1. DIN 976 Threaded Rod – Hot Dip Galvanized (HDG)
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DIN 976 specifies continuously threaded studs and threaded rods with ISO metric screw threads. DIN 976-1 covers standard metric threads manufactured to ISO metric thread dimensions and tolerances. Threaded rods are commonly supplied in carbon steel, alloy steel, stainless steel, and hot dip galvanized finishes for structural, mechanical, and infrastructure applications

1. Thread Tolerance Class

Standard threaded rods are normally supplied with

External Thread Tolerance: 6g

This is the standard tolerance class for general bolt and nut assemblies with normal engagement length.

For hot dip galvanized threaded rods:

• Threads are manufactured undersize before galvanizing.
• Final thread dimensions must comply with ISO 10684 and ISO 965-4.
•  Typical thread class after galvanizing: 6az.
•  Mating nuts are generally tapped oversize to 6AZ or 6AX. 

1. Hot Dip Galvanizing Requirements

Coating Standard

Hot dip galvanizing shall comply with:

ISO 10684

The zinc coating is applied after threading and excess zinc is removed by centrifuging/spinning. 

Coating Thickness

1. Typical minimum coating thickness:

Diameter Range Minimum Coating Thickness

M8 – M10 40 μm

M12 – M24 50 μm

M27 – M64 55–70 μm

ISO 10684 states hot dip galvanized fasteners always have coatings exceeding 40 μm. 

1. Dimensional Tolerances

Rod Length Tolerance

For cut threaded rods:

Length (mm) Tolerance

1000 ±1.0 mm

2000 ±2.0 mm

3000 ±2.0 mm

Unless otherwise specified by purchaser.

1.  Major Diameter Tolerances (External Thread 6g)

The following values represent typical ISO 965 limits used for DIN 976 threaded rods.

Thread Size Maximum Major Diameter (mm) Minimum Major Diameter (mm)

M8 7.972 7.760

M10 9.968 9.732

M12 11.966 11.701

M16 15.962 15.682

M20 19.958 19.623

M24 23.954 23.577

M30 29.947 29.503

M36 35.940 35.433

These values correspond to ISO metric thread tolerance class 6g. 

1. Thread Geometry

ISO Metric Thread Profile:

1. Included angle = 60°
2. External thread class = 6g
3. Internal thread class = 6H
4. Nominal diameter designated by “M”
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8.  Standard Weight Chart

Approximate theoretical weight of carbon steel threaded rod.

Density = 7.85 g/cm³

Size Weight (kg/metre)

M6 0.177

M8 0.314

M10 0.490

M12 0.709

M16 1.260

M20 1.970

M24 2.840

M27 3.600

M30 4.440

M36 6.390

M42 8.700

M48 11.400

M56 15.500

M64 20.300

1. Mechanical Properties

Typical property classes:

Material Grade Yield Strength (MPa) Tensile Strength (MPa)

4.6 240 400

5.8 400 500

8.8 640 800

10.9 940 1040

As specified in ISO 898-1. 

1. Inspection Requirements

Inspection shall include:

•  Major diameter verification
•  Pitch diameter verification
•  Thread gauge testing
•  Length measurement
•  Zinc coating thickness measurement
•  Visual inspection for coating defects
•  Mechanical property verification