High Tensile Fasteners for exhaust systems


High Tensile Fasteners

Structural steel grade Bolts for exhaust systems

High tensile fasteners such as bolts are known to have a strength of about 1200 Mpa. Being the highest grade as compared to commercial or structural grade bolting, high tensile ones are used in those applications where high mechanical strength is a property that is deemed important.

Often, Structural steel fasteners are required to be treated with an external coating or a polishing to either add value or to improve some of its properties. Common finishes performed on high tensile include Zinc phosphate, Geoment and Dacromet, Flouro carbon coating and oiled. Usually zinc based finishes such as Zinc plating with white / blue / yellow / green / black passivations or even Hot dip galvanisation results in an increase in the corrosion resistance properties. Zinc based finishes also protect from getting oxidised, which in turn ensures good performance when exposed to harsh environments. Hence, they are less likely to incur mechanical damage.

Since structural bolts are designed to be strong, they won’t break easily under pressure. These grade 12.9 Bolts are intended to be used for the heaviest jobs.

Standard specification

DIN 931, 933, 5785, 5A325, GB5782, A6914, 5783, 786
Main Forms Hex, Unf/ Unc, U Bolts
  • Gr. 8.8
  • Gr. 12.9
  • Gr. 10.9
Industry Standards ASTM, IS, JIS, ASTM, GB5783, DIN, ANSI, AS, BSW, ASME, EN, DIN, DIN931, BS, ISO4017
Size M2 – M100, 6 to 500mm Length

Different coatings

  • Zinc Plating for Bolting products
  • Xylan Coating
  • Cadmium Plating

High Tensile fasteners different types

High Tensile fasteners different types

Mechanical Properties of Structural grade Bolts

Grade/ Marked Symbol Proof Load (MPa) Min. Yield Stress (MPa) Min. Tensile Stress (MPa)
8.8 580 640 800
600 660 830
10.9 830 940 1040
12.9 970 1100 1220

High Tensile Bolts Equivalent Grades Guidelines

High Tensile Fasteners
Grade Technical Description Metric Size
8.8 quenched and tempered, medium carbon steel material 16- 72mm
10.9 quenched and tempered, alloy steel material 5 - 100mm
12.9 quenched and tempered, alloy steel material 1.6 - 100mm