摘要:
Method and apparatus for leveling or adjusting a power-boat's average angle of bank or list about its roll axis RA regardless of side wind or off-center loading to improve passenger comfort, increase fuel efficiency, and smooth hull passage through waves with reduced pounding. Improved operating characteristics are accomplished by adjusting steering force angle-of-attack of a small fin-rudder mounted under a forward portion of the boat's keel. The boat's heading is maintained by applying an opposite steering force by altering thrust direction of the driving and steering mechanism. Altering thrust direction occurs either by a pilot steering the helm or automatically by adjusting thrust direction independently of pilot steering. In an optional automatic mode, an electronic gravity inclinometer adjusts a fin-rudder servo. An electronic filter processes the inclinometer signal to control the boat's average attitude around its roll axis RA. For providing further automation, thrust direction of the driving and steering mechanism is adjusted substantially simultaneously and proportionally with adjusting fin-rudder angle-of-attack and without pilot steering. The boat's heading is maintained while adjusting fin-rudder angle-of-attack by compensatingly adjusting thrust direction of driving and steering. For further automation, a flux-gate compass controls thrust direction for holding the boat's heading while adjusting fin-rudder angle-of-attack.
摘要:
A radial-flow, wide-pouring molten-metal distributor comprising a curved or arcuate overflow weir which is normally horizontal on its top and which is concave on its upstream side as viewed from above. Over this arc-shaped overflow weir flows molten metal to be continuously cast in an open pool. An impetus is thereby imparted to the molten metal along diverging radial lines. The flow so impelled continues radially onto a horizontal apron. The flow spreads fanwise to the desired width which may be as much as six times the width of the weir. Thence, the metal cascades or flows uniformly into the casting apparatus. The overflow weir is preferably supplemented by a skimmer mounted above it in substantially uniform spaced aligned relationship, thereby completing a slot beneath the skimmer through which the molten metal flows. When employed for the casting of wide, thin product, the invention results in a far more uniform and gentle distribution of metal than heretofore available. Dribbling and "beards" are eliminated. Swirls and porosity are reduced. The temperature profile across the section being cast is rendered more uniform, thereby permitting a lower temperature of the supply of molten metal entering this novel distributor.
摘要:
Method and apparatus for the feeding of molten metals through nozzles having gas-permeable walls, cooperating with twin-belt continuous metal-casing machines. The closed-channeled, multi-passaged nozzles have gas-permeable refractory walls, allowing the escape of gases that may be dissolved in the molten metal and become expelled or liberated from it while the molten metal is flowing through the passageways in the nozzle. Gaseous voids in the continuously cast product are thereby avoided, notably in aluminum casting as shown by experimental results to date. The nozzles are made from gas-permeable refractory material having interconnected porosity--that is, interconnected void interstices--extending through the nozzle walls. The interconnected void interstices are of sufficient size for allowing the passage of hydrogen gas through the walls, while being sufficiently small for preventing the leakage of molten metal. The gas-permeable refractory material is relatively non-wettable by the molten metal. For example, the nozzles are made of fibrous sintered refractory material--for instance, fibers of alumina or silica intertwined and cohered within a major volume-percentage of interstitial voids, which provide the interconnected porosity. Such fibrous material displays high resistance to thermal shock. It is relatively compliant to nozzle clamps, with consequent resistance to breakage, while the coefficients of thermal conductivity and thermal expansion of such fibrous refractory material are advantageously low.
摘要:
For closing gaps between blocks of a moving edge dam prior to its travelling downstream into the entrance of a moving mold defined between upper and lower revolving casting belts moving downstream from the mold entrance to its exit, the moving edge dam is initially elevated into a crest, as shown in FIGS. 12 and 14. This crest is above a plane generally defined by the lower casting belt travelling downstream. Then, a guide roller positioned above thrusts downwardly upon the moving edge dam bending it convex downwardly as shown at "B" in FIG. 14 for causing its dam blocks to press against each other for sliding them along their high strength endless flexibile carrying member, thereby closing gaps between the blocks entering the mold entrance for sealing the entrance against outward leakage of molten metal between blocks. The downward convex bending also produces desired downward pressure of the moving edge dam against the lower casting belt, thereby enhacing sealing action between moving edge dam and lower belt. The downward thrust of this roller is sensed for indicating the amount of tension in the endless flexible carrying member of the moving edge dam. Back-breaker apparatus in rolling contact with a moving edge dam during its sagging return travel from mold exit to mold entrance has remotely controllable lift means for controllably raising or lowering the sagging edge dam for respectivley increasing or decreasing tension of the endless flexible carrying member.
摘要:
The wide, thin, revolvable, flexible, metallic casting belts are made to incorporate differential patterns of residual internal longitudinal tensile and compressive stresses. The two marginal areas are residually longitudinally stretched more than the main middle area straddled by these margins. This main middle area is used as a moving mold and is expected to contact molten metal. Thus, the treated belts have two marginal areas in a state of mild longitudinal compression straddling the main middle area in a state of mild residual longitudinal tension. During casting, when hot metal comes into contact with the main middle area of such treated belt, the main middle area expands. Because of the built-in differential compensating stresses, the stresses throughout such belt during casting advantageously become balanced or equalized across the whole belt width. This equalized stress condition during casting assures that the critical moving belt mold area will be flatter than experienced with belts not having differential stress treatment. Thus, cast metal product typically will be improved in flatness, surface finish, section uniformity, soundness and metallurgy. Two methods are described for longitudinally stretching marginal areas relative to the middle area: (A) Use a work roller effectively of larger diameter toward its end than its middle for stretching both margins relative to the main middle area; (B) Use conventional cylindrical work rollers and heat (for expanding and slacking) the middle area during roller-stretching while leaving cold margins for residually stretching both margins relative to the main middle area.
