Precleaning and Surface Preparation

An unclean surface will not permit the solder to flow, which makes soldering either difficult or impossible and contributes to the formation of a poor joint. Materials such as oil, grease, paint, pencil markings, drawing, and cutting lubricants, general atmospheric dirt, oxide, and rust films must be removed before soldering. The importance of cleanliness cannot be overemphasized in ensuring sound soldered joints. Fluxing alone cannot substitute for adequate precleaning (Ref 19). Because...

Weld Macrostructure

Figures 5(a) and 5(b) show transverse sections of two welds, a submerged arc weld made on a 25 mm (1 in.) thick ASTM A 36 steel and a flux-cored weld made on a 50 mm (2 in.) thick ASTM A 537 steel. Readily apparent features include the number of passes and number of layers, fusion zone area, weld aspect ratio, extent of penetration, face width, and the reinforcement and curvature of the top bead. A transverse macrosection will also show any gross porosity or large inclusions present in a weld...

Powerlaw Creep

FIG. 5 SCHEMATIC OF NUMEROUS PATHS OF MATERIAL TRANSFER GENERATED DURING DIFFUSION BONDING PROCESS. (A) SURFACE SOURCE MECHANISMS. (B) INTERFACE SOURCE MECHANISMS. (C) BULK DEFORMATION MECHANISMS. SEE TEXT FOR SPECIFIC MECHANISMS INDICATED BY NUMBERS SHOWN IN SCHEMATIC. FIG. 5 SCHEMATIC OF NUMEROUS PATHS OF MATERIAL TRANSFER GENERATED DURING DIFFUSION BONDING PROCESS. (A) SURFACE SOURCE MECHANISMS. (B) INTERFACE SOURCE MECHANISMS. (C) BULK DEFORMATION MECHANISMS. SEE TEXT FOR SPECIFIC...

The SMAW Process

The important features of the SMAW process are shown in Fig. 1. The arc is initiated by momentarily touching or scratching the electrode on the base metal. The resulting arc melts both the base metal and the tip of the welding electrode. The molten electrode metal flux is transferred across the arc (by arc forces) to the base-metal pool, where it becomes the weld deposit covered by the protective, less-dense slag from the electrode covering. Advantages and Limitations. The SMAW process is the...

Special Factors Affecting Transformation Behavior in a Weldment

Several aspects of the weld thermal cycle and weld segregation should be considered because of their effect on the transformation upon cooling PEAK TEMPERATURES REACHED IN THE HEAT-AFFECTED ZONE (HAZ) CAN BE VERY MUCH HIGHER THAN THE AC3 TEMPERATURE (THAT IS, THE TEMPERATURE AT WHICH TRANSFORMATION OF FERRITE TO AUSTENITE IS COMPLETED DURING HEATING). THE HEATING RATES ARE VERY HIGH, AND THE TIMES SPENT AT HIGH TEMPERATURE ARE ONLY OF THE ORDER OF A FEW SECONDS. THE TEMPERATURE GRADIENT IN THE...

SiO 1 fAIO TiOj ZrO

Where the chemical components are given in wt . When the basicity index for a given flux is less than one, the flux is considered acidic. A flux with a BI between 1.0 and 1.2 can be classified as neutral. A flux with a BI greater than 1.2 is considered basic. In general, the higher the basicity, the cleaner the weld with respect to nonmetallic inclusions (that is, lower weld metal oxygen content) (Ref 23). Figure 7 illustrates the correlation between weld metal oxygen and the basicity index for...

Shielding Gas Selection for FCAW

The majority of large-diameter (> 1.6 mm, or in.) wires that use a shielding gas use carbon dioxide. Some smaller diameter wires are formulated to operate in 100 CO2. The arcs are generally stable and provide a globular transfer over the usable operating range. Good performance over rust and mill scale on the plate surface is obtained with these large-diameter wires and CO2 shielding. Argon Carbon Dioxide. A significant number of small-diameter (< 1.6 mm, or in.) cored wires...

