Introduction:
Now and then, I try to clean up my study, which in most of the cases just ends in transferring stuff from one end of the room to the other.
During my last cleaning operation I discovered an old record, edited in the mid-seventies by the Dutch Foundry Institute. Although this institute ceased their activities some fifteen years ago, the content on this record is interesting enough to be kept alive.
The introduction of high-pressure molding machines from the seventies on, not only lead to an increase of productivity, but also to the occurrence of new casting defects which were not known before.
Recording of sound effects occurring during the pouring operation of a sand mold showed the ways and means to solve these problems.
To be able to listen to these specific recorded sounds, you need to have a MP3 player installed on your computer. On the bottom of this page you will find a Link where you can download Winamp player for free.
As the record contains a lot of spoken text, I have put this text in writing and added the specific sound effects as small click-able "sound illustrations".
Figure 1, typical casting defect caused by an explosive evaporation of water during mold filling.
Sound of Casting, the record.
Mysterious sound (70K).
This is not the sound of a spacecraft taking off, but a reaction between metal and mold during the casting process, which has been made audible.
Metal casting techniques have been used for thousands of years, but many attended effects are as yet unexplained.
This is obvious, for the entire process takes place at very high temperatures in mold cavities hidden from view, which makes it extremely difficult to watch the process.
Investigating causes of casting defects, technical foundry center TNO tried to catch sounds in mold cavities which accompanied the pouring process.The idea was that particular undesirable effects might betray their presence by specific sounds. What are the sounds we hear? First of course the babble of the metal whilst running into the mold cavity. More or less clearly, this sound can always be heard. Running metal.(40K)
When a metal stream strikes the mold wall, the sound of the impact can be observed as in the next recording of a stream of iron falling on a dry mold surface. Impact of falling metal.(13K)
If the same sudden impact occurs in a wet mold, as is often used, intensive contact may be produced between the metal and the water in the mold surface. This results in an explosive evaporation of water. The explosion then drowns the sound of the impact. Water explosion during impact.(20K)
To demonstrate the difference between impacting metal and the same effect accompanied by an explosion, both sounds should be repeated alternative a few times (use the Mouse-over effect to repeat the sound!).
Water explosions at various moments of the pouring process can be heard. The explosion pressure may disturb the pouring process, as the developing gas process may bring about casting defects such as metal penetration, blow-holes and mold-wall movement.
The identification of water explosion as a cause of these casting defects has already shown ways and means to avoid them. There are still other mysterious metal-mold reactions, a typical example is the sound you heard at the beginning of this record and it will be there again at the end.
The new research technique, introduced to you on this record, will make it possible to study the occurrence of these reactions live, just to make better castings. Mysterious sound.(70K)
Download Link for WinAmp.