G | Index | I
Hadfield Manganese Steel
A specially steel which is austenitic and usually contains approximately 12% Manganese. It is used in mining, earth- moving equipment and in railroad track work.
Hardenability
In a ferrous alloy, the property that determines the depth and distribution of hardness induced by quenching.
Hardness
Resistance of a material to indentation as measured by such methods as Brinell, Rockwell, and Vickers. The term hardness also refers to stiffness of a material, or its resistance to scratching, abrasion, or cutting.
Head Metal
The reservoir of metal in the feeder or riser of a mold.
Heat
The total amount of metal produced which can be represented by one analysis sample and one set of mechanical tests.
Heat Treatment
A combination of heating and cooling operations and applied to a metal or alloy to produce desired properties and microstructures.
High-Alloy Steel
Ferrous alloy with more than 12 weight percent of noncarbon additions.
High Pressure Mold
A strong high-density mold, made by air, hydraulic, or other squeeze process.
High Stress Grinding Abrasion
Abrasion that occurs when the abrasive is crushed between two opposing surfaces.
Hindered Contraction
Casting contraction during solidification and cooling which is hindered by mold or core restraints.
Hollow Drill Test (Trepanning)
Removing a cylindrical sample from a metal section or structure to determine soundness of the section.
Homogenizing
A process of heat treatment at high temperature intended to eliminate or decrease chemical segregation by diffusion.
Horizontal Axis Casting Machine
A centrifugal casting machine in which the axis of rotation of the mold is horizontal.
Hot Box Process
A furan resin-based process similar to shell coremaking; cores produced with it are solid unless mandrelled out.
Hot Strength (Sand)
Tenacity (compressive, shear or transverse) of a sand mixture determined at any temperature above room temperature.
Hot Tear
A crack or fracture formed prior to completion of metal solidification as a result of hindered contraction. A hot tear is frequently open to the surface of the casting and is commonly associated with design limitations.
HSLA
High Strength Low Alloy Steel. Steel with relatively high strength and impact properties. The carbon level is low and the alloying additions are significantly less than 5 weight percent.
Hydrogen Embrittlement
A condition of low ductility resulting from the absorption of hydrogen. A time dependent fracture process which results in a loss of ductility.
Hypereutectoid Steel
A steel containing more than the eutectoid percentage of carbon (0.83 wt. %).
Hypoeutectoid Steel
A steel containing less than the eutectoid percentage of carbon (0.83 wt. %).
Hysteresis (Cooling Lag)
Difference between the critical points on heating and cooling due to tendency of physical changes to lag behind temperature changes.