Example 1 Multipass Weld in a 107 m 42 in Diameter X65 Pipe

This weld is a circumferential weld on a 12.7 mm (0.50 in.) thick, 1.07 m (42 in.) diameter X-65 pipe. The X-65 materials is designated by API as a pipe steel with at least 448 MPa (65 ksi) yield strength and 566 MPa (82 ksi) tensile strength. This type of weld is typical for a large oil or gas pipeline. However, for this example, procedures were deliberately selected to produce a weld with a range of defects. These procedures, given by Table 4, are not representative of standard practice....

Soldering Equipment

The proper application of heat is of paramount importance in any soldering operation. The solder should melt while the surface is heated to permit the molten solder to wet and flow over the surface. The best heating method is therefore another important consideration. Soldering Irons. The traditional soldering tool is the soldering iron, or bit, with a copper tip than can be heated electrically, by direct flame, or in an oven. Because soldering is a heat-transfer process, the maximum surface...

Diffusion Bonding Process

The DB process, that is, the application of pressure and temperature to an interface for a prescribed period of time, is generally considered complete when cavities fully close at the faying surfaces. Relative agreement is found for the mechanisms and sequence of events that lead to the collapse of interface voids, and the discussion below describes these metallurgical processes. Although this theoretical understanding of the DB process is universally applicable, it should be understood that...

Electrode Regions and Arc Column

The cathode and anode are similar in several respects. Both exhibit a voltage drop caused by a space charge that covers a very thin region over their surfaces, and the arc is significantly contracted on the surfaces. Figure 1 shows that the total arc voltage is partitioned between the electrode drops and arc column. The relative magnitude of these drops depends on welding parameters and electrode material. FIG. 1 PLOT OF RELATIVE ARC VOLTAGE DISTRIBUTION VERSUS RELATIVE ARC LENGTH BETWEEN...

Hydrogen Induced Cracking Cold Cracking

Cold cracks are defects that form as the result of the contamination of the weld microstructure by hydrogen. Whereas solidification cracking and HAZ cracking occur during or soon after the actual welding process, hydrogen-induced cracking is usually a delayed phenomenon, occurring possibly weeks or even months after the welding operation. The temperature at which these defects tend to form ranges from -50 to 150 C (-60 to 300 F) in steels. The fracture is either intergranular or transgranular...

Quality Control

Table 3 lists that are commonly used to evaluate the solderability properties of selected soldered components. TABLE 3 TEST STANDARDS USED TO EVALUATE SOLDERABILITY TABLE 3 TEST STANDARDS USED TO EVALUATE SOLDERABILITY Dip Test. The most useful test for assessing solderability is the dip test, because of its accuracy and simplicity. It is conducted with the additions of cams and timers so that standardized conditions are established. The dip test is a reasonable simulation of practical...

Dt5 Electrodes Are Classified Using Dcep However They Are Sometimes Used With Dcen In Practice

Indicates the minimum tensile strength ol the deposited weid metal in a test weld made with the electrode and m accordance with specified welding conditions Indicates the primary welding position lor which the electrode is < Jesigr> ed 0 llat and horizontal positions Indicates usability and performance capabilities Indicates a llux cored electrode FIG. 4 CLASSIFICATION SYSTEM FOR CARBON STEEL FLUX-CORED ELECTRODES. THE LETTER X AS USED IN THIS FIGURE AND IN ELECTRODE CLASSIFICATION...

Inclusion radius lin 440 400 4000

FIG. 17 EFFECT OF PARTICLE RADIUS ON ENERGY BARRIER TO FERRITE NUCLEATION AT INCLUSIONS, AG* (HETEROGENEOUS), NORMALIZED RELATIVE TO THE HOMOGENEOUS NUCLEATION BARRIER, AG*H (HOMOGENEOUS). CORRESPONDING ENERGY BARRIER TO NUCLEATION OF FERRITE AT AUSTENITE GRAIN BOUNDARIES IS INDICATED BY HORIZONTAL BROKEN LINE. SOURCE REF 6 Broadly, the major factors affecting transformation behavior in ferritic steel weld metals are alloy composition, weld heat input (by its effect on y grain size and Ai8.5),...

N 100 [asi Amneq

Where A Si is the change in the weight percent of silicon, and A Mn is the change in the weight percent of manganese. To determine the Wall neutrality number, two different weld deposit pads must be made. One weld pad is welded with the same parameters as those specified for the weld test plate for the flux and electrode being used. The other weld pad is welded with the same parameters except that the voltage is increased by 8 V. The A Si and A Mn quantities in Eq 1 are then determined by the...

