PSI - Issue 22

8

Author name / Structural Integrity Procedia 00 (2019) 000 – 000

Yaorong Feng et al. / Procedia Structural Integrity 22 (2019) 219–228

226

BTC,12MPa BTC*1.43,12MPa BTC,10MPa BTC*1.43,Mpa

220

180

140

100

BTC CVN (J)

60

20

0.72

0.60

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0.40

Design factor of the pipeline

管道设计系数

Fig. 5 comparison calculation and analysis of crack toughness at different regional levels (conveying pressure 12MPa and 10MPa, 15 ℃ )

4. Full-scale gas burst test of the 2 nd WEGP Full-scale gas burst test is the most reliable and effective method to determine the actual pipe crack arrest toughness. From both ends of the test section, the test steel pipe is arranged from high to low according to the toughness value, the steel pipe is cracked and propagated from the steel pipe with lowest toughness in the middle, and finally arrested on the steel pipe with higher toughness. The toughness of the steel pipe with stop cracking is the crack arrest toughness required by the pipe (see Figure 6). If the design parameters of a new pipeline exceed the pipeline parameter range of the existing full-scale burst test database, it is usually done by full-scale burst test to determine the crack arrest toughness of the new pipeline.

Fig. 6 Steel pipe and Test line arrangement during full-scale gas burst test (W-West; E-East)

In order to determine the crack arrest toughness of the gas pipeline accurately and reliably, a large number of full-scale gas burst tests have been carried out from abroad in the 1970s, and many empirical formulas for predicting the cracking arrest toughness have been obtained according to the test results. Up to now, for some new pipelines, many full-scale burst tests have been carried out to verify the predicted crack arrest toughness, such as the Alliance pipeline connecting the United States and Canada, the Mackenzie Valley pipeline in Canada, etc. Based on the statistics of the main test parameters of the existing full-scale gas burst test in the world and the comparison and analysis between the design parameters of the 2 nd WEGP and the design parameters of the existing X80 full-scale burst tested pipeline, some pipeline design parameters such as steel pipe grade, design pressure, design factor, wall thickness and pipe diameters, etc., have been covered by the X80 full-scale burst test database. But in the test steel pipe type (X80 SSAW pipe) as well as the conveying medium (the natural gas component required by the Central Asian gas is close to rich gas) two parameters are not covered. The crack arrest capacity of X80 welded pipe including SSAW pipe should be verified by full-scale burst test. According to the characteristics of the 2 nd WEGP, the main test design parameters of full-scale burst test include: (a) test steel pipe type: LSAW pipe and SSAW pipe; (b) steel pipe diameter 1219 mm, steel grade X80; (c) the test