This standard specifies a test method for determining the specific radius bendability of pipeline anticorrosion coatings. This standard is applicable to determining the possibility of specific radius bending of anticorrosion coatings on steel pipes with an outer diameter of 33.5 mm. SY/T 0038-1997 Test method for specific bendability of pipeline anticorrosion coatingsSY/T0038-1997 Standard download decompression password: www.bzxz.net

1 Scope
Petroleum and Natural Gas Industry Standard of the People's Republic of China Test Method for Specific Bendability of Pipeline Anticorrosion Coatings Approved by: China National Petroleum Corporation Date of Approval: 1997-12-31
Effective Date: 1998-07-01
This standard specifies a test method for determining the specific radius bendability of pipeline anticorrosion coatings. This standard is applicable to determining the effect of specific radius bending on the anticorrosion coating on steel pipes with an outer diameter of 33.5mm. 2 Referenced Standards
SY/T0038—1997
Replaces SYJ38--1989
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T3092—1993 Welded steel pipe for low-pressure fluid transportation SY0063—1992 Test method for leak detection of pipeline anticorrosion layer SY00661992 Non-destructive measurement method for thickness of pipeline anticorrosion layer (magnetic method) 3 Significance and use
3.1 This test method provides data on the ability of the anticorrosion layer on the tested steel pipe to withstand cracking, peeling or other mechanical damage caused by bending. This test is carried out on steel pipes with anticorrosion layer, and the test results can be directly used to screen the anticorrosion materials coated on the steel pipe. When the coating process or material composition of the anticorrosion layer changes and affects the bending performance, this test method can also be used as a quality inspection and control method. 3.2 This method is to bend the steel pipe specimen with anticorrosion layer of 33.5mm outer diameter around the variable radius jig to form a set of specific bent pipe sections, and then visually inspect and electrically measure the bent specimen to find out the damage of the anticorrosion layer, such as cracking of the anticorrosion layer or bonding failure. 4 Equipment and Instruments
4.1 The bending device includes: variable radius jig, pipe clamp, sleeve, etc., see Figures 1 and 2. 4.1.1 Variable radius jig: It consists of four pieces of plywood with a thickness of 18 to 20 mm, connected by screws and conforming to the geometric shape shown in Figure 1. Its geometric shape is formed by arranging seven consecutive arc segments along the outer edge of the jig with decreasing radius (610, 530, 460, 380, 300, 230 and 150 mm). The first six arc segments are turned to the next tangent point at 45°, while the seventh arc segment is turned to the next tangent point at 90°. In order to put the steel pipe in place, the outer edges of two of the jig plates are cut into 45° chamfers, and the two pieces are combined to form a 90° V-shaped groove. Drill some through holes on the jig at the positions shown in Figure 1 to fix the pipe clamps and connect the plywood sheets. 4.1.2 Pipe clamps: All four pipe clamps are welded from 10mm thick steel plates and are numbered Nol~No4, see Figure 1 for details. 4.1.3 Casing: Use a steel pipe with an inner diameter slightly larger than the outer diameter of the test pipe and a length of 1.9m. 4.2 Magnetic thickness gauge; measuring range 1μm~20mm, accuracy is ±2% of the range. 4.3 Anti-corrosion layer leak detector; low voltage wet sponge leak detector with a leak detection voltage less than 100V or an electric spark leak detector with a leak detection voltage of 900-~20000V.
5 Test piece
5.1 The test piece should be made according to the coating process of the anti-corrosion layer steel pipe that can represent mass production. The anti-corrosion layer material should be coated on a pipe with an outer diameter of 33.5mm and a length of 2.5m. The anti-corrosion coating shall not have obvious defects or damage. The steel pipe shall meet the technical requirements specified in GB/T3092.
5.2 The test piece shall be placed at room temperature (20-30°C) for a long enough time to ensure the thermal balance between the steel pipe and the anti-corrosion coating. 150
Tube test piece
Screw
Plywood jig
Jig assembly drawing
Workbench table
[100×48×5.3×250
[100×48×5.3×200
Set 4—16
Explosion bolt 30-M16
6 Test steps
From Nol
Figure 2 Details of jig and support
6.1 This test should be carried out at 21~25℃. SY/T 0038-- 1997
[100 ×48 ×5. 3 × 250
No3申
[100×48×5.3×300
6.2 Determine the thickness of the anti-corrosion layer of each test piece according to the method specified in SY0066 and record it. 6.3 Test the test piece for leaks according to the method specified in SY0063, and require that the test piece has no leaks. 6.4 Place the state-adjusted test piece into the V-groove on the outer edge of the bending jig, insert and fix the No.1 pipe clamp, and tighten the butterfly screw. Put a sleeve on the other end and apply a continuous and steady force, keeping the force action line, the test piece and the jig V-groove in the same plane, so that the test piece bends around the jig. When the bending test piece is completed to a radius of 460mm, insert and fix the No2 pipe clamp and tighten the butterfly screw; when the bending test piece is continued to bend to a radius of 300mm, insert and fix the No3 pipe clamp and tighten the butterfly screw; when the bending test piece is continued to bend to a radius of 230mm, insert and fix the No4 pipe clamp and tighten the butterfly screw (Note: When placing the No2, No3, and No4 pipe clamps, they must be fixed in time and no lag is allowed), thus completing the bending operation of the test piece. 6.5 Use a low-pressure leak detector to check the bent test piece to determine whether the anti-corrosion layer has cracks and the location, type, number and size of the cracks, and record them. Check whether there is any phenomenon of anti-corrosion layer bonding failure caused by the bending operation surface. Note: The possibility of stress cracking of some anti-corrosion layers within a period of time after bending should not be ignored. If necessary, the bent test piece should be retained on the bending jig and tested after 24 hours.
7 Test Report
The test report shall include the following contents:
a) Complete information of the anti-corrosion coated steel pipe used for the test, including the name, type, average thickness, minimum thickness, maximum thickness, production batch number and production date of the anti-corrosion layer;
The number and serial number of the test specimens;bzxz.net
Test temperature;
The bending radius at which cracking first occurs;
Description of the cracking type;
The location and scope of the bond failure between the steel pipe and the anti-corrosion layer; Abnormal phenomena noticed during the test and when the specimens were just removed from the test device; Retention time after bending.
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