DMH UNITED STEEL INDUSTRY offer an extensive range of Line pipes used in sour service environment.
The line pipes can be used for a wide range of petrol and gas transportation under sour service environment. Sour service line pipes are produced accord to GB/T9711.3 and API 5L/ISO31813-2007.
According to metallurgical and environmental factors, hydrogen cracking (HIC) is prone to occur in pipeline steels used in acid service.
Metallurgical factors include alloy elements, microstructure, strength, segregation and the shape of non-metallic inclusions. Some of the environmental factors that affect HIC, also known as SWC, are the partial pressure of hydrogen sulfide (H 2 S) and carbon dioxide, the temperature of the medium, the pH and the corrosive ions such as chloride. Due to HIC, many sour gas pipeline failures occurred around the world.
Steel pipe manufacturers, users and research institutions have made considerable efforts to understand the HIC mechanism, to develop laboratory testing methods to identify and quantify the susceptibility of materials to HIC, and to produce steel with higher HIC resistance. NACE international has developed standard test TM-02-84 for pipeline steel.
The method describes the procedure for evaluating the resistance of pipeline steel to SWC caused by H absorption caused by sulfide corrosion. The test is applicable to line pipes with a wall thickness of 5 mm to 30 mm. The process involves exposing unstressed specimens to 96 hours of synthetic seawater with saturated H 2 S at ambient temperature and pressure values of 4.8 to 5.4 pH. If necessary, the samples are sliced, polished and etched so that cracks can be separated from small inclusions, lamination, scratches or discontinuities. The crack sensitivity ratio (CSR), crack length ratio (CLR) and crack thickness ratio (CTR) of each part were calculated. The average value is determined for each coupon. Recent work in the Canadian mineral and energy center
The technology and the Canadian Standard Association (CSA) acid service work group carried out two experimental parameters for each of the 19 pipeline steels.
(1) threshold H concentration (CthH) or diffusion H concentration in cracked steel.
(2) threshold pH (pHth) or pH value of cracking.
The pipe is marked according to the standard and customer requirements.
The mark is applied to the end of the pipe.
The same data and additional information for each customer request will be marked on the label of the package.
The pipes are bundled with hexagonal or bundled bundles.
Tying weight can reach 5000 kg according to customer requirements.
Each package is equipped with three labels.