| 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. |
July 2010 |
905-827-4171 |
| Vacuum Valves, Penetrations, Feedthrus and Flanges | by Dan Herring | This is the 11th in a series of articles in our Vacuum Heat-Treatment Series. This part discusses vacuum valves, penetrations and flanges found on most vacuum vessels; where they are used, how they operate and a little about how they should be maintained.
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Valves intended for vacuum service are subjected to a variety of special conditions (Fig. 1), ranging from high and ultrahigh vacuum levels to low, high and ultrahigh pressures, differentials in pressure and differentials in temperature as well as variable frequencies of mechanical operation. They can be supplied in a number of configurations: ball valves, gate valves, butterfly valves, needle valves, isolation valves, pressure-relief valves and control valves just to name a few. The type of valve in use is typically identified by its design or function, and each type can be actuated in a variety of ways (manually, electro-magnetically, pneumatically, electro-pneumatically or via electric motor). Position indicators and limit switches located on the valves are common. Read more >> |
Next Time: Part 12 of this series discusses leak testing and leak detection and also reviews the choices available for leak repair.
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| Repair Brazing - Fixing faulty jobs and worn-out components - Part 1 | by Dan Kay | Brazing is a versatile process used in many industries to join materials permanently. Repair brazing is an essential part of the industry and usually is done for one of two reasons - to braze repair parts in-house before they are released to customers and to perform repairs on brazed components that have worn out in service.
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The former involves in-house quality assurance programs designed to detect braze defects before they get out the door. The latter involves brazed components worn out from corrosion, erosion, or fatigue (thermal and/or mechanical) in cyclic service, resulting in surfaces that are cracked, pitted, or eroded. In-house Brazing Repair - Sometimes, brazing repairs must be performed when defective parts are found after the initial joining process but before they are shipped to the customer. This is the most desirable time to track down defects. It's not acceptable to rely on customers to perform parts inspections for braze defects after parts are received. An in-house inspection process should be robust and thorough enough to catch any braze defects before parts are shipped. Read more >> |
Next Month: Part two of this article will deal with cleaning and surface preparation and the application of BFM.
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| Best Practices for Rockwell Hardness Testing | ||
| By Bill O'Neill | ||
Hardness, as applied to most materials and in particular metals, is a valuable, revealing and commonly employed mechanical test that has been in use in various forms for more than 250 years.
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As a material property, the value and importance of hardness cannot be overstated. The information from a hardness test can be used to provide critical material performance information and insight to the durability, strength, flexibility and capabilities of a variety of component types from raw materials to prepared specimens and finished goods. Hardness testing is widely used in a multitude of industries and is particularly significant in structural, aerospace, automotive, quality control, failure analysis and many other forms of manufacturing. |
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