 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
|
Homogenous Materials - Those materials which, to the naked eye, or at low magnification, are uniform and composed of only one distinct material. Heterogeneous Materials - Those materials which, to the naked eye, or at low magnification, are composed of two or more distinct materials. Hardening - Carbon steel, low alloy steel and martensitic stainless steels are hardened by heating to a temperature above the critical temperature range and cooling at a controlled rate. The rate of cooling depends on the composition of the steel. The cooling may be accomplished by quenching in water (normally the fastest cooling rate), by quenching in oil or cooling in air. Heat Affected Zone (HAZ) - The portion of a weldment that has not melted, but has changed due to the heat of welding. The HAZ is between the weld deposit and the unaffected base metal. The physical makeup or mechanical properties of this zone are different after welding. Heat Sink - A good weld needs a certain amount of base metal to absorb the high heat input from the welding arc area. The more base metal, or the thicker the base metal, the better heat sink effect. If this heat sink is not present, too much heat will stay in the weld area, and defects can occur. High Frequency - Covers the entire frequency spectrum above 50,000 Hz. Used in GTAW welding for arc ignition and stabilization. Horizontal Position - Occurs when the axis of the weld is from 0° –15° from the horizontal, and the face rotation is from either 80° –150° or 210° – 280° for groove welds, or from either 125° –150° or 210° – 235° for fillet welds. Halocarbons – Any hydrocarbon combined with any of the five (F2, Cl2, Br, I, At) elements in the V11A group of the periodic table. Heat of Adsorption – The total heat involved in the adsorption process from zero adsorbate loading to some final adsorbate loading at a constant temperature (also called isothermal integral heat of adsorption). Heat of Fusion – The heat energy required to transform one mole of substance from the liquid phase to the vapor phase at one atmosphere of pressure. Heat of Vaporization – Heat required to convert a substance from the liquid to the gaseous state with no temperature change. Hydrocarbon – An organic compound containing carbon and hydrogen.
|
|
 |
| Glossary | Contact | Site Map | (518) 465-5229, (845) 338-6247 |  |