Showing papers on "Shielded metal arc welding published in 1989"

Chromosome aberrations in peripheral blood lymphocytes of welders and characterization of their exposure by biological samples analysis

Abstract: Chromosomal aberrations in cultured lymphocytes obtained from 55 welders and 55 matched controls were analyzed Depending on the welding techniques and the nature of the consumables and metals welded, three separate groups of welders were examined Chromium, nickel, and manganese levels in serum and urine were measured to assess the exposure to welding fumes A statistically significant increase of chromosomal aberrations was found in one of the three analyzed groups of welders This group used the semi-automatic metal active gas welding process with cored wire containing nickel for welding mild steel These welders had significantly higher concentrations of serum and urine manganese and, unlike the other welders, significantly elevated concentrations of nickel, both in serum and urine However, no significant correlations between nickel or manganese levels and the frequency of chromosomal aberrations were found There was a significant correlation between the length of welding employment of these welders and the frequency of chromosomal breaks, although there was no significant correlation between age and the frequency of chromosomal aberrations The other two groups of welders, for which the analyses of biologic fluids proved chromium and manganese exposure, had no statistically significant higher frequency of chromosomal aberrations One of these groups usedmore » the manual metal arc welding process with coated electrodes for welding mainly mild steel and the other group used the tungsten inert gas welding process for welding stainless steel A significant correlation between the daily amount of cigarettes smoked and the frequency of chromosomal breakages, in controls as in welders, was observed The present data indicate that certain welding processes may generate fumes that seem to have a clastogenic activity« less

Spray mode gas metal arc welding process

Abstract: A spray mode gas metal arc welding process employing a shielding gas mixture consisting essentially of (A) 3 to 8 volume percent carbon dioxide, (B) 30 to 40 volume percent argon and (C) the balance helium

Device and process for short circuit arc welding

Abstract: The invention relates to a device and a process for reducing the spatter effect when welding and for improving the welding work, particularly in the case of semi-automatic short-circuit arc welding using a direct-current supply. The welding current flows as a function of the arc voltage while the welding wire is fed towards the workpiece from the holder, the welding wire being subjected to a series of welding cycles. Each welding cycle comprises an arc phase and a short-circuit phase. In the case of this kind of welding, the invention makes provision for the supply of a predetermined amount of energy to the welding wire during the arc phase in each welding cycle, the said amount of energy exceeding the amount of energy, whose energy level is known, which is required to melt a certain volume of metal at the end of the welding wire into a coherent globule (droplet) of molten metal. This constant energy is divided between the resistance heating of the free end of welding wire projecting beyond the welding-wire holder and the anode heating which is effected by the arc in the arc phase of the welding cycle.

Flux cored wire for gas shielded arc welding for heat resistant steel

Abstract: PURPOSE: To improve high temp. characteristic of a welded metal by containing the specific contents of Mo and Nb in a metal fluoride series flux cored welding wire. CONSTITUTION: In the flux cored wire for gas shielded arc welding packing 8-25% of the flux containing 1.0-10.0% metal fluoride and 1.0-6.0% deoxidizer to the total wire wt. in cavity part of a steel-made outer shell, 0.10-0.50% Mo, 0.005-0.025% Nb and further, 0.1-0.4% of (0.5 Mo + 10 Nb) to the wire wt. are contained in one or both of the steel-made outer shell and the packed flux. Nb and Mo form fine carbon-nitride and further, Mo increases high temp. strength with solid-solution strengthening. High temp. characteristic of the welded metal can be improved and can be used to structure without fire resistant covering. COPYRIGHT: (C)1990,JPO&Japio

Magnetically impelled arc butt welding of aluminium pipes

Abstract: (1989). Magnetically impelled arc butt welding of aluminium pipes. Welding International: Vol. 3, No. 11, pp. 941-946.

Effect of additional elements on oxygen absorption by steel weld metal during arc welding. (Part II). Oxygen absorption by Fe-Mn and Fe-Si-Mn weld metal.

