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The brazing guide

The Brazing Guide GH Induction Atmospheres Turnkey Heating Solutions GH Induction Atmospheres • 35 Industrial Park Circle, Rochester New York 14624 USA • Tel: 585.368.2120 • Fax: 585.368.2123 • [email protected] • The Brazing Guide
Brazing is a method of joining two pieces of metal together with a third, molten fil er metal. Of al the methods available for metal joining, brazing may be the most versatile. The process is relatively fast and economical, requires relatively low temperatures and is highly adaptable to automation and lean manufacturing initiatives. Brazed joints have great tensile strength – they are often stronger than the two metals being bonded together. Brazed joints repel gas and liquid, withstand vibration and shock and are unaffected by normal changes in temperature. Because the metals to be joined are not themselves melted, they are not warped or otherwise distorted and retain their original metal urgical characteristics.
Use this guide to learn about the different aspects of brazing and the many advantages offered by this unique process.
Brazing Overview . . . . . . . . . . . . . . . . . . . . . . . . pg 2
Topics include brazing basics, when brazing works best, heat sources for
brazing and types of braze joints.
Basic Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . pg 4
Describes the basic process and offers recommendations to improve your
brazing techniques.
Induction Brazing . . . . . . . . . . . . . . . . . . . . . . . . pg 5
Explains how induction heating can be utilized to produce quick, clean,
consistent braze joints.
Choosing a Brazing Atmosphere . . . . . . . . . . . . . . . . . . .pg 6
Discusses the relative merits of brazing in open air, control ed atmospheres
and vacuum environments.
Atmosphere Comparison Chart . . . . . . . . . . . . . . . . . . . pg 7
Recommends an atmosphere for the most common combinations of metals
being joined and brazing al oys.
Choosing An Al oy. . . . . . . . . . . . . . . . . . . . . . . . pg 7
Compares characteristics of copper, silver, silver with lithium, nickel,
aluminum and gold.
Al oy Suppliers . . . . . . . . . . . . . . . . . . . . . . . . . pg 8
Contact information and links to suppliers of brazing al oys and preforms.
Brazing Equipment . . . . . . . . . . . . . . . . . . . . . . . .pg 9
GH IA manufactures turnkey brazing systems for open air, control ed
atmosphere and vacuum environments.
About GH Induction Atmospheres . . . . . . . . . . . . . . . . . . pg 10
GH IA manufactures turnkey induction brazing systems and offers contract
brazing services for steel, stainless steel, aluminum, brass, nickel, superal oys, copper, titanium and refractories.

The Brazing Guide GH Induction Atmospheres Brazing is a method of joining two pieces of metal together with a third, molten fil er metal. The joint area is heated above the melting point of the fil er metal but below the melting point of the metals being joined; the molten fil er metal flows into the gap between the other two metal pieces by capil ary action and forms a strong metal urgical bond as it cools.
Of al the methods available for metal joining, brazing may be the most versatile. Brazed joints have great tensile strength – they are often stronger than the two metals being bonded together. Brazed joints repel gas and liquid, withstand vibration and shock and are unaf- fected by normal changes in temperature. Because the metals being joined are not themselves melted, they are not warped or otherwise distorted and retain their original metal urgical Brazed joints have great strength. Because brazed joints have a very clean, wel -finished appearance, brazing often is the preferred bonding process for manufacturing plumb- ing fixtures, tools, heavy construction equipment and high-quality consumer products. The process is wel -suited for joining dissimilar met- als, which gives the assembly designer more material options. Complex assemblies can be manufactured in stages by using fil er metals with progressively lower melting points. Brazing is relatively fast and economical, requires relatively low temperatures and is highly adaptable to automation and lean manufacturing initiatives.
WHEN BRAZING WORKS BEST Among the many industrial options for join- ing metal, when does brazing work best? When considering which metal joining pro- cess to choose for a particular assembly, sev- eral factors should be considered: strength and permanence, the physical characteristics of the parts, the shape of the joint, and the production level desired.
