A general rule

1. The provisions of this section apply to titanium and titanium alloy tubes for ship and ocean engineering -- common purposes.

2. If titanium and titanium alloy tubes other than those specified in this section are used, the chemical composition, mechanical properties and application data shall be submitted to CCS for approval. Upon approval, acceptance shall be conducted in accordance with relevant recognized standards.

Secondary manufacturing

1. Titanium and titanium tubes shall be manufactured in factories approved by CCS.

2. Except as provided in this section, the manufacture and testing of titanium alloy tubes shall comply with the relevant provisions of Chapter 1, Chapter 4 of this article.

3. The smelting of titanium and titanium alloys should be carried out under vacuum conditions. If vacuum consumable furnace is used for remelting, two or more remelting processes should be used to ensure the uniformity of chemical composition and microstructure of materials, and reduce the level of oxidation and nitriding inclusions.

4. Titanium alloy tube can be manufactured by rolling, welding or welding and rolling method.

5. Welded tube can be annealed rolled plate strip, with TIG welding or MIG welding method. If filler material is required, the filler material used shall be appropriate to the base material.

6. The manufacturing quality of titanium and titanium alloy tubes shall comply with the relevant provisions of 4.1.3 in Chapter 4 of this specification.

Three-heat treatment

1. Unless otherwise stipulated in the Contract, the titanium and titanium tubes shall be delivered in annealed form.

2. For cold rolled pipe, usually should be annealed at a temperature of not less than 54OC; For the pipe of hot processing, if the end temperature of processing is not lower than 760℃, no further heat treatment is necessary.