stored in a video-computer interface to permit later computer analysis of the data. Special multiple memory techniques can be employed when the rate of which the data is generated is too fast for storage in a single memory in the interface. The width of the weld pool is detected by finding local minima of light intensity associated with these edges. The mass of the weld pool and the weld penetration can be measured and controlled by causing oscillations in the weld pool and measuring the natural frequency of such oscillations. The weld line can be tracked either by bouncing a beam of light off the welding electrode so as to form an illuminated area and detecting the resulting irregularity where the illuminated area crosses the weld line, or by detecting the deformation in the surface of the weld pool as the pool flows into the gap between the metal portions being joined. Prior to welding, the weld line can be detected by establishing a low power welding arc insufficient to create a molten weld pool but generating enough light to produce an irregularity in the reflected light at the location of the weld line.

132 citations


Patent
07 May 1984
TL;DR: In this paper, a hand-held laser tool is comprised of focusing optics for the laser beam, an inert gas supply for welding cover gas, and an oxygen supply for gas assist cutting.
Abstract: Laser processes such as cutting, drilling, and welding metals and other materials are performed manually with a hand held fiber optic laser tool. A near infrared or visible wavelength pulsed laser beam is coupled to the tool by a single clad quartz fiber whose ends are prepared to reduce losses and which transmits laser energy with peak powers in the kilowatt range to the output end. The hand held laser tool is comprised of focusing optics for the laser beam, an inert gas supply for welding cover gas, and an oxygen supply for gas assist cutting.

105 citations


01 Jan 1984
TL;DR: In this article, a technique of using ultrasonic pulse-echo measurements to determine weld pool dimensions is discussed and it is concluded that despite the distortion in the ultrasound reflection due to the thermal gradients produced by welding, it is possible to predict the reflection patterns from hemispheres formed by weld pools sufficiently accurately to enable accurate radius measurements to be made, and this represents an initial step towards realisation of real-time weld pool cross section measurement for in-process control purposes.
Abstract: The automatic production of high-quality welded joints requires a means of measuring weld quality in real time and a feedback method for regulating that quality. Penetration is a good indicator of weld integrity, and a technique of using ultrasonic pulse-echo measurements to determine weld pool dimensions is discussed. It is concluded that despite the distortion in the ultrasound reflection due to the thermal gradients produced by welding, it is possible to predict the reflection patterns from hemispheres formed by weld pools sufficiently accurately to enable accurate radius measurements to be made, and that this represents an initial step towards realisation of real time weld pool cross section measurement for in-process control purposes.

87 citations


Proceedings ArticleDOI
01 Jan 1984
TL;DR: In this article, the solidification microstructures of pulsed Nd:YAG laser or CW CO2 laser welds were studied in commercial SUS 310S and 304 (corresponding to AISI Types 310S, 304) stainless steels and in other several austenitic and duplex steels, and it was shown that the disappearance of ferrite in the laser-welded microstructure was not consistent with the prediction from the Schaeffler diagram.
Abstract: The solidification microstructures of pulsed Nd:YAG laser or CW CO2 laser welds were studied in commercial SUS 310S and 304 (corresponding to AISI Types 310S and 304) austenitic stainless steels and in other several austenitic and duplex stainless steels. In the pulsed laser welding of Type 310S, neither grain growth nor recrystallization grain-refining was observed in the heat-affected zones (HAZ), and planar and cellular growth occurred epitaxially in weld metals from adjacent, incompletely-melted grains in the HAZ. According to the data relating a primary dendrite arm spacing to the cooling rate in Type 310S weld metals, the average local cooling rates within the single laser shot welds were extrapolated to be so rapid as to range from 5×104 to 5×106°C/s depending mainly on the pulse energy. In the case of Type 304, the pulsed laser weld metals were almost fully austenitic in contrast to GTA or CO2 laser weld metals containing about 5% residual delta(δ)-ferrite. It was significantly confirmed that almost fully austenitic structure of Type 304 could be produced with extremely high cooling rates obtained by CW CO2 laser welding process with low heat inputs at high traverse speeds. From the microstructural observation of several materials, it was further revealed that the solidification microstructures of pulsed laser welds were not consistent with the prediction from the Schaeffler diagram. In other words, the steels containing the calculated contents of less than 8% δ-ferrite or more than 30% δ-ferrite exhibited fully austenitic or fully ferritic microstructure, so that the compositional region indicating a duplex microstructure was very narrow in the case of pulsed laser weld metals. The disappearance of ferrite in the laser-welded microstructure was interpreted in terms of the change in the solidification process due to extremely high cooling rates accompanied with large undercooling. In addition, the change from duplex to fully ferritic structure was attributed to the suppression of the solid-state, ferrite-to-austenite transformation.The solidification microstructures of pulsed Nd:YAG laser or CW CO2 laser welds were studied in commercial SUS 310S and 304 (corresponding to AISI Types 310S and 304) austenitic stainless steels and in other several austenitic and duplex stainless steels. In the pulsed laser welding of Type 310S, neither grain growth nor recrystallization grain-refining was observed in the heat-affected zones (HAZ), and planar and cellular growth occurred epitaxially in weld metals from adjacent, incompletely-melted grains in the HAZ. According to the data relating a primary dendrite arm spacing to the cooling rate in Type 310S weld metals, the average local cooling rates within the single laser shot welds were extrapolated to be so rapid as to range from 5×104 to 5×106°C/s depending mainly on the pulse energy. In the case of Type 304, the pulsed laser weld metals were almost fully austenitic in contrast to GTA or CO2 laser weld metals containing about 5% residual delta(δ)-ferrite. It was significantly confirmed that almo...

