coil

A coil, in chemistry, is a tube, frequently in spiral form, used commonly to cool steam originating from a distillation and thus to condense it in liquid form. Usually it is of copper or another material that conducts heat easily. However copper is mostly used as a material, when a higher hardness is required it is combined with other elements to make an alloy such as brass or bronze. Coils are often used in chemical processes in batch reaction or mixing tank as internal source of heat transfer.

A coil spring is a mechanical device which is typically used to store energy and subsequently release it, to absorb shock, or to maintain a force between contacting surfaces. They are made of an elastic material formed into the shape of a helix which returns to its natural length when unloaded.

Under tension or compression, the material (wire) of a coil spring undergoes torsion [扭转]. The spring characteristics therefore depend on the shear modulus, not Young's Modulus [剪切模量，而非杨氏模量]. A coil spring may also be used as a torsion spring: in this case the spring as a whole is subjected to torsion about its helical axis. The material of the spring is thereby subjected to a bending moment, either reducing or increasing the helical radius. In this mode, it is the Young's Modulus of the material that determines the spring characteristics. 杨氏模量是沿纵向的弹性模量。根据胡克定律，在物体的弹性限度内，应力与应变成正比，比值被称为材料的杨氏模量。

Metal coil springs are made by winding a wire around a shaped former - a cylinder is used to form cylindrical coil springs.

Coil springs for vehicles are typically made of hardened steel. A machine called an auto-coiler takes spring wire that has been heated so it can easily be shaped. It is then fed onto a lathe [机床, a machine that shapes wood or metal] that has a metal rod with the desired coil spring size. The machine takes the wire and guides it onto the spinning rod as well as pushing it across the rod to form multiple coils. The spring is then ejected from the machine and an operator will put it in oil to cool off. The spring is then tempered to lose the brittleness from being cooled. The coil size and strength can be controlled by the lathe rod size and material used. Different alloys are used to get certain characteristics out of the spring, such as stiffness, dampening and strength. 使用不同的合金来获得弹簧的某些特性，例如刚度、阻尼和强度。

车床，又称旋床，是一种将加工物固定在一旋转主轴上加工的工具机。

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What is Turning?- Definition, and Types of Operation - Engineering Choice

热处理4把火

• 淬火(quench): cool a hot substance rapidly by placing it in water
• 回火(temper): bring metal to the required degree of hardness and elasticity by heating and then cooling
• 退火(anneal): make metal or glass hard by heating it and then slowly letting it get cold
• 正火(normalize): heat a material to an elevated temperature and then allowing it to cool back to room temperature by exposing it to room temperature air after it is heated

A selection of conical coil springs

An electromagnetic coil is formed when a conductor is wound around a core or form to create an inductor or electromagnet. An induction coil or "spark coil" is a type of electrical transformer used to produce high-voltage pulses from a low-voltage direct current (DC) supply. An ignition coil (also called a spark coil) is an induction coil in an automobile's ignition system that transforms the battery's voltage to the thousands of volts needed to create an electric spark in the spark plugs to ignite the fuel.

An intrauterine [inside the uterus] device (IUD), also known as intrauterine contraceptive device (IUCD or ICD) or coil, is a small, often T-shaped birth control device that is inserted into the uterus to prevent pregnancy. A contraceptive is a device or drug that prevents a woman from becoming pregnant. contra-: acting against sth, or opposite to sth.

六级/考研单词: coil, seldom, spiral, distil, thereby, condense, liquid, copper, conduct, alloy, brass, bronze, batch, elastic, tense, undergo, axis, cylinder, rod, desire, spin, multiple, eject, temper, stiff, rapid, norm, elevate, exposition, wound, spark, pulse, ignite, automobile, volt, plug, insert, pregnant