What is Melting Points?
Melting point is the temperature at which a particular solid substance changes from solid to liquid or melts. When heat is applied to a solid, its temperature increases until it reaches its melting point. More heat turns a solid into a liquid without changing the temperature.
The melting point (rarely the liquefaction point) is the temperature at which a substance changes from a solid to a liquid. At the melting point, the solid and liquid phases are in equilibrium. The melting point of a substance is pressure dependent and is usually specified at standard pressures such as 1 atmosphere or 100 kPa.
When all the solids are melted, the excess heat raises the temperature of the liquid. The melting point of a crystalline solid is a characteristic number used to identify compounds and pure elements. Most mixtures and amorphous solids melt within a range of temperatures.
According to the temperature of reverse change from liquid to solid, it is called freezing point or crystallization point. Freezing points can appear lower than they actually are due to the ability of materials to supercool.
The melting point of a solid is usually considered the same as the freezing point of the corresponding liquid. However, the actual freezing point may not be the same as the melting point because liquids can freeze in different crystal systems and impurities lower the freezing point.
The melting point of iron alloys and steels occurs at high temperatures, approximately 2200 to 2500 Fahrenheit (°Fahrenheit) / 1205 to 1370 Celsius (°C).
Copper alloys (including bronze, pure copper, and brass) have a lower melting point than iron, approximately 1981-1675°F/1082-913°C. Metals alloyed with aluminum and the melting point of aluminum have a lower temperature range than copper alloys.
Pure aluminum melts at around 1218°F/659°C, but alloying it with other elements can increase this. The chart below includes some common metals in our catalog, such as the melting point of stainless steel and the melting point of titanium.
Key Takeaways
- The melting point of a substance is the temperature at which the substance changes from a solid to a liquid.
- For pure substances, melting occurs at one temperature.
- Unless otherwise noted, melting points reported in the literature have been measured under an applied pressure of 1 atm of air.
- All materials absorb heat when melted and most materials expand.
- For solutions of two or more components, melting usually occurs over a range of temperatures.
How to Calculate Melting Points?
In chemistry, it is often necessary to analyze solutions. A solution contains at least one solute dissolved in a solvent. Molarity describes the amount of solute in a solvent. Changes in molarity affect the boiling and freezing points (also called melting points) of solutions. Using a simple formula, you can easily determine the boiling or freezing point of a solution.
Note the molarity (m) of the solution. The higher the molarity, the higher the boiling point of the solution and the lower the freezing point.
Use the table to find the freezing point depression constant (Kf) or boiling point elevation (Kb) for your solvent. Each substance has a unique constant that determines how much one mole of solute lowers the freezing point or raises the boiling point.
Calculate the change in boiling or freezing temperature using one of the following formulas:
ΔTf = Kf*m or ΔTb = Kb*m.
Add the value obtained by ΔTb to the standard boiling point of the solvent (e.g. 100 °C for water) or subtract the value obtained by ΔTf from the standard freezing point of the solvent (e.g. 0 °C for water).
The Melting Points of Metals
When a metal is chosen for its beneficial properties, it can be frustrating only to learn that it cannot withstand the maximum output temperature of your application. Understanding the melting point of the metal being processed is very important.
It is important to remember that alloys containing multiple elements have a melting temperature range that depends on the overall composition of the alloy. The following list includes the types of common metals and their respective melting points.
| Metal | Melting Point |
| Carbon Steel | 1425-1540°C (2597-2800°F) |
| Stainless Steel | 1375 – 1530°C (2500-2785°F) |
| Aluminum | 660°C (1220°F) |
| Copper | 1084°C (1983°F) |
| Brass, Yellow | 930°C (1710°F) |
| Inconel | 1390-1425°C (2540-2600°F) |
| Nickel | 1453°C (2647°F) |
| Molybdenum | 2620°C (4748°F) |
| Silver | 961°C (1762°F) |
| Titanium | 1670°C (3038°F) |
| Tungsten | 3400°C (6152°F) |
| Zinc | 420°C (787°F) |
| Manganese | 1244°C (2271°F) |
| Beryllium | 1285°C (2345°F) |
| Silicon | 1411°C (2572°F) |
| Cobalt | 1495°C (2723°F) |
| Bronze | 913°C (1675°F) |
| Brass, Red | 1880°C (1025°F) |
| Cast Iron | 2200°C (1204°F) |
| Wrought Iron | 2900°C (1593°F) |
| Chromium | 1860°C (3380°F) |
| Gold | 1063°C (1945°F) |
| Lead | 328°C (622°F) |
| Molybdenum | 2620°C (4748°F) |
| Platinum | 1770°C (3218°F) |
| Palladium | 1555°C (2831°F) |
| Tungsten | 3400°C (6152°F) |
| Rhenium | 3186°C (5767°F) |
| Tantalum | 2980°C (5400°F) |
| Rhodium | 1965°C (3569°F) |
FAQs
What do you mean by melting point?
The melting point is usually defined as the point at which materials changes from a solid to a liquid. The temperature at which solid changes its state to liquid at atmospheric pressure is called the melting point of that liquid. This is the point at which both liquid and solid phase exists at equilibrium.
What makes a melting point higher or lower?
The melting point of a pure substance is always higher and has a smaller range than the melting point of an impure substance or, more generally, of mixtures. The higher the quantity of other components, the lower the melting point and the broader will be the melting point range, often referred to as the “pasty range”.
How do you determine a melting point?
The most common and basic method of determination is the capillary method. This method involves placing the sample in a capillary tube and running an experiment that will heat the sample until it reaches the melting point. The melting point can then be recorded.
What does an increase in melting point mean?
The melting point increases (except for ice) with increase in pressure because when a solid melts into liquid its volume increases and if pressure is increased , it would be harder for the molecules to expand , for this solid requires more energy i.e. more temperature i.e. increase in melting point .
What is a simple definition of high melting point?
High melting point of a substance means that there will be more heat required to melt a particular substance from solid to liquid state. There are many elements that have high melting point.Example: for metals, we can say , more than 700° could be considered high melting point.
What are examples of melting point?
For example, the melting point of wax is 63 °C. The greater the melting point of the substances, the more will be the intraparticle forces of attraction binding the particles. For instance, in the solid form of water, ice melts at a temperature of 0 °C to form liquid water.