Melting Points of Metals
- Gavin Leo
In the world of manufacturing, understanding the melting points of metals is critical for optimizing processes like CNC machining and injection molding. This property not only defines the material’s suitability for specific applications but also helps engineers and manufacturers ensure precision, efficiency, and durability in their operations.
What Is a Melting Point?
The melting point of a metal is the temperature at which it transitions from solid to liquid under standard atmospheric pressure. For manufacturers, the melting point determines a material’s thermal stability and suitability for processes involving heat, such as casting, welding, or molding.
Why Melting Points Matter in CNC Machining and Injection Molding?
In both CNC machining and injection molding, understanding the melting points of metals helps in process design and material selection.
CNC Machining
For CNC machining, the melting point is crucial for choosing cutting tools and operating parameters:
High-melting materials like steel require heat-resistant cutting tools.
Low-melting materials may deform under excessive heat, leading to defects.
Injection Molding
In injection molding, the molds themselves are often made from metals with high melting points, such as steel, to withstand the high temperatures of molten plastics. Selecting a mold material with an appropriately high melting point ensures durability and precision.
Lowest melting point metal
Mercury (Hg) has the lowest melting point among metals, at –38.86°C. It is the only metal that remains liquid at room temperature and pressure, making it valuable for applications like thermometers, barometers, and specialized switches.
Highest melting point metal
Tungsten (W) has the highest melting point among metals, at 3422°C, making it ideal for high-temperature applications like filaments, superalloys, and cemented carbides. Its high hardness, density, and excellent strength at elevated temperatures further enhance its industrial and scientific uses.
Melting Points of Common Metals
Metal
Celsius (°C)
Fahrenheit (°F)
Aluminium
660
1220
Yellow Brass
905 – 932
1660 – 1710
Bronze
913
1675
Red Brass
990 – 1025
1810 – 1880
Copper
1084
1983
Cast Iron
1127 – 1204
2060 – 2200
Carbon Steel
1371-1593
2500 – 2800
Nickel
1453
2647
Wrought Iron
1482 – 1593
2700- 2900
Stainless Steel
1510
2750
Titanium
1670
3040
Full List of Metal Melting Points
Metal
Celsius (°C)
Fahrenheit (°F)
Mercury
-39
-38
Phosphorus
44
111
Potassium
63
145
Sodium
98
208
Selenium
217
423
Tin
232
449
Babbitt
249
480
Bismuth
272
521
Cadmium
321
610
Lead
328
621
Magnesium Alloys
349 – 649
660 – 1200
Zinc
420
787
Aluminium Alloys
463 – 671
865 – 1240
Aluminium Bronze
600 – 655
1190 – 1215
Antimony
630
1166
Plutonium
640
1184
Magnesium
650
1200
Aluminium (Pure)
660
1220
Beryllium Copper
865 – 955
1587 – 1750
Manganese Bronze
865 – 890
1590 – 1630
Coin Silver
879
1614
Sterling Silver
893
1640
Admiralty Brass
900 – 940
1650 – 1720
Yellow Brass
905 – 932
1660 – 1710
Bronze
913
1675
Silver (Pure)
961
1761
Red Brass
990 – 1025
1810 – 1880
Gold
1063
1945
Copper
1084
1983
Cast Iron
1127 – 1204
2060 – 2200
Uranium
1132
2070
Ductile Iron
1149
2100
Cupronickel
1170 – 1240
2138 – 2264
Manganese
1244
2271
Beryllium
1285
2345
Monel
1300 – 1350
2370 – 2460
Carbon Steel
1371 – 1540
2500 – 2800
Inconel
1390 – 1425
2540 – 2600
Silicon
1411
2572
Nickel
1453
2647
Wrought Iron
1482 – 1593
2700 – 2900
Cobalt
1495
2723
Stainless Steel
1510
2750
Palladium
1555
2831
Titanium
1670
3040
Thorium
1750
3180
Platinum
1770
3220
Zirconium
1854
3369
Chromium
1860
3380
Vanadium
1900
3452
Rhodium
1965
3569
Niobium (Columbium)
2470
4473
Ruthenium
2482
4500
Tantalum
2980
5400
Osmium
3025
5477
Rhenium
3186
5767
Tungsten
3400
6150
Celsius to Fahrenheit: (°C × 9/5) + 32
Fahrenheit to Celsius: (°F − 32) × 5/9
What are the factors that affect the melting point of metal?
The melting point of a metal is usually a fixed temperature value, which depends on the atomic structure and chemical composition of the metal. However, the melting point of a metal does change slightly due to certain environmental factors. Here are some of the main influencing factors:
Pressure
For most metals, increasing pressure will slightly raise their melting point. This is because increasing the pressure makes the interaction between the metal atoms stronger, which requires a higher temperature to overcome this interaction and melt the metal. However, this effect is usually quite small and only becomes significant under extremely high pressure conditions.
Impurities
Impurities in a metal can significantly affect its melting point. Pure metals usually have a higher melting point, while metal alloys containing impurities tend to have a lower melting point. This is because impurity atoms may disrupt the regularity of the metal lattice, thereby reducing the binding force between the atoms.
Alloying
Mixing different kinds of metals together to form alloys, usually changing their melting point. The melting point of an alloy is usually lower than the melting point of its constituent metal. This is because the interaction between different metal atoms is different from the interaction between pure metal atoms, which changes the ease of melting.
Nanometer effect
For nanoscale metal particles, the melting point may be significantly lower than that of bulk metals. This is because nanoparticles have a large surface-area-to-volume ratio, and the binding force of the surface atoms is weaker, so it is easier to melt.
Why do metals have higher melting points?
Wondering why some metals have exceptionally high melting points? The answer lies in their atomic structure and bonding strength, both critical factors for industrial applications.
Metals have high melting points because of strong metallic bonds between atoms. These bonds require significant energy to break, making metals resilient to heat and suitable for demanding processes like CNC machining.
What Determines the Melting Point of Metals?
The melting point of a metal is determined by the strength of its atomic bonds. In metals, positive atomic nuclei are surrounded by a “sea” of delocalized electrons, forming strong metallic bonds.
Metals with more tightly packed atoms or higher numbers of delocalized electrons exhibit stronger bonds, leading to higher melting points. For example, tungsten has a very high melting point (3,422°C) due to its dense atomic structure and numerous free electrons. In contrast, metals like aluminum, with looser atomic arrangements, have lower melting points (660°C).