When choosing the parts of any mechanical system, it’s important that you make the decision based upon the operational requirements that are needed to fulfill the known task. As such, the first stage of any project is to know exactly what the requisite functions are that you need to account for, before then finding a part that will competently perform to this specified role.
Although many people think of small, interchangeable components like the spring as an inconsequential choice, any system is only as secure as the weakest part. Meaning that a wrong decision at this level is capable of causing a total systems failure, such as an incorrect part being used in the machine.
We take a look below at the role of one of the most common machine parts used across all industries – music wire springs.
The Sound Of Music
The music wire was created with a very singular use in mind, namely, to improve the quality of strings within musical instruments. It was created in tandem with the development of the piano, which is why many people still refer to it as piano wire.
This steel alloy was designed with the sole intention of creating a material that could withstand the forces of sustained high tension. While still being able to perform to an exacting, pitch-perfect specification over a long time period.
By infusing the steel alloy with a high percentage of carbon, the wire retains its properties of flexibility and elasticity, which are inherent in many types of steel while most importantly, allowing it to keep a high degree of structural integrity through sustained, heavy stress. These characteristics have made the wire a unique and specialized material, and as such, it’s now commonly used across several industries in many more applications than just musical instruments.
Music Wire Springs
With a vast array of applications in all areas of life, springs are one of the most under-appreciated designs of the mechanical world.
Considering that music wire is a common material used in the production of springs, you begin to realize just how important and significant this material is.
Music wire is produced by a process known as cold drawing. This is a technique of passing a heated metal rod through increasingly smaller dies to shape the metal into a preferred shape and size. Not only does this produce a solid integrity within the basic structure of the wire, but it’s also an inexpensive process as a result of being carried out at room temperature, which allows the rod to cool into the correct, fabricated form quickly.
Music wire springs are favored for their durability and high uniform yield strength properties that are particularly desirable in the manufacturing of small diameter wire springs.
Music wire provides a cheap and very reliable option in spring choice, but this material is not without its limitations.
The Weaknesses Of A High-Strength Material
The biggest drawback with this type of wire is its vulnerability to high temperatures. With a recommended usage being below 120 Celsius, this is a relatively low and therefore restrictive temperature parameter for machine parts, which often need to work in exothermic environments. More-so, this is particularly the case for small parts such as springs that have a very high surface area to volume ratio, which leaves them particularly susceptible to deformation.
Another characteristic to be aware of with music wire is its reduced protection against corrosion, relative to other steel composites. This can be combated by using a coating on the metal, but it is worth noting that this will often affect the overall performance output of the material.
This all means that despite being an incredibly strong and durable option, music wire springs are not suitable for all applications. With being prone to adverse temperatures and rusting, they must be protected from extreme elements in working environments. This will prevent them from being compromised and suffering complete failures of the system they’re part of.
Considerations For Music Wire Springs
In the same way that there are many types of steel available within the four main categories, which are stainless, alloy, carbon and tool, there’s also a large variety of high-carbon steel to choose between.
As with all springs, the strength, and durability of the product can be tailored through the physical design of the spring. From alterations in wire thickness, shape and finishing such as coatings and shot-peening to the design of the coil itself, which includes:
- Wire length
- Active coil length
- Coil angle
- Coil Diameter
- Angle of coil
All of which are important factors to take into account when calculating the tolerance level of the finished product. However, the composition of the steel alloy is as much of an influencing factor as any of the others.
Carbon steel by definition has a range of chemical ratio parameters of the various elements used in the creation of the alloy. The amount of carbon added to this mixture then further defines whether the steel is low, medium or high carbon steel.
High Carbon Steel Grading
High-carbon steel has a range between 0.61 and 1.5% of carbon within its composition. As more carbon is added to this mix, the steel becomes stronger, harder, rigid but also more susceptible to heat. This means that you’re unable to weld this material or heat-treat it in any way without making the structure incredibly brittle.
Another interesting side effect of carbon steel is that it is slightly more magnetic in comparison to other steel compounds. Although this attribute too can be manipulated through applying a coating to the surface, it is worth being aware that it’s a natural characteristic of the material.
Although the ratio of ingredients can be altered manually in the creation of the metal, there are already many standards which have been thoroughly tested to identify the qualities of each respective type. This information is freely available through charts and data sheets which outline the global standards.
This can then be quickly used in the designing of music wire springs at the manufacturing stage. Customized parts will then be efficiently and accurately created to a customer’s specific requirements.