| The Monthly Newsletter of VAC AERO International Inc. | If you are having trouble viewing this e-mail, click here. To log on to the VAC AERO web site, please click here. |
January 2010 |
905-827-4171 |
| VAC AERO Kalisz Installs a New HVOF System | OAKVILLE, Ontario, (January 7, 2010) - VAC AERO's Kalisz, Poland-based operation recently installed a fully integrated High Velocity Oxygen Fuel (HVOF) system based on a new generation Carbide Jet System (CJS) produced by Dortmund, Germany-based Thermico.
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The system's specially designed combustion chamber is fed by hydrogen, kerosene and oxygen fuel and optimized for spraying MCrAlY coatings on turbine engine components, tungsten carbide coatings on landing gear components and can perform many other coating applications. Precise combustion and fuel configuration settings control particle temperature and velocity to achieve optimal coating efficiency in less time and lower fuel consumption than other HVOF systems. The system was installed in a 13'X13'X 10' high (4X4X3 meters) soundproof booth. The CJS torch is set in motion by a new Fanuc M20 robot with 8 axis movement (6 axes on the robot and 2 axes on a tilting turn-table integrated into and controlled by the robot). Read more >> |
| Vacuum Measurement Systems - Part One | by Dan Herring | This is the fifth in a series of articles in our Vacuum Heat-Treatment Series. Here we begin a discussion of the types and characteristics of vacuum gauges and offer insights into which gauge should be used when working in a specific vacuum range.
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One, two, three...counting molecules is a job for vacuum gauges. Depending on the type of vacuum systems and the required operating vacuum level, different vacuum gauges are required - often in combination with one another - to accurately determine and/or control the vacuum level of the chamber at any given moment in time.
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The criteria for selecting a vacuum gauge are dependent on various conditions, such as: the vacuum range to be detected, the gas composition (inert, reactive, corrosive), required accuracy and repeatability and environmental conditions. Vacuum gauges are divided into three basic categories based on their working pressure (Fig. 1). These include: absolute-pressure gauges, medium-vacuum gauges - useful down to around 0.001 mbar (1 micron) and high-vacuum gauges for use below 0.001 mbar (1 micron). Read more >> |
NEXT TIME - Part six of this series concludes our discussion of the types and characteristics of vacuum gauges and offers insights into which gauge should be used when working in a specific vacuum range.
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| Voids in Brazed Joints | by Dan Kay | Brazers commonly encounter voids in brazed joints and often wonder where they come from and how to avoid them in future brazements. Some common sources of voids in braze joints are: surface contamination, base metal and brazing filler-metal (BFM) constituents, brazing methods/temperatures used and poor joint fitup.
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The first three items listed above can often result in gas bubbles being formed in brazed joints. Such gas-bubble voids will usually try to form in spherical shape as they move through a joint. The "rounded" edges of such bubble-voids can often be clearly seen in cross-section photomicrographs of brazed joints, especially under high magnification. The inside surfaces of a bubble-void will often appear "clean" or "shiny" as well. Let's briefly look a little more closely at these sources of voids in brazed joints with a look at surface contamination. |
It is not uncommon to hear some brazers say, "Don't worry about surface contamination - the furnace will take care of it," or "Don't worry about surface contamination - just put more flux on the part to take care of it." Both statements are dangerous and can lead to weakened joints and, in many cases, to failed joints. Read more >> |
| Practical Vacuum: Good Design, Procedures and Maintenance Equals Good Vacuum | ||
| by Dick Amos and Simon Bruce | ||
Vacuum is used to control the environment in many heat treatment processes and the vacuum pumping systems used may be simple or complex. This article offers practical recommendations to handle operational issues that can arise with these systems to optimize performance, reliability and safety.
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Depending upon the carbon content of the parent austenite phase, either lath (low-carbon) or plate (high-carbon) martensite may form, as well as mixtures of the two. In general, lath martensite is associated with high toughness and ductility but low strength, while plate martensite structures are much higher strength but may be rather brittle and non-ductile. |
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