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Nuts · ISO 4161 / DIN 6923

Grade 8.8 Steel Hex Flange Nuts

Specifying Hex Flange Nuts in Grade 8.8 Steel pairs the dimensional form of Hex Flange Nuts (ISO 4161 / DIN 6923) with the engineering properties of Grade 8.8 Steel. This page explains when to choose the grade, how it behaves in service, and which grades to compare it against.

Why Choose Grade 8.8 Steel for Hex Flange Nuts

The workhorse medium-carbon alloy grade for structural joints. For hex flange nuts, this matters when requires plating (zinc) for corrosion protection is the primary requirement.

Mechanical & Physical Properties

Grade designationclass 8.8
Magnetic responseMagnetic
Service temperatureup to approx. +300 °C
Corrosion characteristicRequires plating (zinc) for corrosion protection

Galvanic & Galling Considerations

For hex flange nuts in steel, the dominant compatibility issue is hydrogen embrittlement at high property classes (10.9 and above) when electroplated. Plating must be followed by an appropriate baking treatment, or a non-electroplated finish (mechanical zinc, zinc flake) should be substituted.

Comparable Grades

For Hex Flange Nuts, class 10.9 or 12.9 is the comparable strength step. Move up when the joint preload approaches the proof load of the current class; move down when the joint is over-specified. For corrosion-critical service, switch to stainless A2 or A4.

Sizes of Hex Flange Nuts Available in Grade 8.8 Steel

SizePitch (mm)Flange diameter dc (mm)Nut height m (mm)Width across flats s (mm)Reference standard
M50.811.85.08.0ISO 4161 / DIN 6923
M61.014.26.010.0ISO 4161 / DIN 6923
M81.2517.98.013.0ISO 4161 / DIN 6923
M101.521.810.015.0ISO 4161 / DIN 6923
M121.7526.012.018.0ISO 4161 / DIN 6923
M142.029.914.021.0ISO 4161 / DIN 6923
M162.034.516.024.0ISO 4161 / DIN 6923
M202.542.820.030.0ISO 4161 / DIN 6923
M243.051.124.036.0ISO 4161 / DIN 6923

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Sends the selected values to the quote form below.

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Adjust the parameters in the drawing above and click "Request this configuration" to send the exact specification straight to this form.

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Specification
Business Information

Dimensions & Specifications (ISO 4161 / DIN 6923)

SizePitch (mm)Flange diameter dc (mm)Nut height m (mm)Width across flats s (mm)Reference standard
M50.811.85.08.0ISO 4161 / DIN 6923
M61.014.26.010.0ISO 4161 / DIN 6923
M81.2517.98.013.0ISO 4161 / DIN 6923
M101.521.810.015.0ISO 4161 / DIN 6923
M121.7526.012.018.0ISO 4161 / DIN 6923
M142.029.914.021.0ISO 4161 / DIN 6923
M162.034.516.024.0ISO 4161 / DIN 6923
M202.542.820.030.0ISO 4161 / DIN 6923
M243.051.124.036.0ISO 4161 / DIN 6923

Frequently Asked Questions

When should I move from class 8.8 to class 10.9 / 12.9 for Hex Flange Nuts?

Step up to class 10.9 / 12.9 when the joint preload approaches the proof load of the current class. The higher class adds preload at the same diameter, often saving size and weight.

Is Grade 8.8 Steel prone to hydrogen embrittlement?

Class 10.9 and above can be susceptible to hydrogen embrittlement when electroplated. Specify post-plating baking, or use mechanical-zinc / zinc-flake finishes which avoid the cathodic plating step.

Which finish is best for outdoor Hex Flange Nuts?

For outdoor service in steel, hot-dip galvanizing gives the longest life; zinc-flake (Geomet/Delta-Tone family) gives a thinner film with excellent salt-spray performance; standard zinc plating is the lowest-cost option for general indoor / shielded outdoor use.

What's the service temperature limit for Grade 8.8 Steel?

The practical service range is up to approx. +300 °C.

How do I request a quotation?

Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.