摘要:
An improved process and apparatus for casting a strip with laterally extending lugs by introducing molten metal at the inlet of a molding zone having a bottom and sidewalls, the bottom of the molding zone being formed by the upper surface of a moving endless belt and the sidewalls being formed by a first and second moving endless sidedam. The sidedams move with the belt from the inlet to the outlet of the molding zone and return from the outlet to the inlet. Each sidedam comprises an endless strap and a multiplicity of blocks strung thereon. Some of the blocks form lug molding pockets, the height of each pocket being lower than the height of the molding zone. A cast strip with laterally extending lugs is extracted at the outlet of the molding zone. The passage of lug molding pockets or blocks forming these pockets in each sidedam is detected. The difference between the temperatures of the first and the second sidedams is corrected so as to change the advancing speed of at least one of these dams, a warmer sidedam moving slower than a colder sidedam, if an unwanted lag is found between the molding pockets of the first sidedam and those of the second sidedam. The improvement comprises controlling the result of the correction measures by detecting the passage of the externally extending lugs in the cast product, modifying the correction as a function of the lug detection, and modifying the difference between the temperatures of the first and the second sidedams by use of cooling and heating units.
摘要:
Continuous casting methods and apparatus are described wherein the flexible casting belts in twin-belt machines having two or more main rolls in each belt carriage are sensed by mechanical probes, and belt temperatures are controllably elevated prior to contact with the molten metal to improve the casting conditions and the operation of the thin flexible casting belts; the temperature elevation preferably being relatively gradual may be carried out while the travelling belts are approaching the nip rolls or while the belts are in contact with the nip rolls, or both. Zone control of belt pre-heating is disclosed, and control of the coolant streams issuing from the curved nip roll tubes by use of fingernail-like extenders may be provided to aid in pre-heating the belts and in controlling their operation. Intensive infra-red heaters are shown directed at close range toward the casting surfaces of the belts, these heaters serving also to cure and dry any coating material on the belts. Heating by means of hot fluid, such as steam, is described, with the hot fluid being directed into the deep grooves in the nip roll beneath the rear surfaces of the casting belts. Mechanical and thermal sensors are employed to sense the distortion of the belts and to measure their operating temperatures, these sensors being shown with automatic control of the belt pre-heating action. The methods and apparatus of the invention can be applied to twin-belt casting machines regardless of whether the molten metal is supplied by open pool, closed pool or injection feeding.
摘要:
Continuous casting apparatus is described wherein the temperature of the flexible casting belts in twin-belt machines having two or more main rolls in each belt carriage is controllably elevated prior to contact with the molten metal to improve the casting conditions and the operation of the thin flexible casting belts; the temperature elevation preferably being relatively gradual may be carried out while the travelling belts are approaching the nip rolls or while the belts are in contact with the nip rolls, or both. Zone control of belt pre-heating is disclosed, and control of the coolant streams issuing from the curved nip roll tubes by use of fingernail-like extenders may be provided to aid in pre-heating the belts and in controlling their operation. Intensive infra-red heaters are shown directed at close range toward the casting surfaces of the belts, these heaters serving also to cure and dry any coating material on the belts. Heating of the nip rolls by means of hot fluid, such as steam, is described, with the hot fluid being directed into the interior of the nip roll or being directed into the deep grooves in the nip roll beneath the rear surfaces of the casting belts. Mechanical and thermal sensors may be employed to sense the distortion of the belts and to measure their operating temperatures, these sensors being shown with automatic control of the belt pre-heating action. The apparatus of the invention can be applied to twin-belt casting machines regardless of whether the molten metal is supplied by open pool, closed pool or injection feeding.
摘要:
A continuous casting apparatus includes a first belt carried by a first upstream pulley and a first downstream pulley, a second belt carried by a second upstream pulley and a second downstream pulley, and a mold region defined by a first mold support section arranged behind the first belt and a second mold support section arranged behind the second belt. The first mold support section supports the first belt and defines a shape of the first belt in the mold region and the second mold support section supports the second belt and defines a shape of the second belt in the mold region. At least one of the first mold support section and the second mold support section includes a transition portion and a generally planar portion downstream from the transition portion. The transition portion has a variable radius configured to receive molten metal from a metal feeding device.
摘要:
A continuous casting apparatus includes a first belt carried by a first upstream pulley and a first downstream pulley, a second belt carried by a second upstream pulley and a second downstream pulley, and a mold region defined by a first mold support section arranged behind the first belt and a second mold support section arranged behind the second belt. The first mold support section supports the first belt and defines a shape of the first belt in the mold region and the second mold support section supports the second belt and defines a shape of the second belt in the mold region. At least one of the first mold support section and the second mold support section includes a transition portion and a generally planar portion downstream from the transition portion. The transition portion has a variable radius configured to receive molten metal from a metal feeding device.