As shown in Table 1, there are many tech- niques used to join metal: mechanical meth- ods such as threading or bolting, adhesive bonding, soldering, welding and brazing. Each has its own advantages and limitations.
Brazing or welding are preferred when strength and permanence are primary considerations. Due to the fact that in brazing a fil er metal is always used and general y the entire joint area is heated at the same time, brazing is a more robust process. This means that the joint clear- ances, fixturing, etc are much more forgiving in brazing than in welding. If strength is not a determining factor – or if the joint may be disassembled in the future – soldering, adhesive bonding or a simple mechanical fastening method are likely better choices.
Although brazing, soldering and welding are similar in many respects, there are important dif- ferences. Soldering general y can be done at lower temperatures (below 450°C), but does not produce as strong a joint. Welding, a higher-temperature process in which the two metals to be joined are actual y melted and fused together, requires the most heat energy. Welded and brazed joints are usual y at least as strong as the metals being joined. The welding process is ideal for applications which benefit from highly localized, pinpoint heating. But it is more difficult to apply to linear joining, not as easy to automate, and not easily adaptable for joining metals with different melting points.
It is also important to consider the physical characteristics of the parts and joint area. Because of its high temperature requirements, welding works best with relatively strong, thick parts Brazed provides a clean, wel -finished appearance.

The Brazing Guide GH Induction Atmospheres that can withstand the heat. Brazing, which works at lower temperatures, may be the best choice for thinner parts because metal warpage and distortion can be minimized. Spot joints can be easily welded or brazed, but linear joints are easier to braze because the fil er metal natural y flows into the joint area.
Both brazing and welding work wel for joining metals with similar melting points, but it is general y easier to join dissimilar metals with brazing. Simply choose a fil er metal with a lower melting point than either of the metals to be joined. While welding is difficult to automate partial y or in stages, brazing is a more flexible process; pre-fluxing and pre-positioning sta- tions can be set up to increase speed for high throughput requirements, or a conveyor can be used to transport groups of parts past the brazing station.
So for many metal joining procedures, brazing becomes the most logical solution. The ad- vantages and flexibility that brazing offers are most ful y realized when the heating process is careful y considered at the assembly design stage. Parts once visualized and manufactured as monolithic, one-piece units machined out of solid bar stock can be often be produced more Multi-joint brazing quickly and economical y by brazing together one or more metal components. Because a variety of metals can be utilized, brazing enables designers to optimize component functionality, weight and economy. Expensive machining, casting and forging processes can be eliminated without compromising the integrity of the part, and lower cost raw materials such as sheet metal, extrusions and stampings can be utilized. The manufacturing process becomes leaner, faster and ultimately more profitable.
HEAT SOURCES FOR BRAZING The heat for brazing is typical y provided by a hand-held torch, a furnace or an induction heating system. Other techniques include dip brazing and resistance brazing.
Torch brazing is often used for smal assemblies and low-volume applications. A "neutral" flame with a bluish to orange tip, a wel -defined bluish white inner cone and no acetylene feather works the best; a flame with a colorless tip can cause oxidation. Although the quality of the joint is largely dependent on operator skil and consistency is sometimes an issue, torch brazing requires only a smal investment and is very popular.
Furnace brazing does not required a skil ed operator, and is often used to braze many assem- blies at once. This method is only practical if the fil er metal can be pre-positioned. Furnaces normal y must be left on 24/7 to eliminate long start up and cool down delays, and are not Torch brazing is often used for smal assemblies. Dip brazing is used for smal wires, sheets and other components that are smal enough to be immersed. The parts are dipped in a molten flux bath which doubles as the heating agent. Resistance brazing is effective for joining relatively smal , highly conductive metal parts. Heat is produced by the resistance of the parts to the current.
