铸造技术
我们可以提供离心铸造、砂型铸造、真空成型铸造和锻造技术零件，并具备精良的机械加工能力以满足严格的要求。
离心铸造
In centrifugal casting, a permanent mold is rotated continuously about its axis at high speeds (300 to 3000 rpm) as the molten metal is poured. The molten metal is centrifugally thrown towards the inside mold wall, where it solidifies after cooling. The casting is usually a fine-grained casting with a very fine-grained outer diameter, owing to chilling against the mould surface. Impurities and inclusions are thrown to the surface of the inside diameter, which can be machined away. Casting machines may be either horizontal or vertical-axis. Horizontal axis machines are preferred for long, thin cylinders, vertical machines for rings. Most castings are solidified from the outside first. This may be used to encourage directional solidification of the casting, and thus give useful metallurgical properties to it. Often the inner and outer layers are discarded and only the intermediary columnar zone is used. Centrifugal casting was the invention of Alfred Krupp, who used it to manufacture cast steel tyres for railway wheels in 1852.
离心铸造的特点
铸件可以制成几乎任何长度、厚度和直径。
同一尺寸模具可生产不同壁厚的产品。
Eliminates the need for cores.
耐大气腐蚀，管道中的典型情况。
Mechanical properties of centrifugal castings are excellent.
Only cylindrical shapes can be produced with this process.
尺寸限制最大为直径3米（10英尺）和长度15米（50英尺）。
Wall thickness range from 2.5 mm to 125 mm (0.1 - 5.0 in).
公差限制：外径可为2.5毫米（0.1英寸），内径可为3.8毫米（0.15英寸）。
表面粗糙度范围为2.5毫米至12.5毫米（0.1-0.5英寸）均方根值。
离心铸造的优势
Cylinders and shapes with rotational symmetry are most commonly cast by this technique. "Tall" castings (in the direction of the settling force acting, usually gravity) are always more difficult than short castings. In the centrifugal casting technique the radius of the rotation, along which the centrifugal force acts, replaces the vertical axis. The casting machine may be rotated to place this in any convenient orientation, relative to gravity's vertical. Horizontal and vertical axis machines are both used, simply to place the casting's longest dimension conveniently horizontal. Thin-walled cylinders are difficult to cast by other means, but centrifugal casting is particularly suited to them. To the rotation radius, these are effectively shallow flat castings and are thus simple. Centrifugal casting is also applied to the casting of disk and cylindrical shaped objects such as railway carriage wheels or machine fittings where the grain, flow, and balance are important to the durability and utility of the finished product. Providing that the shape is relatively constant in radius, noncircular shapes may also be cast.
砂型铸造
Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand as the mold material. The term sand casting can also refer to an object produced via the sand casting process. Sand castings are produced in specialized factories called foundries. Over 70% of all metal castings are produced via a sand casting process.
砂型铸造相对便宜且耐火性足够，甚至可用于钢铁铸造。除了砂子外，还需混入或本身含有合适的粘结剂（通常是粘土）。混合物通常用水（有时也用其他物质）润湿，以增强粘土的强度和可塑性，并使骨料适合成型。砂子通常装在称为砂箱的框架或模具盒系统中。通过将砂子压实围绕模型或模样，或直接在砂中雕刻，形成型腔和浇注系统。
砂型铸造的工艺模式
From the design, provided by an engineer or designer, a skilled pattern maker builds a pattern of the object to be produced, using wood, metal, or a plastic such as expanded polystyrene. Sand can be ground, swept or strickled into shape. The metal to be cast will contract during solidification, and this may be non-uniform due to uneven cooling. Therefore, the pattern must be slightly larger than the finished product, a difference known as contraction allowance. Pattern-makers are able to produce suitable patterns using Contraction rules (these are sometimes called shrink allowance rulers where the ruled markings are deliberately made to a larger spacing according to the percentage of extra length needed). Different scaled rules are used for different metals, because each metal and alloy contracts by an amount distinct from all others. Patterns also have core prints that create registers within the molds into which are placed sand cores. Such cores, sometimes reinforced by wires, are used to create under-cut profiles and cavities which cannot be molded with the cope and drag, such as the interior passages of valves or cooling passages in engine blocks.
