Fastener Literature Review

Chapter 1

Introduction

Fasteners are integral part of any Automotive industries. A Fastener is a mechanical device which fixes or joins two or more objects together like bolts,nuts,screws,studs,rivets, etc. They provide flexibility in engineering design and ease of maintenance. The fastener making practices, inspection systems and application conditions always decide extent of problems encountered. Present Conditions does not allow for any downtime for rework or replacement. One of the most important failure is just due to improper selection of Fastener material, followed by improper Heat Treatment. [1]

A fastener is normally subjected to variety of loading viz. static and dynamic loading. The type of static load may be tensile, shear, bending,

These all factors make Fasteners weak or sometimes even impossible to function properly.
Even fasteners being perfect, still most of them tends to fail. The main causes of these are mostly due to improper assembling of Fasteners.
Analyzing these fasteners shows us where in the process we went wrong, so this is an important stage after failure. [1]

Chapter 2
Literature Review
2.1 Introduction
A fastener is normally subjected to variety of loading viz. static and dynamic loading. The type of static load may be tensile, shear, bending, torsional or combination thereof whereas the dynamic load is most often of fatigue type arising out of vibrations and rotating force. [1]
2.2 Processing of Fasteners
Processing is generally done in 4 stages:
2.2.1. Material Selection
Material selection depends totally on application of Fastener, which is further decided on Physical Properties and Chemical composition.
2.2.2. Fabrication of Fasteners [3]
This process can be done with the help of different process like Hot/Cold rolling, drawing,etc which again depends on type of Bolt to be

The heat transfer from the part to the fluid is mostly due to convection and some boiling heat transfer for liquids (water, oils and polymers).
2.2.3.B Hardening followed by Tempering
The use of this treatment will result in an improvement of the mechanical properties, as well as an increase in the level of hardness, producing a tougher, more durable item. Alloys are heated above the critical transformation temperature for the material, then cooled rapidly enough to cause the soft initial material to transform to a much harder, stronger structure.
Alloys may be air cooled, or cooled by quenching in oil, water, or another liquid, depending upon the amount of alloying elements in the material. Hardened materials are usually tempered or stress relieved to improve their dimensional stability and toughness.
Tempering is done to develop the required combination of hardness, strength and toughness or to relieve the brittleness of fully hardened steels. Steels are never used in the as quenched condition. The combination of quenching and tempering is important to make tough parts.
2.2.3.C