85 citations


Patent
Youichiro Tabata1, Shigeo Ueguri1, Takaji Mizuno1, Hirohisa Segawa1, Seigo Hiramoto1 
07 Sep 1984
TL;DR: In this paper, a short circuiting arc welding machine is used to increase the depth of bead penetration into a workpiece by adding a pulsed current having upper and lower limits to a current flowing when an arc is produced.
Abstract: A short circuiting arc welding machine increases an arc current density by adding a pulsed current having upper and lower limits to a current flowing when an arc is produced, thereby increasing the depth of bead penetration into a workpiece, removing welding defects, and speeding up the welding operation. The welding machine is capable of alternately changing the direction of flow of a welding current at desired periods to produce arcs in straight, reverse and mixed polarities for achieving intermediate characteristics of arcs of straight and reverse polarities, with a resultant ability to adjust in a wide range a wire melting rate and the amount of heat applied to the workpiece.

80 citations


Patent
17 Feb 1984
TL;DR: In this paper, a control unit for use with the welding gun of an arc welding assembly is described, which is used to regulate welding voltage as well as the speed at which the wire is fed to the welding site.
Abstract: The specification describes a control unit for use with the welding gun of an arc welding assembly. A single adjustable means in the welding gun effects changes in the control unit to regulate welding voltage as well as the speed at which the electrode wire is fed to the welding site.

78 citations


Journal ArticleDOI
TL;DR: In this article, it is demonstrated that the relative rates of vaporization of any two elements from the molten pool can serve as an indicator of weld pool temperature, irrespective of the element pair selected.
Abstract: Alloying element vaporization rates, plasma composition, and the changes in weld composition during laser welding of 202 stainless steel are discussed in this paper. Iron, manganese, and chromium were the most dominant species in the plasma. During laser welding it is always a difficult task to measure the temperature of the weld pool since this region is surrounded by hot plasma. In this paper a novel technique for the determination of weld pool temperature is presented. It is demonstrated that the relative rates of vaporization of any two elements from the molten pool can serve as an indicator of weld pool temperature, irrespective of the element pair selected. The composition of the solidified region calculated from the measured values of vaporization rate, plasma composition, and the volume of the solidified region was in good agreement with the weld composition determined by electron probe microanalyis technique.

Patent
18 May 1984
TL;DR: In this article, a portable wirefeed and control apparatus for use in consumable electrode arc welding systems which is capable of being powered by conventional AC or DC variable voltage or variable current supplies without modification of the power supply or the wirefeed, is presented.
Abstract: A portable wirefeed and control apparatus for use in consumable electrode arc welding systems which is capable of being powered by conventional AC or DC variable voltage or variable current supplies without modification of the power supply or the wirefeed and control apparatus. The portable wirefeed unit incorporates a wirefeed motor, a supply of weld wire, optional gas controls, and voltage regulating and protective control circuits all powered at welding arc voltage carried by the welding current supply conductor. The unit is circuit connected to the power supply by means of a single welding electrode supply conductor and a ground return. Electrode power, weld wire, optional shielding gas supply and welding gun control switch conductors are carried in a single flexible conduit extending between the control unit and a remote welding gun and wirefeed speed and thus wirefeed rate are partially responsive to variations in welding arc voltage.

