本帖最后由 PZL 于 2013-2-14 11:34 编辑
| Making the Model The barrel model was built up on a tapered wooden spindle of a size appropriate to the gun to be cast, with an extension at the muzzle end to form a 'dead head' or 'feeding head' intended to form a reservoir of molten metal in the mould. After being greased (to make removal easy later), the spindle was tightly wound with rope made of plaited straw to approach the form of the barrel to within a margin of one inch (25.4 mm).
| Around the straw-covered spindle the actual shape of the barrel was then sculpted using layers of a paste made from clay, horse dung (!) and water, each layer being thoroughly dried before application of the next. This resulted in a model very close to the required size and shape. After the final layer had been applied the profile of the piece was checked with a template called a strickle. Finally the model was covered with a layer of molten wax and again smoothed by the strickle. This was to give the model a smooth surface to prevent it adhering to the mould, and to assist its removal from the latter. This last application of the strickle was used to accurately delineate decorative bands on the piece, as well as to locate the position of the trunnions. Next the trunnions in the form of turned wooden blocks shaped at the ends to suit the profile of the barrel were attached by iron skewers driven into the spindle of the model. In order to allow for contraction of the bronze on cooling all model dimensions were made greater than those on the design drawing by 2½ inches in 100 (63.5 mm in 2540 mm). |
制模
炮管模型建立在一个尺寸合适的锥形木制的主轴以便火炮浇铸，在炮口上延伸物出“冒口”或叫做“进料口”，用于在模具中存贮金属熔液。在抹油（方便以后拆卸）后，主轴被稻草辫成的绳子紧紧缠绕，在一英寸的厚度内，接近成炮管外形。
炮管的实际形状通过使用粘土、马粪和水制成的数层糊状物环绕涂抹在覆盖着稻草的主轴上塑成。每一层在下一步制作前彻底干燥。这造成一个非常接近所需要的尺寸和形状的模型。在最后一层涂抹完毕后， 用一块被称为刮板的模版检查炮的轮廓。最后模型被覆盖上一层熔化的蜡，然后用刮板使之平滑。这样使得模型表面光滑，防止它粘附在模具上，有助于从后者移走。刮板的最后一个功能是被用于精确勾画炮上的装饰和定位耳轴的位置。
下一步，作为的木块底部经过车削以适合炮管的轮廓，通过铁串打进模型的主轴。为了能让青铜在冷却时收缩，所有的模型尺寸大于设计图纸上的尺寸2.5%。
| The Mould The mould was made by applying layers of a semi-liquid mixture of clay, potters' or refractory clay, sand | and water, all of which had been finely sifted or strained so it would flow freely into the smallest details of the model. Each layer was left to dry before the next was added. Ultimate thickness depended upon the size of the gun to be cast, about 3 inches (76 mm) for a 24-pr. The outside of the mould was formed to a pattern (checked by a template similar to the strickle mentioned above), so that standard reinforcing staves and hoops could be fitted (lower diagram opposite). After removing the skewers securing the trunnion patterns the model was removed from the mould, first by pulling out the tapered spindle, then unwinding the straw rope, after which the trunnion patterns were removed. Lastly the mould was stood on its breech end and a fire started at the bottom to melt the wax on the model thus making the clay part of it easier to remove without damaging the mould.
After removal of the trunnion patterns the ends of the trunnion holes in the mould were squared off and covered by tiles suitably secured. Note that the mould had first to be made open at both ends to enable the model to be removed, hence a separate model and mould had to be made for the breech and cascable. The breech mould was then attached to the main mould. After the complete mould had been made ready to take the molten metal it was placed breech end down in a pit adjacent to the furnace and surrounded by tightly rammed earth for its entire length. The molten metal was then run into the mould to the top of the dead head. Twenty four hours after the pour mould and casting had cooled sufficiently to permit their being dug out and removed from the pit. Further cooling enabled the staves and hoops to be removed. The mould material was then broken away from the casting, the latter being cleared of rough burrs and crust with hammer and cold chisel, after which the dead head was sawn off. Thus each mould could be used once only.
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模具
模具是由粘土、陶土或者耐火泥、沙子和水的半液体混合物组成的数层涂层做成。所有这些都要被精心筛选或过滤。所以它会自由地流动进模型上的最小的细节。每一层在增加下一层前侯干。模具的最终厚度取决于 要浇铸的炮的尺寸，24磅炮的大约是三英寸（76mm）。（注：6磅炮的厚1.5英寸） 在模具外，形成一个外形（通过类似上述刮板的模板检查），这样可以安装直的加固条和箍。在取出固定耳轴模型用的铁串后，模型就可以从模具中取出了。先拉出锥形主轴，然后解除稻草绳，之后耳轴模型就可以被拆除。最后，模具被树立在炮尾上，从底部生火，融化模型上的蜡，从而使得模型上的粘土部分更容易地不损坏模具的情况下消除掉。
在拆除耳轴模型后，模具上留下耳轴底部的洞，通过砖块的相适应地关紧而平齐和被覆盖。需要注意的是模具首先是被做成两端贯通的，以使得模型能够被移除，因此，必须为炮尾和尾珠制造单独的模型和模具。炮尾模具然后才被连接到主模具上。在完整的模具被制作好准备接受熔化的金属后，被放置在炮尾底部下地一个毗邻炉子的坑，按照它的整个长度，四周被紧密得夯实土。然后，熔化的金属被流进模具的冒口上方。在倒入模具铸造的二十四小时后，经充分冷却， 已可以被挖出，并从坑中移走。进一步冷却使加固条和箍可以被拆除。模具材料从铸件中剥离。使用铁锤和冷凿清除后者粗糙的毛刺和硬皮，之后铸件上的冒口被剧掉。因此，每个模具只能使用一次。
上文有问题，没有提到模心的制作和安装
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发表于 2013-2-14 11:14:01
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发表于 2013-2-14 11:31:27
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