Abstract: Pure iron plates were welded using Fe-Mn and Fe-Si-Mn alloy electrode wires in a controlled arc atmosphere. The effects of manganese and silicon-manganese on the oxygen contents and non-metallic inclusions in the weld metals were investigated under various welding conditions in Ar-O2 and Ar-CO2 welding atmospheres. The oxygen contents of the Fe-Mn and Fe-Si-Mn weld metals increase with an increasing the partial pressure of oxidizing gases and decrease with an increasing manganese and silicon-manganese contents in the weld metals. The oxygen contents of the weld metals welded in Ar-CO2 are lower than those in Ar-O2. The oxygen contents of the Fe-Si-Mn weld metals significantly decrease comparing with those of the Fe-Si and Fe-Mn weld metals. The nonmetallic inclusions in the Fe-Mn and Fe-Si-Mn weld metals increase with an increasing oxygen contents of the weld metals. The nonmetallic inclusions in the Fe-Mn weld metals are oxide of manganese-oxide accompanying with iron-oxide. The nonmetallic inclusions in the Fe-Si-Mn weld metals are oxide composed of silica, manganese-oxide and iron-oxide. Behavior of the oxygen absorption into the Fe-Mn and Fe-Si-Mn weld metals is discussed using thermodynamic data.

Welding joining method of surface treated steel plates

Abstract: PURPOSE: To reduce the scattering of molten metal during welding and to improve corrosion resistance and rust prevention of a weld zone by removing surface treating coating films of the weld zone and then, performing welding thereon and further, forming metallic sprayed deposit on the bead surface. CONSTITUTION: Surface treating coating films 2a and 2b of both surfaces in the vicinity of the end faces to be a welding joining part of secondary material 2 in lap joint fillet welding or only a surface treating coating film 2a in the vicinity of the end face left side to be a welding joining part of the secondary material 2 in Tee joint fillet welding are removed partially respectively and welding is performed. Further, after cleaning treatment of the bead 3 surface after welding is carried out, metallic sprayed deposit 5 or nonmetallic sprayed deposit 6 is formed thereon. Accordingly, since the surface treating coating films 1a, 2a and 2b are removed in advance, these are not evaporated and scattered during welding. In addition, since a welded bead 3 is covered with the metallic sprayed deposit 5 with high corrosion prevention, the corrosion resistance is improved and welding joining with high reliability can be performed. COPYRIGHT: (C)1990,JPO&Japio

Effect of the composition of flux and welding wire on the properties of deposited metal of 05N4MYu type

Abstract: (1989). Effect of the composition of flux and welding wire on the properties of deposited metal of 05N4MYu type. Welding International: Vol. 3, No. 2, pp. 109-111.

Manufacture of pipe interior build-up clad pipe

Abstract: PURPOSE:To facilitate manufacturing a small dia. clad pipe by performing build-up welding of clad material to the external surface of a metal core member and subsequently, removing the core member. CONSTITUTION:After the clad material is subjected to build-up welding to the metal core member 1 to form a build-up interior layer 2 in a first stage, pipe exterior layer forming material is subjected to build-up welding to the external surface of said build-up interior layer 2 to form a build-up exterior layer 3. The core member 1 is removed to manufacture the clad pipe consisting of the build-up interior layer 2 and the build-up exterior layer 3 in a second stage. At this time, carbon steel, a Co base alloy or a Cr-Ni alloy and carbon steel or stainless steel are used as the core member 1, the clad material and the pipe exterior layer forming material respectively. In addition, a powder plasma welding method, a TIG welding method, a shielded metal arc welding method or a MIG welding method, etc., can be used as welding methods. Cutting, etc., can be used as a removing method for the core member 1 in the second stage.

Spot welding of Fe-Si-B amorphous metal foil

Abstract: The possibility of the welding of amorphous metal foils was examined.Fe78Si9B13 amorphous metal foil having 20 microns in thickness was welded by using a stored energy type spot welding machine. This foil was possible to weld without crystallization at a welding time within 0.4 milliseconds.The irregularity of weld nugget shape was due to the unevenness of the foil surfaces employed. This resulted in the scattering of tensile-shear strength of single spot welds.Increasing weld time with the use of the capacitor bank having excessive capacitance led to a brittle weld nugget, though crystallization did not occur.In tension-shear test, a crack initiated near the periphery of the weld nugget and propagated in the base metal. It means that the enhancement of joint strength was difficult by multiple spot welding.

