60849
Description
Flashcards by Brandon Alcaraz, updated more than 1 year ago
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Created by Brandon Alcaraz
almost 11 years ago
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| Question | Answer |
| What were the two discoveries of Sir Humphrey Davy that led to the development of modern welding technology? | The two discoveries of Sir Humphrey Davy were (1) the electric arc and (2) acetylene gas. |
| What is meant by the term faying surface? | The faying surfaces are the contacting surfaces in a welded joint. |
| Define the term fusion weld. | A fusion weld is a weld in which the metal surfaces have been melted in order to cause coalescence. |
| What is the fundamental difference between a fusion weld and a solid state weld? | In a fusion weld, the metal is melted. In a solid state weld, the metal is not melted. |
| What is an autogenous weld? | An autogenous weld is a fusion weld made without the addition of filler metal. |
| Name and sketch the five joint types. | Five joint types are (1) butt, (2) corner, (3) lap, (4) tee, (5) edge. For sketches see Figure 28.3 in the text. |
| Define and sketch a fillet weld. | A fillet weld is a weld joint of approximately triangular cross section used to fill in the edges of corner, lap, and tee joints. |
| Define and sketch a groove weld. | A groove weld is a weld joint used to fill in the space between the adjoining edges of butt and other weld types except lap. |
| Why is a surfacing weld different from the other weld types? | Because it does not join to distinct parts, but instead adds only filler metal to a surface. |
| Why is it desirable to use energy sources for welding that have high heat densities? | Because the heat is concentrated in a small region for greatest efficiency and minimum metallurgical damage. |
| What is the unit melting energy in welding, and what are the factors on which it depends? | The unit melting energy is the amount of heat energy required to melt one cubic inch or one cubic mm of metal. The factors on which it depends are (1) specific heat, (2) melting point, and (3) heat of fusion of the metal. |
| Define and distinguish the two terms heat transfer factor and melting factor in welding. | Heat transfer factor is the ratio of the actual heat received at the work surface divided by the total heat generated by the source. Melting factor is the ratio of heat required for melting divided by the heat received at the work surface. |
| What is the heat-affected zone (HAZ) in a fusion weld? | The HAZ is a region of base metal surrounding the fusion zone in which melting has not occurred, but temperatures from welding were high enough to cause solid state microstructural changes. |
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