金属进入模腔的路径构成浇注系统，包括浇口、维持良好金属补给的各类冒口，以及将浇注系统与铸型型腔相连的内浇口。铸造过程中产生的气体和水蒸气通过透气砂或增设的冒口排出，这些冒口可在模型本体上制作，也可作为独立部件添加。
砂型铸造的模具箱与材料
A multi-part molding box (known as a casting flask, the top and bottom halves of which are known respectively as the cope and drag) is prepared to receive the pattern. Molding boxes are made in segments that may be latched to each other and to end closures. For a simple object—flat on one side—the lower portion of the box, closed at the bottom, will be filled with a molding sand. The sand is packed in through a vibratory process called ramming, and in this case, periodically screeded level. The surface of the sand may then be stabilized with a sizing compound. The pattern is placed on the sand and another molding box segment is added. Additional sand is rammed over and around the pattern. Finally a cover is placed on the box and it is turned and unlatched, so that the halves of the mold may be parted and the pattern with its sprue and vent patterns removed. Additional sizing may be added and any defects introduced by the removal of the pattern are corrected. The box is closed again. This forms a green mold which must be dried to receive the hot metal. If the mold is not sufficiently dried a steam explosion can occur that can throw molten metal about. In some cases, the sand may be oiled instead of moistened, which makes possible casting without waiting for the sand to dry. Sand may also be bonded by chemical binders, such as furane resins or amine-hardened resins.
砂型铸造的寒意
为了控制金属的凝固结构，可以在模具中放置金属板（冷铁）。这种快速的局部冷却会形成更细的晶粒结构，并可能在这些位置形成稍硬的金属。在铁铸件中，效果类似于锻造工作中的金属淬火。发动机气缸的内径通过冷铁芯变硬。在其他金属中，冷铁可用于促进铸件的定向凝固。通过控制铸件的凝固方式，可以防止铸件内部的空洞或孔隙。
砂型铸造的型芯
为了在铸件内部形成空腔（如发动机缸体和缸盖中的液体冷却通道），需使用负模来制作型芯；型芯通常由砂型制成，在移除模具后放入铸型箱中。由于会增加设置时间从而提高成本，设计时尽可能避免使用型芯。
With a completed mold at the appropriate moisture content, the box containing the sand mold is then positioned for filling with molten metal—typically iron, steel, bronze, brass, aluminium, magnesium alloys, or various pot metal alloys, which often include lead, tin, and zinc. After filling with liquid metal the box is set aside until the metal is sufficiently cool to be strong. The sand is then removed revealing a rough casting that, in the case of iron or steel, may still be glowing red. When casting with metals like iron or lead, which are significantly heavier than the casting sand, the casting flask is often covered with a heavy plate to prevent a problem known as floating the mold. Floating the mold occurs when the pressure of the metal pushes the sand above the mold cavity out of shape, causing the casting to fail.
浇注后，型芯通过棒击或喷丸破碎并从铸件中清除。浇口和冒口的金属从毛坯铸件上切除。可施加各种热处理以消除初始冷却产生的应力并增加硬度——对于钢或铁件，采用水淬或油淬。铸件可通过表面压缩处理（如喷丸强化）进一步增强，这种处理能提高抗拉裂性能并使粗糙表面光滑化。
砂型铸造的设计要求
The part to be made and its pattern must be designed to accommodate each stage of the process, as it must be possible to remove the pattern without disturbing the molding sand and to have proper locations to receive and position the cores. A slight taper, known as draft, must be used on surfaces perpendicular to the parting line, in order to be able to remove the pattern from the mold. This requirement also applies to cores, as they must be removed from the core box in which they are formed. The sprue and risers must be arranged to allow a proper flow of metal and gasses within the mold in order to avoid an incomplete casting. Should a piece of core or mold become dislodged it may be embedded in the final casting, forming a sand pit, which may render the casting unusable. Gas pockets can cause internal voids. These may be immediately visible or may only be revealed after extensive machining has been performed. For critical applications, or where the cost of wasted effort is a factor, non-destructive testing methods may be applied before further work is performed.