What Are The Mechanical Properties Of The Weld Metal

In addition, a number of very application-specific corrosion and elevated-temperature tests were performed on the dissimilar metal welds. In contrast with the pipe weld of the first example, the primary tools used in this characterization were macrostructural examination, compositional mapping, x-ray diffraction, tension testing of all weld metal specimens, and microhardness traverses. FIG. 14 MICROHARDNESS READINGS (LOCATION IN MULTI-PASS WELD INDICATED BY DOTS) BELOW 240 HV INDICATING THAT NO...

Shielding Gas Selection for PAW

The physical configuration of the PAW system requires the use of two gases a plasma or orifice gas and a shielding gas. The primary role of the plasma gas, which exits the torch through the center orifice, is to control arc characteristics and shield the electrode. The shielding gas, introduced around the periphery of the arc, shields or protects the weld area. In many applications, the shielding gas is also partially ionized to enhance the performance of the plasma gas. Low-Current (< 100 A)...

Civil Engineering Advantage Of Filler Welds

GAS-METAL ARC WELDING (GMAW) is an arc welding process that joins metals together by heating them with an electric arc that is established between a consumable electrode (wire) and the workpiece. An externally supplied gas or gas mixture acts to shield the arc and molten weld pool. Although the basic GMAW concept was introduced in the 1920s, it was not commercially available until 1948. At first, it was considered to be fundamentally a high-current-density, small-diameter, bare-metal electrode...

6 M C Noland Hm Gadberry Jb Loser And E C Sneegas High Velocity Metal

WORKING A SURVEY, NASA REPORT N67-26560, SP 5062, NASA, 1967 7. A.A. EZRA, PRINCIPLES AND PRACTICE OF EXPLOSIVE METAL WORKING, INDUSTRIAL NEWSPAPERS LIMITED, JOHN ADAMS HOUSE, LONDON, 1973 9. R.W. GURNEY, THE INITIAL VELOCITIES OF FRAGMENTS FROM BOMBS, SHELLS, AND GRENADES, REPORT 405, BALLISTIC RESEARCH LABORATORY, 1943 10. S. CARPENTER, RH. WITTMAN, AND R.J. CARLSON, RELATIONSHIPS OF EXPLOSIVE WELDING PARAMETERS TO MATERIAL PROPERTIES AND GEOMETRY FACTORS, PROC. FIRST INT. CONF. OF THE CENTER...

Mechanism of Diffusion Bonding

In diffusion bonding, the nature of the joining process is essentially the coalescence of two atomically clean solid surfaces. Complete coalescence comes about through a three-stage metallurgical sequence of events. Each stage, as shown in Fig. 2, is associated with a particular metallurgical mechanism that makes the dominant contribution to the bonding process. Consequently, the stages are not discretely defined, but begin and end gradually, because the metallurgical mechanisms overlap in...

References cited in this section

BORLAND, GENERALIZED THEORY OF SUPER-SOLIDUS CRACKING IN WELDS (AND CASTINGS), BR. WELD. J., VOL 7 (NO. 8), 1960, P 508-512 2. J.C. BORLAND, HOT CRACKING IN WELDS, BR. WELD. J., VOL 7 (NO. 9), 1960, P 558-559 3. DA. CANONICO, W.F. SAVAGE, W.J. WERNER, AND G.M. GOODWIN, EFFECTS OF MINOR ADDITIONS ON THE WELDABILITY OF INCOLOY 800, EFFECTS OF MINOR ELEMENTS ON THE WELDABILITY OF HIGH-NICKEL ALLOYS, WRC, JULY 1969, P 68-92 4. M.J. CIESLAK, THE WELDING AND SOLIDIFICATION METALLURGY OF ALLOY...

