OCTG Tube, which refers to Oil Country Tube, is a collection of rolled metal products, commonly known as drill pipe, casing and tubing, manufactured to API specifications and used in the petroleum industry onshore and offshore. This severe corrosive environment requires pipelines to have high corrosion resistance and pressure resistance. Especially in areas with complex geology, there are higher requirements for coating performance. According to the specific application of anti-corrosion coating and different corrosive environments, it can be divided into drill pipe inner coating, oil casing inner coating and oil pipeline inner/outer coating.
High temperature and high pressure resistance test for oil casing coatings is a standard laboratory method developed with reference to the NACE TM 0185 standard, which can be used to test the quality of steel pipe coatings. This experiment was conducted in an autoclave under certain corrosive media, temperature and pressure conditions. It is recommended to use special oil shell coating test equipment, such as autoclave, booster device, autoclave heating device, autoclave safety system and comprehensive control system. The test procedures and methods are as follows:
1. Prepare liquid phase or gas phase corrosion medium;
2. Open the autoclave lid and put the sample inside. If the autoclave capacity allows, multiple sample tests can be conducted at the same time, and a certain distance between each sample can be ensured;
3. Slowly pour the liquid medium into the kettle, tighten the lid, enter the gas phase corrosion medium, slowly increase the pressure, and heat the kettle body; pay attention to depressurizing the kettle body during the heating process so that the test pressure cannot exceed the test conditions. the maximum pressure;
4. Keep the pressure and temperature in the kettle under the specified test conditions, and the test time for heating the coating sample is not less than 16 hours;
5. After the test is completed, cool the autoclave body to below 93°C, then reduce the pressure evenly to normal within 15min~30min, discharge the corrosive medium, and take out the sample;
6. Immediately check whether the outer coating has expanded and softened, then cool it to room temperature for comparison with untested samples.
