Husky Heavy Duty Welded 20-Gauge Steel

Twenty or 20 may refer to:

• 20 (number), the natural number following 19 and preceding 21
• one of the years 20 BC, AD 20, 1920, 2020

A duty (from "due" meaning "that which is owing"; Old French: deu, did, past participle of devoir; Latin: debere, debitum, whence "debt") is a commitment or expectation to perform some action in general or if certain circumstances arise. A duty may arise from a system of ethics or morality, especially in an honor culture. Many duties are created by law, sometimes including a codified punishment or liability for non-performance. Performing one's duty may require some sacrifice of self-interest.

A sense-of-duty is also a virtue or personality trait that characterizes someone who is diligent about fulfilling individual duties or who confidently knows their calling. A sense-of-duty can also come from a need to fulfill familial pressures and desires. This is typically seen in a militaristic/patriotic way.

Cicero, an early Roman philosopher who discusses duty in his work “On Duties", suggests that duties can come from four different sources:

1. as a result of being a human
2. as a result of one's particular place in life (one's family, one's country, one's job)
3. as a result of one's character
4. as a result of one's own moral expectations for oneself

The specific duties imposed by law or culture vary considerably, depending on jurisdiction, religion, and social normalities.

Husky is a general term for a dog used in the polar regions, primarily and specifically for work as sled dogs. It refers to a traditional northern type, notable for its cold-weather tolerance and overall hardiness. Modern racing huskies that maintain arctic breed traits (also known as Alaskan huskies) represent an ever-changing crossbreed of the fastest dogs.

Huskies have continued to be used in sled-dog racing, as well as expedition and trek style tour businesses, and as a means of essential transportation in rural communities. Huskies are also kept as pets, and groups work to find new pet homes for retired racing and adventure-trekking dogs.

Steel is an alloy of iron and carbon with improved strength and fracture resistance compared to other forms of iron. Because of its high tensile strength and low cost, steel is one of the most commonly manufactured materials in the world. Steel is used in buildings, as concrete reinforcing rods, in bridges, infrastructure, tools, ships, trains, cars, bicycles, machines, electrical appliances, furniture, and weapons.

Iron is always the main element in steel, but many other elements may be present or added. Stainless steels, which are resistant to corrosion and oxidation, typically need an additional 11% chromium.

Iron is the base metal of steel. Depending on the temperature, it can take two crystalline forms (allotropic forms): body-centred cubic and face-centred cubic. The interaction of the allotropes of iron with the alloying elements, primarily carbon, gives steel and cast iron their range of unique properties. In pure iron, the crystal structure has relatively little resistance to the iron atoms slipping past one another, and so pure iron is quite ductile, or soft and easily formed. In steel, small amounts of carbon, other elements, and inclusions within the iron act as hardening agents that prevent the movement of dislocations.

The carbon in typical steel alloys may contribute up to 2.14% of its weight. Varying the amount of carbon and many other alloying elements, as well as controlling their chemical and physical makeup in the final steel (either as solute elements, or as precipitated phases), impedes the movement of the dislocations that make pure iron ductile, and thus controls and enhances its qualities. These qualities include the hardness, quenching behaviour, need for annealing, tempering behaviour, yield strength, and tensile strength of the resulting steel. The increase in steel's strength compared to pure iron is possible only by reducing iron's ductility.

Steel was produced in bloomery furnaces for thousands of years, but its large-scale, industrial use began only after more efficient production methods were devised in the 17th century, with the introduction of the blast furnace and production of crucible steel. This was followed by the Bessemer process in England in the mid-19th century, and then by the open-hearth furnace. With the invention of the Bessemer process, a new era of mass-produced steel began. Mild steel replaced wrought iron. The German states were the major steel producers in Europe in the 19th century. American steel production was centred in Pittsburgh, Bethlehem, Pennsylvania, and Cleveland until the late 20th century. Currently, world steel production is centered in China, which produced 54% of the world's steel in 2023.

Further refinements in the process, such as basic oxygen steelmaking (BOS), largely replaced earlier methods by further lowering the cost of production and increasing the quality of the final product. Today more than 1.6 billion tons of steel is produced annually. Modern steel is generally identified by various grades defined by assorted standards organizations. The modern steel industry is one of the largest manufacturing industries in the world, but also one of the most energy and greenhouse gas emission intense industries, contributing 8% of global emissions. However, steel is also very reusable: it is one of the world's most-recycled materials, with a recycling rate of over 60% globally.