Sand casting is the process of creating metal components by pouring molten metal into molds made out of sand and additives. The main ingredient is sand which is combined with binders and formed into a pattern, based on the final desired component. The molten metal is added to the mold after which the sand mold is broken, leaving behind the metal component.
The process of sand casting is the oldest and most popular method of metal casting. While the process is time intensive, it is capable of creating metal components ranging from a few ounces in weight to those weighing in tons. A wide variety of metals and alloys can also be used due to the high heat tolerance of sand.
Key Industries
The process of sand casting is used to produce a considerable amount of all metal castings, with the main industries driving the demand consisting of automotive, industrial machinery, railways, and energy and construction sectors. Almost any alloy, ferrous or non-ferrous can be used in sand casting, including metals with high melting temperatures such as steel and titanium.
Sand casting is used to produce smaller parts such as gears, propellers, pulleys and crankshafts and larger equipment such as engine blocks, transmission cases, and cylinder heads. By using sand for the mold, there is an added flexibility in designing the pattern, and further cores can be used to increase the complexity of the design to suit the usage. The use of 3D printers to design the mold patterns has made the process easier and quicker, and therefore more adaptable.
Global Sand Casting Market
The 5 nations that are the top sand casting suppliers are China, India, US, Japan, and Germany with China contributing to approximately 45-47 percent of the global production of sand castings. Around 70 percent of ferrous castings are produced using the sand casting method and 25 percent of non-ferrous castings.
In developed countries, environmental regulations force foundries to take up more environment-friendly protocols, such as the recycling of sand and use of silicate binders. In developing nations, the demand for metal castings is higher so as to boost infrastructure. As the process of sand casting is labor intensive, the growth of the industry has expanded more in nations with low-cost labor.
Challenges
Sand casting is a highly customizable and time-consuming process, as each mold is modified as per needs. The sand mold cannot be reused as each mold has to be broken entirely to recover the metal component created, as a result of which sand casting is expensive. The entire process of sand casting is labor intensive, and the rise in labor costs has further increased the expense of sand casting. The costs are also influenced by expensive raw materials.
Due to the high porosity of the sand mold, the metal component generally has low material strength, low dimensional accuracy, and a poor surface finish, despite the characteristics of the metal used.
The sand casting process to create metal components continues to gain in popularity due to its wide applications and versatility. Sand casting can be used to create metal items of virtually any size or weight. While the high costs involved in sand casting may act as a deterrent, in countries with low labor costs the sand casting market continues to flourish.