Melting time vs Temperature and Mass

Click For Summary

Discussion Overview

The discussion revolves around the relationship between temperature, time, and mass in the context of melting steel, particularly in scenarios similar to those depicted in popular media. Participants explore how to calculate the temperature required to melt steel of a certain mass within a specified time frame, as well as the underlying principles of heat transfer involved in this process.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions how to calculate the temperature needed to melt steel quickly, suggesting a function that relates temperature, time, and mass.
  • Another participant asserts that if steel reaches a sufficient temperature, it will melt almost instantaneously, raising the issue of how to achieve uniform heating throughout the material.
  • A participant references Newton's Law of Heating, indicating that heating an object to a certain temperature takes time, which complicates the initial query.
  • Further discussion highlights the importance of considering thermal conductivity and the need for numerical simulations to model heat transfer effectively, as there may not be an analytic solution for the problem posed.
  • Participants mention a specific equation for heat transfer, emphasizing that it applies under certain conditions and may not be suitable for the scenario described.
  • There is a suggestion that numerical simulations may be necessary to accurately determine the melting time for a substance of a given size and mass under specific ambient conditions.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of calculating melting time based on temperature and mass. While some agree that sufficient temperature leads to rapid melting, others emphasize the complexities of heat transfer and the need for simulations, indicating that the discussion remains unresolved.

Contextual Notes

Limitations include the dependence on specific conditions such as thermal conductivity and the uniformity of heat distribution, which are not fully addressed in the discussion. The need for numerical simulations suggests that the problem may not have a straightforward analytical solution.

h1a8
Messages
86
Reaction score
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!
 
Science news on Phys.org
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.
 
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.
 
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.
 
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.
 
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.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 44 ·
2
Replies
44
Views
9K
  • · Replies 8 ·
Replies
8
Views
3K
Replies
1
Views
3K
  • · Replies 4 ·
Replies
4
Views
16K
  • · Replies 10 ·
Replies
10
Views
6K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
2
Views
9K