Patent
24 Apr 1984
TL;DR: In this article, a method of controlling the output of a power source in consumable electrode arc welding in which a short circuiting phase and an arcing phase alternately take place between a consumable electrodes and a workpiece in a shielding gas atmosphere is described.
Abstract: A method of controlling the output of a power source in consumable electrode arc welding in which a short circuiting phase and an arcing phase alternately take place between a consumable electrode and a workpiece in a shielding gas atmosphere, the method being characterized by repetition of a cycle of operation consisting of: a first stage of maintaining the output welding current at a first value of a relatively low level upon establishment of a short circuit across a gap between a consumable electrode and a workpiece; a second stage of maintaining the welding current at a second value of a relatively high level succeedingly to the first stage; a third stage of lowering the welding current to a third value of a low level upon detection of necking as a premonition of rupture of short circuiting molten metal between the electrode and workpiece; a fourth stage of, upon generation of an arc across a gap between the electrode and workpiece subsequent to the third stage, maintaining the welding current at a fourth value of a relatively high level exceeding the value of average welding current; and a fifth stage of maintaining the welding current at a fifth value of a relatively low level until the gap between the electrode and workpiece is short-circuited, under control of substantially constant current characteristics to feed current of constant level irrespective of variations in arc length.

Patent
26 Mar 1984
TL;DR: In this paper, a measurement head in an arc welding machine modulates the light intensity of a laser light beam with a modulating signal of 50 KHz or higher, and radiates the light beam onto an object to be measured while changing the direction of laser beam emission in one plane.
Abstract: A measurement head in an arc welding machine modulates the light intensity of a laser light beam with a modulating signal of 50 KHz or higher, and radiates the laser light beam onto an object to be measured while changing the direction of laser beam emission in one plane. A light receiving unit in the measurement head changes its direction of detecting a reflected beam in the same plane. Angles at which the light beams are emitted and detected are detected at the time a modulated signal component is detected from an output from the light receiving unit. The position of a bright spot produced on the surface by the radiated laser light beam is computed from the detected angles based on the principle of triangulation.

Patent
24 Dec 1984
TL;DR: In this paper, a weld metal cooling rate indication system is provided for a welding mace, which is capable of producing a weld bead and has a speed sensor which senses the speed at which the torch travels as selected by an operator.
Abstract: A weld metal cooling rate indication system is provided for a welding mace. The welding machine has a torch which is capable of producing a weld bead and has a speed sensor which senses the speed at which the torch travels as selected by an operator. The indication system includes a device for continuously sensing a profile of temperatures along the weld bead, this profile including a predetermined weld temperature. Another device receives the temperature profile and travel speed of the torch information for calculating and producing a signal which represents rate of change of weld temperature at the predetermined weld temperature. A range of acceptable rates of change of weld temperatures at the predetermined weld temperature is provided so that the rate of change of weld temperature at the predetermined weld temperature can be compared with this range. A device is then provided which is responsive to the comparing information for indicating whether the rate of change of weld temperature is within, above, or below the range of acceptable rates of change of weld temperatures. With this arrangement the welding operator can adjust the speed of the welding torch so that a proper rate of change of weld temperature is maintained at all times to increase the quality of the weld.

Patent
31 Oct 1984
TL;DR: In this paper, a method of laser welding sheet metal protected by using low-vaporizing-temperature materials was proposed, whereby, before being subjected to a laser welding beam along a weld area, two metal sheets are placed on top of each other in such a manner that at least one layer of the said protecting material is located between the sheets at the weld area and that the welding area communicates directly externally of the weld surface between the two sheets whereby gases generated by vaporization of said protective material may escape from the weld areas.
Abstract: Method of laser welding sheet metal protected by using low-vaporizing-temperature materials, whereby, before being subjected to a laser welding beam along a weld area, two metal sheets are placed on top of each other in such a manner that at least one layer of the said protecting material is located between the sheets at the weld area and that the weld area communicates directly externally of the weld area between the sheets whereby gases generated by vaporization of said protective material may escape from the weld area.

