Showing papers on "Welding published in 1985"

Voice controlled welding system

Abstract: Apparatus and method are provided for permitting human voice control of a welding system. A human operator, remote from a welding power supply, uses a welding torch connected by a power line to the welding power supply. The human operator is provided with an audio transmitter which permits the operator to adjust the welding power supply through verbal commands. The verbal commands are issued by the human operator, and are transmitted through a receiver, a voice recognition unit, and a computer, which is electrically connected to deliver power control signals to the welding power supply to thereby adjust the power delivered to the welding torch. The operator may also issue verbal commands to start and stop an internal combustion engine which drives the welding power supply, when such an engine is used. Additionally, when the welding process incorporates a consumable wire electrode, the operator may verbally alter the speed at which the wire electrode is fed through the welding torch. A major advantage of the system is that changes are made without interrupting the welding process.

Laser sealed vacuum insulation window

Abstract: A laser sealed evacuated window panel is comprised of two glass panes held spaced apart in relation to each other by a plurality of spherical glass beads and glass welded around the edges to provide an evacuated space between the glass panes that is completely glass sealed from the exterior. The glass welded edge seal is obtained by welding the edges of the glass panes together with a laser beam while the glass panes and bead spacers are positioned in a vacuum furnace and heated to the annealing point of the glass to avoid stress fracture in the area of the glass weld. The laser welding in the furnace can be directed around the perimeter of the glass panel by a combination of rotating the glass panel and linearly translating or aiming the laser with a relay mirror.

Concurrent ultrasonic weld evaluation system

Abstract: A system for concurrent, non-destructive evaluation of partially completed welds for use in conjunction with an automated welder. The system utilizes real time, automated ultrasonic inspection of a welding operation as the welds are being made by providing a transducer which follows a short distance behind the welding head. Reflected ultrasonic signals are analyzed utilizing computer based digital pattern recognition techniques to discriminate between good and flawed welds on a pass by pass basis. The system also distinguishes between types of weld flaws.

Method of carrying out a treatment on metal pieces with the addition of an added material and with the use of a power laser

Abstract: The method allows a treatment (cutting, welding, alloying or surface hardening, etc.) to be carried out on a metal piece with the addition of an added material and with the use of a power laser. The metal piece is heated locally and the added material is brought into a plastic or liquid state by means of laser radiation so as to fuse it with the piece. The added material used is a powder.

Cancer risk of arc welders exposed to fumes containing chromium and nickel.

Abstract: A retrospective follow-up study among chromium- and nickel-exposed welders, which took into consideration welding procedures, duration of exposure, and smoking habits, yielded an increased cancer risk in a comparison with an internal reference group of turners, milling cutters, and drillers, as well as in a comparison with the general population of the Federal Republic of Germany. Due to the cohort size (1 224 welders, 1 694 turners) and the fact that the observation period is still too short, confirmed statements as to the target cancer sites cannot yet be made. However, it emerges that welding with coated electrodes shows a higher cancer risk as compared to the other welding processes observed. This finding may be explained by the fact that the share of hexavalent chromium compounds in the welding fumes is greater with coated electrodes than with other processes so that a follow-up study observing the health risks of chromium and nickel fumes separately would be warranted. For the confirmation of a more favorable outcome with gas-shielded welding, a larger investigation group or a longer observation period would be required.

Arc welding instruction monitor

Abstract: A monitor designed to aid in the instruction of electric arc welding. The device is electrically isolated from the welder arc voltage by an optical coupling device which provides an isolated output signal linearly proportional to either arc voltage or arc current. Audio alarms are triggered when the arc voltage is either too high or too low indicating arc lengths that are too low indicating arc lengths that are too long or too short to provide acceptable weld quality. A self test switch is included to demonstrate the upper and lower voltage alarm operation.

Welder's trainer

Abstract: The welder's trainer comprises an welding electrode simulator, an electric-arc welding heat balance electronic model, a welding situation visual synthesis electronic model, a welding situation simulator made in the form of a television-type display, to which the welding situation visual synthesis electronic model is connected, and a training control and monitoring unit connected to the display through the visual synthesis electronic model.

Metal transfer in arc welding as a varicose instability. II. Development of model for arc welding

Abstract: For pt.I see ibid., vol.18, p.1431 (1985). A model of metal transfer in open arc welding is developed which provides a framework for predicting the influence of welding parameters in steady and pulsed current welding. It is found possible to present results in terms of simple expressions which are in broad agreement with available observations. Considered here are aspects such as droplet evolution, detachment frequency and size, selection of pulse parameters, influence of electrostatic stress on transfer, drop dynamics and the relationship between balance of force approaches to transfer and the present instability model.

Adaptive welding guidance apparatus

Abstract: An apparatus (8) for guiding a welding torch (14) along a weld groove (81) has a visual sensing system for detecting the weld groove cross sectional configuration and relative position of the edges of weld groove (81). The positional and cross sectional information is assimilated under microprocessor (38) control to actively guide the welding torch (14) through the control of a series of servo motors (24) and adaptively position the welding electrode at an optimal preselected location with the weld groove.

