scholarly journals Determination of the Crack-Arrest Toughness of the Pipeline Steel X 70

1996 ◽  
Author(s):  
S. Felber
Keyword(s):  
Pipeline Steel ◽  
Base Material ◽  
Crack Arrest ◽  
Standard Test ◽  
Test Method ◽  
Materials Testing ◽  
High Crack ◽  
Point Bend ◽  
Arrest Toughness

The resistance of a material against fracture is influenced by its behaviour during the three possible steps of the fracture process, which are crack initiation, crack extension, and crack-arrest. It is the task of materials testing, especially of fracture mechanics, to find out the relevant parameters. To stop a crack in a pipeline in order to limit the crack length it is of great interest to know the crack-arrest toughness, KIa, of the material used. There are two main possibilities to stop a crack in a pipeline: The first one is to apply special crack arrestors, and the second one is to use a material with a high crack-arrest toughness. The first possibility is rarely realized, and so it is of great interest to gain knowledge of the fracture toughness values of the pipeline steels employed. In the past, big specimens, like Robertson plates for example, were used for the determination of the crack-arrest toughness, KIa, but they are very expensive and so nowadays they are replaced by small specimens like: 1st, the three-point bend specimens (specimens used in a proposal published by TVFA, University of Technology, Vienna), 2nd, the compact-crack-arrest specimens (specimens of the standard test method ASTM E 1221) and 3rd, the full-thickness compact-crack-arrest specimens (specimens proposed in the test method of Ripling and Crosley). This work deals with the determination of the crack-arrest toughness, KIa, of the base material, the weld metal and the heat affected zone of a weld of the pipeline steel X 70. For this purpose tests were performed with each of the three materials, employing each of the three mentioned test specimens. Finally, this work contains a discussion and a comparison of the measured crack-arrest toughness values.

Determination of Crack Arrest Toughness at High Temperatures Using Compact Specimens

1988 ◽  
Vol 110 (2) ◽  
pp. 129-136 ◽  
Author(s):  
K. Kussmaul ◽  
R. Gillot
Keyword(s):  
High Temperatures ◽  
Impact Energy ◽  
Pressure Vessel ◽  
Crack Arrest ◽  
Test Method ◽  
Ferritic Steels ◽  
Pressure Vessel Steels ◽  
Reference Curves ◽  
Arrest Toughness

In order to determine the influence of the test temperature on the crack arrest toughness, investigations were carried out on pressure vessel steels of various strength and toughness up to the upper-shelf of the Charpy V-notch impact energy (CV-energy). The tests were conducted on the basis of the proposed ASTM test method for ferritic steels with modified wedge-loaded compact specimens. The thickness ranged from 0.75–6.69 in. (19–170 mm), the in-plane dimensions from 3.94–15.75 in. (100–400 mm). The comparison with the reference curves of the American and German guidelines showed significant discrepancies at high temperatures.

Determination of Steady-State Adhesive Wear Rate

2005 ◽  
Author(s):  
L. J. Yang
Keyword(s):  
Steady State ◽  
Wear Rate ◽  
Wear Test ◽  
Standard Test ◽  
Test Method ◽  
Testing Time ◽  
Wear Coefficient ◽  
Wear Rates ◽  
Test Methodology

Wear rates obtained from different investigators could vary significantly due to lack of a standard test method. A test methodology is therefore proposed in this paper to enable the steady-state wear rate to be determined more accurately, consistently, and efficiently. The wear test will be divided into four stages: (i) to conduct the transient wear test; (ii) to predict the steady-state wear coefficient with the required sliding distance based on the transient wear data by using Yang’s second wear coefficient equation; (iii) to conduct confirmation runs to obtain the measured steady-state wear coefficient value; and (iv) to convert the steady-state wear coefficient value into a steady-state wear rate. The proposed methodology is supported by wear data obtained previously on aluminium based matrix composite materials. It is capable of giving more accurate steady-state wear coefficient and wear rate values, as well as saving a lot of testing time and labour, by reducing the number of trial runs required to achieve the steady-state wear condition.

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