Stainless steel is the name of a family of iron-based alloys known for their corrosion and heat resistance. One of the main characteristics of stainless steel is its minimum chromium content of 10.5%, which gives it its superior resistance to corrosion in comparison to other types of steels. Like other steels, stainless steel is composed primarily from iron and carbon, but with the addition of several other alloying elements, the most prominent being chromium. Other common alloys found in stainless steel are nickel, magnesium, molybdenum, and nitrogen.
Stainless steel has many desirable properties that contribute greatly to its widespread application in the making of parts and components across many industrial sectors. Above all, because of its chromium content, it is extremely resistant to corrosion. The 10.5% minimum content makes steel approximately 200 times more resistant to corrosion than steel without chromium. Other favorable properties for consumers are its high strength and durability, high and low-temperature resistance, increased formability and easy fabrication, low maintenance, long-lasting, attractive appearance and it is environmentally friendly and recyclable. Once stainless steel is put into service, it does not need to be treated, coated, or painted.
There are many numerical grading systems for stainless steel, designated according to their composition, physical properties, and applications. Each type of stainless steel is classified by its series number and then assigned a numerical grade. The most popular series numbers are 200, 300, 400, 600, and 2000. The most common grades are type 304 and 316 which consist of austenitic chromium-nickel alloys. Cutlery-grade stainless steels are found in the 400 Series, which is derived from ferritic and martensitic chromium alloys. Type 420 is known as surgical steel, and type 440 is known as razor blade steel.
For more information, see our page on stainless steel types.
The family of stainless steels is primarily classified into four main categories based upon their crystal microstructure.
Ferritic steels are the 400-grade stainless steels noted for their high chromium content, which can range from 10.5% to 27%. They have magnetic properties, too, offer good ductility, tensile-property stability, and resistance to corrosion, thermal fatigue, and stress-corrosion cracking.
Typical applications for ferritic stainless steels include automotive components and parts, the petrochemical industry, heat exchangers, furnaces, and durable goods like appliances and food equipment.
Perhaps the most common category of stainless steel, austenitic grade steels are high in chromium, with varying amounts of nickel, manganese, nitrogen, and some carbon. Austenitic steels are divided into the 300 series and 200 series subcategories, which are determined by which alloys are used. The austenitic structure of the 300 series is distinguished via the addition of nickel. The 200 series primarily uses the addition of manganese and nitrogen. Grade 304 is the most common stainless steel.
Sometimes referred to as 18/8 because of its 18% chromium and 8% nickel, it is used in kitchen equipment, cutlery, food processing equipment, and structural components in the automotive and aerospace industries. Grade 316 is another common stainless steel. It is used in the making of a wide range of products such as food preparation equipment, laboratory benches, medical and surgical equipment, boat fittings, pharmaceutical, textile, and chemical processing equipment.
Read more about 304 vs 316 stainless steel
Martensitic stainless steels are in the 400 Grade series of stainless steels. They have a low to high carbon content, and contain 12% to 15% chromium and up to 1% molybdenum. It’s used whenever corrosion resistance and-or oxidation resistance are required along with either high strength at low temperatures or creep resistance at elevated temperatures. Martensitic steels are also magnetic and possess relatively high ductility and toughness, which make them easier to form.
Applications for martensitic stainless steels include a wide range of parts and components, from compressor blades and turbine parts, kitchen utensils, bolts, nuts and screws, pump and valve parts, dental and surgical instruments, to electric motors, pumps, valves, machine parts sharp surgical instruments, cutlery, knife blades, and other cutting hand tools.
As the name implies, duplex stainless steels possess a mixed microstructure of ferrite and austenite. The chromium and molybdenum content is high, with 22% to 25%, and up to 5%, respectively, with very low nickel content. The duplex structure gives the stainless steel many desirable properties. For starters, it offers double the strength of ordinary austenitic or ferritic stainless steels, with excellent corrosion resistance and toughness.
Designated in the 2000 Grade series, duplex stainless steel is ideal for applications in demanding environments such as in chemical, oil, and gas processing and equipment, marine, high chloride environments, pulp and paper industry, cargo tanks for ships and truck, and bio-fuels plants, chloride containment or pressure vessels, transportation, heat exchanger tubes, construction, the food industry, desalination plants, and components for FGD systems.
Swaging sleeves for steel cable assemblies is one of the most commonly performed rigging functions for lighter duty applications. Watch our video for everything you need to know to swage sleeves safely and correctly for your next application.
For a text and picture version of this information, keep reading.
We’re often asked whether it is better to make an eye with hour glass sleeves or with wire rope clips
Swaged hour glass sleeves are stronger, more cost effective, and do not require future maintenance or re-torquing of nuts. They are also more streamlined than wire rope clips.
When forming swaged cable assemblies, there are primarily two types of wire rope that are used: 7x7 and 7x19 strand cable
The shape of the cable is not perfectly round and is made of several strands of wires.
7x19 refers to the cable having six outer strands surrounding the center core strand that counts as the seventh. Each strand is composed of 19 smaller wires.
If you look closely, you can see the V-shaped area between the strands. This is referred to as a “valley.”
Most commonly, aluminum hour glass sleeves are used with hot dip galvanized cable to form cable assemblies.
The aluminum is soft. When compressed by the swaging tool, it will be forced into the valleys of the cable, locking the aluminum sleeve into place.
Make an eye by passing the cable through the sleeve and doubling it back.
Before swaging, make sure the “cut end” of the cable sticks out at a length at least 2 cable diameters. This will allow for full contact with the cable when the sleeve expands during swaging.
Place the sleeve into the tool jaws.
Note the proper orientation of the swage tool cavity with the aluminum sleeve.
The sleeve should always be vertically aligned and never horizontal.
With the sleeve in the proper position, make your first swage by squeezing the swage tool handles together until the jaws are completely closed.
For each sleeve size, there is a prescribed number of swage crimps that must be made.
In the case of this ¼” sleeve, it requires 4 swage crimps.
Be sure to leave a small space in between each of the crimps. Your finished assembly should look as shown.
Different sized sleeves will require a different number of swages.
2 swages are required for sizes 1/16ths" and 3/32nds" sleeves.
3 swages are required for sizes 1/8th" and 5/32nds" sleeves.
4 swages are required for 3/16ths" and ¼ inch sleeves.
5 swages are required for 5/16ths" and 3/8ths" sleeves.
When making multiple swages, it is important to follow the correct sequence for each sized sleeve.
The diagram here can be referenced for the swaging sequences of different sized sleeves.
To make sure the swage crimps are done properly, use an “after swage gauge” like the Tyler Tool Go-No-Go Gauge
Using the corresponding gauge cavity, slide the gauge over the sleeve.
If the gauge turns around the swage crimp area freely, you then know it was done properly.
If the gauge does not slip over the swage crimp area, use the tool to swage again to make sure the sleeve was compressed fully.
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