Terms used in the Metals Industry
There are 182 entries in this glossary.H
| Term | Definition |
|---|---|
| Hardness |
Resistance to plastic deformation, usually measured by indentation. |
| Hardness, Brinell |
The Brinell scale characterizes the indentation hardness of materials through the scale of penetration of an indenter, loaded on a material test-piece. It is one of several definitions of hardness in materials science. Proposed by Swedish engineer Johan August Brinell in 1900, it was the first widely used and standardized hardness test in engineering and metallurgy. The large size of indentation and possible damage to test-piece limits its usefulness. The typical test uses a 10 mm diameter steel ball as an indenter with a 3,000 kgf (29 kN) force. For softer materials, a smaller force is used; for harder materials, a tungsten carbide ball is substituted for the steel ball. |
| Hardness, Rockwell |
The Rockwell scale is a hardness scale based on the indentation hardness of a material. The Rockwell test determines the hardness by measuring the depth of penetration of an indenter under a large load compared to the penetration made by a preload. There are different scales, which are denoted by a single letter, that use different loads or indenters. The result, which is a dimensionless number, is noted by HRX where X is the scale letter. |
| Heat Treatment |
Heating and cooling a solid metal or alloy in such a way as to obtain desired conditions or properties. Commonly used as a shop term to denote a thermal treatment to increase strength. Heating for the sole purpose of hot working is excluded from the meaning of this definition. |
| Heat-Exchanger Tube |
A tube for use in apparatus in which fluid inside the tube will be heated or cooled by fluid outside the tube. The term usually is not applied to coiled tubes or to tubes for use in refrigerators or radiators. |
| Heat-Treat Stain |
A discoloration due to oxidation of the metal surface during thermal treatment. |
| Heat-Treatable Alloy |
An alloy which may be strengthened by a suitable thermal treatment. |
| Herringbone Streaks |
Elongated alternate bright and dull markings at an angle to the rolling direction and having the appearance of a herringbone pattern. |
| Homogenizing |
A high temperature soaking treatment to eliminate or reduce segregation by diffusion. |
| Hot Working |
Plastic deformation of metal at such temperature and rate that strain hardening does not occur. |