Induction heat has the advantages of speed, accuracy and consistency. In a wel -designed induction system, each part is identical y positioned in the induction coil and the fil er material is careful y regulated. This type of system consistently and quickly delivers a precise amount of heat to a smal area. The induction heating power supply's internal timer can be used to control cycle time; temperature control feedback for each individual part can be provided with thermocouples, IR thermometers or visual temperature sensors. Induction furnaces are also available for TYPES OF BRAZE JOINTS Although there are a wide variety of braze joints to suit varying part and assembly geometries and functions, most braze joints are variations of one of two basic types – the butt joint and the lap joint.
To form a butt joint, the two pieces of metal are positioned in an edge to edge, in an end-to-end arrangement as shown on Page 4. The strength of the bond depends to a large extent on the amount of bonding surface, but a properly formed butt joint wil be strong enough to meet many application needs. The setup is relatively simple, and for some applications, it may be an advantage to have a consistent part thickness at the

The Brazing Guide GH Induction Atmospheres For applications which require a stronger bond, an alternative type of joint may be prefer- able. Lap joints have a larger bonding surface because the two metals overlap each other. Therefore a stronger bond is produced.
Lap joints do have a double thickness in the joint area, which may be a potential problem for applications where space is restricted. But for plumbing fixtures and similar applications, this is not a problem. The overlapping nature of the lap joint actual y assists in positioning the parts for brazing; particularly with tubular parts, the joint becomes self-supporting because one part fits into the other.
The advantages of both basic joint types are combined in a butt-lap joint. Although this type of joint requires more work to assemble, it has both a single thickness and maximum strength, and is usual y self-supporting.
Three types of braze joints Basic Brazing Procedures
DETERMINE THE JOINT SPACING In the brazing process, the fil er metal is drawn into the joint by a pul ing force known as capil ary action during the heat cycle. So it is par- ticularly important to maintain the right amount of space between the parts to al ow this to happen. Usual y, the strongest joints are made by al owing just enough space for the fil er metal to flow into the joint area, typical y in the range of .001" to .005" (0.25 mm to .127 mm). Wider spacing wil general y result in a weaker joint.
It is also important to remember that metals expand and contract at different rates when heated and cooled. Particularly when joining dissimilar metals, expansion/contraction rates must be al owed for when the parts are positioned.
CHOOSE THE RIGHT BRAZING ALLOY Silver, copper and aluminum al oys are commonly-used fil er metals; silver is frequently chosen because it has a relatively low melting point. Copper braze has a higher melting point but is general y more economical. Depending on the application, the al oy may be in the form of a stick, paste or preform. A pre-formed brazing al oy is normal y the best choice when even distribution and repeatability are paramount con- ELIMINATE GREASE AND CONTAMINANTS The braze material wil not flow properly if grease, dirt or rust blocks its path. First remove any oil or grease with a degreasing solvent or other method. Then remove rust and scaling with a chemical bath, stainless steel wire brush or emory cloth. The joint area MUST be clean.
ADD FLUX OR USE PROTECTIVE ATMOSPHERE When brazing is done in the open air, the joints are normal y pre-coated with flux, a chemical compound which protects the part surfaces from air. A flux coating helps prevent oxidation when the metal heats up, protects the braze al oy and improves its flow. As heat is applied to the joint, the flux wil dissolve and absorb the oxides that form. A variety of fluxes are available for use at different temperatures, with different metals and for a variety of environmental conditions. The point to remember is that the flux should melt and become completely liquid before the al oy melts. Most often flux is sold in paste form so it can be brushed on to the parts just before the actual heating cycle.
To eliminate flux, eliminate the presence of oxygen and braze your parts in a protective at- mosphere such as nitrogen, hydrogen or dissociated ammonia. This type of brazing is usual y completed in a control ed atmosphere glove box or a vacuum furnace. Without oxygen in the surrounding atmosphere, there is no potential for oxidation and the finished joint retains a clean, high quality appearance. The utilization of a protective atmosphere also eliminates any need for the post-braze acid cleaning bath.
