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What is PARACHROM?
Bump onto this article,dun know if anyone posted it here before..find it very good read,and informative too.
Posted by Wei Koh in Revolution Magazine (watch magazine) No. 12 p.286
WHAT IS PARACHROM? What exactly is Parachrom and how is it made? Its base material consists of 85 percent niobium and 15 percent zirconium. These materials are also used to create heat shields in nuclear power plants, so their melting point is supremely high. To merge the two materials, Rolex utilizes electron bombardment inside a high vacuum condition, which creates an environment of 2,300 degrees Celsius. It is remarkable to witness these two materials becoming one. They are fed vertically through an arc-melting ring, and while they appear as solid metal below the melting point, they transform into a ring of fire at the point at which they combine. To ensure that the two materials are perfectly combined, this fusion takes place three times, with the bar of Parachrom rotated at each pass. The end result is a bar of Parachrom 30 centimeters long that can be used to create 10,000 hairsprings.
The processes after this reduce the thinness of the metal to the diameter of a strand of human hair. During these operations, the 30-cm bar of Parachrom comes to occupy a length of two kilometers. It is rolled, heat-treated to temper it, and then wire drawn. In the first pass through a wire die, it is pulled with a force of 100 kilograms. After this, an additional element, oxygen, is introduced to the alloy. By passing the wire through a furnace, the Parachrom is encouraged to absorb oxygen through its surface. Oxygen changes the thermal coefficient of the material, allowing it to react in the desired manner when the balance wheel’s inertia changes.
Finally, the wire goes through its last drawing when it is reduced to 100 microns in diameter, resulting in a length of three kilometers. The wire is then flattened using high-pressure rolling, reducing it to 50 microns in thickness and 150 microns in height. It is cut into sections 20 cm in length, which are placed inside a mold to provide the coiled shape of the hairspring, and then handrolled in the traditional technique. Remarkably, for all the work done by the massive and intimidating drawing and rolling machines, the operation to create the hairspring’s form is conducted by the human hand. Once the springs are separated, they are given a final heat treatment to relieve stress and ensure that they stay permanently in shape. The blue color of the springs is not due to flame bluing, but added during an electro-chemical process, which stabilizes the properties of the hairspring by adding a layer of oxide — essentially oxygen ions bonded to the exterior of the spring. After which, the hairsprings are given their signature Breguet overcoil, where the exterior of the spring is bent across the top of the entire spiral to aid concentric breathing, before being fixed to the collet and stud.
The strictest levels of precision are observed throughout the entire manufacturing of the hairspring — an embodiment of Rolex’s philosophy of ensuring that quality is optimized right from the very start of production. Says Rolex’s technical director Jacques Baur, “During hairspring manufacturing, precision is of incredible importance. A variation between 44.9 and 45.1 microns represents a difference of four minutes in error per day. At Rolex, our philosophy is always to focus on quality right from the beginning.”
The entire article can be found at the following link,
http://www.horomundi.com/forum/showthread.php?t=3577
Posted by Wei Koh in Revolution Magazine (watch magazine) No. 12 p.286
WHAT IS PARACHROM? What exactly is Parachrom and how is it made? Its base material consists of 85 percent niobium and 15 percent zirconium. These materials are also used to create heat shields in nuclear power plants, so their melting point is supremely high. To merge the two materials, Rolex utilizes electron bombardment inside a high vacuum condition, which creates an environment of 2,300 degrees Celsius. It is remarkable to witness these two materials becoming one. They are fed vertically through an arc-melting ring, and while they appear as solid metal below the melting point, they transform into a ring of fire at the point at which they combine. To ensure that the two materials are perfectly combined, this fusion takes place three times, with the bar of Parachrom rotated at each pass. The end result is a bar of Parachrom 30 centimeters long that can be used to create 10,000 hairsprings.
The processes after this reduce the thinness of the metal to the diameter of a strand of human hair. During these operations, the 30-cm bar of Parachrom comes to occupy a length of two kilometers. It is rolled, heat-treated to temper it, and then wire drawn. In the first pass through a wire die, it is pulled with a force of 100 kilograms. After this, an additional element, oxygen, is introduced to the alloy. By passing the wire through a furnace, the Parachrom is encouraged to absorb oxygen through its surface. Oxygen changes the thermal coefficient of the material, allowing it to react in the desired manner when the balance wheel’s inertia changes.
Finally, the wire goes through its last drawing when it is reduced to 100 microns in diameter, resulting in a length of three kilometers. The wire is then flattened using high-pressure rolling, reducing it to 50 microns in thickness and 150 microns in height. It is cut into sections 20 cm in length, which are placed inside a mold to provide the coiled shape of the hairspring, and then handrolled in the traditional technique. Remarkably, for all the work done by the massive and intimidating drawing and rolling machines, the operation to create the hairspring’s form is conducted by the human hand. Once the springs are separated, they are given a final heat treatment to relieve stress and ensure that they stay permanently in shape. The blue color of the springs is not due to flame bluing, but added during an electro-chemical process, which stabilizes the properties of the hairspring by adding a layer of oxide — essentially oxygen ions bonded to the exterior of the spring. After which, the hairsprings are given their signature Breguet overcoil, where the exterior of the spring is bent across the top of the entire spiral to aid concentric breathing, before being fixed to the collet and stud.
The strictest levels of precision are observed throughout the entire manufacturing of the hairspring — an embodiment of Rolex’s philosophy of ensuring that quality is optimized right from the very start of production. Says Rolex’s technical director Jacques Baur, “During hairspring manufacturing, precision is of incredible importance. A variation between 44.9 and 45.1 microns represents a difference of four minutes in error per day. At Rolex, our philosophy is always to focus on quality right from the beginning.”
The entire article can be found at the following link,
http://www.horomundi.com/forum/showthread.php?t=3577
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