An alternate way to initiate the arc is the "scratch start". Scratching the electrode against the work with the power on also serves to strike an arc, in the same way as SMAW ("stick") arc welding. However, scratch starting can cause contamination of the weld and electrode. Some GTAW equipment is capable of a mode called "touch start" or "lift arc"; here the equipment reduces the voltage on the electrode to only a few volts, with a current limit of one or two amps (well below the limit that causes metal to transfer and contamination of the weld or electrode). When the GTAW equipment detects that the electrode has left the surface and a spark is present, it immediately (within microseconds) increases power, converting the spark to a full arc.

Once the arc is struck, the welder moves the torch in a small circle to create a welding pool, the size of which depends on the size of the electrode and the amount of current. While maintaining a constant separation between the electrode and the workpiece, the operator then moves the torch back slightly and tilts it backward about 10–15 degrees from vertical. Filler metal is added manually to the front end of the weld pool as it is needed.

Welders often develop a technique of rapidly alternating between moving the torch forward (to advance the weld pool) and adding filler metal. The filler rod is withdrawn from the weld pool each time the electrode advances, but it is never removed from the gas shield to prevent oxidation of its surface and contamination of the weld. Filler rods composed of metals with low melting temperature, such as aluminum, require that the operator maintain some distance from the arc while staying inside the gas shield. If held too close to the arc, the filler rod can melt before it makes contact with the weld puddle. As the weld nears completion, the arc current is often gradually reduced to allow the weld crater to solidify and prevent the formation of crater cracks at the end of the weld.
 

Tungsten Manufacturer & Supplier: Chinatungsten Online - http://www.chinatungsten.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
 

Manual gas tungsten arc welding is often considered the most difficult of all the welding processes commonly used in industry. Because the welder must maintain a short arc length, great care and skill are required to prevent contact between the electrode and the workpiece. Similar to torch welding, GTAW normally requires two hands, since most applications require that the welder manually feed a filler metal into the weld area with one hand while manipulating the welding torch in the other. However, some welds combining thin materials (known as autogenous or fusion welds) can be accomplished without filler metal; most notably edge, corner, and butt joints.

To strike the welding arc, a high frequency generator (similar to a Tesla coil) provides an electric spark; this spark is a conductive path for the welding current through the shielding gas and allows the arc to be initiated while the electrode and the workpiece are separated, typically about 1.5–3 mm (0.06–0.12 in) apart. This high voltage, high frequency burst can be damaging to some vehicle electrical systems and electronics, because induced voltages on vehicle wiring can also cause small conductive sparks in the vehicle wiring or within semiconductor packaging. Vehicle 12V power may conduct across these ionized paths, driven by the high-current 12V vehicle battery. These currents can be sufficiently destructive as to disable the vehicle; thus the warning to disconnect the vehicle battery power from both +12 and ground before using welding equipment on vehicles.
 

Tungsten Manufacturer & Supplier: Chinatungsten Online - http://www.chinatungsten.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
 

There are many types of wave solder machines, however the basic components and principles of these machines are the same. A standard wave solder machine consists of three zones: the preheating zone, the fluxing zone, and the soldering zone. An additional fourth zone, cleaning, is used depending on the type of flux applied. The basic equipment used during the process is a conveyor that moves the PCB through the different zones, a pan of solder used in the soldering process, a pump that produces the actual wave, the sprayer for the flux and the preheating pad. The solder is usually a mixture of metals.

A typical solder has the chemical makeup of 50% tin, 49.5% lead, and 0.5% antimony.[citation needed] There are three types of waves: normal wave, a medium speed, long leads used for horizontal soldering; cascade wave, high speed, short leads, used for inclined soldering; and flat wave with extenders; medium to high speeds, long leads that is used for horizontal soldering.
 

Tungsten Manufacturer & Supplier: Chinatungsten Online - http://www.chinatungsten.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
 

Wave soldering is a large-scale soldering process by which electronic components are soldered to a printed circuit board (PCB) to form an electronic assembly. The name is derived from the use of waves of molten solder to attach metal components to the PCB. The process uses a tank to hold a quantity of molten solder; the components are inserted into or placed on the PCB and the loaded PCB is passed across a pumped wave or waterfall of solder. The solder wets the exposed metallic areas of the board (those not protected with solder mask, a protective coating that prevents the solder from bridging between connections), creating a reliable mechanical and electrical connection. The process is much faster than manual soldering of components.

Wave soldering is used for both through-hole printed circuit assemblies, and surface mount. In the latter case, the components are glued by the placement equipment onto the printed circuit board surface before being run through the molten solder wave.

As through-hole components have been largely replaced by surface mount components, wave soldering has been supplanted by reflow soldering methods in many large-scale electronics applications. However, there is still significant wave soldering where SMT is not suitable (e.g., large power devices and high pin count connectors), or where simple through-hole technology prevails (certain major appliances).
 

Tungsten Manufacturer & Supplier: Chinatungsten Online - http://www.chinatungsten.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
 

1.Substrate remains solid throughout, therefore less heat energy is required
2.Less of the substrate is affected metallurgically by the application of heat
3.The process is less expensive because it requires less energy

Soldering can be differentiated from brazing because of the lower melting temperature of the filler material. Typically solder constitutes primarily of a tin/lead* alloy with alternative alloy components or percentage changes being introduced and varied to increase/decrease the melting temperature. The cut off between soldering and brazing is generally recognized as being above or below 450C.

