Spiral steel pipe hydrostatic test, each steel pipe should be done hydrostatic test without leakage, test pressure according to the test accounting P = 2ST/D formula S – hydrostatic test test stress Mpa, hydrostatic test test stress according to the corresponding steel strip standard rules yield degree small value (Q235 for 235Mpa) of 60 percent selected.
Stabilization time: D < 508 test pressure holding time of not less than 5 seconds; D ≥ 508 test pressure holding time of not less than 10 seconds 4 nondestructive testing of steel pipe patch welds, steel strip enemy welds and circumferential seams should be X-ray or ultrasonic inspection. On the combustible general fluid transportation with the steel to the spiral weld should be 100 percent S X-ray or ultrasonic inspection, for water, sewage, air, heating steam and other general fluid transportation with the spiral weld of steel pipe should be X-ray or ultrasonic inspection view (20 percent).
According to the spiral steel pipe quality inspection effect, the spiral steel pipe is usually divided into three categories: qualified products, reworked products and scrap. Qualified products refer to the appearance and quality of the quality of the spiral steel pipe in accordance with the relevant standards or delivery inspection technical conditions; reworked products refer to the appearance and quality of the quality is not fully in line with the standards and inspection of the body, but allow the rework, after repair can reach the standard and inspection conditions of spiral steel pipe.
Scrap refers to the appearance and quality of the quality of the internal failure, not allowed to repair or after repair still can not meet the standards and inspection conditions of spiral steel pipe. Scrap is divided into two kinds of internal and external waste. Internal scrap refers to the scrap spiral steel pipe found in the foundry or casting workshop; external scrap refers to the scrap of spiral steel pipe found in the handover, usually in the machining, heat treatment or use of the process before revealing the economic loss it constitutes is much larger than the internal scrap.