I think he wanted to ask What kind of Heat Treatmengt is the burnishing(什么是光亮热处理?) ,perhaps.THX is equivalent to thans.
Bright Heat Treatment(Bright annealed) - refers to the process of heat treatment (quenching and annealing, mainly), using gas or vacuum heat treatment may prevent or reduce the contact surface oxidation and oxygen to reach the surface ,So as to achieve the light or the relative surface brightness.
I don't agree with the fifth floor! If HT means 灰铁, the question he want to ask should be"What kind of HT is burnished". So he want to ask "What kind of heat treatment is birght heat treatment". And the answer is perfectly given by the ninth floor.
Additionally when asking a question, pls. use less abbreviation to avoid misunderstanding.
Thx