Half Hard Temper
(A) No. 2 Temper. In low carbon cold-rolled strip steel, produced by cold rolling to a hardness next to but somewhat softer than full hard temper. (B) In brass Stainless Steel Strip, tempers are based on minimum tensile or yield strength. For Chromium-Nickel grades Half-Hard Temper 150,000 TS., 110,000 YS. Min.

Hammer Forging
Forging in which the work is deformed by repeated blows. Compare with press forging.

Hard Drawing
Drawing metal wire through a die to reduce cross section and increase tensile strength.

Hard Drawn
Wire or tubing drawn to high tensile strength by a high degree of cold work.

Hard Drawn Spring Steel Wire
A medium high carbon cold drawn spring steel wire. Used principally for cold springs.

The ability of a metal, usually steel, to harden in depth as distinguished from the terms “hardness.” 

Hardened & Tempered Spring Steel Strip
A medium or high carbon quality steel strip which has been subjected to the sequence of heating, quenching and tempering.

Degree to which a metal will resist cutting, abrasion, penetration, bending and stretching. The indicated hardness of metals will differ somewhat with the specific apparatus measuring hardness. (See Brinell Hardness, Rockwell Hardness, Vickers Hardness, Scleroscope Hardness) Tensile Strength also is an indication of hardness.

See Heads (Dished) for more information.

Hard Temper
(A) For Steel see Full Hard Temper.
(B) In brass mill terminology. Hard Temper is four B & S numbers hard or 37.1 % reduction.

  • WHAT
    Process that increases the hardness of steel, i.e., the degree to which steel will resist cutting, abrasion, penetration, bending, and stretching.

  • WHY
    The increased endurance provided by hardening makes steel suitable for additional applications.

  • HOW
    Hardening can be achieved through various methods, including (1) heat treatment, where the properties of steel are altered by subjecting the steel to a series of temperature changes; and (2) cold working, in which changes in the structure and shape of steel are achieved through rolling, hammering, or stretching the steel at a relatively low temperature.

Heat (of steel)
A batch of refined steel. A basic oxygen or electric furnace full of steel. One heat of steel will be used to cast several slabs, blooms or billets.

Heat Number
The identification that describes the origin of the slab (heat).

Heat Tinting
Coloration of a metal surface through oxidation by heating to reveal details of structure.

Heat Treatment

  • WHAT
     Altering the properties of steel by subjecting it to a series of temperature changes.
  • WHY
    To increase the hardness, strength, or ductility of steel so that it is suitable for additional applications.
  • HOW
    The steel is heated and then cooled as necessary to provide changes in the structural form that will impart the desired characteristics. The time spent at each temperature and the rates of cooling have significant impact on the effect of the treatment.

Heat affected zone (HAZ)
The part of the parent metal which is metallurgically affected by the heat of welding or thermal cutting but not melted. (Also known as the zone of thermal disturbance).

Heavy Structural Shapes
A general term given to rolled flanged sections that have at least one dimension of their cross sections three inches or greater. The category includes beams, channels, tees and zees if the depth dimension is three inches or greater, and angles if the length of the leg is three inches or greater.

The oxide of iron of highest valency which has a composition close to the stoichiometric composition Fe2O3.

High Brass
65% - A copper-zinc alloy containing 35% zinc. Possesses high tensile strength and is used for springs, screws, rivets, etc.

High-Carbon Steel
Steel with more than 0.3% carbon. The more carbon that is dissolved in the iron, the less formable and the tougher the steel becomes. High-carbon steel's hardness makes it suitable for plow blades, shovels, bedsprings, cutting edges, or other high-wear applications.

High Strength
Product intended for applications where greater strength is critical.  High Strength typically begins at 35 ksi minimum yield strength.
High Strength Low Alloy (HSLA)
A specific group of steels in which the strength levels are achieved by the addition of moderate amounts of alloying elements.  The most common are columbium, vanadium or titanium.
High Temperature Hydrogen Attack
A loss of strength and malleability of steel due to high temperature reactions of absorbed hydrogen with carbides in the steel, resulting in decarburisation and internal fissuring.
Hollow Structural Sections
A high-strength, cold-formed steel tubing used in used for structural purposes in a broad range of applications. Its biggest advantage is the high strength-to-weight ratio it possesses.
Holding at high temperature to eliminate or decrease chemical segregation by diffusion.
Homogenizing Annealing
An annealing treatment carried out at a high temperature, approaching the solidus temperature, for a sufficiently long time that inhomogeneous distributions of alloying elements are reduced by diffusional processes.

