Steel Glossary
Carbon Steels
Carbon steel – Steel combined with varying amounts of carbon. Has no specified minimum quantity for any alloying element (other than the commonly accepted amounts of manganese, silicon, and copper) and contains only an incidental amount of any element other than carbon, silicon, manganese, copper, sulfur, and phosphorus
Alloy Steels
Alloy steels are derivatives of carbon steels where elements are added or deleted to yield certain properties. Typically these properties include machinability, wearability, and strength. An iron-based mixture is considered to be an alloy steel when manganese is greater than 0.165%, silicon over 0.5%, copper above 0.6%, or other minimum quantities of alloying elements such as chromium, nickel, molybdenum, or tungsten are present
Tool Steels
Tool Steel – Any of a class of carbon and alloy steels commonly used to make tools. Tool steels are characterized by high hardness and resistance to abrasion, often accompanied by high toughness and resistance to softening at elevated temperatures. These attributes are generally attained with high carbon and alloy contents.
| ELEMENT | EFFECT ON STEEL |
|---|---|
| Aluminum | Deoxidizes and restricts grain growth |
| Boron | Increases hardenability |
| Carbon | Increases hardenability and strength |
| Chromium | Increases corrosion resistance, hardenability, and wear resistance |
| Lead | Increases machinability |
| Manganese | Increases hardenability and counteracts brittleness from sulfur |
| Molybdenum | Deepens hardening, raises creep strength and hot hardness, enhances corrosion resistance, and increases wear resistance |
| Nickel | Increases strength and toughness |
| Phosphorus | Increases strength, machinability, and corrosion resistance |
| Silicon | Deoxidizes, improves electrical and magnetic properties, increases hardness, and oxidation resistance |
| Sulfur | Increases machinability but reduces hot forming characteristics |
| Titanium | Forms carbides and reduces hardness in stainless steels |
| Tungsten | Increases wear resistance, hot strength, and hot hardness |
| Vanadium | Increases wear resistance, strength, hot hardness, and refines grain structure |
Quenching (Rapid Cooling)
When applicable, the following more specific terms should be used: Direct Quenching, Fog Quenching, Hot Quenching, Interrupted Quenching, Selective Quenching, Slack Quenching, Spray Quenching, and Time Quenching.
Direct Hardening
Through hardening is applied to medium and high carbon parts that possess sufficient carbon content for hardening through the entire depth of the part. The parts are heated and quenched (cooled) to fix the structure of the part in a hardened state
Case hardening
Case hardening (or indirect hardening) is applied to low-carbon content steel parts to increase surface hardness. During case hardening, carbon molecules are introduced to the part via solids, liquids, or gases in a process known as carburizing.
Stress relieving
Annealing designed to relieve internal stresses caused by machining, welding, casting, cold working, quenching, or normalizing
Tempering
Heating a quench-hardened or normalized ferrous alloy to a temperature below the transformation range to produce desired changes in properties.
Annealing
Softening a metal by heating it to and holding at a controlled temperature, then cooling it at a controlled rate. Also performed to produce simultaneously desired changes in other properties or in microstructure. The purposes of such changes include improvement of machinability, facilitation of cold work, improvement of mechanical or electrical properties, and/or increase in stability of dimensions.
Hardness Tester
Tool designed to record the amount of pressure required to form an indentation in a material. A variety of scales are used to measure hardness, with the Rockwell C and the Brinell hardness scales being the most frequently encountered in the shop or plant
Ultrasonic Testing
A nonconductive test applied to sound-conductive materials having elastic properties for the purpose of locating inhomogeneities or structural discontinuities within a material by means of an ultrasonic beam