Because of these advantages, protective atmosphere brazing has great appeal for manufactur- ers concerned with high throughput in a lean, continuous flow manufacturing environment.
Brazing in a protective atmosphere The Brazing Guide GH Induction Atmospheres POSITION PARTS CAREFULLY Before applying heat to the parts, make sure they are properly-positioned and braced to remain in proper alignment. Particularly with lap joints, the laws of gravity help in this regard. Clamps, vises, additional weights and supports are sometimes needed. When choosing support materials, select those that are poor conductors of heat, such as stainless steel, inconel or ceramics. These wil draw minimal heat away from the joint and preserve the efficiency of the heating process. Also look for support materials with compatible expansion rates so that the alignment is not disturbed.
TURN ON THE HEAT! Most brazing processes run at temperatures between 800°F and 2,000°F. For a strongest braze joint, the metals that are being joined together need to be at close to the same temperature. Slow heat cycles general y produce better results than fast heat cycles. In many brazing operations, the fil er metal is applied to the joint after the proper temperature is reached. Alternatively, brazing preforms can be positioned around the joint before the heat cycle begins. The melting fil er metal wil tend to flow toward areas of higher temperature, so it is good practice to apply heat to the side of the assembly opposite to where the fil er metal is positioned. The heat then helps draw the molten metal down into the joint area.
CLEAN JOINTS (Not Required For Protected Atmosphere Brazing) Parts which are brazed in an open-air atmosphere require a two-step cleaning operation. Flux residues are chemical y corrosive and may weaken the joint if not completely removed. After the fil er has solidified, a hot water quench immediately after the heat cycle is recommended. To remove residual oxidation, the parts can be dipped in hot sulfuric or hydrochloric acid. Care should be taken to avoid etching the joint with too strong an acid solution. Parts brazed in a protective atmosphere require no cleaning.
In addition to the general benefits induction heating brings to virtual y any heating process, there are very specific reasons to use induction heating for industrial brazing. These include selective heating, better joint quality, reduced oxidation and acid cleaning, faster heating cycles and more consistent results.
• SELECTIVE HEATING Induction heating can be targeted to provide heat to very smal areas within tight production tolerances. Only those areas of the part within close proximity to the joint are heated; the rest of the part is not affected. Since there is no direct contact with the part, there is no opportunity for breakage. The life of the fixturing is substantial y increased because problems due to repeated exposure to heat (such as distortion and metal fatigue) are eliminated. This advantage becomes particularly important with high-temperature brazing processes. With efficient coil design, careful fixturing and consistent part placement, it is possible to simultaneously provide heat in different areas of the same part.
• BETTER QUALITY JOINTS Induction heating produces clean, leakproof joints by preventing the fil er from flowing into areas that it shouldn't. This ability to create clean and control able joints is one of the reasons that induction brazing is being used extensively for high-precision, high-reliability applications.
• REDUCED OXIDATION AND CLEANING Flame heating in a normal atmosphere causes oxidation, scaling and carbon build up on the parts. To clean the parts, applications of joint-weakening flux and expensive acid cleaning baths have traditional y been required. Batch vacuum furnaces solve these problems, but have significant limitations of their own because of their large size, poor efficiency and lack of qual- ity control. Brazing with induction reduces both oxidation and costly cleaning requirements, especial y when a rapid cool-down cycle is used.
• FAST HEATING CYCLES Regular heating vs. atmospheric heating Because the induction heating cycle is very short in comparison to flame brazing, more parts can be processed in the same amount of time, and less heat is released to the surrounding environment.
• CONSISTENT RESULTS Induction brazing is a very repeatable process because variables such as time, temperature, al oy, fixturing, and part positioning are very con- trol able. The internal power supply of the RF power supply can be used to control cycle time, and temperature control can be accomplished with pyrometers, visual temperature sensors or thermocouples.
For processes which involve medium to high production runs of the same parts, an automated part handling system is often utilized to The Brazing Guide GH Induction Atmospheres further improve consistency and maximize productivity. The GH IA brazing system at right incorporates a four-position turntable with stations for automatic fluxing, induction heating and water cooling.