Effect of Using Filler Wire and Magnetic Control in MIG Arc Welding

Abstract: Compared to conventional MIG welding, the MIG welding with filler wire, where a filler wire is fed into MIG welding arc, improves efficiency by minimizing the heat input and increasing the deposition rate. However, discussion arises on controlling the convex bead which arises at increased deposition rate.In this study, it is attempted to control the uneven bead in the MIG welding with filler wire by applying magnetic control of the arc. Furthermore, possibility of controlling the weld metal content is investigated which is favourable for cladding by welding of dissimilar metal i.e. clad steel, corrosion and heat resistant alloys and so on.The diameter of the filler wire was 1.2 mm, the electric current for the welding was 180-350A, the magnetic field for oscillating the arc was 0.004-0.006T and 5Hz.Experimental results showed that the bead of excellent appearance was obtained and it could be flattened by applying magnetic field even at increased deposition rate of MIG welding with filler wire. The penetration was found to be approximately 50% of conventional MIG welding.It was also found possible to control the amount of Ni and Cr, which are important elements for corrosion and heat resistant alloys, and to deviate for them to the bead surface by varying composition and feed rate of the electrode wire and the filler wire. It is said from these findings that this welding method is suitable for cladding by welding to improve efficiency and quality.

Low-Cycle Fatigue Properties of Steels and Their Weld Metals

Abstract: Completely reversed, strain-controlled, low-cycle fatigue behavior at room temperature is investigated for steels and their weld metals. Weld metal specimens were taken from multi-pass weld metal deposited by shield metal arc welding (SMAW) and gas metal arc welding (GMAW), such that their gage length consisted entirely of the weld metal. Results indicate that there is a trend toward reduction in the low-cycle fatigue life of weld metals as compared with the base metals. In low carbon steel weld metals, the tendency described above is explained in terms of local plastic strain concentration by lack of uniformity of the multi-pass weld metals. The weld metals do not have the same mechanical properties anywhere as confirmed by hardness distribution, and the fatigue crack grows preferentially through the temper softened region in the multi-pass welds. In Type 308 stainless steel weld metals, the ductility reduction causes reductions in low-cycle fatigue life. This study leads to the conclusion that fairly accurate estimates of the low-cycle fatigue life of weld metals can be obtained using Manson’s universal slope method. However, life estimates of the Type 304 stainless steel is difficult due to a lack of ductility caused by a deformation-induced martensitic transformation.

Wire for gas shielded arc welding of galvanized steel sheet

Abstract: PURPOSE: To form weld beads free from pits and blowholes by forming the flux of the flux cored wire for welding galvanized steel sheets of a mixture composed of Fe as an essential component and a deoxidizing agent and arc stabilizer and incorporating specific ratios of few C, P, Zr or further Ti and Nb into the wire CONSTITUTION: The flux compsn of the flux cored wire used at the time of gas shielded arc welding of the galvanized steel sheets is constituted of the mixture composed, by weight%, of 65 to 90% Fe, 5 to 30% deoxidizing agent consisting of Si, Mn and the iron alloy thereof, and 01 to 10% arc stabilizer consisting of an alkaline metal and Li or the compd thereof and the flux fills a steel sheath at 10 to 35% flux rate Also, 010 to 030% C, 0025 to 015% P, and 001 to 015% Zr are used as the essential components or further one or two kinds of 001 to 015% Ti and 001 to 015% Nb are incorporated into the flux or the steel sheath COPYRIGHT: (C)1990,JPO&Japio

High deposition rate submerged arc welding

Abstract: In this paper the authors discuss four developments in submerged arc welding which are of significance for high deposition rates. These developments include the use of microalloyed wires which enhance weld root toughness, the process of metal powder additions, improved consumables for higher strength steels and increasing productivity in pipe welding.

The Influence of Current Supply Type on the Composition, Microstructure, and Mechanical Properties of C-Mn and C-Mn-Ni Shielded Metal Arc Welds

Abstract: An American Welding Society (AWS) E7016 type C-Mn electrode and an AWS E7018 type C-Mn-Ni electrode were each used to produce a series of butt welds in 25-mm (1-in.) thick British Standard (BS) 4360 50E (C-Mn-Nb) steel plate in the flat (1G) position. For each consumable, direct current (DC) reverse polarity (electrode positive), DC straight polarity (electrode negative), and AC power supplies were each used for a complete panel. In addition, DC straight polarity was employed for vertical-up (3G) welding with the C-Mn-Ni electrode. The chemical composition, strength, microstructure, and toughness of the deposits were studied in the as-welded condition. For the C-Mn-Ni 1G welds (and to a lesser extent for the C-Mn welds), manganese and silicon decreased in the order DC reverse polarity, AC and DC straight polarity. For both consumables, there was a concomitant increase in nitrogen content. There were no associated changes in strength or microstructure, but there was generally a progressive decrease in crack tip opening displacement (CTOD), measured at -10°C, and in Charpy toughness. As a consequence of strain aging, Charpy toughness was lower in the root than in the fill region. The 3G DC straight polarity C-Mn-Ni deposit had higher strength in the root and higher Charpy toughness than the corresponding 1G deposit. The CTOD of the former was lower and showed much more scatter, to which locally low toughness regions (revealed by fractographic examination) contributed.

