Introduction

“Most industrial fasteners are covered by two basic standards: one for materials and properties; the other, for dimensions and tolerances. Specifications for materials and properties are published by the American Society for Testing and Materials (ASTM), although other groups such as the Society of Automotive Engineers (SAE) also publish specifications covering these requirements. Standards for dimensions and tolerances are issued by the American National Standards Institute (ANSI) in cooperation with the American Society of Mechanical Engineers (ASME) and the Industrial Fasteners Institute (IFI).Where applicable, published specifications covering a particular fastener will be referenced in the section of this booklet dealing with that fastener. When referring to standards and specifications, we will use only the well-known initials of the above societies-ANSI, ASME, IFI, ASTM and SAE”

These include a vast range of sizes and types stocked by distributors and manufacturers for an almost limitless range of applications: the assembly and maintenance of vehicles, appliances, farm equipment, construction equipment, industrial and plant machinery of all kinds, furniture and toys. Wherever thereÂ’s a need for holding parts together, holding them apart, holding them up, or holding them down, a standard fastener can usually be found to do the job efficiently and economically. Modern industrial fasteners are manufactured to a variety of standards covering dimensions, tolerances, materials, mechanical properties, testing procedures, etc.

ASME ST-LLC does not take any position with respect to the validity of any patent rights asserted in connection with any items mentioned in this document, and does not undertake to insure anyone utilizing a publication against liability for infringement of any applicable Letters Patent, nor assumes any such liability. Users of a publication are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, is entirely their own responsibility.

ASME is the registered trademark of The American Society of Mechanical Engineers

“Most ASTM and ASME standards list the steel grades by their UNS (Unified Numbering system) numbers but also make reference, where appropriate to the more general AISI (American Iron and Steel Institute) grade designations. These grade numbering systems are widely used in the USA, where they originated and are recognised by most stainless steel specifiers and users. The American Iron and Steel Institute (AISI) developed designations such as 304, 430 etc and published compositions for these in their ‘Steel Products Manual’ (1974).
These are NOT specifications, but steel grade composition ranges only.
These grades were used by the American Society Testing and Materials (ASTM) to identify grades in a wide range of standards they published for stainless products, such as sheets and plates (ASTM A240), bars (ASTM A276) and tubes (ASTM A269). The compositions of the AISI grades were made more specific with the introduction of the ‘Unified Numbering System’, jointly established by ASTM and SAE (Society of Automotive Engineers). This five digit number, preceded by the letter ‘S’ for most stainless steels, identified the specific variant of the grade”.

Strain Rate

“ASME SA-370 specification is identical with ASTM A 370. For determination of yield strength, ASME SA-370 specifies a strain rate in the reduced section not more than 0.001in./in./sec. and not less than 0.1 times the maximum rate when the stress exceeds one half of the specified yield point or yield strength. As an altern ative, the rate of stressing shall not exceed 100 ksi/min. (11.5 MPa/sec), or be less than 10 ksi/min (1.15 MPa/sec).For determination of the upper yield strength, ReH, EN 10002-1 specifies a minimum stress rate of 6 MPa/sec and a maximum stress rate of 60 MPa/sec, which are somewhat higher than the ASTM and ASME permissible strain rates”

Fasteners houses commonly sell Grades 2, 5 & 8 in industrial applications. While these grades are extremely popular, they are an SAE (Society of Automotive Engineers) specification, found commonly in automotive & commercial applications. Most plants prefer to use ASTM specifications for their industrial bolting applications, especially piping & structural applications.

Some Of The More Common ASTM Specs Relevant To The Industrial Industry Are Listed Below

  • A153 – Hot dip galvanizing specification, applying to material coating.
  • A193 – Alloy steel and stainless steel bolting materials for high temperature service; the most common spec for studs.
  • A194 – Carbon and alloy nuts for bolts for high pressure and high temperature service.
  • A307 – Carbon steel bolts and studs; “low carbon” steel.
  • A320 – Alloy steel and stainless steel bolting materials for low temperature service. A325 – Structural bolts, steel, heat treated, 120/105 ksi minimum tensile strength; considered standard strength structural bolts.
  • A354 – Quenched and tempered alloy bolts, studs, and other externally threaded fasteners.
  • A490 – Structural bolts, alloy steel, heat treated, 150 ksi tensile strength; considered high strength structural bolts.
  • A563 – Standard specification for carbon and alloy steel nuts.

ASME fasteners are used on pressure vessels. We inventory a selection of the common bolts, nuts and studs, and can ship specials on an emergency basis.

Some of the specifications we supply include :

  • ASME SA193
  • ASME SA194
  • ASME SA320
  • ASME SA354
  • ASME SA453

Heat Treatment

Heat treatment covers various techniques that may be used to develop certain end-product characteristics. Customary procedures for fasteners include annealing, stress relieving, case hardening, direct quench and temper, and carbon restoration.

Annealing

A thermal cycle involving heating to, and holding at a suitable temperature and then cooling at a suitable rate, for such purposes as reducing hardness, improving machinability, facilitating cold working, producing a desired micro-structure, or obtaining desired mechanical or other properties.

Stress Relieving

A thermal cycle involving heating to a suitable temperature, usually 1000/1200°F, holding long enough to reduce residual stresses from either cold deformation or thermal treatment, and then cooling slowly enough to minimize the development of new residual stresses.

Case Hardening

A term descriptive of one or more processes of hardening steel in which the outer portion, or case, is made substantially harder than the inner portion, or core. Most of the processes involve either enriching the surface layer with carbon and/or nitrogen, usually followed by quenching and tempering, or the selective hardening of the surface layer by means of flame or induction hardening.

Quenching And Tempering

A thermal process used to increase the hardness and strength of steel. It consists of austenitizing, then cooling at a rate sufficient to achieve partial or complete transformation to martensite. Tempering should follow immediately, and involves reheating to a temperature below the transformation range and then cooling at any rate desired. Tempering improves ductility and toughness, but reduces the quenched hardness by an amount determined by the tempering temperature used.

Fasteners houses commonly sell Grades 2, 5 & 8 in industrial applications. While these grades are extremely popular, they are an SAE (Society of Automotive Engineers) specification, found commonly in automotive & commercial applications. Most plants prefer to use ASTM specifications for their industrial bolting applications, especially piping & structural applications.