Types of Austenitic Steel Used for Construction Fasteners

Construction fasteners

Your construction’s fasteners are generally its most crucial element. These, after all, will hold your structure together and determine its overall safety and durability. You have different materials to pick from for your construction’s fasteners, including bronze, aluminium, brass and steel. Stainless steel, however, is the best choice for construction projects in most applications.

There are different materials used for stainless steel screw fasteners including austenitic, ferritic and martensitic. Most construction projects call for austenitic stainless steel fasteners. This is because these have the highest corrosion resistance among the three and tensile strengths of 80000-150000 PSI. As such, they can perfectly support different construction materials and magnitudes.

Here are the common austenitic stainless steel types used for construction fasteners.

305 Stainless Steel

This fastener option contains 8-10% nickel, 17-19% chrome and 12% carbon. 305 stainless steel is specifically designed as an improvement of the cold heading qualities associated with 18-8 steel. The physical qualities and corrosion resistance of 305 steel are largely similar to type 304 steel. Type 305 steel is generally used for deck screws, which fasten composite boards or wood to your deck’s main beams.

18-8 Stainless Steel

This fastener material type contains 8% nickel, 18% chrome and 0.8% carbon. 18-8 stainless steel fasteners are commonly graded as 303 and 304 steel fasteners. 18-8 stainless steel is durable and corrosion resistant. As such, it is generally used in highly corrosive applications, such as marine machines in freshwater bodies, and household applications. The fasteners are also ideal for the food processing and brewing industries and those that use inorganic chemicals. 18-8 steel, however, is not very suitable for saltwater environments.

316 Stainless Steel

Bolts and nuts organized

This variety contains 16-18% chrome, 0.8% carbon, 2% molybdenum and 10-14% nickel. The molybdenum is the primary element that sets 316 steel apart from 18-8 and 305 stainless steel. This is the recommended option in harsh, medical or marine applications, particularly saltwater applications. This is because it has a greater corrosion resistance compared to 18-8 steel. Type 316 steel can also withstand phosphoric, sodium and sulphuric acids, sulphite liquors, hypochlorite solutions, and calcium brines. As such, type 316 steel fasteners are used in swimming pools, vessels used in saltwater, piers and docks.

410 Stainless Steel

This category contains 15% carbon and 11-14% chrome. It can be toughened to about 40 Rockwell C, making it among the most durable options. 410 stainless steel also has higher corrosion resistance compared to 18-8 steel. Its durability and corrosion resistance make this stainless steel variety ideal for self-tapping/drilling, and siding screws used for roofing.

The above austenitic types are guaranteed to meet virtually all the needs of your construction. One of the concerns associated with fasteners is that they might significantly increase your project’s costs if not well handled. This is because it might be a challenge to factor in the exact number and type of fasteners you need for your project. Fortunately, the above options are inexpensive and will not significantly impact your project’s overall cost, more so when sourced from one supplier throughout your project.

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