Laser welding of sandwich structures

Abstract: A process is disclosed for bonding multi-layer sheet struc­ture by using controlled depth laser welding. The laser energy may be applied in stages, whereby the inner sheets are first welded together and, the outer sheets are then joined thereto. The sheets are thereafter expanded to form the desired struc­ture. Although the laser energy may be varied to control the depth of penetration, one embodiment utilizes a shield material to be applied between two sheets to prevent the laser energy from penetrating and joining the two sheets together. Similarly, shields may be used to control the width of the laser weld.

Chemical reactions during submerged arc welding with FeO-MnO-SiO2 fluxes

Abstract: Measurements have been made of the compositional changes of fluxes and weld metal during submerged arc flux welding with a series of synthetic MnO-FeO-SiO2 model fluxes containing 40 wt pct SiO2 and different ratios of MnO to FeO. Mechanisms for the transfer of Mn, O, Si, C, S, and P are discussed in terms of the thermodynamic driving forces and kinetic factors such as diffusion, nucleation, and segregation. One unique deduction is that interfacial, not bulk activities of components (such as FeO) govern transfer into (or out of) the metal phase. The concentrations of C, P, S, and possibly Si tend to be larger in the molten weld metal than in the base plate.

Optical filter for protective welding lens assemblies

Abstract: An optical filter for welding protective lens assemblies has two parallel electro-optical cells (303-305; 305, 307), at least one of the cells (305, 307) being of the nematic type with admixture of dye molecules with anisotropic light absorption. The filter comprises a filter sheet (309) disposed in the ray path of the cells and allowing transmission within a wave range which is offset with respect to the wave range within which said one cell (305, 307) is transmitting residual light in its absorbing state.

Method of producing weld overlay of austenitic stainless steel

Abstract: A method of producing a weld overlay on a ferrous base metal surface, by applying to the surface by electric arc welding a plurality of layers of an austenitic stainless steel filler of specific composition, and providing a flux which produces a substantially fully austenitic overlay at least in the uppermost layer. The overlay has improved machinability, metal-to-metal wear resistance and corrosion resistance, and the capability of work hardening.

Surface properties of liquid metals and their effects on weldability

Abstract: The levitating–drop method has been used to determine surface tension as a function of temperature for four transition metals, and also for samples of type 316 stainless steel which exhibited variable weld penetration during tungsten-inert-gas welding. The results obtained verify the predictions of weld-pool models in that the differences in weldability of the steels can be related to the surface properties of the melts. To obtain good weldability in type 316 steels, it is necessary to ensure that the concentration of uncombined surface-active elements (such as sulphur) should exceed a specified minimum level. An indication of the amounts required for consistent weld penetration is given.MST/194

Image processing welding control method

Abstract: An image processing welding control method comprises detection of isothermal pattern of a weld zone in the welding state through photographing the weld zone by an infrared camera; calculation of the area of the region defined by the isothermal line detected; comparison of the area with a standard area which is obtained in advance; control of welding heat input such that the area will be substantially the same as the standard area whereby a suitable welding heat is input the welding portion; detection of an asymmetric extent of said isothermal pattern; and controlling the torch position such that the asymmetric extent will be within a predetermined value, so that the torch will be strictly aligned with the welding groove center. This method enables two kinds of welding control methods, torch position control and welding heat input control, based on the same image information.

Method of protecting eyes from welding rays in arc welding and apparatus therefor

Abstract: A method of protecting eyes from welding rays in arc welding and an apparatus therefor are disclosed which are capable of closing a filter plate over a period from right before the generation of arc welding rays to the termination of the generation to fully intercept the rays, to thereby effectively protect the eyes of an operator from the rays. The invention is constructed in a manner such that a controller carries out the on-off control of a voltage applied from a filter power source to a PLZT filter plate depending upon a signal supplied from a detection circuit thereto when the detection circuit detects a built-up current occurring in a welding current, to thereby carry out the actuation of the filter plate.

Cored wire filler metals and a method for their manufacture

Abstract: Welding, soldering and brazing and wire filler metals having a metallic sheath enclosing a core wire and, preferably, filler powder materials. The diameter of the composite wire is reduced by drawing, rolling or swaging. The composite wire is easier for filler metal manufacturers to make and can have better operating characteristics leading to improved bead appearance and joint quality.

Viscoplastic constitutive relation incorporating phase transformation – application to welding

Abstract: A viscoplastic constitutive relation of the Perznya type is used to describe structural changes for a wide range of material behaviour from solid to liquid states. Using the constitutive model, finite element simulations were carried out for two types of welding process: a circular plate welded in the centre and a butt-welded plate. The residual stress and temperature were calculated and compared with experimentally measured data.MST/24

Laser welding of galvanized steel

Abstract: An improved method is disclosed for producing a welded joint between galvanized steel sheet members utilizing a laser beam or the like. Surface regions of the galvanized member in the weld zone are selectively pretreated to remove the zinc coating and apply a nickel-base coating. The nickel coating avoids the vaporization problems associated with zinc, while providing suitable corrosion protection in the welded joint.

