Home > Knowledge > Content
Test method for casing and tubing thread
- Feb 25, 2018 -

The inspection of oil pipe thread is more complicated, which is divided into coupling thread inspection and pipe body thread inspection.

1 Coupling thread Inspection

After the thread is machined, the single parameters of internal taper, internal pitch, thread height and concentricity are tested, and the tight distance and the comprehensive parameters are tested by screw plug gauge and partial single head plug. In addition, the thread surface according to API standards for human visual inspection.

2 Pipe Body Thread inspection

For casing and tubing thread,to inspect the external taper, external pitch, thread height test, with the thread contour microscope for the thread angle sampling, with the thread ring gauge and smooth ring gauge to the tight distance and comprehensive parameters, in addition, the thread surface according to API standard requirements for inspection. After the machine is screwed, the casing collar is inspected by the plug gauge and the incomplete single head plug gauge.

Finished products before packaging on the review stage with the collar of the female end of the thread and not fully-shaped single head plug gauges for inspection, external thread male buckle end with thread ring gauge and smooth gauge for inspection. In the actual inspection work, the tight distance value is a comprehensive parameter, after the single parameter test is qualified, the tight distance can be qualified, the tight distance is unqualified, the unqualified single parameter should be found first, then the problem in the process is solved according to the reason affecting the parameter. The API standard specification of the American Petroleum Institute has high requirements for single parameter precision in the process of oil casing processing, but the company's individual instrument and thread gauges are purchased from the domestic and foreign manufacturers recognized by the API Petroleum Society, so the quality of the products can be ensured in the thread inspection