Showing papers on "Filler metal published in 1991"

Fabrication of cast articles from high melting temperature superalloy compositions

Abstract: A superalloy article is fabricated by casting a high melting temperature superalloy composition and then refurbishing the primary defects that are found in the surface of the cast piece. The article is refurbished by excising the primary defects and a surrounding portion of metal by grinding, filling the excised volume with metal of the same composition as the cast article by welding or a similar technique, smoothing the surface around any resulting filler metal defects, and applying a cladding powder to the surface from which the filler metal defects are removed. The cladding powder is applied by painting a binder onto the surface and then dusting cladding powder onto the binder before it has dried. The cladding powder is a mixture of particles of a high melting temperature superalloy and particles of a lower melting temperature metal. The article is heated to a preselected temperature, depending on the alloy, to melt and subsequently solidify the cladding powder. Finally, the article is hot isostatically pressed to achieve final closure of surface defects.

Experimental investigation on induction brazing of diamond with Ni-Cr hardfacing alloy under argon atmosphere

Abstract: In recent years direct brazing of a monolayer of diamond crystals on a steel substrate with active filler metals has gained tremendous importance in the industry, with a view to developing tools which can out-perform the conventional galvanically bonded diamond tools. An existing proprietary process uses a specially prepared Ni-Cr filler metal to facilitate its application on a steel substrate. The brazing is done either in a vacuum or a dry hydrogen furnace. The present study has shown that a commercially available Ni-Cr hardfacing alloy, flame-sprayed on a steel substrate with an oxyacetylene gun, could be used for direct brazing of diamond particles. Induction brazing was carried out in an argon atmosphere only for short durations. During brazing under such conditions, the chromium present in the alloy segregated preferentially to the interface with diamond to form a chromium-rich reaction product promoting the wettability of the alloy. It has been further revealed that under a given set of brazing conditions, the wettability of the Ni-Cr hardfacing alloy towards diamond grits primarily depended on its layer thickness. Such dependence resulted in significant variation of topographical features of the tool and its wear mode in simulated grinding tests.

Thermal Residual Stresses in Ceramic‐to‐Metal Brazed Joints

Abstract: When a ceramic-to-metal brazed joint is fabricated, residual stresses develop as the material is cooled from the brazing temperature to room temperature. These residual stresses reduce the strength of the brazed joint, and in some cases lead to catastrophic failure at or near an interface, during the brazing process itself. Finite element analysis modeling techniques are presented and used to determine the residual stresses inherent in the bonding process. Elastoplastic material behavior of the active filler metal, including its temperature-dependent stress–strain response, is accounted for. Various combinations of ceramics and metals are considered. Residual stresses are calculated and used to explain joint strength. The effects of the filler metal work-hardening rate and thickness on the levels of residual stresses are investigated. Analysis shows that the conclusions reached from a laboratory-brazed coupon test may not be applicable to the practical case in which ceramic tiles are brazed onto a metal substrate. There is qualitative agreement between analytical predictions and experimental findings regarding failure modes that occur during cooling from the brazing temperature to room temperature.

Modeling of base metal dissolution behavior during transient liquid-phase brazing

Abstract: Detailed finite difference modeling of dissolution during transient liquid-phase (TLP) brazing of nickel using Ni-11 wt pct P and Ni-14 wt pct Cr-10 wt pct P filler metals is carried out assuminginfinite andfinite heating rates between the filler melting temperature (T m) and the brazing temperature (T b). Two conditions are modeled during brazing, namely, where the liquid width due to base metal dissolution isunrestrained (variable) and where the liquid width is keptconstant due to expulsion of excess liquid during the brazing process. The time required for completion of dissolution is proportional to the square of the filler metal thickness when an infinite heating rate betweenT m andT b is assumed. This occurs for both for constant and unrestrained liquid width situations. Also, the advance of the solid-liquid interface is approximately related to the reciprocal of the square root of the solute diffusivity in the liquid, except in the final stages of the dissolution process. When a multicomponent filler metal composition (Ni14 wt pct Cr-10 wt pct P) is used, the time for completion of dissolution exceeds that when using a simple binary filler metal composition. The phosphorous concentration in the liquid approaches that of the liquidus line when the heating rate betweenT m andT b decreases and thin filler metals are used. This tendency can be estimated using a homogenizing index (z) which combines the effects of filler metal thickness, diffusivity in the liquid, brazing temperature and heating rate, and a distribution index(a). When thick filler metals are used, lower heating rates produce more dissolution at temperatures betweenT m andT b and less dissolution at the final brazing temperature. Conversely, heating slowly when using thin filler metals produces less base metal dissolution (at any temperature) and negligible dissolution at the final brazing temperature. At very low heating rates, solidification can occur while heating fromT m toT b.

