Optimas designed the Parts Imperial Blog Series to provide detailed information about the fasteners you use and the ones you may need. Curated to help you find the right parts, these technical releases supply information on components&#; specifications, applications and standards. This Imperial Series is comprised of five types of components: flat washers, hex cap screws, locknuts, machine screws and tapping screws. Once you have determined the parts suited for your application, Optimas can source them through manufacturing and distribution, ensuring you get the parts you need.
Hardened flat washers are designed for assembly with a Grade 5 or higher strength bolt between the bearing surface of the fastener and the part to which it is attached. They are made of carbon steel and may either be thru-hardened to Rc 38-45 or carburized (case hardened) to a minimum depth of .015&#; and have a surface hardness of 37-45 Rc with a minimum core hardness of Rc 30.
Unhardened flat washers are designed for assembly with Grade 2 or lower strength bolts or tapping screws between the bearing surface of the fastener and the part to which it is attached. Narrow (SAE) and wide (USS) flat washers are available for specification&#;depending on the preferred outside diameter needed.
Dimensional characteristics are covered by ANSI B18.22.1* and mechanical properties are covered by ASTM F844.
Top and side views of a hardened or unhardened flat washer with the dimensional attributes listed in the charts below.
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B
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*Sizes indicated in this chart are generally available.
**These are common dimensions in inches.
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*Common dimensions of unhardened steel washers are given in inches.
Link to Hebei Bentley Technology
For more information on hardened and unhardened flat washers or any type of fastener, contact one of our experts at optimas.com/contact.
Written by Michael Eusanio
Applications Engineer, Optimas Solutions
It&#;s common to assume a single part is stronger than an assembly of parts. However, fasteners can ensure the strength and reliability of a product, given certain considerations. For example, by tweaking the type of fastener material, size, or other specifications, manufacturing engineers can resolve torque, weight, stability, and durability concerns with no change to assembly or procedure.
One such tweak: using hardened steel washers. Replacing standard washers with hardened steel means fasteners can be more reliably tightened. In fact, research shows these fasteners can be torqued with up to 50% higher clamping pressures, resolving bolt failure issues without making significant changes to the product design.
Mild steel is a generic low-carbon material used in typical washers and fastening systems. In comparison, unhardened steel is any steel material that has not undergone the hardening process. Understanding the difference between mild, low-carbon, and unhardened and hardened steel washers can make a difference in an engineer&#;s part design. The result: fastener assemblies that are more reliable, durable, and longer lasting.
Hardened vs. unhardened flat washers
Hardened flat washers are designed for assembly with a Grade 5 or higher strength bolt between the bearing surface of the fastener and the part to which it&#;s attached. These washers are carbon steel and can be through-hardened to Rc 38-45 or carburized (case hardened) to a minimum depth of .015&#;. They have a surface hardness of 37-45 Rc with a minimum core hardness of Rc 30.
Unhardened flat washers are designed for assembly with Grade 2 or lower strength bolts or tapping screws between the bearing surface of the fastener and the part to which it&#;s attached. Narrow (SAE) and wide (USS) flat washers are available for specification, depending on the required outside diameter.
The benefits
Hardened and unhardened flat washers offer several advantages in a fastener assembly, including:
&#; Protecting the mating surface from damage during assembly
&#; Improving the stress distribution on the mating surface
&#; Spanning larger clearance holes
&#; Providing a consistent bearing surface between the mating surfaces for torquing
The standards
In hardened and unhardened flat washers, the dimensional characteristics are covered by ANSI B18.22.1*, and the mechanical properties are covered by ASTM F844. Both ANSI (the American National Standards Institute) and ASTM (formerly the American Society for Testing and Materials), develop and oversee technical standards.
Understanding the effect a washer has on the entire fastener solution and assembly is critical before deciding on the ideal match for an application. This includes the fastener material and the tool and torque used during installation.
A washer can be instrumental in adjusting torque &#; ultimately adding more strength and longevity to an assembly.
Are you interested in learning more about Heavy Duty Flat Washer? Contact us today to secure an expert consultation!