Journal Article
TL;DR: In this paper, variable polarity plasma arc (VPPA) welding was used at NASA's Marshall Space Flight Center for the fabrication of the Space Shuttle External Tank (SSET).
Abstract: Variable polarity plasma arc (VPPA) techniques used at NASA's Marshall Space Flight Center for the fabrication of the Space Shuttle External Tank are presentedd. The high plasma arc jet velocities of 300-2000 m/s are produced by heating the plasma gas as it passes through a constraining orifice, with the plasma arc torch becoming a miniature jet engine. As compared to the GTA jet, the VPPA has the following advantages: (1) less sensitive to contamination, (2) a more symmetrical fusion zone, and (3) greater joint penetration. The VPPA welding system is computerized, operating with a microprocessor, to set welding variables in accordance with set points inputs, including the manipulator and wire feeder, as well as torch control and power supply. Some other VPPA welding technique advantages are: reduction in weld repair costs by elimination of porosity; reduction of joint preparation costs through elimination of the need to scrape or file faying surfaces; reduction in depeaking costs; eventual reduction of the 100 percent-X-ray inspection requirements. The paper includes a series of schematic and block diagrams.

Patent
17 Aug 1984
TL;DR: An axle assembly includes an axle member, a flange, and a spindle as mentioned in this paper, and a preferred method of manufacturing the assembly is by a friction or inertia welding process, which may be removed to allow for visual inspection.
Abstract: An axle assembly includes an axle member, a flange, and a spindle. The flange is provided with a central bore. An end portion of the spindle extends through the central bore of the flange to contact an end of the axle member. A central portion of the spindle contacts a surface of the flange. Separate weld joints are formed between the axle assembly components at the two contact areas. The welding flash around the outer circumference of the weld may be removed to allow for visual inspection. A preferred method of manufacturing the assembly is by a friction or inertia welding process.

Patent
16 Jan 1984
TL;DR: In this article, a multivariable process monitor and method of monitoring a resistance spot welding process to yield instantaneous information on weld quality during the weld cycle is presented, which is the reference for the weld quality logic that accepts or rejects the weld.
Abstract: A multivariable process monitor and method of monitoring a resistance spot welding process to yield instantaneous information on weld quality during the weld cycle. Sensors on the machine measure welding input variables and workpiece response variables and provide signals to a microcomputer system. A simplified analytical model of the spot welding process is incorporated in the microcomputer and is the reference for the weld quality logic that accepts or rejects the weld. Faulty welds are diagnosed and the reason displayed.

Patent
30 Oct 1984
TL;DR: A robotic welding apparatus has means for moving a tool assembly through a three-dimensional space and along a computer controlled path as discussed by the authors, where the tool assembly and a welding torch can be rotated about intersecting axes so as to change either or both the lead or drag angle and the weld angle of the welding torch.
Abstract: A robotic welding apparatus has means for moving a tool assembly through a three dimensional space and along a computer controlled path. The tool assembly and a welding torch can be rotated about intersecting axes so as to change either or both the lead or drag angle and the weld angle of the welding torch.

Patent
30 Apr 1984
TL;DR: In this paper, a welding head is mounted for movement relative to a fixed base about a plurality of axes, and a laser beam is transmitted from a laser generator to the welding head by an axially flexible but torsionally rigid transmission tube including one or more optically transmitting fibers.
Abstract: A welding head is mounted for movement relative to a fixed base about a plurality of axes. A laser beam, is transmitted from a laser generator to the welding head by an axially flexible but torsionally rigid transmission tube including one or more optically transmitting fibers. The transmission tube is rotatably mounted on the welding head for free rotation about the axis of the emitted laser beam. A lens or other focusing means is provided to focus the laser beam relative to the workpiece, and moving means is provided to move the welding head relative to the laser generating means and the fixed base. A mini-computer or other control means allows control of the moving means to direct the laser beam along the workpiece in a predetermined path. An apertured hood provides protection for the focusing means, and an optional removable probe member provides assistance in programming the apparatus.

Patent
10 Sep 1984
TL;DR: In this paper, a docking body having utilities passages therethrough is mountable at the welding station, and means are provided at one end of the body for accepting incoming utilities such as consumable wire electrode, shielding gas, welding potential and cooling water.
Abstract: In a MIG arc welding system, a docking body having utilities passages therethrough is mountable at the welding station. Means are provided at one end of the body for accepting incoming utilities such as consumable wire electrode, shielding gas, welding potential and cooling water. Different types of welding gun or torch assemblies are interchangeably manually mountable and demountable at the other end of the welding body without disturbing the docking body or the utilities coupled thereto. Plug-type water fittings on the welding gun or torch assembly are receivable in receptacles in the docking body which communicate with the water passages, actuator tips on the fittings actuating normally-closed, spring-biased check valves in the passages to prevent leakage of water from the docking body when the welding gun or torch assembly is demounted. The gun or torch assembly is held in place by a coupling nut which is threadedly engaged with the docking body. There are provided a fixed-mount embodiment, wherein all utilities but the welding wire enter the docking body radially, and a remote or movable mount embodiment, suitable for mounting on a movable mechanized or robotic support, wherein all utilities enter the docking body axially. A positioning ring on the latter embodiment accurately positions the docking body on the movable support.