Fundamentals of welding metallurgy

Abstract: Metallurgical presentation of the general welding processes and characteristics of the welding operation Thermal and thermochemical study of welding Introduction to the metallographical examination of welds Formation of the fusion zone Solidification of the weld metal Solid phase transformations during welding (heating) Solid phase transformations during welding (cooling) Hardening and cold cracking in steel welding Heat treatments for steel welds Metallurgical aspects of destructive and non-destructive weld tests.

Interlayer selection and thermal stresses in brazed Si3N4-steel joints

Abstract: The influence of Cu, Kovar, Mo, and W interlayers on the magnitude and distribution of thermal stresses and on the tensile strength of brazed Si3N4 − steel joints is examined using a combination offinite element modelling (FEM) calculations and direct experiment. The FEM takes into account plastic flow and changes of mechanical properties of the interlayer, the steel substrate, and the filler metal as temperature decreases following the brazing operation. Joints made using low yield strength/high ductility interlayers, such as Cu, have lower thermal stresses and higher strengths than those made using low thermal expansivity/high yield strength interlayers, such as Mo or W. A composite interlayer comprising Cu and W will produce the lowest thermal stresses during brazing. Increasing the thickness of the interlayer decreases the thermal stresses produced during brazing, since the rigid restraint effect due to the high yield strength/high elastic modulus steel substrate is reduced.MST/1442

Gas metal arc welding and shielding gas therefor

Abstract: A welding method and shielding gas therefor which enables the use of gas metal arc welding to produce smooth welds with little or no surface oxidation and without encountering arc instability during the metal deposition.

Influence of isothermal solidification on microstructural development in Ni–Si–B filler metals

Abstract: An examination is reported of the microstructure of joints between nickel substrates fabricated using Ni–Si–B filler metal (AWS classification BNi-3). This investigation was undertaken because the presence of residual boride and silicide phases after joining can affect the subsequent mechanical properties of the joint. The microstructures developed in the joints are compared with those formed in similarly heat treated filler metal. Various models of the transient liquid phase process are also considered and predicted times to complete isothermal solidification are compared with experimental values. An initial examination of the influence on filler metal microstructure of a ternary addition (chromium) to the substrate is included.MST/1506

Welding material for low coefficient of thermal expansion alloys

Abstract: The invention provides a welding material for welding iron containing low CTE alloys. The filler metal contains 25-55% nickel, 0-30% cobalt, 0.05-0.5% carbon, 0.25-5% niobium and balance iron with incidental impurities. The welding material also is operable with fluxes for submerged arc welding. In addition, the welding material may be configured to function as a flux coated or flux-cored electrode.

Method of fabricating metallic workpieces with a welding apparatus, and apparatus for carrying out the method

Abstract: With an apparatus for shaping by hardfacing, welding material is deposited in track-like layers starting on the surface of a parent body (2), and a workpiece (1) is thus produced, in which case the parent body (2) can be a component of the workpiece (1). The progress of the track-like layers as well as the approximate deposition rate of the welding material are calculated by a computer unit (11), starting from a software, two- or three-dimensional model of the workpiece (1), and are preset for the system control (10), which mutually positions the welding torch (7) by means of the robot (5) as well as the workpiece (1) fixed on a rotary table (4) with a clamping device (3) and regulates the deposition rate of welding material at the welding apparatus (8) in such a way that the liquid welding material adheres to the underlying layer without flowing off and irregularities in the track-like layers are compensated for. Thus metallic workpieces with the most diverse body shapes, theoretically of any size and of any wall thickness, and even consisting of different metallic materials, can be produced by shaping by hardfacing without auxiliary cores or other devices supporting the liquid welding material.

Shielding gas for arc welding of aluminum

Abstract: A shielding gas for the arc welding of aluminum consists of argon or mixtures of argon and helium. The shielding gas also includes an admixture of 80 ppm to 250 ppm of nitrogen.