A melting point below 450C is typically considered to be soldering and above 450C it is typically considered to be brazing, although silver soldering or hard soldering is normally above 450C and consequently should be considered to be the first level of brazing even though it is never really referred to as brazing and nearly always as soldering.
 

Tungsten Manufacturer & Supplier: Chinatungsten Online - http://www.chinatungsten.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
 

Cycle times are dependent on heating and cooling times and the quality of the joint is dependent on the care taken preparing the surfaces. Inadequate surface preparation will cause defects due to incomplete wetting of the joints.

Equipment costs are low so consequently the process of brazing and soldering is a low cost option. Costs will increase where automated systems are employed dependent on the level of sophistication required. There is also virtually no waste of the soldering or brazing alloy, particularly where pre-sized charges are use, but the flux used for the process is consumed.

Brazing and soldering, when you consider that you are introducing a layer of material between two surfaces and rely on the chemical and physical bonding of the materials to hold the joint together, can be considered a gluing process for metals.

Abrasion of the surfaces can provide the mechanism for allowing the molten liquid to penetrate into the resulting surface crevices which when solidified effectively anchors the filler material to the surface and holds the parts together mechanically.

Tungsten Manufacturer & Supplier: Chinatungsten Online - http://www.chinatungsten.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
 

Brazing and soldering comes under the manufacturing processes category of joining. The process in both cases involves introducing a low temperature alloy into a controlled gap between metal surfaces. An important aspect of the brazing and soldering process is the preparation of the component material in the area of the joint before starting to braze or solder the joint.

The operator needs to ensure the surfaces to be joined are scrupulously cleaned, degreased and if necessary abraded. Without proper preparation the flow of liquid metal into the joint will not occur satisfactorily. Brazing and soldering relies on a capillary action taking place for the molten metal to flow between the components being joined. The parent metal remains above melting point for the duration of the process and a flux is used, specifically chosen for the metal being joined, to aid the capillary flow of the liquid metal.

High production volumes of components being joined using the brazing or soldering process are normally pre-assembled (or where necessary jigged), often with a pre-sized charge of alloy which has been calculated to be sufficient to fill the joint adequately. Heat can be applied in a number of ways but one of the most common methods is using a conveyer furnace with a torch or induction heating as the heat source.
 

Tungsten Manufacturer & Supplier: Chinatungsten Online - http://www.chinatungsten.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
 

Soldering is a process in which two or more metal items are joined together by melting and flowing a filler metal (solder) into the joint, the filler metal having a lower melting point than the workpiece. Soldering differs from welding in that soldering does not involve melting the work pieces. In brazing, the filler metal melts at a higher temperature, but the workpiece metal does not melt. Formerly nearly all solders contained lead, but environmental concerns have increasingly dictated use of lead-free alloys for electronics and plumbing purposes.

In the joining of tungsten tube, failure to properly heat and fill a joint may lead to a 'void' being formed. This is usually a result of improper placement of the flame. If the heat of the flame is not directed at the back of the fitting cup, and the solder wire applied 180 degrees opposite the flame, then solder will quickly fill the opening of the fitting, trapping some flux inside the joint. This bubble of trapped flux is the void; an area inside a soldered joint where solder is unable to completely fill the fittings' cup, because flux has become sealed inside the joint, preventing solder from occupying that space.
 

Tungsten Manufacturer & Supplier: Chinatungsten Online - http://www.chinatungsten.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
 

The distinction between soldering and brazing is based on the melting temperature of the filler alloy. A temperature of 450 °C is usually used as a practical delineating point between soldering and brazing . Soft soldering can be done with a heated iron whereas the other methods require a higher temperature torch or furnace to melt the filler metal.

Different equipment is usually required since a soldering iron cannot achieve high enough temperatures for hard soldering or brazing. Brazing filler metal is stronger than silver solder, which is stronger than lead-based soft solder. Brazing solders are formulated primarily for strength, silver solder is used by jewelers to protect the precious metal and by machinists and refrigeration technicians for its tensile strength but lower melting temperature than brazing, and the primary benefit of soft solder is the low temperature used (to prevent heat damage to electronic components and insulation).

Since the joint is produced using a metal with a lower melting temperature than the workpiece, the joint will weaken as the ambient temperature approaches the melting point of the filler metal. For that reason, the higher temperature processes produce joints which are effective at higher temperatures. Brazed connections can be as strong or nearly as strong as the parts they connect, even at elevated temperatures.

Tungsten Manufacturer & Supplier: Chinatungsten Online - http://www.chinatungsten.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
 

Electric resistance welding (ERW) refers to a group of welding processes such as spot and seam welding that produce coalescence of faying surfaces where heat to form the weld is generated by the electrical resistance of material vs. the time and the force used to hold the materials together during welding. Some factors influencing heat or welding temperatures are the proportions of the workpieces, the metal coating or the lack of coating, the electrode materials, electrode geometry, electrode pressing force, electrical current and length of welding time. Small pools of molten metal are formed at the point of most electrical resistance (the connecting or "faying" surfaces) as an electrical current (100–100,000 A) is passed through the metal. In general, resistance welding methods are efficient and cause little pollution, but their applications are limited to relatively thin materials and the equipment cost can be high (although in production situations the cost per weld may be as low as $0.04 USD[citation needed] per weld depending on application and manufacturing rate).
 

Tungsten Manufacturer & Supplier: Chinatungsten Online - http://www.chinatungsten.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten Picture Center: http://picture.chinatungsten.com
Tungsten Video Center: http://v.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com