H

FIG. 4 SPRAY TRANSFER MODE IN GAS-METAL ARC WELDING OF STEEL. (A) SCHEMATIC SHOWING TRANSFER OF ELECTRODE MATERIAL DROPLETS ONTO CATHODE BASE METAL. (B) HIGH-SPEED PHOTOGRAPH OF SPRAY METAL TRANSFER MODE FIG. 5 HIGH-SPEED PHOTOGRAPH OF STREAMING TRANSFER MODE IN GAS-METAL ARC WELDING OF STEEL FIG. 6 SHORT-CIRCUITING TRANSFER MODE IN GAS-METAL ARC WELDING OF STEEL. (A) SCHEMATIC SHOWING TRANSFER OF ELECTRODE MATERIAL BY SURFACE TENSION OF WELD POOL ONTO CATHODE BASE METAL. (B) HIGH-SPEED...

Stainless Steels

It has long been known that solidification cracking can be avoided in austenitic stainless steel welds by having a small concentration of ferrite in them. Recent work has shown, however, that residual ferrite content at room temperature is no more than a symptom and that it is really the solidification mode (whether the weld metal solidifies as primary austenite or ferrite) that is the deciding criterion (Ref 43). It has been found that susceptibility to solidification cracking is least for a...

R r

0.00441-I (550- 25) 32.2 (EQ 65) resulting in R being equal to 2n(0.028)32.2, which is equal to 5.7 C s (10.3 F s). This value is the maximum safe cooling rate for this steel and the actual cooling rate cannot exceed this value. Preheating Temperature Requirement. Although the critical cooling rate cannot be exceeded, in the actual welding operation a preheat can be used to reduce the cooling rate to 5.7 C s (10.3 F s). Assume that the welding condition is 25(250)0.9 aniT. Hnet - 804J mm (EQ...

3sp Chen Theoretical Studies Of Metallic Interfaces Mater Sci Eng B Vol 6 1990p 113121

MCMAHON, JR., A MICROSCOPIC THEORY OF BRITTLE FRACTURE IN DEFORMABLE SOLIDS A RELATION BETWEEN IDEAL WORK TO FRACTURE AND PLASTIC WORK, ACTA METALL., VOL 28, 1980, P 1479-1488 5. ML. JOKL, V. VITEK, AND C.J. MCMAHON, JR., ON THE MICROMECHANICS OF BRITTLE FRACTURE EXISTING VS INJECTED CRACKS, ACTA METALL., VOL 37, 1989, P 87-97 6. J. HACK, S.P. CHEN, AND D. SROLOVITZ, A KINETIC CRITERION FOR QUASI-BRITTLE FRACTURE, ACTA METALL., VOL 37, 1989, P 1957-1970 7. A. KELLY...

GTAW Process Variations

Manual welding refers to the GTAW process in which the welder manipulates the welding torch by hand. If a motorized wire feeder is attached to the torch, the process is classified as semiautomatic welding. Products generated by skilled manual welders account for a large proportion of GTAW applications. The equipment can be quite inexpensive, and properly trained welders can join a wide variety of materials. Manual welding is used extensively in stainless steel piping as well as for the root...

The Material Has Poor Ductility In The Z Direction

FIG. 16 TYPICAL LOCATION FOR LAMELLAR TEARING IN A T-JOINT FIG. 16 TYPICAL LOCATION FOR LAMELLAR TEARING IN A T-JOINT Lamellar tearing can occur during flame cutting and cold shearing operations. Low material strength in the z direction is the primary cause, with stress in that direction initiating the tearing. Thermal heating and stresses from weld shrinking create the fracture. Lamellar tearing can take place shortly after welding or occasionally months later. Thicker, higher-strength...

Development of Weld Microstructures

Solidification Metals

Nonplanar solidification develops when a protrusion moves ahead of the rest of the solid-liquid interface and continues to grow in a stable manner. This increases the surface area. The stable radius is given by Eq 4, which shows that the protrusion must move into a supercooled region in order to be stable. This is possible in a casting, because a negative temperature gradient is developed (that is, the temperature decreases from the solid-liquid interface into the liquid). In a pure material...

Process Parameters

Current is one of the most important operating conditions to control in any welding operation, because it is related to the depth of penetration, welding speed, deposition rate, and quality of the weld. Fundamentally, there are but three choices of welding current DIRECT CURRENT ELECTRODE NEGATIVE (DCEN) DIRECT CURRENT ELECTRODE POSITIVE (DCEP) Figures 5 and 6 show the effect of dc and ac on weld shape. Table 2 gives the recommended current relative to workpiece material. TABLE...