A Study on Prediction of Welding Current in Gas Metal arc Welding Part 2: Experimental Modelling of Relationship Between Welding Current and Tip-to-Workpiece Distance and its Application to Weld Seam Tracking System

Abstract: The weld joint tracking sensor is indispensable to improve the flexibility of the arc welding robot application. Recently, some sensing methods that utilize the electric arc signal, or more correct...

Formation of stainless steel layer on mild steel by welding arc cladding

Abstract: The discrete microstructural characterization and the formation of stainless steel layer on mild steel where produced in cladding deposits, and fusion boundary region were investigated using tungsten inert gas (TIG) arc, high current pulsed arc and constricted plasma arc. The experimental procedure involved making bead-on-plate method for controlled travel speed, employing filler metal by using tungsten inert gas arc, pulsed current gas tungsten arc and transferred plasma arc, with subsequent sectioning and examination of the reaction interface. For TIG arc cladding, using filler metal of small diameter the deposit does not become stainless steel, but on using 3.2 mm diameter filler metal it becomes stainless steel with less than 50% dilution. For pulsed arc cladding, the complete stainless steel is not obtained on account of the existence of an incomplete mixture, particularly at the fusion boundary region. However, on using a large diameter filler metal at a pulse frequency of 500 Hz, the complete stainless steel microstructure has been accomplished. The plasma arc cladding can be achieved in such a way that the conversion into stainless steel on the mild steel surface — which is the microstructures of cellular austenite in cladding deposit and cellular dendritic austenite containing δ or σ-phase in fusion boundary region — is possible irrespective of the melt penetration and the dilution. The following conditions were found to be beneficial for the formation of stainless steel microstructure layer on the mild steel: using large diameter filler metal, below 50% dilution, and further rendering arc localized and constricted.

Hot diffusion welding method

Abstract: A hot diffusion welding method wherein a first part generally made from a material different from a second part and the second part made from copper alloy are united with an insert material interposed between the joint faces thereof under a heated and pressurized condition. The insert material at the joint between the first and second parts is copper plating formed on the joint face of the first part made from the different material, so that the thermal conductivity between the two parts is improved to perform smooth resistance heating. This enables continuous welding operation without polishing the conductive surfaces of a pair of electrodes in order to eliminate oxides therefrom. When the insert material interposed between the joint faces of the two parts is a normal brazing filler metal, resistance heating is carried out with an even number of superposed bodies in each of which the second part, insert material, first part are superposed, the superposed bodies being assembled in such a manner that the respective second parts are brought into contact with each other. In this case, the first parts having a greater thermal capacity are in contact with the pair of electrodes, whereby polishing for eliminating oxides from the conductive surfaces of the electrodes is no longer necessary and continuous welding operation can be thus accomplished.

Laser Welding of Titanium Alloy

Abstract: (1991). Laser Welding of Titanium Alloy. Welding International: Vol. 5, No. 5, pp. 346-351.

Method for brazing an element transversely to a wall, a brazed-joint assembly for carrying out said method, and a package for electronic components

Abstract: A reservoir for the introduction of a preform of solid brazing filler metal is formed by a recess in the outer wall of an electronic component package and opens into a package through-hole. A lead-wire and bushing are placed within the through-hole with allowance for a clearance space so as to permit liquefaction and capillary diffusion of the filler metal within the space.

Tig welding method in combination with laser beam

Abstract: PURPOSE:To provide the TIG welding method in combination with a laser beam where feed space of filler metal is secured and the occurrence of inside defects of a weld zone, etc., are prevented. CONSTITUTION:The laser beam welding side is constituted of an optical fiber 3 to transmit the laser beam 2, a condenser lens 5 and a hollow part of a hollow electrode 1 arranged on the same axis in front thereof. The TIG welding side is constituted of the hollow electrode 1 and an electrode fitting body 16. The optical fiber is protected by a fiber protecting tube 6 and fitted to lens housing 4, an irradiation part is formed of the optical fiber, the condenser lens and the lens housing and the optical fiber is inserted into the electrode fitting body, by which two welding means are formed into one system on the same axis. The electrode fitting body receives an electric current carried through a feeder 9 from a welding power source 7 which is passed to the hollow electrode and a TIG arc 22 is generated between the electrode 1 and welding base metal 23.

