][ STEEL
STRUCTURES ][
][ STEEL
STRUCTURES ][
Manufacturing Processes ------------------------------- Iron (FE - Ferrum) ductile - capable of being drawn out malleable - capable of being hammered or rolled to shape Raw Materials for Steel: Iron Ore iron oxides phosphorus silica sulfur manganese silicon Coke heated coal without volatile portions Limestone to remove impurities
Steel Production --------------------- Mining iron ore coal limestone Processing benefication or sinter coke flux crushing & screening Smelting oxygen plant (molten iron (in ladle car blast furnace (cast pig iron Refining basic oxygen furnace open hearth furnace electric furnace (steel ingots Intermediate Milling Hot rolling Cold finishing slabs plates pipe & tubing tin plate blooms structural shapes rails tube rounds seamless pipe billets bars wire cold drawn bars tube rounds seamless pipe Milling ---------- Hot-rolling Mills sheets strips 3500 ft/min (coils Cold Reducing Mills cold reduced plates & strip blackplate Electroplating annealed temper rolled zinc or tin coated
Classification by Carbon Contents: ========================= Wrought Iron: < 0.1% carbon Pig Iron < 2-4% carbon direct from blast furnace must be remelted to remove unwanted elements no structural use Cast Iron: < 2-4% carbon Steel: < 2% carbon Carbon Steel Classifications: ===================== low carbon < 0.25% medium carbon 0.25 - 0.50% high carbon > 0.50% Mild Steel similar to wrought iron billets will be rolled 0.80% strength increased ductability decreased Stainless Steel Alloy of Steel & other metals (nickel,chromium) corrosion resistant Structural Steel: ============ ASTM A36 steel Fy = 36 ksi Fu= 58 ksi
Structural Steel Shapes: ================= W Wide Flange Shapes W 12x 210 12"deep 210 lbs/ft = weight C American Standard Channels C 10 x 15.3 10" deep 15.3 lbs/ft = weight L Angles L 5 x 3 x 1/4 5" and 3" leg length 1/4" leg thickness T Structural Tees WT Structural Tees WT 12 x 52 12" deep cut from w shapes 52 lbs/ft = weight Z Zees see table 5-1 for other shapes HP bearing pile shapes S American Standard beams C American Standard channels 2:12 slope M shapes that can not be classified as W, HP, S MC channels that can not be classified as C shapes Double Angles Combination Section Structural Tubing square rectangular unfilled Steel Pipe standard extra strong double-extra strong Tubing and Pipes are available in electric resistance welded A53 Type E seamless Type S cold formed A500 hot formed A501 high-strength low-alloy A618 Bars 6" or less in width 0.203 in and over in thickness over 6" to 8" in width 0.203 in and over in thickness square round Plates over 8 in to 48 inch in width 0.203 in and over in thickness over 48 in in width 0.180 in and over in thicknes sheared plates - trimmed on all edges universal (UM) plates - trimmed on ends only stripped plates - cut from wider plates floorplates - raised patterns Crane Rails 104 - 175 lb ASCE Bethlehem light 40 lb rails 30 ft 60-lb rails 30,33,39 ft length crane rail splices Gages: ===== 12 0.1046" 7/64" 16 0.0598 1/16" 18 0.0478 3/64" 22 0.0299 1/32" Stainless steel alloys: =============== 302 Chrome nickel stainless steel for all architectural purposes 305 Bolts & Nuts 316 Salt water applications 430 Chromium stainless steel used for interior work least expensive Stainless Steel Finishes ================= 1 Unfinished annealed pickled 2D Nonreflective 2B Bright Matte use special rolls Scratch simulated polished see table 5-4 for others Construction Specification Institute (CSI) ============================= Masterformat Division 5 Metals 05200 Metal Joists 05300 Metal Decking 05400 Cold formed metal framing Production Processes: ================ wire formed by pulling = drawing extrusion similar to drawing other than round shapes casting pouring molten steel into a mold forging pounding into a mold Reworked by: ========== cutting shearing sawing punching flame cutting machining drilling planing grinding routing turning on a lathe bending of ductile material like: sheets plates linear elements stamping similar to forging punched into a mold to form three-dimensional shape rerolling reworking a linear element into a curved form (arched) Assembled: ======== fitting threated parts interlocking techniques tongue-and-groove friction clamping wedging squeezing pinning pin-type device bolt rivet pin nailing nails screws welding gas electri adhesive bond chemical bonding susion of the material
