The use of aluminium in the ocean

At present, the commonly used drill pipe in horizontal wells, high corrosive media wells, ultra-deep wells and other construction often encounter problems such as frictional thermal cracking of drill pipe, hydrogen embrittlement, stress corrosion fracture, reduced drilling speed and efficiency, and excessive loading of large hooks. All the above problems are determined by the physical and chemical properties of the ocean aluminum alloy material itself. If the performance of the drill pipe is to be fundamentally improved, it is necessary to improve the raw material of the drill pipe body. High drilling depth capability is very important at this time. The density of aluminium alloy drill pipe is about 1/3 of that of steel drill pipe. The ratio of strength to mass of aluminium alloy drill pipe is 1.5 to 2.0 times higher than that of steel drill pipe, and the application of aluminium alloy drill pipe can reach well depths that cannot be reached by steel drill pipe under certain drilling rig capacity.

Then we come to the common ocean aluminum alloys used for large extrusion profiles.

①Low-strength aluminium alloys: industrial pure aluminium, 3A21, 5005, 5A02, 5A03, 5086, etc. are not strengthened after heat treatment, and their semi-finished products are used in the annealed state and after cold work hardening.

② Medium-strength aluminium alloys are divided into two groups: heat-treated non-reinforced aluminium alloys (5A05, 5A06, 5B06) and heat-treated strengthenable aluminium alloys (6A02, 2A70, 2A06), etc.

③High-strength ocean aluminium alloys 7A04 and 2A12 can be sharply strengthened during heat treatment.