Dc arc welding machine

Abstract: PURPOSE: To quicken the transfer to an arc and to increase the efficiency in tacking by prohibiting the wire slowdown control for a fixed time after the detecting signal of the welding current being cutoff with the completion of the welding of the DC arc welding machine having the wire slowdown control function CONSTITUTION: A timer circuit 18 works at the time when the welding current detecting signal of a welding current detecting circuit 13 is cut with the completion of a continuous welding, counts for a certain time and in this period, continues to send the signal to a wire slowdown control circuit 14 and stops the control of the wire slowdown And when the following welding is started while in the fixed time, the wire slowdown control is not performed and a wire 1 is fed at the feeding speed under welding from the beginning At the time when the melting ball at the wire tip is warm with the completion of the welding, therefore, the wire slowdown control is not performed and good arc starting characteristic is obtd COPYRIGHT: (C)1987,JPO&Japio

Exposure in welding of high nickel alloy.

Abstract: Nickel (Ni) levels in air during welding of high-Ni alloy (75% Ni) were very high (mean 0.44 mg/m3, range 0.07-1.1 mg/m3; 20 person-days of measurements). In six welders the Ni level in urine after four weeks of vacation was slightly but statistically significantly enhanced as compared to ten unexposed controls (means 8.7 vs 5.1 micrograms/l; P less than 0.005). The level on Monday mornings increased somewhat during a period of six weeks of high-Ni alloy welding (mean 13 micrograms/l; P less than 0.05). The level was slightly higher Thursday afternoon (mean 18 micrograms/l; P less than 0.0001). The data indicate the existence of a very slow pool of Ni in the body in addition to a faster one. There was no correlation between Ni levels in air and urine. Thus, in spite of the very high Ni levels in air, urinary Ni levels were thus of little use for biological monitoring of exposure and risk during high-Ni alloy welding. All eleven welders studied reported one or more symptoms (irritation of upper airways, headache, tiredness) as occurring more often (P less than 0.006) during high-Ni welding than when welding ordinary stainless steel. Lung-functions studies were normal.

Welding apparatus method for depositing wear surfacing material and a substrate having a weld bead thereon

Abstract: The welding method may be used to lay down weld beads on metallic substrates with a narrow width of 0.125 inch and less. The process employs a plasma transferred arc and pulses the current delivered to the arc such that a wave form having at least a main amplitude and a lower auxiliary amplitude is provided. The powdered metal which is delivered is laid down in a series of overlapping weld deposits which solidify very rapidly and produce a fine grain structure.

Feasibility Study of the Welding of Sic

Abstract: In a brief study of the feasibility of welding sintered alpha-SiC, solid-state welding and brazing were investigated Joint quality was determined solely by microstructural examination Hot-pressure welding was shown to be feasible at 1950 C Diffusion welding and brazing were also successful under hot isostatic pressure at 1950 C when boride, carbide, and silicide interlayers were used Furnace brazing was accomplished at 1750 C when a TiSi2 interlayer was introduced

A Microprocessor-Based Electrode Movement Controller for Spot Weld Quality Assurance

Abstract: Quality assurance has been of a great concern in the process of resistance spot welding, since considerable variation in the weld quality often arises even when the machine variables are held constant. In this paper a new microprocessor-based control method is developed to obtain uniform weld quality regardless of the changing welding environments. The control system utilizes a proportional (P) control algorithm, incorporating with the electrode movement as a feedback variable. The controller generates the welding control current so as to track a desired trace of the electrode movement (reference electrode movement curve) throughout weld cycle. A series of experiments was performed to evaluate the performance of this control method. The results show that, as a result of the electrode movement tracking, weld strengths of all the weldments approach to a desired strength level.

The Effect of High-Frequency Pulsing of a Welding Arc

Abstract: Pulsed and nonpulsed nonconsumable electrode welding arcs are compared on the basis of equal average power input. A relationship is developed between the pressure of the high-frequency (typically greater than 5 kHz) pulsed arc and a dc arc with equal power input. It is shown that the arc pressure, and hence arc stiffness, of the pulsed arc may be as much as ten times that of the equivalent dc arc. As expected, the pressure ratio of the pulsed arc to nonpulsed arc decreases as the form factor of the pulsed arc decreases.

Method and apparatus for determining weld quality in percussion welding

Abstract: The quality of welds produced during a percussion welding process are determined in real time by sensing the vibrational impulse signals produced during the percussion welding process, filtering the impulse signal to select a frequency band containing frequency components associated with the vibrations imparted to the forge rod of the welding machine, measuring the mechanical damping characteristics of the selected spectral portion of the signal by determining the log-decrement of the envelope of the signal, and comparing the measured log-decrement value obtained with a preselected threshold value.