Melting time vs Temperature and Mass

In summary, the conversation discusses the difficulty in calculating the temperature needed to melt steel within a certain amount of time, as it depends on various factors such as the steel's thermal conductivity and the external heating source. It is noted that there is no analytic solution and numerical simulations are required for accurate calculations.
  • #1
h1a8
87
4
I recently saw the movie “Man of Steel”. In Superman’s fight with Zod, Superman cuts (by melting) a steel I-beam, that Zod is about to hit him with, with a swipe of his heat vision. To melt steel that fast (under 3 seconds) requires a large temperature. My question is how can we calculate the temperature needed to melt (or heat to a certain temperature) steel of a certain mass within a certain amount or time? Basically a temperature vs time and mass function is what I’m trying to achieve.

Thanks!
 
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  • #2
There is no such thing. If the steel gets hot enough it will melt without delay (well, maybe picoseconds). How to make a steel bar hot enough throughout the bar is a different question.
 
  • #3
mfb said:
There is no such thing. If the steel gets hot enough it will melt without delay (well, maybe picoseconds). How to make a steel bar hot enough throughout the bar is a different question.

So a 3000 degree arc from a wielding torch could melt a certain amount of steel the same speed as a 2500 degrees arc could?

According to Newtons Law of Heating, it’s takes a certain amount of time for a medium to heat an object to a certain temperature.
 
  • #4
h1a8 said:
it’s takes a certain amount of time for a medium to heat an object to a certain temperature
That is a different question than in your original post.
If you consider heat flow from some external heating source to the metal you'll have to consider thermal conductivity, and in general you will need numerical simulations because there is no analytic solution.
 
  • #5
mfb said:
That is a different question than in your original post.
If you consider heat flow from some external heating source to the metal you'll have to consider thermal conductivity, and in general you will need numerical simulations because there is no analytic solution.
I seen the equation
Rate of Heat transfer = k(T1 - T2) /d
Where K is the thermal conductivity, T1 is the temperature of the object 1, T2 is the temperature of object 2,and d is the thickness of the object.
I'm basically trying to calculate how long it will take for a substance of certain size and mass to melt under a given ambient temperature.
 
  • #6
h1a8 said:
Where K is the thermal conductivity, T1 is the temperature of the object 1, T2 is the temperature of object 2,and d is the thickness of the object.
That works for flat objects where opposing surfaces have the same constant temperature and there is a steady flow of heat. That is not the situation you have, although that formula can be used in simulations for small mass elements and small time steps.
h1a8 said:
I'm basically trying to calculate how long it will take for a substance of certain size and mass to melt under a given ambient temperature.
This will likely need a numerical simulation.
 

1. What is the relationship between melting time and temperature?

The higher the temperature, the faster the melting time. This is because increasing the temperature provides more energy to the molecules, causing them to move faster and overcome the forces holding them together.

2. Does the mass of a substance affect its melting time?

Yes, the mass of a substance does affect its melting time. The larger the mass, the longer it will take to melt. This is because it takes more energy to heat a larger mass of molecules compared to a smaller mass.

3. Can melting time and temperature be accurately predicted?

While there are equations and models that can estimate melting time and temperature, it is difficult to accurately predict them. This is because there are many variables that can affect the melting process, such as impurities in the substance, external factors like pressure and humidity, and the specific properties of the substance itself.

4. Is there a difference in melting time between different substances?

Yes, different substances have different melting points and therefore will have different melting times. This is due to variations in the strength of the intermolecular forces between molecules, which determines how much energy is needed to break them apart and cause melting.

5. How does melting time and temperature relate to the state of matter?

Melting time and temperature are closely related to the state of matter. For a substance to melt, it must transition from a solid state to a liquid state. This transition occurs at a specific temperature known as the melting point. If the temperature is below the melting point, the substance will remain solid, and if it is above the melting point, the substance will become liquid.

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