Mortar

A refractory material preparation used for laying and bonding refractory bricks.

Protective coating

A corrosion-resistant material applied to a metal surface; for example, on casing plates behind porous refractory materials to protect against sulfur in the flue gases.

Bulging of a tube

      Bulging is generally an indication of overheating. Continuing under the same temperature and stress conditions will eventually lead to creep and stress rupture. The amount of bulging varies with the specific metal and the type of damage, creep or overstress. If the bulge is attributed to overstress (short-term overheating), and the temperature and stress have been returned to normal, typically the life of the tube has not been reduced. Creep life will be reduced, if the bulge is the result of creep damage (long-term overheating). Bulging is considered more serious than sagging or bowing.

Bowing of a tube

Excessive bowing is generally caused by uneven metal temperatures, which may be due to flame impingement or coke accumulation inside the tube. Heating on one side of the tube causes greater thermal expansion on the hotter side and bowing toward the heat source. Bowing may also be caused by binding of the tube in the tube sheets or improper suspension of the tube so that longitudinal expansion is restricted or by the use of improper tube lengths when individual tube replacements are made.

Sagging of a tube

Excessive sagging is usually because of a decrease in the structural strength of the tube caused by overheating. It may also be caused by improper spacing of hangers, uneven metal temperatures, or failure of one or more tube supports or hangers.

Elastomers

Long chain rubber molecules cross linked by sulphur are called elastomers

Decarburization

In decarburization, carbon content is reduced from outer surface. So the surface layer becomes soft which is responsible for lowering of fatigue resistance.

Case Hardening or Carburizing of steel

It is diffusing carbon into surfaces of steel components. This is done when a component should be hard on the outer face but tough inside.

Whiskers

Whiskers are obtained by elongating single crystal into fibrous form. Greatest Strength is usually observed in whiskers of smallest diameter.

Allotropy

Allotropy or allotropism is the property of some chemical elements to exist in two or more different forms, known as allotropes of these elements. An allotropy is polymorphism of metals.

Ploymorphism

Polymorphism is exhibiting different crystal structures at different temperatures and pressures.

Lever Rule

The lever rule is a tool used to determine weight percentages of each phase of a binary equilibrium phase diagram. It is used to determine the percent weight of liquid and solid phases for a given binary composition and temperature that is between the liquidus and solidus.

Lever rule is employed to obtain relative amounts of co-existing phases as a binary system. This rule is not applicable at eutectic or peritectic points as three phases exist in equilibrium at these temperatures.

Peritectoid

Two Solid phases transform into a different solid phase on cooling.

Peritectic

When the melting point of tow components differ too much from each other. Solid liquid phase transforms to a single solid phase.

Eutectoid

A solid phase replaces the liquid phase of eutectic system. Eutectoid reaction involves transformation of a solid phase into two other solid phases on cooling and vice versa

Eutectic phase / point, Hpyoeutectic Alloy, Hypereutectic Alloy

Eutectic: An Eutectic phase diagram is obtained when the melting points of the two components of phase diagram are neither very close nor much different.

Hpyoeutectic Alloy - Alloys to the left of eutectic point
Hypereutectic Alloy - Alloys to the right of eutectic point

Ferrite, Cementite, Pearlite & Austenite

alpha-Iron is Ferrite
Fe3C - Cementite
Ferrite + Cementite is Pearlite
Gamma-phase Iron is Austenite

Graphite

1. Used in Pencil making with a blend of clay.
2. Used as solid lubricant or in a graphited oil 
3. Has directional properties
4. Thermal and electrical conductivity are much higher along the direction of sheet as compared to its perpendicular direction.
5. Can be used as dry powder, as a spray, as a paste, as grease or as a liquid dispersion.
6. Suitable for use at hight temperature and pressure because of its low coefficient of friction.
7. Opaque
8. Grey in color
9. Also used in dry cells
10. Moderator in nuclear reactor

Corrosion Rate

The reduction in the material thickness due to the chemical attack from the process fluid or flue gas or both, expressed in mils per year or millimeters per year.