For the most part, induction brazing and soldering is done in an open-air environment. A control ed atmosphere can be utilized when it is necessary to keep the parts completely clean and free of oxidation.
Induction brazing general y works best with two pieces of similar metal. Dissimilar metals can also be joined by induction heating but they require special attention and techniques. This is due to differences in the materials' resistivity, relative magnetic permeability and coefficients of thermal expansion.
Choosing A Brazing Atmosphere
The induction brazing process can be carried out in three different environments, each with its own advantages and disadvantages: open air; a control ed atmosphere of argon or other inert gas; or a high vacuum/high pressure environment.
GH IA automated brazing system An open air, oxygen atmosphere is frequently used for induction brazing. Open air has the advantages simplicity and economy. However, heating metals to high temperatures in a normal atmosphere causes chemical changes such as oxidation, scaling and carbon buildup on the parts. Applications of various types of flux are often used to reduce oxidation and improve the flow of the braze material, but at the same time they can reduce the strength of the joint. Acid cleaning baths are used to clean the parts as needed, but the extra cleaning step can be both expensive and time-consuming But for some brazing processes, an open oxygen atmosphere may be the best choice; the oxidation, scaling and carbon buildup may not af- fect the part's performance or in some cases may even be beneficial. Or further machining and cleaning at a later stage of the manufacturing process make the whole issue irrelevant.
CONTROLLED ATMOSPHERE BRAZING For lean manufacturing environments in which more control over joint quality is required and cycle times must be minimized, the next step beyond an open-air environment is to use a control ed atmosphere under normal or close-to-normal atmospheric pressure. In this environment, a high de- gree of control over the overal process can be achieved and open-air issues of oxidation, scaling and carbon buildup can be virtual y eliminated.
A control ed atmosphere can be produced in a vacuum furnace, a sealed "glove box" or with an atmospheric bel jar. With a bel jar system, the parts are positioned before the bel jar is lowered into place and the control ed atmosphere is created. The glove box system is ideal for processes which require hands-on heating control. Learn more about brazing equipment.
Inert atmospheres of nitrogen, argon, hydrogen and dissociated ammonia are common choices for control ed atmosphere brazing. Argon is more inert than nitrogen and therefore provides more control, but it is general y more expensive. The process temperature can also affect the performance of the gas chosen; nitrogen is often an economical choice but it is known to react with some steels above certain temperatures. Hydrogen - a strong deoxidizer with high thermal conductivity - is often used for copper brazing and annealing steel. Dissociated am- monia (75% hydrogen + 25% mononuclear nitrogen) is a relatively inexpensive atmosphere which can be successful y used for many types of brazing and annealing processes.
The selection of a gas for atmospheric brazing depends on a variety of process requirements including purity and heating temperature as wel as cost considerations. The engineers at GH Induction Atmospheres have extensive experience in selecting the best atmosphere for A control ed atmosphere eliminates oxidation. a specific combination of material being brazed and fil er metal, and have prepared a helpful Atmosphere Comparison Matrix. An additional Fil er Metals Comparison Chart provides information about various fil er metal characteristics.
Each atmospheric gas is general y available in different purity grades; the lower grades retain smal amounts of water vapor or oxygen remain mixed with the pure gas. Using the highest grade is more expensive but a smal amount of impurity may be just enough to contaminate a tightly- control ed process. The gases are available in cylinders, dewars bottles or in liquid bulk.
The Brazing Guide GH Induction Atmospheres Brazing in a high vacuum environment provides the most process control and produces the cleanest parts, free of any oxidation or scaling. It is the preferred brazing environment for brazing aerospace components, hardening medical devices and other applications that require the absolute highest part quality.
