So I understand that matter emits EM waves when hot. And that the higher the temperature, the shorter the wavelength, so cooler flames start off orange and the hotter flames reach light blue and white. What I'm wondering is if, hypothetically, you could take that blue-white flame and could make it considerably hotter, would the emitted wavelength reach UV thus making it invisible to the human eye? If so what temperature would need to be reached?
According to Wien's displacement law, for rising temperatures the maximum of emitted radiation shifts from infrared to visible, ultaviolet, X-rays, ...
But the maximum of perceived light shifts from red, orange, yellow, white to bluish-white and then stays there even for infinitely high temperature (see the point marked with $\infty$ in the image below).
(image from Color temperature)