Views:0 Author:Site Editor Publish Time: 2020-07-11 Origin:Site
Basic requirements of standard test blocks:
The material of the standard test block should be uniform, with little internal impurities, and no defects affecting the use. It is easy to process, not easy to be deformed and embroidered, and has good acoustic properties. The parallelism, perpendicularity, roughness and dimensional accuracy of the test block should be strictly inspected and meet certain requirements.
The standard test block should be made of open-hearth killed steel or electric furnace mild steel, such as No. 20 carbon steel.
The flat-bottomed hole on the test block should be inspected for its diameter, surface roughness and flatness at the bottom of the hole. The following inspection methods are commonly used: first clean the hole with a non-corrosive solvent and dry it, then use a syringe to inject the silicone rubber into the hole, draw out the syringe, insert a pin, take out the rubber model with the pin after the rubber is solidified, and check on the optical projector The roughness and flatness of the hole bottom.
Commonly used standard test blocks:
IIW test block (V 1 test block): IIW is the English abbreviation of the International Welding Society. The modified test block was first proposed by the representative of the Netherlands, so it is called the Dutch test block. The shape of the modified test block is similar to that of a ship, so it is also called a ship test block. The material of the IIW test block is equivalent to my country's No. 20 steel, normalized, and the grain size is 7-8.
The main purpose of IIW test block (V1 test block):
1. Adjust the longitudinal wave detection range and scanning speed (time-baseline ratio): use the 25mm and 100mm sizes on the test block.
2. Test the horizontal linearity, vertical linearity and dynamic range of the instrument: use the 25mm and 100mm sizes on the test block.
3. Determine the far-field resolution of the straight probe and the instrument combination: use the dimensions 85, 91 and 100 on the test block.
4. Measure the maximum penetration ability after the combination of a straight probe and the instrument: use the multiple reflection waves from the bottom of the Φ50mm plexiglass block.
5. Determine the blind area of the straight probe and the instrument combination: use the Φ50mm plexiglass arc surface to the side of the test block with a distance of 5mm and 10mm.
6. Determine the incident point of the oblique probe: use the R100 arc surface.
7. Determine the refraction angle of the oblique probe: the refraction angle is measured with a Φ50mm hole in the range of 35°～76°, and the refraction angle is measured with a Φ1.5mm hole in the range of 74°～80°.
8. Determine the sensitivity margin of the combination of the inclined probe and the instrument: use the test block R100 or Φ1.5mm.
9. Adjust the detection range and scanning speed of transverse wave: Since the sound path of longitudinal wave 91mm is equivalent to the sound path of transverse wave 50mm, the 91mm on the test block can be used to adjust the detection range and scanning speed of transverse wave.
10. Determine the deviation of the sound beam axis of the inclined probe: use the right-angle edge of the test block to measure.
IIW2 test block (V 2 test block): The IIW2 test block is also the standard test block of the International Welding Society proposed by the representative of the Netherlands. Because the shape is similar to a horn, it is also called a horn test block. Compared with the IIW test block, the IIW2 test block is light in weight, small in size, simple in shape, easy to process and easy to carry, but the function is not as good as the IIW test block.
The main purpose of IIW2 test block:
1. Determine the incident point of the oblique probe: use the R25 and R50 arc reflecting surface to measure.
2. Determine the refraction angle of the oblique probe: use Φ5mm constant through hole to measure.
3. Measuring the horizontal, vertical and dynamic range of the instrument: use the thickness of 12.5 to measure.
4. Adjust the detection range and scanning speed: the longitudinal wave straight probe uses the 12.5 bottom surface multiple reflection wave to adjust, the transverse wave oblique probe uses R25 and R50 to adjust.
5. The combined sensitivity of measuring instrument and probe: use Φ5mm and R50 arc surface to measure.