NF E 25-513 and NF E 25-514 share the same nominal dimensions for each series. The difference is the product grade, so choose the one your drawing or customer specifies.
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What is an NF E 25-513 washer?
An NF E 25-513 washer is a plain round flat washer made to the French AFNOR standard NF E 25-513, in product grade C. It is placed under a bolt head or nut to spread the clamping load, protect the surface and bridge slotted or oversize holes. The standard covers four series, Z, M, L and LL, which share the same bore and thickness for each thread size but have different outer diameters. Excel Trading Corporation supplies NF E 25-513 washers in SS 304 and SS 316 stainless steel.
What do series Z, M, L and LL mean on an AFNOR washer?
The series letter sets the outer diameter of the washer. Z is the narrow series (étroite), M the medium series (moyenne), L the large series (large) and LL the extra-large series (extra-large). For a given thread size, all four series have the same inner diameter and thickness, so only the bearing area changes. For example, an M8 washer has an 8.4 mm bore and 1.5 mm thickness in every series, with an outer diameter of 16 mm in Z, 18 mm in M, 22 mm in L and 30 mm in LL.
What is the difference between NF E 25-513 and NF E 25-514?
Both are French AFNOR standards for plain flat washers with the same four series and the same nominal dimensions. NF E 25-513 is product grade C, the commercial grade for general fastening, while NF E 25-514 is product grade A, the precision grade with closer dimensional tolerances for mechanical assemblies. If a drawing does not specify the grade, grade C is the usual choice for structural, sheet metal and panel work, and grade A for machinery and precision assemblies.
Is NF E 25-513 still a valid standard?
AFNOR has withdrawn NF E 25-513 and replaced it with the NF EN ISO plain washer standards, such as ISO 7091 and ISO 7093-2. However, many French and European drawings, catalogues and customer specifications still call up washers as NF E 25-513 with a series letter, so the designation remains in everyday use. When a drawing specifies NF E 25-513, supplying washers to those dimensions keeps the assembly exactly as designed.
How do I specify an NF E 25-513 washer when ordering?
State the standard, the thread size, the series and the material, for example "Washer NF E 25-513, M8, series L, SS 304". That washer has an inner diameter of 8.4 mm, an outer diameter of 22 mm and a thickness of 1.5 mm (8.4 × 22 × 1.5 mm). The series letter is the part most often left out of enquiries, and without it the outer diameter is unknown, so always include Z, M, L or LL.
Which series should I use on sheet metal or soft materials?
Use the L or LL series on thin sheet metal, aluminium, plastics, wood and composite panels, and over slotted or oversize holes. Their larger outer diameter spreads the clamp load over a wider area, which stops the material from being crushed, dished or pulled through. On solid steel parts with normal holes, the Z or M series is usually enough and keeps the joint compact.
Should I choose SS 304 or SS 316 NF E 25-513 washers?
SS 304 (A2) washers suit most indoor and normal outdoor applications, including panels, enclosures, machinery and sheet metal work. SS 316 (A4) washers contain molybdenum, which gives better resistance to chlorides, salt spray and chemicals, so they are preferred in marine, coastal, food, pharmaceutical and chemical plant applications. Always match the washer to the bolt material, A2 with A2 and A4 with A4, to avoid galvanic corrosion.
Where can I buy NF E 25-513 washers in Bangalore or India?
Excel Trading Corporation supplies NF E 25-513 AFNOR flat washers in series Z, M, L and LL, in SS 304 and SS 316, from Bengaluru to customers across India. Use the Request a Quote button on this page, call +91 7204435253 or email info@exceltrading.in with the thread size, series, material and quantity you need.
