The cast-steel creeper tread is a part with complex external surface and internal shape, having a hot spot cased by the uneven wall thickness. As the hot spot is far away from the gating system and the feeding channel...The cast-steel creeper tread is a part with complex external surface and internal shape, having a hot spot cased by the uneven wall thickness. As the hot spot is far away from the gating system and the feeding channel is narrow, it is difficult to be fed by setting up a casting head, leading easily to shrinkage and causing great problems for investment casting. In this paper, the qualified castings can be successfully poured by feeding method of insert chill iron melt, smart design and placement process of chill, to realize simultaneous solidification of castings. The shrinkage of creeper tread is solved and the precision of castings is improved. This method exhibits easy operation, excellent feeding effect and simplified gating system to improve yield rate. Furthermore, it could save raw material, reduce waste product and lower product cost by using the insert chill iron melt in investment casting. The production practices showed that the qualified castings can be successfully poured by increasing feeding pressure, placing an internal chill to adjust the temperature of hot junction segments and realizing simultaneous solidification of castings.展开更多
This paper examines environmental change associated with climbing plants (ivy/creeper) on several historical buildings in central Oxford using archival photographs. ViewFinder from English Heritage was used to access ...This paper examines environmental change associated with climbing plants (ivy/creeper) on several historical buildings in central Oxford using archival photographs. ViewFinder from English Heritage was used to access the photo archives in an advanced search of the area of “Oxford” and in the county of “Oxfordshire”. The study includes a variety of buildings, including colleges, churches, chapels, asylums, inns/hotels, factories, a brewery, pubs, a castle as well as architectural elements, such as doorways, cloisters, gates, and walls. The findings reveal that a majority of photographs denoted ivy-/creeper-clad buildings (in nearly 53% of photographs found mostly in the Taunt collection). The greatest abundance of climbing plants was found in the 1880s followed by the 1900s. A further examination of University colleges is warranted due to the earlier and more frequent appearance of ivy/creeper on these buildings.展开更多
文摘The cast-steel creeper tread is a part with complex external surface and internal shape, having a hot spot cased by the uneven wall thickness. As the hot spot is far away from the gating system and the feeding channel is narrow, it is difficult to be fed by setting up a casting head, leading easily to shrinkage and causing great problems for investment casting. In this paper, the qualified castings can be successfully poured by feeding method of insert chill iron melt, smart design and placement process of chill, to realize simultaneous solidification of castings. The shrinkage of creeper tread is solved and the precision of castings is improved. This method exhibits easy operation, excellent feeding effect and simplified gating system to improve yield rate. Furthermore, it could save raw material, reduce waste product and lower product cost by using the insert chill iron melt in investment casting. The production practices showed that the qualified castings can be successfully poured by increasing feeding pressure, placing an internal chill to adjust the temperature of hot junction segments and realizing simultaneous solidification of castings.
文摘This paper examines environmental change associated with climbing plants (ivy/creeper) on several historical buildings in central Oxford using archival photographs. ViewFinder from English Heritage was used to access the photo archives in an advanced search of the area of “Oxford” and in the county of “Oxfordshire”. The study includes a variety of buildings, including colleges, churches, chapels, asylums, inns/hotels, factories, a brewery, pubs, a castle as well as architectural elements, such as doorways, cloisters, gates, and walls. The findings reveal that a majority of photographs denoted ivy-/creeper-clad buildings (in nearly 53% of photographs found mostly in the Taunt collection). The greatest abundance of climbing plants was found in the 1880s followed by the 1900s. A further examination of University colleges is warranted due to the earlier and more frequent appearance of ivy/creeper on these buildings.