In a vacuum system, parts are heated in a ful y enclosed, stainless steel chamber, which can be pumped down to 10-6 Torr. Special fixturing can be designed for automatic part loading and unloading, and quartz viewports can provide access for infrared temperature sensing of each individual part. This type of system is often used for brazing steel or nickel al oys with steel. An alternative method is to use a vacuum furnace, which is often the best choice for brazing parts of unusual shapes or "orphans" from other heating processes. The difference is that the induc- tion furnace wil heat the entire part rather than just a narrowly focused joint area.
Atmosphere Comparison Chart
What's the best fil er metal for brazing stainless steel? What's the best atmosphere for brazing copper with silver? Our Selection Guide gives you the answers! Find your braze material and fil er metal at left, read across to the suggested atmospheric environment at right, Common Brazing Combinations
Suggested Brazing Atmospheres
Material Being Brazed Choosing An Al oy
Copper, nickel and silver are the most frequently-used base metals for brazing al oys; aluminum and gold are also used for specific purposes. The table below compares important characteristics and advantages of the most commonly used base metals.
interference to 0.002" Joint Strength, Low Cost Silver with Lithium Low Temperature, Self-Fluxing Joint Strength, Resistance to Corrosion Only braze for aluminum Resistance to oxidation and corrosion For each base metal, many different al oy compositions are available. The additional metals combined with the base determine the al oy's com- patibility for use in joining specific metals and individual process requirements. For example, vacuum brazing requires an al oy free of volatile elements such as cadmium. In addition to the composition of the al oy, other important characteristics to consider are melting range, required joint clearance and ease of flow.
The melting range for a brazing al oy is defined by the minimum temperature at which the al oy wil start to melt ("solidus") and the temperature at which the al oy is 100% liquid ("liquidus"). For most purposes, the actual brazing temperature is 50°F to 200°F (30°C to 110°C) above the liquidus. The melting range is based on the al oy's chemical composition, but it is important to note that individual batch characteristics may very slightly. Some al oys (eutectics) have a very narrow melting range while other al oys have a comparatively wide range. Al oys with a narrow melting range are used for fil ing very narrow gaps while wider range al oys general y work better for fil ing larger gaps. Wide range al oys have a tendency to separate into their basic components if heated too slowly (liquidation). So it is almost always better heat rapidly through the melting range to reach brazing temperature.
The Brazing Guide GH Induction Atmospheres High temperature brazing al oys such as gold, nickel and copper can be used for brazing many joints at once, but care must be taken with the joint design and joint clearance. Heating time should be minimized to the time needed to bring al components to the heating temperature and for the molten al oy to flow quickly. High temperature brazing is often used for joining cobalt or nickel-based superal oys.
Most brazing al oys are normal y available in forms such as wire, foil, tape, powder and paste. For links to more information about individual brazing al oys and their characteristics, use GH IA's helpful Brazing Al oy Suppliers Guide.
Al oy Suppliers
DISCLAIMER: We are pleased to present this reference guide for your convenience. This list should not be interpreted as an endorsement of any specific
company, nor wil IA be responsible for the accuracy of any information presented on these sites. But it might save you some time!
Aluminum Brazing Al oys
Alco Tech Wire Company
Tel: 231-941-4111 Bel man-Melcor, Inc Tel: 708-532-5000 Lucas-Milhaupt, Inc. Tel: 800-558-3856 Omni Technologies Corporation Tel: 603-679-2211 Copper Brazing Al oys
Aufhauser Corporation
Tel: 800-645-9486 Bellman-Melcor, Inc Tel: 708-532-5000 J.W. Harris Co, Inc Tel: 513-754-2000 Lucas-Milhaupt, Inc. Tel: 800-558-3856 SCM Metal Products Tel: 919-544-8090 Stan Rubinstein Assoc., Inc Tel: 800-545-4570 Tricon Industries, Inc Tel: 800-654-6850 Precious Metal Brazing Al oys (Gold, Platinum, Silver, Pal adium)
Aufhauser Corporation
Tel: 800-645-9486 Bellman-Melcor, Inc Tel: 708-532-5000 J.W. Harris Co, Inc.