A study on an arc sensor for gas metal arc welding of horizontal fillets

Abstract: The weld joint tracking sensor is indispensable for improving the flexibil­ ity of arc welding robot applications. Re­ cently, some sensing methods that utilize the electric arc signal, or more correctly the welding current in GMA welding, have been developed and are prevalently in use. The welding current is directly af­ fected by the contact tip-to-workpiece distance for the given welding voltage and wire feed speed. Armed with a means of measuring the welding current, the tip-to- workpiece distance and then the weld joint geometry can be obtained by weav­ ing the arc back and forth across the line of travel. Knowledge of the weld joint geometry relative to the welding gun per­ mits the welding gun to trace the joint. In this study, the welding current signal was fitted to a curve, which is inversely proportional to the trace of contact tip- to-workpiece distance by using the qua­ dratic curve-fitting method in order to ex­ tract useful information on the welding gun position from the welding current sig­ nal. Furthermore, the availability of the curve-fitted welding current signal was in­ vestigated and a joint tracking system for horizontal fillet joints was developed by using this curve-fitting method.

High strength and high corrosion resistant aluminum brazing sheet

Abstract: PURPOSE:To improve the brazability, strength and corrosion resistance of a brazing sheet by coating both faces of a core material constituted of Mn, Mg, Cu, Al or the like with an Al-Si brazing filler metal layer, via a diffusion preventing layer constituted of Mn, Ti, Fe, Al or the like. CONSTITUTION:This aluminum brazing sheet is formed in such a manner that both faces of a core material 1 are coated with an Al-Si brazing filler metal layer 3 via a diffusion preventing layer 2. The above core material 1 is formed of a compsn. constituted of, by weight, 0.1 to 1.3% Mn, 0.1 to 1% Mg, 0.1 to 0.6% Cu, 0.05 to 1% Si, 0.05 to 0.6 Fe and the balance Al. Furthermore, the above diffusion preventing layer 2 is formed of a compsn. constituted of 0.1 to 1.3% Mn, 0.05 to 0.2% Ti, 0.05 to O.6% Fe, 0.05 to 1% Si and the balance Al. Then, the thickness t1 per face of the diffusion preventing layer 2 is prescribed to the range of 3 to 10% of the total thickness (t) of the sheet.

Silver brazing filler metal

Abstract: PURPOSE: To provide the brazing filler metal for joining a gold alloy and a platinum alloy. CONSTITUTION: This silver brazing filler metal contains 15 to 90% silver(Ag), 3 to 83% copper(Cu), 2 to 10% germanium(Ge), and the balance consisting of at least one kind selected from ≤10% phosphorus (P), ≤8% zinc(Zn), ≤6% tin(Sn), ≤12% gallium(Ga), ≤9% indium (In), ≤7% cadmium(Cd), and ≤2% antimony(Sb). This brazing filler metal is used for forming jewellery combined with the gold alloy and the platinum alloy and has particularly the high joint strength at the boundary with the platinum alloy. COPYRIGHT: (C)1992,JPO&Japio

Manufacture of ceramic-metal joined body

Abstract: PURPOSE: To manufacture a substrate material having high reliability by improving the wettability of a ceramic substrate with a brazing filler metal and preventing the occurrence of a defectively joined region even when the ceramic substrate is joined to a metal sheet over large area. CONSTITUTION: A Ti layer 2 of several μm thickness is formed on each side of a ceramic substrate 1 by sputtering or other method and is coated with a Cu-Ag-Ti brazing filler metal 3 by screen printing. A metal sheet 4 such as a Cu sheet is put on the brazing filler metal 3 and they are heated in vacuum. By this heating, the metal 3 is allowed to react with the Ti layer 2 and the ceramic substrate 1 is joined to the metal sheet 4 with the metal 3. COPYRIGHT: (C)1992,JPO&Japio

Aluminum brazing sheet for vacuum brazing

Abstract: PURPOSE:To obtain a brazing sheet having excellent vacuum brazing property without shortage of the brazing, etc, by applying the specific composition of Al-Si-Mg series alloy brazing filler metal on both surfaces or one side surface of a core material composed of Al or Al alloy and specifying surface film thickness of the brazing filler metal CONSTITUTION:On both surfaces or the one side surface of core material composed of Al or Al alloy, the Al-Si-Mg series alloy brazing filler metal composed of 6-20wt% Si, 005wt%<=Mg<06wt%, <=03wt% Fe and the balance of Al with inevitable impurities is applied Then, the surface film thickness of brazing filler metal is made to <=120Angstrom By this method, the Al alloy brazing sheet for vacuum brazing having excellent vacuum brazing property without shortage of the brazing, etc, is obtd