Diffusion Bonding with Interface Aids

Additional layers of material in the form of coatings or foils are often used as bonding aids for a variety of reasons. For example, an intermediate material can be used when joining dissimilar materials where a brittle intermetallic would otherwise form. In this case, the interfacial material would be selected for its compatibility with each of the materials to be joined and for its ability to prevent the creation of a brittle reaction layer. To promote diffusion in materials that contain...

References

RIEPPEL, DIFFUSION BONDING BELOW 1000 F, WELD. J., VOL 37, 1958, P 337S-342S 2. I.M. BARTA, LOW TEMPERATURE DIFFUSION BONDING OF ALUMINUM ALLOYS, WELD. J, VOL 43, 1964, P 241S-247S 3. D. HAUSER, P.A. KAMMER, AND J.H. DEDRICK, SOLID-STATE WELDING OF ALUMINUM, WELD. J., VOL 46, 1967, P 11S-22S 4. P.A. KAMMER, RE. MONROE, AND DC. MARTIN, FURTHER STUDIES OF DIFFUSION BONDING BELOW 1000 F, WELD. J., VOL 48, 1969, P 116S-124S 5. Y. IINO AND N. TAGAUCHI,...

Fusion Zone of a Single Pass Weld

Transformations in Single-Pass Weld Metal. It is usually not necessary to select a filler metal that has exactly the same composition as the base metal it is more important that the weld metal has the same strength and other properties (such as toughness or corrosion resistance). Because these properties are governed by the microstructure, it is important to understand the influence of different factors on phase transformations in the weld metal. But first, for a meaningful communication of the...

50 Ew Collings Introduction To Titanium Alloy Design Alloying Jl Walter

SIMS, ED., ASM INTERNATIONAL, 1988, P 267 51. C R. THOMAS AND F.P.A. ROBINSON, KINETICS AND MECHANISM OF GRAIN GROWTH DURING WELDING IN NIOBIUM STABILISED 17 CHROMIUM STAINLESS STEELS, MET. TECHNOL, APRIL 1978, P 133-138 52. J.C. WILLIAMS AND E.A. STARKE, JR., THE ROLE OF THERMOMECHANICAL PROCESSING IN TAILORING THE PROPERTIES OF ALUMINUM AND TITANIUM ALLOYS, DEFORMATION, PROCESSING AND STRUCTURE, G. KRAUSS, ED., AMERICAN SOCIETY FOR METALS, 1984, P 279-354 53. W.A....

Dynamic Bend Angle And The Physical And Mechanical Properties Of The Metal Constituents

FIG. 1 SCHEMATIC SHOWING KEY COMPONENTS USED IN THE PARALLEL GAP EXPLOSIVE WELDING PROCESS Flyer Plate Acceleration FIG. 1 SCHEMATIC SHOWING KEY COMPONENTS USED IN THE PARALLEL GAP EXPLOSIVE WELDING PROCESS Flyer Plate Acceleration Figure 2, an intermediate view of the explosive bonding process, shows an idealization of the metal deformation that results after explosive detonation. Flash radiography performed during the bonding process has been used to develop this pictorial representation (Ref...

Joint Design

Joints should be designed to fulfill the requirements of the finished assembly, as well as to permit the application of the flux and solder. Joint design should maintain proper clearance during heating and upon solidification of the filler metal. Special fixtures may be necessary or the units can be crimped, clinched, wrapped, or otherwise held together. The selection of a joint design for a specific application will primarily depend on the service requirements of the assembly. It may also...

Inclusions Due To Entrapped Slag Tungsten Electrode Pieces Or Defects Present In The Starting Material

A number of techniques are widely used to assess the presence of surface and subsurface defects in welds. The most common of these are liquid penetrant inspection for surface cracks, magnetic particle inspection, x-ray radiography, and ultrasonic inspection. Penetrant inspection involves the application of an indicator fluid that has a surface tension sufficiently low to be drawn into surface cracks too small to be detected visually. The excess dye or fluorescent material is then removed from...

