Head Markings

Metric Bolt Class

Mechanical Properties

Proof Load (MPa)

Min Yield (MPa)

Min Tensile Strength (MPa)

MonsterBolts | Grade 8.8 Metric Hex Bolts

Class 8.8

Medium carbon steel, quenched and tempered

580-600

640-660

800-830

MonsterBolts | Grade 10.9 Metric Hex Bolts

Class 10.9

Alloy Steel, quenched and tempered

830

940

1040

MonsterBolts | Grade 12.9 Heavy Duty Metric Hex Bolts

Class 12.9

Alloy Steel, quenched and tempered

970

1100

1220

MonsterBolts | Grade A2 Stainless Metric Hex Bolts

A2 Stainless

Also called 18-8 or type 304 stainless steel*

N/A

210 Min.

450 Typical

500 Min.

700 Typical

Proof Load: An axial tensile load which the product must withstand without evidence of any permanent set.

Yield Strength: The maximum load at which a material exhibits a specific permanent deformation

1MPa = 1N/mm2 = 145 pounds/inch2

Tensile Strength: The maximum load in tension (pulling apart) which a material can withstand before breaking or fracturing.

* Stainless markings often vary, though commonly stamped A-2. Most stainless is non-magnetic, though 410 Hardened stainless is ALWAYS magnetic.