Bolt Grade 8.8 Specification Guide

Any material whose mechanical qualities satisfy or are above the specifications stated in. The pertinent harmonized standards are capable of producing a grade of 8.8. Only metric fasteners described by ISO 965 (as well as derivative standards) are covered by the two-digit nomenclature, which is not used to identify specific steel grades. Many of the producers offer various guidelines and points mentioning the measurement,  bolt grade 8.8 specification, etc. The system of designation is based on two numerals, for example, 8.8.

The tensile strength of the bolt material (N/mm2)/100 is the first number. The second figure is equal to 1/100. The proof (or yield) stress to tensile strength ratio, stated as a percentage, is equal to 100. Tensile strength / [Yield (Proof stress)] / 100 implies that a grade 8.8 bolt has a nominal yield strength of 640N/mm2 and a nominal ultimate tensile strength (UTS) of 800N/mm2 (or Mpa) (or Mpa).

Characteristic Features of Bolt Grade 8.8 Fasteners

1. 8 Stainless steel fasteners (plain, black oxide, or galvanized) will typically be in medium alloy carbon steel, with 0.30–0.50% carbon and alloyed with other elements such as molybdenum, vanadium, manganese, and occasionally boron or cobalt in trace amounts. The precise steel grade used by manufacturers may vary, but in most cases, grade 8.8 will be useful. To achieve the minimal strength specified by the harmonized requirements, these alloying elements offer the necessary mechanical qualities.
2. Grade 8.8 and higher bolts should always be distinguishable from “low-tensile bolts” by having their grade. Permanently marked on the head, as doing so unintentionally could have disastrous results.
3. Grade 4.6 bolts, often known as “low tensile” bolts, are frequently useful in the construction sector. Because they provide greater ductility and durability than high-strength bolts.
4. Keep in mind that when people talk about “high-tensile bolts,” they usually mean metric fasteners with a grade of 8.8 or higher.

To get a better idea visit the Bolt Grade 8.8 Specification chart.