One of the first things to consider when purchasing cable for industrial projects or construction is the material it is made of. The cable is generally made of steel, as this type of metal is strong and very durable. The cable is sold in two types: galvanized and stainless steel.
When you are looking to buy cable, you will see that cable sizes are available in both finishes, as the sizing refers to the number of strands and wires.
For instance, a 7X19 galvanized cable is made of seven strands which are composed of 19 wires woven together and galvanized. A 7X19 stainless steel cable is also made of the same number of strands and wires – but they are made of different materials.
Each type of metal finishing has its own strengths and weaknesses and the type that you use is quite dependent on the application. Choosing the wrong type for a project could be disastrous – not to mention dangerous – as the incorrect type could wear down too quickly or not be strong enough for its intended use.
So, first and foremost, it is critical to understand the main differences between galvanized and stainless steel.
Let’s dive in.
What is Galvanized Cable?
Galvanized steel cable is made of traditional steel which is coated in a thin layer of zinc. This coating helps to protect the steel from corrosion, as untreated steel has an iron will rust if it is exposed to water or moisture.
There are four different ways that steel may be galvanized.
The first (and typically most common with industrial hardware) is hot-dip galvanizing. The metal pieces are dipped into a flux solution of zinc ammonium chloride which creates an even protective coating.
Steel cables may also be electro galvanized, which creates a very thin layer over the metal via an electric current. The zinc solution conducts this electricity, which positively charges the ions and attaches to the steel. This creates an extremely thin layer that has been mechanically-bonded.
Another method of galvanization is sherardizing, which is when the zinc layer is applied with heat. The metal is covered in powdered zinc rather than a liquid solution and placed into an airtight container that is heated to extreme temperature and then cooled. This also creates a thin layer, but it is more commonly used on smaller metal objects.
The last method of galvanization is metallic spraying. A zinc solution is sprayed over the metal object and then heated so that the coating sticks to the surface. This method is less protective than others, but it is also less likely to peel or flake off over time.
In addition to cables, common objects made with galvanized steel include:
- Wire Ropes
- Hardware pieces
What is Stainless Steel Cable?
Stainless steel cable is made of an iron alloy containing at least 10.5% chromium and may also be mixed with nickel, silicon, manganese, nitrogen, or carbon. This chromium is naturally corrosion-resistant, so stainless steel does not require an additional galvanized coating for protection.
Stainless steel is produced by melting together all of the raw materials for 8 to 12 hours until it is completely molten. The excess carbon is then removed by pouring the molten metal into an Argon Oxygen Decarburization (AOD) converter. Additional elements may also be added in the converter.
Molten stainless steel is then tuned, which helps to improve the consistency by stirring the metal and maintaining an even temperature until it is ready to be formed.
Stainless steel is quite a bit harder and stronger than other types of iron and steel.
It may be cast in several different ways:
- Forming – pouring molten metals into preformed shapes or molds.
- Hot rolling – heated steel is passed through rolls to form wires, bars, plates, strips, or sheets.
- Cold rolling – used for precise shapes or the production of wide sheets.
- Annealing – this involves heating and cooling the metal repeatedly to soften the steel to improve ductility.
- Cutting – stainless steel may also be cut after being formed into sheets by using sharp knives, saws, high-speed blades, flame cutters, or ionized gas.
There are two different grades of stainless steel: 304 and 316.
Grade 304 is far more common, largely due to its shiny finishing. It is made with a higher percentage of chromium, typically between 18 to 20%, which is exceptionally corrosion-resistant. It is commonly used in:
Grade 316 is made with a high amount of chromium, as well as nickel, silicon, manganese, and carbon with a significant amount of molybdenum. This element has an extremely high melting point and it is added to the alloy to make the metal even stronger.
Grade 316 stainless steel is commonly used for:
- Chemical storage
- Refinery equipment
- Marine environments
- Medical devices
What are the Major Differences?
In addition to the chemical composition and finishing processes, there are some important differences to note between galvanized steel and stainless steel.
First, is the price. The galvanized cable is typically less expensive than stainless steel because the process is much quicker and involves fewer steps. Stainless steel is also more expensive because of the added elements, which increases the cost.
Another difference is strength. Stainless steel is significantly stronger than galvanized steel, which has a lower breaking point. The exterior layer of zinc may wear off over time if the cable is exposed to a lot of friction, which weakens the steel beneath.
The next major difference is to wear resistance. Although stainless steel is exceptionally strong, the mixture of nickel actually softens the metal and will present signs of wear and tear sooner than galvanized cable would. The shiny exterior also shows scratches and dents more than galvanized metal does.
The appearance of both metals is also different. Galvanized steel is not as shiny as stainless steel and appears to be a bit duller and streakier. While the appearance of cable is typically not incredibly important, it may matter in some applications.
And finally, the most significant difference between galvanized steel cable and stainless steel cable is the way they are both used.
When is it Best to Use Galvanized?
Since galvanized metal is not as strong as stainless steel, it is commonly used for lighter-duty applications that do not require extremely heavyweights. It is also far more cost-effective, so it is typically used when budgets are tight.
Finally, galvanized cable is best in environments that are corrosive, such as on boats in saltwater or near chemical compounds. And although the zinc coating will eventually wear, it does provide an additional layer on cables that are used with pulleys to reduce friction.
Galvanized cables are typically used in:
- Hanging cables or wires
- Pulley and winches
- Stage rigging
- Motorized doors (such as garage doors)
- Exercise equipment
When is it Best to Use Stainless Steel?
Since stainless steel cable is extremely strong, it is largely used in more heavy-duty applications to secure heavier weights. It is also best in more moist environments as it is extremely rust-resistant.
Stainless steel also tends to last longer than galvanized steel in certain environments. Therefore, the higher cost ends up evening out as it does not need to be replaced as quickly.
Stainless steel cables are commonly used in:
- Rigging and overhead lifting
- Load and cargo securement
- Fall protection barriers
- Guy-wires for added stability to structures like ship masts, wind turbines, and large tents
- Boat docks
- Overhead doors
The most important thing to keep in mind when you need to buy stainless steel cable or galvanized cable is to choose a manufacturer that offers high-quality products. Quality is key, and it can ensure that your application is far safer and lasts longer.
You can trust Elite Sales to be your provider for any and all industrial hardware equipment. We offer a wide variety of cables, as well as wire ropes, chains, and other products in numerous sizes and finishes.
Reach out to our sales team today to learn more about the items we offer and to place an order.