Tel: 513-754-2000 Tel: 800-558-3856 Stan Rubinstein Assoc., Inc Tel: 800-545-4570 Turbo Braze Corporation Tel: 800-526-4932 Tel: 510-491-1100 Wolverine Joining Technologies, Inc Tel: 401-739-9550 Nickel Brazing Al oys
North American Höganäs, Inc.
Tel: 814-479-3500 Strong Welding Products Tel: 909-483-3222 Carpenter Powder Products Tel: 412-257-5102 Lucas-Milhaupt, Inc. Tel: 800-558-3856 Praxair Technology, Inc.
Tel: 800-825-3093 Tel: 248-288-1200 Vitta Corporation Tel: 203-790-8155 Wall Colmonoy Corporation Tel: 248-585-6400 Brazing Preform Rings
Bel man-Melcor, Inc
Tel: 708-532-5000 J.W. Harris Co, Inc.
Tel: 513-754-2000 Tel: 800-558-3856 Stan Rubinstein Assoc., Inc Tel: 800-545-4570 Tricon Industries, Inc Tel: 800-654-6850 The Brazing Guide GH Induction Atmospheres Brazing Equipment
Semi-Automatic Indexing Turntable
• Eight part positions • For smal part induction brazing • Ful manual control for automatic override and process development • Perfect for high speed automated processes AB-1 Automated Brazing System
• Smal 4'+x4' footprint fits your mfg. cel • Indexing turntable for easy loading/unloading • Multiple heat program capability • Energy-efficient induction heating system • Facilitates continuous flow manufacturing CONTROLLED ATMOSPHERE BRAZING VF-30 Vacuum Furnace
• Smal 6'x5' footprint fits your mfg. cel • Heats to 1900°F in less than 15 minutes • Cool down to 1200°F in 4.5 minutes • 12" high, 12" ID heating zone (customizable) • Ideal for unusual y shaped parts and "orphans" from other processes • Quickly heats entire part in stainless steel chamber Atmospheric Glove Boxes
• Integrated systems for auto and manual operation • For use with nickel, titanium, superal oys, stainless steel and refractories • Replacement for hydrogen belt furnaces • Reduces a typical 25-minute, quartz lamp heating cycle to just three minutes • Ergonomics increase operator comfort & safety Bel Jar Heating Systems
• Vacuum chamber moves up & away to provide easy access to parts & fixturing • Designed to handle 10-5 Torr pressure at moderate temperature • Single chamber units ideal for lab use; automatic systems for high volume production • Amazing flexibility in a cost-effective package • Optional temperature control Triple Quartz Chamber Brazing System
• Designed for moderate vacuum processes • For brazing silver, copper and brass components with silver and copper al oys • For use with standard atmospheric gases such as Nitrogen, Argon and Hydrogen • Ideal for brazing HVAC, plumbing fixtures HIGH VACUUM BRAZING High Vacuum Brazing System
High Vacuum Brazing System • Ideal for nickel brazing, aerospace applications • For superal oys, titanium, refractories • Individual part temperature measurement • Auto/Manual Control with easy-to-use touchscreen • Made for continuous operation CONTINUOUS BELT FURNACE • First belt furnace to utilize RF induction heating • Heats only parts being processed, as they travel through heating zone • High operating efficiency with continuous operation • Designed for use with nitrogen, hydrogen and dissociated ammonia Continuous Belt Furnace The Brazing Guide GH Induction Atmospheres About GH Induction Atmospheres
At GH Induction Atmospheres, we design and build turnkey induc-
tion heating solutions based on your part and process requirements. Designed for continuous flow manufacturing, our systems wil bring advanced heating technology directly to your factory floor or work cel .
We are an experienced system integrator with extensive laboratory facilities, engineering expertise, in-house machining and manufactur- ing capabilities. We take pride in recommending the induction power supply that is best suited to your long term application requirements.
