How Crane is made

How Crane is made Crane:
A crane is a machine that is capable of raising and lowering heavy objects and moving them horizontally. Cranes are distinguished from hoists, which can lift objects but that cannot move them sideways. Cranes are also distinguished from conveyors, that lift and move bulk materials, such as grain and coal, in a continuous process. The word crane is taken from the fact that these machines have a shape similar to that of the tall, long-necked bird of the same name.

Cranes continued to rely on human or animal power until the middle of the nineteenth century, when steam engines were developed. By the end of the nineteenth century, internal combustion engines and electric motors were used to power cranes. By this time, steel rather than wood was used to build most cranes.

Raw Materials:
The most important substance used to manufacture cranes is steel. Steel is an alloy of iron and a small amount of carbon. For structures that do not require very high strength, a common form of steel known as carbon steel is used. By definition, carbon steel contains less than 2% of elements other than iron and carbon. Carbon steel exists in a wide variety of forms. The most important factor in determining the properties of carbon steel is the amount of carbon present, which ranges from less than 0.015% to more than 0.5%.

Design:
Very few machines exist in as wide a variety of designs as cranes. Before the crane is constructed, the manufacturer must consider the site where it will be used and the weight it will need to lift. Cranes are often modified to suit the needs of the user.

Cranes used for industrial purposes are generally designed to remain permanently in one location. These cranes often perform repetitive tasks that can be automated. An important type of industrial crane is the bridge crane. Traveling on tracks attached to two horizontal beams, known as a bridge, a trolley enables the movement of the bridge crane. Usually, the bridge itself can be moved along a pair of parallel rails, allowing the crane to reach a large, rectangular area. A bridge crane may also be designed so that one end of the bridge is supported by a central pivot while the other end moves on a circular rail, allowing a large, round area to be reached.

The Manufacturing Process:

Making steel components:
Molten steel is made by melting iron ore and coke in a furnace, then removing most of the carbon by blasting oxygen into the liquid. The molten steel is then poured into large, thick-walled iron molds, where it cools into ingots.

In order to form flat products such as plates and sheets, or long products such as bars and rods, ingots are shaped between large rollers under enormous pressure. Hollow tubes, such as those used to form the latticed booms of large cranes, may be made by bending sheets of steel and welding the long sides together. They may also be made by piercing steel rods with a rotating steel cone.

An external tower crane:
The cables used to lift weights are made from steel wires. To make wire, steel is first rolled into a long rod. The rod is then drawn through a series of dies which reduce its diameter to the desired size. Several wires are then twisted together to form cable.

Assembling the crane:
A crane is put together from the necessary components. As the crane moves along the assembly line, the steel components are welded or bolted into place. The exact procedures followed during this process vary depending on the type of crane being assembled. For a mobile crane, the components are then assembled to a standardized truck or crawler of the appropriate type.

Quality Control:
Safety is the most important factor to be considered during crane manufacturing.

An internal tower crane: ensure that it has no structural flaws that would weaken the crane. Welds and bolts joints are inspected as well.

A completed crane is first tested without a weight to ensure that all of its components operate properly. It is then tested with a weight to ensure that the crane is able to lift heavy objects without losing stability.

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