真空成型铸造
Vacuum molding (V-process) is a variation of the sand casting process for most ferrous and non-ferrous metals, in which unbonded sand is held in the flask with a vacuum. The pattern is specially vented so that a vacuum can be pulled through it. A heat-softened thin sheet (0.003 to 0.008 in (0.076 to 0.203 mm)) of plastic film is draped over the pattern and a vacuum is drawn (200 to 400 mmHg (27 to 53 kPa)). A special vacuum forming flask is placed over the plastic pattern and is filled with a free-flowing sand. The sand is vibrated to compact the sand and a sprue and pouring cup are formed in the cope. Another sheet of plastic is placed over the top of the sand in the flask and a vacuum is drawn through the special flask; this hardens and strengthens the unbonded sand. The vacuum is then released on the pattern and the cope is removed. The drag is made in the same way (without the sprue and pouring cup). Any cores are set in place and the mold is closed. The molten metal is poured while the cope and drag are still under a vacuum, because the plastic vaporizes but the vacuum keeps the shape of the sand while the metal solidifies. When the metal has solidified, the vacuum is turned off and the sand runs out freely, releasing the casting.
The V-process is known for not requiring a draft because the plastic film has a certain degree of lubricity and it expands slightly when the vacuum is drawn in the flask. The process has high dimensional accuracy, with a tolerance of ±0.010 in for the first inch and ±0.002 in there after. Cross-sections as small as 0.090 in (2.3 mm) are possible. The surface finish is very good, usually between 150 to 125 rms. Other advantages include no moisture related defects, no cost for binders, excellent sand permeability, and no toxic fumes from burning the binders. Finally, the pattern does not wear out because the sand does not touch it. The main disadvantage is that the process is slower than traditional sand casting so it is only suitable for low to medium production volumes; approximately 10 to 15,000 pieces a year. However, this makes it perfect for prototype work, because the pattern can be easily modified as it is made from plastic.
锻造
锻造是已知最古老的金属加工工艺之一。传统上，锻造由铁匠使用锤子和铁砧完成，尽管12世纪水力应用于铁的生产和加工使得锤砧逐渐被淘汰。历经数世纪发展，铁匠铺已演变为拥有工程化流程、生产设备、工具、原材料和产品的现代化设施，以满足现代工业需求。
现代工业锻造采用压力机或由压缩空气、电力、液压或蒸汽驱动的锻锤，这些锻锤的往复重量可达数千磅。500磅（230公斤）以下的小型动力锤和液压机在艺术锻造坊也很常见。部分蒸汽锤仍在使用，但随着其他更便捷动力源的普及，它们已逐渐被淘汰。
锻造的优缺点
锻造可以生产出比同等铸造或机加工零件更坚固的部件。在锻造过程中，金属成型时其内部晶粒会变形以顺应零件的整体形状，从而使晶粒在整个部件中保持连续，从而产生具有更高强度特性的部件。
某些金属可以冷锻，但钢铁几乎总是热锻。热锻可防止冷锻导致的加工硬化，这会增加对工件进行二次机加工的难度。此外，虽然加工硬化在某些情况下可能是有益的，但其他硬化方法（如热处理）通常更经济且更可控。适用于沉淀硬化的合金（如大多数铝合金和钛合金）可先热锻后硬化。
生产锻造涉及机械、模具、设施和人员的大量资本支出。对于热锻而言，需要高温炉（有时称为锻炉）来加热钢锭或坯料。由于大型锻锤和压力机及其可生产部件的庞大性，以及处理热金属固有的危险性，通常需要专门建筑来容纳这些操作。对于落锤锻造操作，必须采取措施吸收锤子产生的冲击和振动。大多数锻造操作使用金属成形模具，这些模具必须精密加工并经过仔细热处理，以正确塑造工件，并承受所涉及的巨大力量。
锻造工艺
锻造工艺种类繁多，但主要可分为三大类：
拉长：长度增加，横截面减小
沮丧：长度减小，横截面增大
挤入封闭压缩模具中：产生多向流动
常见的锻造工艺包括：辊锻、旋锻、开坯、自由锻、模锻、压力机锻造、自动热锻和镦粗。