High strength clad aluminum alloy material for low temperature brazing

Abstract: PURPOSE: To provide a high strength clad aluminum alloy material for low temp brazing used, as a heat exchanger member, eg for brazing at ≤500°C in automobile, and having high strength and also corrosion resistance equal to or higher than that of the conventional material CONSTITUTION: At least one side of an aluminum alloy material, which has a composition containing, by weight, 05-75% Cu or one or two kinds among 05-75% Cu, 003-35% Mg, and 003-25% Si, further containing one or ≥2 kinds among 001-035% Cr, 001-180% Mn, 001-035% Zr, 003-05% Hf, 003-035% V, 003-35% Ni, 002-15% Fe, and 0005-035% Ti, and having the balance Al with inevitable impurities, is coated with a brazing filler metal melting at ≤500°C, or one side of the aluminum alloy material is clad with a sacrificial material and the opposite side of the sacrificial material is clad with the brazing filler metal COPYRIGHT: (C)1992,JPO&Japio

Brazing sheet having excellent corrosion resistance and production thereof

Abstract: PURPOSE: To obtain the brazing sheet which has excellent corrosion resistance, brazability, and strength after brazing, etc., and is useful as the member for constituting a heat exchanger reduced in thickness by selecting materials, such as core materials, sheath materials, and brazing filler metals, by taking the diffusion reaction between respective layers into consideration. CONSTITUTION: This brazing sheet is formed by cladding the sheath materials and brazing filler metals on both surfaces of the core material. An aluminum alloy contg. 0.1 to 0.8wt.% Cu, 0.8 to 2.5wt.% Mn, 0.3 to 1.2wt.% Si, 0.2 to 0.8wt.% Fe, 0.05 to 0.2wt.% Ti, and 0.05 to 0.2wt.% Mg is used for the core material. An aluminum alloy contg. 0.5 to 2.5wt.% Mg, 1.3 to 3.0wt.% Zn, 0.05 to 0.5wt.% Si, and 0.05 to 0.5wt.% Fe is used for the sheath materials. An Al-Zi brazing filler metal or Al-Si-Zn brazing filler metal is used for the brazing filler metal. COPYRIGHT: (C)1992,JPO&Japio

Manufacture of aluminum alloy brazing sheet excellent in brazability and corrosion resistance

Abstract: PURPOSE:To obtain an aluminium alloy brazing sheet excellent in brazability and corrosion resistance, in an Al-Mn series alloy core material in which the content of Fe is limited, by controlling its homogenizing treatment temp. and the temp., time and temp. rising rate in its final annealing. CONSTITUTION:The ingot of an alloy contg., by weight, 0.3 to 2.0% Mn, 0.1 to 1.0% Cu, <=0.3% Fe and the balance Al is subjected to homogenizing treatment. This ingot is regulated as a core material, and either side of both sides thereof is clad with an Al alloy brazing filler metal contg. at least Si as a surface material. This clad material is hot-rolled, is thereafter cold-rolled and is subjected to final annealing to obtain a brazing sheet. In this method, the above homogenizing treatment is executed at 560 to 620 deg.C, and the final annealing is executed at <=200 deg.C/hr temp. rising rate at 350 to 500 deg.C annealing temp. for the time under the conditions satisfying the inequality I and formulas II and III. By this method, the ratio of Mn series compounds having <=0.1mu grain size can be reduced, by which the material in which the corrosion in the core material caused by the brazing filler metal from the surface material can be prevented and excellent in brazability is obtainable.

Cutting wire tool

Abstract: PURPOSE:To cause no gap on the boundary face of a brazing filler metal and an abrasive grain even at the curved part abutting on a wheel, by brazing the high hardness abrasive grain of a diamond, etc, to a high tension wire CONSTITUTION:A cutting wire tool 1B brazes and fixes a diamond crystal particle abrasive grains 2 by a silver solder containing titanium on the outer peripheral face 9 of a core wire 5 In this case, the abrasive grain 2 and a brazing filler metal 4 are well wet, the boundary face is chemically bonded and so no gap is caused on the boundary face of the brazing filler metal 4 and abrasive grain 2 even at the curved part abutting to a wheel Consequently, the tool life can be extended