The Influence of Current Supply Type and Arc Length on C-Mn, C-Mn-Ni, and C-Mn-Ti-B Shielded Metal Arc Deposit Nitrogen and Oxygen Contents

Abstract: Nitrogen and oxygen contents have been determined for welds simulating root and hot passes, and deposited with progressively longer arc lengths to give arc voltages in the range 18 to 28 V Commercial basic-coated C-Mn, C-Mn-Ni, and C-Mn-Ti-B shielded metal arc electrodes were employed in the flat (1G) position with DC straight polarity (electrode negative), DC reverse polarity (electrode positive), and alternating current (AC) supplies In all deposits, nitrogen content increased with increasing arc length, with the C-Mn-Ti-B deposits showing the most rapid rise The highest low voltage nitrogen levels and the most rapid increases always occurred for DC straight polarity welding, which gave >006% nitrogen at the highest arc voltage for each of the consumables Deposit nitrogen content always exceeded the level in the core wire, but approached it at the lowest voltage for DC reverse polarity welds, with two of the C-Mn-Ti-B deposits showing the lowest nitrogen contents Deposit oxygen contents were not related to core wire levels For DC straight polarity deposits, oxygen increased progressively over the voltage range studied For DC reverse polarity deposits, oxygen decreased progressively for AWS E7016 type electrodes, and showed an initial decrease and a subsequent increase for AWS E7018 type electrodes The AC deposits showed either a small increase or decrease at low arc voltages and an increase at higher arc voltages The findings reflect the incomplete shielding provided by the gas shield and slag layer at high arc voltages, particularly for DC straight polarity welding They suggest that reactions involving the molten droplets emanating from the electrode tip are important in influencing deposit nitrogen content, and that those occurring in the slag layer at the surface of the weld pool are important in influencing deposit oxygen content

Measurement of the arc force produced during welding with covered electrodes

Abstract: In this paper the method and apparatus used to measure the arc force produced during welding with covered electrodes were studied and developed. The factor which caused the main error of measurement was revealed, and the experimental results were corrected. The arc force of typical electrodes under different welding conditions was measured and the factors affecting the force were also investigated. Furthermore, the effects of such components of the electrode coatings, as marble, feldspar and fluorspar, on the arc force were studied, and the origin of the arc force in MMA welding with covered electrodes was preliminarily analysed.

Method of arc welding with a ferrite stainless steel welding rod

Abstract: The ferrite stainless steel welding rod of this invention comprises the following: 0.03% by weight or less of carbon, 1.00% by weight or less of silicon, 1.00% by weight or less of manganese, from 16.0 to 21.0% by weight of chromium, from 0.30 to 0.80% by weight of niobium, from 0.30 to 0.80% by weight of copper, 0.025% by weight or less of nitrogen, and the balance of iron. The ferrite stainless steel welding rod of this invention offers a good weldability not only in welding stainless steels of the same type but also in welding stainless steels of different types. Further, the welding steel of this invention has a good oxidation resistance, and a good workability and mechanical property.

Influence of Strain Aging on Tearing Resistance of C–Mn Plates and Welds for PWR Secondary Systems

Abstract: Carbon-Manganese steels and associated welds made by Submerged Arc Welding and Manual Metal Arc Welding are the main materials used for PWR secondary systems. A better knowledge of the fracture toughness properties of these materials is needed for an improved structural integrity analysis of the concerned systems. In this paper, experimental results of tensile, Charpy V Notch impact and J resistance tests are presented and discussed, with a particular emphasis on the effect of temperature on tearing resistance, taking into account the susceptibility of C-Mn steels and welds to static and dynamic strain aging. The tearing resistance was found to be minimum at the temperature where the dynamic strain aging effect is maximum; in addition a correlation between tensile properties and J value at initiation was developped.