How can GR1 exhaust titanium tubing be heat treated to remove residues?

When the hydrogen content in titanium tubing is too high, the impact toughness and notched tensile strength will drop dramatically due to the brittleness of titanium tubing, so the hydrogen content in titanium tubing should not exceed 0.015%. In order to reduce the amount of hydrogen absorption, the parts must have fingerprints, rolling mill marks, grease and other residues removed before heat treatment, and the atmosphere in the heat treatment furnace must be free of water vapor. If the hydrogen content of titanium tubing exceeds the allowable value, it must be removed by vacuum annealing. Vacuum annealing for hydrogen removal is generally held at 538-760°C for 2-4 hours at a pressure of less than 0.066Pa.

When the temperature does not exceed 540 ℃, the oxide film on the surface of the titanium tube will not significantly thicken, while at higher heat treatment temperatures (more than 760 ℃), the oxidation rate will be rapidly accelerated, while the oxygen to the internal expansion of the material, the formation of the diffusion layer - pollution layer. Oxygen pollution layer embrittlement rate is high, resulting in cracks and damage on the surface of the part.

There are mechanical processing methods (e.g. sandblasting, house cutting, etc.) or chemical methods such as pickling and chemical grinding to remove the oxygen contamination layer. Heat treatment, should be in the premise of ensuring that the meteorite heat treatment, as short as possible heating time, can also be carried out in a vacuum furnace or a heating furnace with inert gas (argon, nitrogen, etc.). . Appropriate application can also avoid or reduce the contamination caused by heating titanium tube parts in an air furnace.