Patent
20 Dec 1984
TL;DR: A rotating welding fixture for holding a pipe fitting against a welding table so that socket welds can be fabricated in one continuous operation is described in this article, where a locking dowel is passed into an opening in the fitting and the fitting is locked between the table top and the dowel so that the entire weld region is fully exposed to the welding rod.
Abstract: A rotating welding fixture for holding a pipe fitting against a welding table so that socket welds can be fabricated in one continuous operation. A locking dowel is passed into an opening in the fitting and the fitting locked between the table top and the dowel so that the entire weld region is fully exposed to the welding rod. The table is rotatably supported in a base so that the work can be turned past the welding rod to complete the weld without having to break the weld bead.

Journal ArticleDOI
TL;DR: In this paper, the chemical surface structure of three types of welding fumes-manual metal arc and metal inert gas welding fumes of stainless steel and manual metal arc welding emissions of mild steel-were analyzed using X-ray photoelectron spectroscopy.

Patent
11 May 1984
TL;DR: In this paper, a non-uniform pressure distribution and non-parallel welding surface over at least a portion of the resulting weld near the outside edge are used to increase the lip compliance and reduce the effective pressure of molten material acting on the lip during welding.
Abstract: Joints between thermoplastic parts are friction welded (e.g., as by vibration welding) or otherwise thermally welded in such a manner that a non-uniform temperature distribution results during welding which effectively blocks flash flow from the edge of the joint, and upon cooling, produces a joint that is at least partially stress relieved and is resistant to solvent-induced crazing and cracking. Joints may employ nonparallel adjoining surfaces and/or flexural lips, which bend slightly under pressure applied during welding so as to produce a non-uniform pressure distribution and nonparallel welding surface over at least a portion of the resulting weld near the outside edge. In addition, one or more axial grooves may be used to isolate the nonparallel or lipped area of the weld from the remainder of the weld area so as to increase the lip compliance and reduce the effective pressure of molten material acting on the lip during welding.

Patent
26 Jun 1984
TL;DR: A method of spot welding by laser beam, comprising a laser beam generator (10) and at least one means receiving the laser beam and focusing it on the pieces to be welded, is described in this paper.
Abstract: A method of spot-welding by laser beam, comprising a laser beam generator (10) and at least one means receiving the laser beam and focusing it on the pieces to be welded.

Journal ArticleDOI
TL;DR: In this article, the properties of 13 thermite rail welds produced using CrMo, CrV and chromium alloy rails, American Railway Engineering Association controlled-cooled rails (i.e. standard rails) and heat-hardened rails are reported.

Patent
03 May 1984
TL;DR: In this article, a method and a device for controlling a welding power supply employing a control device essentially including a first switch means consisting of at least one switch in element to be turned on and off to control the output current of the power supply.
Abstract: A method and a device for controlling a welding power supply, employing a control device essentially including a first switch means consisting of at least one switch in element to be turned on and off to control the output current of the power supply, second switch means adapted to be inserted in a welding current attenuating path when the first switch means is in off state, and an impedance means consisting of at least one impedance element connected parallel with the second switch means.

Patent
20 Jan 1984
TL;DR: In this article, both gas-metal and gas-tungsten arc welding processes are disclosed, along with apparatus used in these processes, and the circulation of current from a preheating power supply through a segment of the wire.
Abstract: An arc welding process is provided with a preheating step in which a consumable wire electrode is heated prior to insertion into the electrode stick-out region. This is accomplished by the circulation of current from a preheating power supply through a segment of the wire. Both gas-metal and gas-tungsten arc welding processes are disclosed, along with apparatus used in these processes.

Journal ArticleDOI
TL;DR: In this paper, the fundamental phenomena of ultrasonic welding are investigated, covering the sound field, energy conversion and energy transmission, and the significance of joining pressure for welded seam quality.