Lately we've been getting orders for the welding of big cylinder heads (75,000hp B&W) and fabrication of big gear box housings (conversion from old casted steel housings) and fabrication of big gears, among others. Because of this, we have decided to purchase a portable vibratory stress-relieving machine from California, USA.
Through our machine shop training course handbooks, we've known that there are generally three methods of relieving stresses in welding and machining, namely:
- heating to the corresponding stress-relieving temperature and slowly/uniformly cooling;
- hanging and banging like a bell making the part vibrate at its resonant frequency; and
exposing to the elements and be subject to different temperature, etc. This process, sometimes called "seasoning" takes the longest time since it removes stresses at an average of only 10% a month.
The machine we bought is an improvement of the second method since the vibrating motor is clamped to the part to be relieved and made to rotate at the part's resonant frequency after the same is obtained by the resonant meter.
This is just an update to remind our customer that, at DECO we strive to be continuously deserving of your trust as one of your business partners.