Can video cameras perceive lights in a way that they will totally change the color of molten metals?
For starters,

You need to research Infrared light pollution caused by the high temperatures of the materials you're trying to image.  Most cameras have an IR filter on the sensor, which blocks incoming wavelengths which are imperceptible to the human eye.  These filters often have different characteristics depending on the camera make/model/manufacturer, which is why I say you need to do some research in that area.

It's possible to remove these filters, and photographers who are interested in IR photography often do; but because the glass of the lens bends visible light differently than IR light, there's effectively different focal planes for the two, and you can't focus them both at the same time.  So, IR photographers will typically remove the sensor filter, and then attach an IR-pass filter to the front of the lens, which blocks the visible spectrum, and only allows IR light through, allowing the IR image to be properly focused.  These IR pass filters are available in different wavelengths.  IR pass filters won't be particularly relevant to your situation.  However, IR cut filters may be.

When IR photographers remove the IR filter from their sensors, they effectively destroy the camera's ability to take "normal" pictures.  This is one reason IR cut filters exist.  They screw on to the front of a lens, and cut the incoming IR light, allowing a modified camera to behave normally again.  But also (and here is where you might be interested) they supplement the IR-blocking capabilities of normal cameras, which may be suffering from IR pollution for various other reasons.  Pointing a camera at hot metal isn't the typical scenario; more commonly, cheap Neutral Density filters and long exposures introduce IR light that the sensor filter wasn't designed to handle.  However, ensuring that only the spectrum you want to capture is striking your sensor should help in your situation.

Other than that, make sure your white balance is set, because that can also tint the image, and get a good quality color chip chart for reference; most of them are made from plastic and wouldn't stand up to high temperatures, but there are some metal ones.  You'd still need to keep it from melting, and be sure the dyes on the color chips were stable at whatever temperature you needed them to be.

Since you're pointing a camera at something very bright, you should be aware of the phenomenon known as aperture diffraction, which will affect the image's sharpness, but not so much overall color (although the colors of edges might be affected slightly; see halation, fringing, and chromatic aberration).

You might also be interested in a more full-spectrum camera, designed to image light invisible to humans, depending on your budget.  I think Flir might make some, maybe?  They're more commonly used in manufacturing and agriculture.