Are domestic flat washers a standard stock item?

Standard flat washers are a mass-produced item that Portland Bolt stocks as an accessory to accompany custom sized bolts we manufacture. A washer is a steel ring placed under a nut and/or bolt head to spread the pressure when the assembly is tightened. A washer also creates a smooth bearing surface for the nut to turn against. There are two common grades of flat washers used in the construction industry, and they differ in strength, chemistry, size, application, and material origin.

F844 washer (left), F436 (right)
F844 washer (left), F436 washer (right)

ASTM F844 Flat Washer – Also referred to as a USS pattern cut washer, these washers are intended for general use and are typically paired with low strength fasteners. These washers have no chemical or strength requirements, and simply must be made from steel. F844 washers, unless otherwise specified, conform to dimensional requirements outlined in ASME B18.21.1, Type A and have a relatively large outside diameter compared to F436 washers. F844 washers require no identifying markings. Most washer manufacturers currently producing F844 flat washers have moved to using imported steel, making 100% domestic F844 standard flat washers unavailable unless they are specially ordered at a significantly higher price and extended lead time.

ASTM F436 (Type 1) Hard Washer – Also referred to as hardened washers, these circular washers are high strength and typically used with heat-treated structural bolts, F1554 anchor bolts, and most other high strength fasteners. F436 washers have a small outside diameter compared to F844 washers and have specific chemical and hardness requirements. These washers are strengthened either through a heat treating or carburizing process. This specification requires washers to be marked with a symbol, or other distinguishing marks, to identify the manufacturer or private label distributor, as appropriate. Many also choose to mark these washers with “F436” although that is not a requirement of the specification. Most F436 hard washer manufacturers use domestically manufactured steel, resulting in 100% domestic F436 hard washers. In addition to circular F436 Type 1 washers, the specification outlines requirements for clipped, beveled, extra thick, and circular Type 3 (weathering steel).

As stated above, standard F844 washers are no longer mass produced with 100% domestic origin in many sizes and with a hot-dip galvanized finish. This can create problems when these washers are needed for jobs requiring 100% domestic products, including federally funded highway projects, some government and military projects, and other jobs that typically involve federal funding. When domestic F844 washers are required, there are three common solutions:

  • Substitute: F436 hardened washers can often be used in lieu of F844 washers. The one concern is that F844 washers have a significantly larger outside diameter than F436 washers. If the customer and/or engineer approve the substitution, that is the simplest solution. As always, avoid liability issues by getting any substitution approved by the Engineer of Record.
  • Custom Manufactured Washers: ASTM F844 flat washers can be custom manufactured in small runs using domestically produced steel. However, there will be a significant price difference and a longer lead time involved in manufacturing domestic washers versus the mass-produced F844 washers that are made from imported steel.
  • Import Allowance: Most Buy American projects have a small import allowance that is used for materials that are either simply not available domestically or for products in which there is a significant difference between the price of domestic versus import. The price of imported F844 cut washers is very small and a portion of the  import allowance is often used on this type of product.

F844 Versus F436 Mass-Produced Washer Comparison

F844 F436
Application General purpose paired with low strength bolts. Used with structural bolts, F1554 anchor bolts, and other high strength fasteners.
Chemistry No requirements other than made from steel. Carbon steel with specific chemical requirements.
Strength No strength requirements Specific HRC hardness requirements
Size Relatively large outside diameter Relatively small outside diameter
Origin Imported steel / domestic manufacture 100% domestic
Markings No identifying makings required Manufacturer or private label distributor identifier with “F436” optional
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2 comments

    @V.S. Kinser. Thank you for the feedback and we appreciate your business. We look forward to working with you again in the future.

    Mr. Lindsay,
    Your article written November 12, 2015 regarding the flat washers, F844 and F436, was interesting and informative to me. I am a metal artisan who is interested in the creations having structural Integrity. I have ordered hard to find items from your company before and I look forward to the information Portland Bolts provides in their newsletters.
    Thank you very much.
    Sincerely,
    An avid reader/follower

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