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SPRING 2013

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Distributor's Link Magazine Spring Issue 2013 / VOL 36 / NO.2

28 THE DISTRIBUTOR’S

28 THE DISTRIBUTOR’S LINK Guy Avellon Guy Avellon has been in the MRO and fastener distribution industry for over 30 years. He began his metallurgical engineering career at Republic Steel Research Center in metal coatings and has since held positions as sales engineer; Chief Engineer; Manager of Product Marketing, Product Engineering and Quality and Director of Quality and Engineering. He founded GT Technical Consultants where he performs failure analysis, presents lectures on fastener safety, worked for law firms and designs and audits Quality systems. He is a member of SAE and is Vice Chairman of the ASTM F16 Fastener Committee and Chairman of the F16.01 Test Methods Committee, since 1988. He also received the ASTM Award of Merit in 2005. Guy and his wife, Linda currently reside in Lake Zurich, IL and may be reached at 847-477-5057 or visit his website at http://www.BoltDoc.com. FASTENER STEELS Production of a ferrous cap screw using the cold heading process on an automated bolt-maker begins with the selection of the steel to be used. This is determined by the desired finished mechanical properties of the product. Hot heading is performed on larger sized fasteners and is a more manual process for specialized fasteners, but the majority of production fasteners are cold formed. The steels as supplied by the mill are produced in manufacturing runs. The production of a manufacturing run is known as a “heat”. Each heat is assigned a traceable number that is kept with the steel as it is drawn into wire forms and separated into lots. Samples from each heat are checked for quality, hardenability and composition to assure they are suitable for the particular grade of fastener for which they are intended. Refer to the ASTM F2282 for Quality Assurance Requirements for alloy steel wire. Superior quality, fine grain steels are used in cap screws manufactured in the United States and by reputable steel manufacturers abroad. These fine grained steels offer greater resistance to fracture caused by vibration, stress, and fatigue than coarse grain steels, which are much easier and less expensive to produce. Selection of Steels Carbon steels are called such as they contain a certain amount of carbon. That amount of carbon determines its ability to be heat treatable. The addition of certain alloying elements will provide the performance characteristics of the finished product. The base steel or alloy is designated by the first series of digits in the steel number, as developed cooperatively by the AISI (American Iron and Steel Institute) and the SAE (Society of Automotive Engineers), followed by the carbon content as a per cent. Typical, but not limited to, steels used for fastener products are as follows: 10xx - Plain Carbon Steel 15xx - Manganese Steel 40xx - Molybdenum Steel (0.25%) 41xx - Chromium-Molybdenum Steel (1% Cr, 0.20% Mo) 43xx - Nickel-Chromium-Molybdenum Steel 50xx - Nickel Steel (50B46) 51xx - Chromium Steel (51B60) (0.80% Cr) 87xx - Chromium-Nickel-Molybdenum Steel (0.55% Ni, 0.50% Cr, 0.25% Mo) 94xx - Nickel-Chromium-Molybdenum Steel (94B40) To be considered an alloy steel, one or more alloying elements must be added to the steel. The American Iron and Steel Institute has defined that a steel is considered to be an alloy when the maximum of the range given for the content of alloying elements exceeds one or more of the following limits: manganese, 1.65%; silicon, 0.60%; copper, 0.60%; or in which a definite minimum quantity of any of the following elements is specified or required within the limits of the recognized field of constructional alloy steels: aluminum, chromium up to 3.99%, cobalt, columbium, molybdenum 0.30%, nickel 0.30%, titanium, tungsten, vanadium 0.10%, zirconium, or any other alloying elements added to obtain a desired alloying effect. Where elements are specified in combinations of two, three or more and have alloy contents less than described above, the limit value to be applied for steel class determination is 70% of the sum of the individual values of the concerned elements. Fastener Grades Grade 2 (5.8) Cap Screws are produced from low carbon steels, typically ranging from 1018 to 1025 and are not heat treated. Grade 5 (8.8) Cap Screws are produced from several different steel types; typically ranging, but not limited, from 1032 to 1038, and is classified as a medium carbon steel or low alloy 1541 steel. Grade 5.2 Bolts and studs for automotive applications, made from low carbon boron steel. please turn to page 115

THE DISTRIBUTOR’S LINK 29

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