| 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. |
February 2010 |
905-827-4171 |
| VAC AERO's Coatings Division Receives Two New NADCAP Approvals |  |
Boucherville, Quebec, February 9, 2010 - VAC AERO's Boucherville, Quebec, Canada-based Coatings division recently received two new approvals for coatings and chemical processing. The facility was qualified to the stringent SAE Aerospace Standard AS70003 for Coatings and for Chemical Processing. These two new approvals have now been added to the many other heat treating and coating accreditations that VAC AERO has acquired throughout the years. VAC AERO's facilities in Quebec and Poland offer thermal spray coatings (plasma and HVOF), grinding and inorganic coating services to international Aerospace and other high-tech companies. |
| Vacuum Measurement Systems - Part Two | by Dan Herring | This is the sixth in a series of articles in our Vacuum Heat Treatment series. Here we continue 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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Counting molecules is a job for vacuum gauges and it's now time to understand the differences between these devices and when to use them. Recall first that the vacuum level in a vessel is determined by the pressure differential between the evacuated volume and the surrounding atmosphere (Table 1). The two basic reference points in all these measurements are standard atmospheric pressure (760 torr) and perfect vacuum (0 torr), so calculating changes in volume in vacuum systems requires conversions to negative pressure (psig) or absolute pressure (psia). Read more >> |
NEXT TIME - Part seven of this series talks about vapor pressure and how it is influenced by the various materials of construction used in a typical vacuum furnace.
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| Differential Metal Expansion - Part One | by Dan Kay | In this article I will explore the effect that thermal expansion has on joint clearance, and thus, on brazed joint strength and quality. It's an important concept, and although it is well known in the brazing world, many folks today still do not take this topic seriously enough when designing brazed assemblies.
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This article is based on one I wrote many years ago for an in-house brazing publication at a brazing filler metal supplier, and will be written in two parts. Next month's segment will look more closely at polymorphic metals, such as carbon steels, and will attempt to explain why they exhibit their very strange thermal expansion curves. Please note that ALL metals expand (grow) when they are heated, and contract (shrink) when they are cooled. This fact has been thoroughly explored over the years, and data-tables have been published showing how fast each metal expands as temperature increases. Read more >> |
NEXT TIME - In my next article, I'll examine the thermal expansion curve for 1018 carbon steel to see why there are strange "reversals" in the thermal expansion curve for that alloy (and for similar metals).
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| When and Why Ion Nitriding Nitrocarburizing Makes Good Sense | ||
| by E. Rolinski and G. Sharp | ||
Ion nitriding can be used in many applications, but some are so unique that they can be called "the best applications, where the competitive treatments such as salt bath and gas nitriding cannot easily duplicate the unique results of ion nitriding.
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Ion, or plasma, nitriding has been studied and used industrially for more than 40 years [1-8], but the technology has not been used to its full potential. Ion nitriding/nitrocarburizing is a low temperature (800-1100?F, or 430-595?C) process, which results in little or no distortion of the treated parts even if significant residual compressive stress is induced to the surface layer of the treated products. |
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