The Aspiration Of Atmosphere Air Into The

Shielding gas may contain oxidizing reagents a common gas is 75Ar-25CO2 or 100 CO2. As a 100 to 1000 ppm, depending on the type of welding consumable used. The weld metal oxygen measured directly at the molten electrode tip has been reported to be as high as 1400 ppm. Individual droplets have been found to contain as much as 2000 ppm O2. There are two views concerning the genesis of the high oxygen content. One suggests that pyrochemical or electrochemical reactions (or both) provide oxygen to...

Special Applications of the SMAW Process

Underwater welding began during World War I when the British naval force used it to make temporary repairs of leaking rivets on ship hulls. The introduction of covered electrodes enabled succesful underwater welding and the production of welds having approximately 80 of the strength and 40 of the ductility of similar welds made in air. Because of the somewhat diminished weld properties, this SMAW application is generally restricted to salvage operations or underwater repair work. Underwater...

Introduction

SOLID-STATE TRANSFORMATIONS occurring in a weld are highly nonequilibrium in nature and differ distinctly from those experienced during casting, thermomechanical processing, and heat treatment. This discussion will primarily focus on the welding metallurgy of fusion welding of steels and attempt to highlight the fundamental principles that form the basis of many of the recent developments in steels and consumables for welding. Accordingly, examples are largely drawn from the well-known and...

Bringing The Workpiece Joint Area To The Soldering Temperature

Soldering Dip Bath Method

The angle at which the copper tip is applied to the work is important in terms of delivering maximum heat. The flat side of the tip should be applied to the work to obtain the maximum area of contact. Flux-cored solders should not be melted on the soldering tip, because this destroys the effectiveness of the flux. The cored solder should be touched to the soldering tip to initiate good heat transfer, and then the solder should be melted on the work parts to complete the solder joint (Ref 11)....

Inertia Drive Welding

The inertia-drive FRW method uses a similar type of machine except that the spindle holding the rotating piece is attached to a flywheel. The flywheel controls the energy input to the weld. The moment of inertia of the flywheel is an important variable that is adjusted by adding or removing flywheels. The amount of energy stored in the flywheel is controlled by its speed. Once the spindle is at the correct speed, the drive system is disengaged, leaving a rotating flywheel mass. Axial pressure...

Shielding Gases for GMAW

By far, the largest number of gas blends have been developed for GMAW, especially for joining carbon steel. These can be roughly divided into four categories pure gases, argon-oxygen mixes, argon carbon dioxide mixes, and three-part gas blends composed of either argon, helium, oxygen, carbon dioxide, or hydrogen. Table 3 contains suggestions for shielding gas selection based on material type, thickness, and mode of metal transfer. TABLE 3 RECOMMENDED SHIELDING GAS SELECTION FOR GMAW TABLE 3...

Soldering

Like brazing and other joining processes, soldering involves several fields of science, including mechanics, chemistry, and metallurgy. Soldering is a simple operation (Ref 2), consisting of the relative placement of the parts to be joined, wetting the surfaces with molten solder, and allowing the solder to cool until it has solidified. Soldering in the field of electronics is in many respects different from soldering in other branches of industry. Although the physical principles of all...

Nondestructive Characterization Techniques

Externally Observed Macroscopic Features. Several factors associated with the production and performance of welds are macroscopic and easily observed. The most obvious of these are the size, shape, and general appearance of the weld. To a large extent, these parameters depend on the geometry of the weld joint and the welding process selected. Figure 1 shows schematic representations of fillet, lap, butt, and groove welds, in which a number of features (defined in Table 1) are labeled. TABLE 1...

Unaltered Graincoarsened Uagc Zone The Zone That Is Not Reheated Above About 200 C 390 F Or The Zone That Is Again

Figure 30 shows how the crack tip opening displacement (CTOD) value of simulated specimens varies with the peak temperature of the second thermal cycle, Tp2 (Tp1 1400 C, or 2550 F). It is seen that the ICGC, UAGC, and SCGC regions have CTOD values less than about 0.1 mm (0.004 in.). Similar low values have been obtained by locating the crack tip in the CTOD tests at corresponding locations in the HAZ of actual multipass weldments. These low toughness regions are commonly known as local brittle...

