Fergana polytechnic insitute mechanical engineering faculty department of mechanical engineering and automation

7 – Laboratory work 
REPORT 
Topic: Microstructural analysis of cast irons 
1. Purpose of work. 
2. Necessary equipment and measuring instruments. 
3 . Summary of the work done. 
Control questions. 
1. What is a state diagram? 
2. What is eutectic? 
3. What is the melting point of metals?

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APPENDIX 

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GLOSSARY 
1. Tolerance 
Tolerance is the allowable deviation from a standard, especially the range of 
variation permitted in maintaining a specified dimension in machining a piece. 
2. Temper 
Synonyms: Tempering
Tempering is a process of heat treating, which is used to increase the toughness of 
iron-based alloys. Tempering is usually performed after hardening, to reduce some 
of the excess hardness, and is done by heating the metal to a much lower temperature 
than was used for hardening 
3. Hot Rolled 
Synonyms: Tempering 
In metalworking, rolling is a metal forming process in which metal stock is passed 
through a pair of rolls. Rolling is classified according to the temperature of the metal 
rolled. If the temperature of the metal is above its recrystallization temperature, then 
the process is termed as hot rolling. 
4. Annealed 
Annealing, in metallurgy and materials science, is a heat treatment that alters a 
material to increase its ductility and to make it more workable. It involves heating 
material to above its critical temperature, maintaining a suitable temperature, and 
then cooling. Annealing can induce ductility, soften material, relieve internal 
stresses, refine the structure by making it homogeneous, and improve cold working 
properties. 
5. Alloy 
Alloys are mixtures of a metal with other elements, the precise combination being 
governed by the required properties. Alloys can be manufactured by various routes, 
the most widely used being to melt the constituents together and to cool the resultant 
mixture to form a single or multi-phase solid. 
6. UNS 

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The unified numbering system (UNS) is an alloy designation system widely 
accepted in North America. It consists of a prefix letter and five digits designating a 
material composition. A prefix of S indicates stainless steel alloys, C for copper, 
brass, or bronze alloys, T for tool steels, etc. The first three digits often match older 
three-digit numbering systems, while the last two digits indicate more modern 
variations. For example, Copper Alloy No. 377 (forging brass) in the original three-
digit system became C37700 in the UNS System. The UNS is managed jointly by 
the ASTM International and SAE International. A UNS number alone does not 
constitute a full material specification because it establishes no requirements for 
material properties, heat treatment, form, or quality. 
7. ASTM 
ASTM International, known until 2001 as the American Society for Testing and 
Materials (ASTM), is an international standards organization that develops and 
publishes voluntary consensus technical standards for a wide range of materials, 
products, systems, and services. 
8. Hardness 
Hardness is a measure of how resistant solid matter is to various kinds of permanent 
shape change when a force is applied. Macroscopic hardness is generally 
characterized by strong intermolecular bonds, but the behavior of solid materials 
under force is complex; therefore, there are different measurements of hardness: 
scratch hardness, indentation hardness, and rebound hardness.