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Welding Glossary

Hand Drill - **The Hand Drill is used for boring holes and driving screws into various materials. The main advantages of the Hand Drill over the Drill Press there is almost no limit to where holes can be made in material and the Hand Drill is very portable**


 * Hand Shield - ** A protective device, used in arc welding, for shielding the eyes, face and neck. A hand shield is equipped with a suitable filter plate and it is designed to be held by the hand.

Hand Tools - The greatest hazards posed by hand tools result from misuse and improper maintenance. When tools are used for purposes other than what they were designed for injuries may occur.


 * Hard Facing ** - A particular form of surfacing in which a coating or cladding is applied to a substrate for the main purpose of reducing wear or loss of material by abrasion, impact, erosion, galling, and cavitation. See also - coating, cladding, and surfacing.


 * Heat-Affected Zone (HAZ) ** -That portion of the base metal which has not been melted, but whose mechanical properties or microstructure have been already altered by the heat of welding, brazing, soldering, or cutting.


 * Helmet ** (eye protection) – A helmet is a protection device, used in arc welding, for shielding the eyes, face, and neck. A helmet is equipped with a suitable filter plate. Most welding helmets are worn on the head.


 * Hertz ** - Hertz is often referred to as "cycles per second". In the United States, the frequency or directional change of alternating current is usually 60 hertz.

**Hexavalent chromium (Cr(VI))** compounds are a large group of chemicals with varying chemical properties, uses, and workplace exposures. Their properties include corrosion-resistance, durability, and hardness. Workers may be exposed to airborne Cr(VI) when these compounds are manufactured from other forms of chromium (e.g., the production of chromates from chromite ore); when products containing Cr(VI) are used to manufacture other products (e.g., chromate-containing paints, electroplating); or when products containing other forms of chromium are used in processes that result in the formation of Cr(VI) as a by-product (e.g., welding). NIOSH considers all Cr(VI) compounds to be occupational carcinogens. Cr(VI) is a well-established carcinogen associated with lung, nasal, and sinus cancer. Some of the industries in which the largest numbers of workers are exposed to high concentrations of airborne Cr(VI) compounds include electroplating, welding, and chromate painting. A hierarchy of controls, including elimination, substitution, engineering controls, administrative controls, and the use of personal protective equipment, should be followed to control workplace exposures. Dermal exposure to Cr(VI) should also be prevented to reduce the risk of skin irritation, corrosion, ulcers, sensitization, and allergic contact dermatitis.
 * High Frequency ** - Covers the entire frequency spectrum above 50,000 Hz. Used in TIG welding for arc ignition and stabilization.


 * Horizontal Fixed Position ** (pipe welding) - In pipe welding the position of a pipe joint in which the axis of the pipe is approximately horizontal and the pipe is not rotated during welding.

Horizontal Metal Bandsaw


 * Hot Work **


 * Hydrogen Sulphide (H2S) **

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