API 5L3 2020 pdf free download
API 5L3 2020 pdf free download.Drop-Weight Tear Tests on Line Pipe.
5 Specimens 5.1 Orientation 5.1.1 The specimens shall be removed from pipe such that the length of the specimen is in the circumferential direction of the pipe. 5.1.2 The specimens shall be flattened unless the D/t is less than 40. If the D/t is less than 40, then the center 1 in. to 2 in. (25 mm to 51 mm) may be left unflattened. If buckling occurs, the test results are not valid and replacement tests shall be conducted. Flattening has been observed to decrease the percent shear of the fracture. In the case of a difference between flattened and nonflattened specimen results, or in referee testing, the results from nonflattened specimens shall govern. 5.1.3 The specimens may be removed from the pipe wall by sawing, shearing, or flame cutting with or without machining, provided the dimensions of the finished specimen are within the tolerances shown in Figure 1. NOTE If the specimen is flame cut, it is usually difficult to press in the notch unless the heat-affected zone is removed by machining.
5.2 Notch Geometry The pressed notch is the preferred notch. The chevron notch may be considered an alternative to the pressed notch, particularly for higher Charpy V-notch energy steels where invalid results are more likely to occur with pressed notch. The chevron notch can eliminate excess initiation energy associated with some higher toughness line-pipe steels, which frequently result in invalid specimens as defined in 7.1. a) Pressed Notch. The pressed notch shall be pressed to the depth shown in Figure 1 with a sharp (no radius) tool steel chisel with an included angle of 45° ±2°. Machined notches are prohibited. When many specimens are to be tested, it is helpful to use a jig which will guide the chisel and stop it at the proper depth. b) Chevron Notch. The chevron notch shall be cut or machined to the 90° nominal configuration shown in Figure 2 with a width not to exceed 0.047 in. (1.2 mm). There is no notch radius requirement (i.e. the notch may be round or have a flat bottom).
The specimens shall be separated from each other and the bath sides and bottom by at least 1 in. (25 mm) or one wall thickness of the specimen, whichever is greater. Provision shall be made for circulation to ensure uniform bath temperature. NOTE Alternate heating or cooling methods may be used provided they produce an equivalent temperature at the mid- thickness of the specimen. 6.2 The specimens shall be removed from the bath and broken as described herein within a time period of 10 seconds. If this time is exceeded, the specimen shall be returned to the bath for a minimum of 10 minutes. The specimen shall not be handled in the center by devices whose temperature appreciably differs from the test temperature. 7 Specimen Evaluation 7.1 Valid specimens exhibit cleavage fracture from the notch tip with the exception being those specimens that exhibit ductile fracture on the complete fracture surface. In cases where welded pipe exhibits an upper shelf CVN energy greater than 148 ft-lbs (200 J), ductile initiation shall be acceptable. 7.2 The shear fracture appearance (dull, gray, and silky) is to be rated by differentiating the percent of shear fracture as opposed to cleavage fracture which is typically bright and crystalline in appearance. The fracture appearance of the specimen to be evaluated is the surface observed when looking parallel to the fracture specimen.
7.5 The percent shear area of the fracture surface can be determined in several ways, as described below. a) Measure the shear area of the fracture surface with a planimeter on a photograph or optical projection of the fracture surface. b) Compare the fracture surface with a calibrated set of photographs of previously fractured specimens or with actual specimens of calibrated percent areas for a specific thickness. c) Follow procedure as described in Annex B. d) Use any other procedure which has been demonstrated to produce results equivalent to those obtained from 7.5 a, 7.5 b, or 7.5 c above. 8 Report Inspection documentation shall conform to the requirement of API Specification 5L. A report of the test results shall be furnished to the purchaser and shall include: — steel heat number; — specimen number or identification; — wall thickness within ±0.005 in. (±0.127 mm); — test temperature; — total shear area, percent; and — notch type.