3 O Grong And Dk Matlock Microstructural Development In Mild And Low Alloy Steel Weld Metals Int Met Rev Vol 31 No 1

EASTERLING, INTRODUCTION TO THE PHYSICAL METALLURGY OF WELDING, BUTTERWORTHS, 1983 14. S. KOU, WELDING METALLURGY, JOHN WILEY & SONS, 1987 22. L.E. SAMUELS, OPTICAL MICROSCOPY OF CARBON STEELS, AMERICAN SOCIETY FOR METALS, 1980 23. GUIDE TO THE LIGHT MICROSCOPE EXAMINATION OF FERRITIC STEEL WELD METALS, DOC. NO. IX-1533-88, INTERNATIONAL INSTITUTE OF WELDING, 1988 24. H.K.D.H. BHADESHIA AND L.E. SVENSSON, MODELLING THE EVOLUTION OF MICROSTRUCTURE OF STEEL WELD METAL, MATHEMATICAL...

W

NOWICKI, AND I. CRAIG, SLAG METAL INTERACTION, OXYGEN, AND TOUGHNESS IN SUBMERGED ARC WELDING, WELD. J, VOL 57 (NO. 3), 1978, P 63S-75S 5. N. CHRISTENSEN AND J. CHIPMAN, SLAG-METAL INTERACTION IN ARC WELDING, WELD. RES. BULL, NO. 15, JAN 1953, P 1-14 6. R.H. FROST, D.L. OLSON, AND S. LIU, PYROCHEMICAL EVALUATION OF WELD METAL INCLUSION EVOLUTION, PROC. 3RD INT. CONF. TRENDS IN WELDING, ASM INTERNATIONAL, JUNE 1992 7. C.A. NATALIE, D.L. OLSON, AND M. BLANDER, PHYSICAL...

Variations of the SMAW Process

Gravity feed is considered to be an automatic method of applying the SMAW process. It utilizes a relatively low-cost mechanism that includes an electrode holder attached to a bracket, which slides down an inclined bar arranged along the line of weld. Special electrodes with a heavy coating are maintained in contact with the workpiece by the weight of the electrode holder and electrode. Once the process is started, it continues automatically until the electrode has burned to a...

Plasma Arc Cutting

Alternating current power sources for shielded metal arc welding (SMAW) and submerged arc welding (SAW) can be as simple as a single transformer (Fig. 2a). Low-voltage machines with open-circuit voltages of 50 V or less are transformer types. Output alternating current reflects the sinusoidal waveform of the utility input line (Fig. 3a). FIG. 2 SELECTED ALTERNATING CURRENT POWER SOURCES. (A) ALTERNATING CURRENT WELDING TRANSFORMER, ADJUSTABLE CORE OR WINDINGS. (B) THREE-PHASE SCR-CONTROLLED DC...

Bone Test Only

These data provide a means of comparing the wettability of beryllium by various liquids. If one assumes wettability for contact angles less than 90 and nonwetting for angles greater than 90 , then these data permit qualitative separation of the systems into two classes those with contact angles less than 90 , and those with contact angles greater than 90 . Gold, Pd-2.1Be, and Ti-6Be were found to wet beryllium at both temperatures. The latter two brazing filler metals, as well as silver and...

Formation Of Intermetallic Phases Between Normal Constituents Of The Alloys Being Welded

Intermetallic phase formation is common when welding refractory metal alloys to stainless steel alloys and in several other systems. In the case of stainless steels to refractory metals, o phase or similar phases may occur upon welding at the interface. Proper weld procedure development reduces the amount of brittle phases that are formed, but typically does not eliminate their formation completely. Properly developed welds have satisfactory structural properties, because only small,...

Resistance Welding Power Sources

The function of the power source for resistance welding (RW) is to deliver a predetermined amplitude of current to the welding electrodes that are clamping the workpiece. Current flows from the power source to one electrode, through the workpiece to the opposing electrode, and returns to the power source. The electrodes concentrate current into a small, usually circular area. The flow of this constricted current generates heat, concentrated largely at the interface(s) of the workpiece details...

Control Of Washing Or Control Of Erosion Between The Brazing Filler Metal And The Base Metal Within The Limits Required

It should be noted that the strength of the brazed joint is not directly related to the method of filler-metal melting. For example, if constructional metals are produced by vacuum melting, then there is a definite relationship between the vacuum-melting practice and the final strength of the ingot, bar, or rolled sheet. With a brazing filler metal, however, joint strength is dependent on joint design, brazing temperature, amount of brazing filler metal applied, location and method of...

