Thermit welding is a welding process that employs molten metal to permanently join the conductors.
The process employs an exothermic reaction of a thermite composition to heat the metal, and requires no external source of heat or current.
Thermit welding is often used in replacing broken gear teeth, repairing broken shears and joining rails, truck frames and locomotive frames etc.
Materials are limited to ductile materials because the threads are cold formed. .
Also, materials with good deformation characteristics are necessary for rolling; these materials include softer (more ductile) metals and exclude brittle materials, such as cast iron.
When a pattern is made in three parts, the ________ is known as a drag.
Materials used. Typically, materials used for pattern making are wood, metal or plastics. Wax and Plaster of Paris are also used,
Sugar pine is the most commonly used material for patterns, primarily because it is soft, light, and easy to work
A riser, also known as a feeder, is a reservoir built into a metal casting mold to prevent cavities due to shrinkage.
Most metals are less dense as a liquid than as a solid so castings shrink upon cooling, which can leave a void at the last point to solidify.
Which of the following welding method uses a pool of molten metal?
This is a well established and extremely versatile method of welding. Submerged-arc welding (SAW) involves the formation of an arc between a continuously fed electrode and the work piece.
A blanket of powdered flux, which generates a protective gas shield and a slag (and may also be used to add alloying elements to the weld pool), protects the weld zone. A shielding gas is not required.
A casting defect which occurs due to improper venting of sand is known as