Hooke’s Law
Stress is proportional to strain in the elastic range. The value of the stress at which a material ceases to obey Hooke’s law is known as the elastic limit.

Hose protector
A small non-return valve fitted to the blow-pipe end of a hose to resist the retrogressive force of a flashback.

Hot Band (Hot-Rolled Steel)
A coil of steel rolled on a hot-strip mill (hot-rolled steel). It can be sold in this form to customers or further processed into other finished products.

Hot Briquetted Iron (HBI)
Direct reduced iron that has been processed into briquettes. Instead of using a blast furnace, the oxygen is removed from the ore using natural gas and results in a substance that is 90%-92% iron. Because DRI may spontaneously combust during transportation, HBI is preferred when the metallic material must be stored or moved.

Hot Dip
In steel mill practice, a process whereby ferrous alloy base metals are dipped into molten metal, usually zinc, tin or terne, for the purpose of fixing a rust resistant coating.

Hot End
The section of a steelmaking complex from the furnace up to, but not including, the hot-strip mill.

Hot Metal
The name for the molten iron produced in a blast furnace. It proceeds to the basic oxygen furnace in molten form or is cast as pig iron.

Hot Rolled Sheet
Steel sheet that is processed to its final thickness by rolling at high temperatures on a specially designed hot-rolling facility.  Also commonly known as hot rolled unprocessed.
Hot Rolled Sheet Non-Temper Rolled
A U. S. Steel definition for product supplied as a coil directly off the Hot Strip Mill with no additional processing.
Hot Rolled Sheet Pickled
A U. S. Steel definition for a mill edge coil that is pickled, oiled and temper rolled with coil ends cropped back to meet gauge tolerances.
Hot Rolled Sheet Pickled Non-Temper Rolled
A U. S. Steel definition for a mill edge coil that is pickled and oiled with coil ends cropped back to meet gauge tolerances.
Hot Rolled Sheet Products
Flat steel products that are brought to final thickness by rolling through a Hot Strip Mill at high temperatures.

Hot Short
Brittleness in hot metal.

Hot-Strip Mill
A rolling mill of several stands of rolls that converts slabs into hot-rolled coils. The hot-strip mill squeezes slabs, which can range in thickness from 2-10 inches, depending on the type of continuous caster, between horizontal rolls with a progressively smaller space between them (while vertical rolls govern the width) to produce a coil of flat-rolled steel about a quarter-inch in thickness and a quarter mile in length.

Hot Top
(See Sinkhead)

Hot Working
Plastic deformation of metal at a temperature sufficiently high not to create strain hardening. The lower limit of temperature for this process is the re-crystallization temperature.

A forming process in which a tube is placed into a forming die. The tube is then formed to the shape of the die through the application of internal water pressure. The hydroforming process allows for severe shape deformation, making it ideal for automotive structural parts such as engine cradles, radiator supports and body rails. Various shaped and sized holes can be punched in the tube almost anywhere during the process.

Hydrogen Embrittlement
(1) Brittleness of metal, resulting from the occlusion of hydrogen (usually as a by-product of pickling or by co-deposition in electroplating).
(2) A condition of low ductility resulting from hydrogen absorption and internal pressure developed subsequently. Electrolytic copper exhibits similar results when exposed to reducing atmosphere at elevated temperature.

Hydrogen-Induced Cracking
Stepwise internal cracks that connect adjacent hydrogen blisters on different planes in the metal, or to the metal surface.

Hydrogen Stress Cracking
Cracking of a metal resulting from the combination of hydrogen and tensile stress.

Hypereutectoid Steel
A steel having more than the eutectoid percentage of carbon. (See Eutectoid Steel)

Hupoeutectoid Steel
Steel with less than eutectoid percentage of carbon. (See Eutectoid Steel)

Processes for producing DRI and HBI developed by Hylsa. The processes reduce iron ore lump or pellets with reformed natural gas in a vertical shaft furnace. The HYL I process uses four fixed-bed reactors; HYL III uses a single-shaft furnace.