010365 202 127c 18000

Scatter Plots Cooling Rate

Also from Eq 32, we can calculate the cooling rate in the heat-affected zone at a temperature of 615 C (1140 F) Therefore, at the same temperature, the cooling rate at the centerline is greater than the cooling rate at the location a distance y from the centerline. In addition, the cooling rate of the heat-affected zone is less than the cooling rate in the weld pool at the same temperature. A weld pass of 800 J mm (20.3 kJ in.) in net energy input is deposited on a steel plate. The initial...

2im Barta Low Temperature Diffusion Bonding Of Aluminum Alloys Weld J Vol 43 1964 P 241s247s

DEDRICK, SOLID-STATE WELDING OF ALUMINUM, WELD. J., VOL 46, 1967, P 11S-22S 4. P.A. KAMMER, RE. MONROE, AND DC. MARTIN, FURTHER STUDIES OF DIFFUSION BONDING BELOW 1000 F, WELD. J., VOL 48, 1969, P 116S-124S 5. Y. IINO AND N. TAGAUCHI, INTERDIFFUSING METALS LAYER TECHNIQUE OF CERAMIC-METAL BONDING, J. MATER. SCI. LETT., VOL 7 (NO. 9), 1988, P 981-982 6. A. URENA, J.M.G.D. SALAZAR, AND J. QUINONES, DIFFUSION BONDING OF ALUMINA TO STEEL USING SOFT COPPER...

Pence Penitration

DAVIES, AND K. GJERMUNDSEN, DISTRIBUTION OF TEMPERATURES IN ARC WELDING BR. WELD J, VOL 12, 1965, P 54-75 2. K. ISHIZAKE, K. MURAI, AND Y. KANBE, PENETRATION IN ARC WELDING AND CONVECTION IN MOLTEN METAL, DOCUMENT 77-66, INTERNATIONAL INSTITUTE OF WELDING, STUDY GROUP 212, 1966 3. J. THOMSON, ON CERTAIN CURIOUS MOTIONS OBSERVABLE AT THE SURFACES OF WINE AND OTHER ALCOHOLIC LIQUORS, PHILOSMAG, VOL 10, 1855, P 330-333 4. C. MARANGONI, BER DIE AUSBREITUNG DER TROPFEN EINER...

The Soldering Process Can Be Easily Automated Offering The Possibility Of Inline Arrangements Of Soldering Machines

Mass soldering by wave, drag, or dip machines has been the preferred method for making high-quality, reliable connections for many decades. Despite the appearance of new connecting systems, it still retains this position. Correctly controlled, soldering is one of the least expensive methods for fabricating electrical connections. Incorrectly controlled, it can be one of the most costly processes--not because of the initial cost, but because of the many far-reaching effects of poor workmanship....

Flux Classification

Fluxes can be categorized depending on the method of manufacture, the extent to which they can affect the alloy content of the weld deposit, and the effect on weld deposit properties. Classification Relative to Production Method. Based on the manufacturing process, there are two different types of fluxes fused and bonded. Fused Fluxes. The raw materials for a fused flux are dry mixed and melted in a furnace. The molten mixture is then rapidly solidified, crushed, screened, and packaged. Because...

Bonding Surfaces Containing Oxides

Diffusion bonding can be achieved for materials with adherent surface oxides, but the resultant interface strengths of these materials are considerably less than that measured for the parent material. Aluminum alloys are prime examples of this class of material. Research since 1960 has demonstrated only limited diffusion bond properties. Although interface strength can be increased for oxide-bearing materials, it requires considerable surface extension of the faying interfaces to create...

Solidification Cracking Hot Cracking

Hot cracks are solidification cracks that occur in the fusion zone near the end of solidification. Simplistically, they result from the inability of the semisolid material to accommodate the thermal shrinkage strains associated with weld solidification and cooling. Cracks then form at susceptible sites to relieves the accumulating strain. Susceptible sites are interfaces, such as solidification grain boundaries and interdendritic regions, that are at least partially wetted. Figure 1 is a...