ASME B18-12:2001 pdf free download GLOSSARY OF TERMS FOR MECHANICAL FASTENERS
1 INTRODUCTION
1.1 Scope This Standard is a summary of nomenclature and terminology currently used to define and/or describe mechanical fasteners, related characteristics, and the manufacturing processes that produce these products. Utilization of these terms by manufacturers and consum- ers is intended to reduce or eliminate confusion and serve as a sound basis for communication.
(a) Primary Operations. Mechanical fasteners are produced by forming or screw machine operations. Forming is generally scrapless and, depending upon size, may produce fasteners at rates exceeding 500 pieces per minute. Screw machining, although more tightly toleranced, is significantly slower and generates scrap because it involves the removal of material.
(b) Secondary Operations. Fasteners generally un- dergo several secondary operations or processes such as thread rolling, heat treating, or plating.
(c) Fastener. A fastener is a mechanical device designed specifically to hold, join, couple, assemble, or maintain equilibrium of single or multiple compo- nents. The resulting assembly may function dynamically or statically as a primary or secondary component of a mechanism or structure. Based on the intended application, a fastener is produced with varying degrees of built-in precision and engineering capability, ensuring adequate, sound service under planned, preestablished environmental conditions.
(d) Bolts, Studs, Screws, Nuts, Washers, Rivets, Pins, and Custom Formed Parts. These items are the general product families in which mechanical fasteners are best classified. Within each product family are numerous types that may have a name conforming to the technical language of a national standard or alternately may have a name that has its origins in commercial or marketing nomenclature often taken from its intended application. Such names, for example, include the “stove bolt” and “carriage bolt.” Because mechanical fasteners are used in just about every mechanical assembly, they necessarily have been designed to meet a broad range of applications from watch and computer assembly to the space shuttle design. The names given to fasteners appear to be as limitless as the designer’s imagination.While many fasteners may look alike,they generallyhave defined engineered capabilities based upon theirintended application.
1.2 Referenced Documents
In the development of this Standard, a number ofterms were written based upon language found inmore than 230 standards and other publications of thefollowing organizations:
(a) American Society for Testing and Materials(ASTM)，100 Barr Harbor Drive，West Conshohocken,PA 19428-2959
(b)The American Society of Mechanical Engineers(ASME)，Three Park Avenue，New York,NY10016-5990
(c) Industrial Fasteners Institute (IFD,1717 EastNinth Street，Suite 1105,Cleveland,OH 44114-2879(d) Society of Automotive Engineers (SAE)，400Commonwealth Drive，Warrendale，PA 15096-00O1
2TERMINOLOGY
2.1 Basic Fastener Terminology
2.1.1 commercial fastener: manufactured to pub-lished consensus standards and stocked by manufactur-ers or distributors.
2.1.2 compression fastener: a fastener whose primaryfunction is to resist compressive forces.
2.1.3 endurance limit or endurance strength: themaximum alternating stress that a fastener can withstandfor a specified number of stress cycles without failure.
2.1.4 headed fastener: a fastener having one endenlarged or formed.
2.1.5 headless fastener: a fastener，either threadedor unthreaded, that does not have either end enlarged.
2.1.6 high strength fastener: a fastener having hightensile and shear strengths attained through combina-tions of materials，work-hardening, and heat treatment.
These fasteners usually have a tensile strength in excess of 120,000 psi.
2.1.7 lockpins and collars: a headed and externally grooved mechanical device designed for insertion through holes in assembled parts. A cylindrical collar is swaged into the external groove as the lock pin is hydraulically tensioned. Collars are either smooth bored or may contain a fit-tab. An optional flange provides a built-in washer.
2.1.8 mechanical properties: identify the reaction of a fastener to applied loads. Rarely are the mechanical properties of the fastener those of the raw material from which it was made. Properties such as tensile and yield strengths, hardness, and ductility will vary widely, depending upon choice of manufacturing meth- ods and metallurgical treatments.
2.1.9 modified standard: a part that is standard with one or more of its features or characteristics slightly changed. Such a part is normally ordered to a customer’s print is used by that customer in a particular application, but the part is such that any interested manufacturer can produce it.
2.1.10 nonstandard fastener or special fastener: a fastener that differs in size, length, configuration, material, or finish from established and published standards.
2.1.11 physical properties: inherent in the raw mate- rial and remain unchanged, or with only slight alteration in the fastener following manufacture. Such properties are density, thermal conductivity, and magnetic susceptibility.
2.1.12 Part Identifying Number (PIN): a 21-character code that identifies an ASME B18 manufactured product by specific characteristic fields such as fastener family identification, B18 standard identification, fastener style or type, thread series, nominal diameter, nominal length or dimensional/other characteristics, material and treat- ment, plating, coating, and passivation and special features relevant to the fastener product.
2.1.13 precision fastener: manufactured to close dimensional and geometric tolerances.
ASME B18-12:2001 pdf free download
