Hydrogen, Oxygen, and Nitrogen can react in the weld puddle and cause changes in the structure of the weld weakening the weld. Properties of Metals (The following information is available from Integrated Publishing at ) This section is devoted primarily to the used in describing various properties and characteristics of metals in general. Of primary concern in advanced manufacturing and advanced manufacturing and aerospace maintenance are such general properties of metals and their alloys as hardness, brittleness, malleability, ductility, elasticity, toughness, density, fusibility, conductivity, and contraction and expansion. Knowledge of these terms is essential as it helps to form the basis for further discussion of metals used in advanced manufacturing and aerospace. Hardness Hardness refers to the ability of a metal to resist abrasion, penetration, cutting action, or permanent distortion. Hardness may be increased by working the metal and, in the case of steel and certain titanium and aluminum alloys, by heat treatment and cold-working (discussed later). Structural parts are often formed from metals in their soft state and then heat treated to harden them so that the finished shape will be retained. Hardness and strength are closely associated properties of all metals. Brittleness Brittleness is the property of a that allows little bending or deformation without shattering. In other words, a brittle metal is apt to break or crack without change of shape. Because structural metals are often subjected to shock loads, brittleness is not a very desirable property. Cast iron, cast aluminum, and very hard steel are brittle metals.
Hydrogen, Oxygen, and Nitrogen can react in the weld puddle and cause changes in the structure of the weld weakening the weld. Properties of Metals (The following information is available from Integrated Publishing at ) This section is devoted primarily to the used in describing various properties and characteristics of metals in general. Of primary concern in advanced manufacturing and advanced manufacturing and aerospace maintenance are such general properties of metals and their alloys as hardness, brittleness, malleability, ductility, elasticity, toughness, density, fusibility, conductivity, and contraction and expansion. Knowledge of these terms is essential as it helps to form the basis for further discussion of metals used in advanced manufacturing and aerospace. Hardness Hardness refers to the ability of a metal to resist abrasion, penetration, cutting action, or permanent distortion. Hardness may be increased by working the metal and, in the case of steel and certain titanium and aluminum alloys, by heat treatment and cold-working (discussed later). Structural parts are often formed from metals in their soft state and then heat treated to harden them so that the finished shape will be retained. Hardness and strength are closely associated properties of all metals. Brittleness Brittleness is the property of a that allows little bending or deformation without shattering. In other words, a brittle metal is apt to break or crack without change of shape. Because structural metals are often subjected to shock loads, brittleness is not a very desirable property. Cast iron, cast aluminum, and very hard steel are brittle metals.
the_science_and_math_of_arc_welding.docx