Steel METALLURGY Steel High strength machined formed easily

Steel METALLURGY

Steel -High strength, machined & formed easily, readily available & reasonably priced -Steel is primarily iron 90 -99% -Carbon content of just above 0 up to 2% -Above 2% is called cast iron -The carbon is dissolved into the steel -Most steels have btwn. 15 -1. 0% carbon -The more carbon the less ductile but stronger and harder

Steel Numbering System Consists of 4 -5 numbers First number-type of steel Second # - % of main alloying element Last 2 -3 numbers=carbon content

Alloying Elements Most steels do contain other ingredients called alloying elements besides iron & carbon (usually no more than 2% per element) These alloying elements are in small amounts, but effect the steel greatly Carbon, Manganese, Nickel=strength Chromium, Copper=corrosion resistance Sulfur, Lead=Machinability

Types of Steel Most steel classified as carbon steel or alloy steel Carbon steel-few alloying elements so less expensive Alloy steel-special qualities like increased strength, corrosion resistance Carbon steel classified as low-carbon, medium-carbon, high carbon

Types of alloy steel-structural & maraging steels Other types of steel-stainless steels, tool steels, spring steels 90% of all steel is carbon steel

Carbon Steel Most Common Used Steel • Carbon Range----. 05% to 1. 5% Iron Range---99. 95% to 98. 5% Carbon Iron • Low/Mild Carbon Steel. 05% to. 35% . 95% to 99. 65% • Medium Carbon Steel. 35% to. 50%_ 99. 65% to 99. 50% • High Carbon Steel 99. 50% to 99. 00% . 50% to 1. 00%_

Low-Carbon Steel Largest percentage of carbon steel is low-carbon Contains btwn. 05 -. 35% carbon Not as strong & hard Easy to machine & form Less expensive Nails, auto body, sheets, angle, tubes

Medium-Carbon Steel Contains. 35 -. 5% carbon Heat treatable for strength and hardness More expensive Axles, crank shafts, rebar, bolts

High-Carbon Steel Contains. 5 -1. 5% carbon Heat treatable More expensive Difficult to weld because of distortion and cracking Drill bits, shear blades, files, railroad wheels

Alloy Steel Grade of steel in which 1 or more alloying elements have been added in larger quantities to produce special properties such as high strength, corrosion resistance & wear resistance

Quench & Temper Structural Steel Stronger Better impact resistance at lower temp. More corrosion resistance Structural applications Pressure vessels, submarine bodies

Stainless Steel Extremely resistant to corrosion High strength & toughness Contains at least 11. 5% chromium, some contain nickel Used for sanitary requirements in food processing

Spring Steel Special classification of steel that has excellent hardness, strength, and elasticity Carbon content of. 35 -1. 4% Springs, golf clubs, blades, trowels, measuring tapes

Cast Iron Primarily iron & 2 -6% carbon, silicon also added Easy to machine High compressive strength, good wear resistance Frames of large equipment, engine blocks, brake drums, rollers, crushers, furnace grates & in ornamental applications

Types of Cast Iron Gray cast iron-most common & cheapest White cast iron-extremely hard & brittle, used for parts subjected to extreme wear & abrasion Malleable cast-annealed after casting to slightly soften, tougher and more impact resistant