FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1938
1938 - 1885.PDF
JUNE 30, 1938 41 THE AIRCRAFT ENGINEER SUPPLEMENT TOFLIGHT 648c Left, a billet being inserted into the container. Right, the diehead after completion of extrusion. models, and two by Schloemann are 950- and 3,000-ton presses. In a large new extension to the works a much bigger (5,ooo-ton) press having working pressures up to 4,500 lb. /sq. in. will be assembled to deal with sections up to hah0 a ton in weight. , • The speed and pressure of the presses can be very accur- ately controlled, and great care is taken to maintain the correct temperature. Depending-upon the alloy, between 380 deg. C. and 480 deg. C. is usual. : The furnaces for heating billets are automatically con- trolled and all electric. They are semi-automatic in that the billets are carried through them on chain conveyor belts and discharged when a button is pressed. The con- trols and recording mechanism are grouped in a separate room, and each furnace has its temperature maintained by means of one or more '' Cambridge'' controllers. Rate of production is, of course, closely connected with the speed of extrusion. This varies with the alloy used and the section being extruded, but an average speed is about three feet per minute. During the whole period of extrusion the billet must be maintained at a steady temperature, so it is necessary for the billet container in the presses to be heated. The dies are also pre-heated to extrusion temperature to avoid any chilling of the billet. A 20 deg. C. temperature differ- ence is observed between the metal in the container and that issuing from the die. As already mentioned, the billet furnaces are carefully placed beside the presses and the hot billets are mechanically fed to the presses. After extrusion the sections are heat treated in special furnaces Straightening an extruded section in a Bigwood stretching machine.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