We'l evaluate your parts and process requirements in our labora- tory to determine the optimum induction heating approach. Then our engineering staff wil work with you one-to-one to design a cost-ef- fective system that matches your process requirements. Final y, we'll build your system to the highest manufacturing standards from the finest components.
Our tunkey systems are designed for lean, continous flow manufacturing. GH IA is part of the worldwide GH Group. GH Electrotermia S.A., headquartered in Valencia, Spain, is a leading worldwide supplier of induction heating systems for industrial heat treating, forging, and many other applications. Since 1961, The GH Group has instal ed over 3,000 systems in Europe, Asia, and South America. With over 100 years of combined engineering experience, our engineers will help you reduce cycle time, improve part quality and minimize utility costs. If you're interested in developing a lean, continuous flow manufacturing process, call us today at 1.585.368.2120 or send us CONTRACT BRAZING SERVICES For Steel • Stainless Steel • Aluminum • Brass • Nickel • Superal oys • Copper • Titanium • Refractories
GH Induction Atmospheres provides contract brazing services to companies who want to out-source some or al of their brazing processes, and to those that have capacity issues with their current resources. Whether your requirements dictate standard brazing or control ed atmosphere brazing, we'l utilize the latest induction heating technology to process your parts with speed, accuracy and efficiency.
STANDARD ATMOSPHERE BRAZING SERVICES Our modern induction heating technology delivers strong, high quality braze joints; since induction is a highly directional and non-contact heating method, we are able to heat only the joint area, without affecting the sur- rounding areas. Our induction systems eliminate the inconsistencies of flame brazing, delivering consistently high quality joints with maximum repeatability. Our compact induction furnace is ideal for unusual y sized parts, parts with multiple joints, or "orphans" from other heating processes. Our semi-automatic indexing turntables wil meet your needs for high volume production. Whatever your volume requirements and part dimensions, we can provide a cost-effective contract brazing solution.
Contract brazing services CONTROLLED ATMOSPHERE BRAZING SERVICES Control ed atmosphere brazing in an oxygen-free environment produces strong, durable joints and clean parts without scaling or oxidation. Our automated systems are ideal for high volume processes such as copper brazing of steel, while our glove boxes and manual systems make short work of low volume production runs for new product development or prototyping. To maintain the highest level of quality control, our high vacuum brazing systems provide individual part temperature measurement. Cal GH IA if your parts require brazing in a vacuum, or in con-trol ed atmospheres such as argon, nitrogen or hydrogen. We can handle part diameters as smal as 1 mm. & up to 4 ft.
35 Industrial Park Circle, Rochester, New York USA 14624 Tel: 585.368.2120 • Fax: 585.368.2123 • eMail: [email protected] June 2010, GH Induction Atmospheres LLC. All information subject to change without notice.



Expert Review of the Evidence Base for Arthropod Bite Avoidance Larry I. Goodyer, PhD,∗ Ashley M. Croft, MD,† Steve P. Frances, PhD,‡ Nigel Hill, PhD,§Sarah J. Moore, PhD,§ Sangoro P. Onyango, BSc,§ and Mustapha Debboun, PhD¶∗Leicester School of Pharmacy, De Montfort University, Gateway, Leicester, UK; †Surgeon General's Department, London,UK; ‡Australian Army Malaria Institute, Brisbane, Qld., Australia; §London School of Hygiene and Tropical Medicine, London,UK; Ifakara Health Institute, Ifakara, Morogoro, Tanzania; ¶US Army Medical Department Center & School, Center forHealth Education & Training, Fort Sam, Houston, TX, USA

Information For Patients 93 st George's road, Cheltenham, Gloucestershire Gl50 3eD Appointments: (01242) 255337 • Tel: (01242) 519049 fax: (01242) 253556 Urgent out-of-hours service: 0300 4210 220 Surgery Opening Hours The Surgery Is Open .Monday - Friday 8.00am - 6.30pm Extended Opening Hours .Monday Evening 6.30 - 8.00pm