Crack Control Test
MAIN MENU
MAC BRIGHT STEEL
- +90 232 877 17 29
- info@macbrightsteel.com.tr
- Bağyurdu Halilbeyli Organized Industrial Zone District, Nif Street, No:20 Kemalpaşa / İzmir, Turkey
Crack Control Test
| Surface Quality Classes | |||||
| Condition | Class | ||||
| 1 | 2 | 3 | 4 | ||
| Permissible depth of discontinuities | max. 0,3 mm for t ≤ 15 mm; max. 0,02t for 15 < t ≤ 100 mm |
max. 0,3 mm for t ≤ 15 mm; max. 0,02t for 15 < t ≤ 75 mm max. 1,5 mm for t > 75 mm |
max. 0,2 mm for t ≤ 20 mm; max. 0,01t for 20 < t ≤ 75 mm; max. 0,75 mm for t > 75 mm |
technically crack free by manufacturee | |
| Maximum percentage of delivered weight with discontinuities in excess of specified level | 4 % | 1 % | 1 % | 0,2 % | |
| Product forma | |||||
| Rounds | + | + | + | + | |
| Squares | + | + (for t ≤ 20 mm)c | - | - | |
| Hexagons | + | + (for t ≤ 50 mm)c | - | - | |
| Flats | +b | - | - | - | |
| Special sections | +d | - | - | - | |
| NOTE t = nominal thickness that means diameter of bars and distance across flats of squares and hexagons. | |||||
| a + indicates commonly available in these classes, - indicates not commonly available in these classes. b Maximum depth of discontinuities refers to respective section (width or thickness). c Crack detection with eddy current device not possible for t > 20 mm or t > 50 mm as indicated. d Reference dimensions to be agreed at the time of enquiry and order e The surface quality class shall be better than class 3. The requirements and the kind of verification are to be agreed at the time of enquiry and order. |
|||||
Discontinuities and defects are detected by applying one or more of the non-destructive testing (NDT) methods to the material.
Discontinuities are regions of inhomogeneity within a homogeneous material structure. Discontinuities are located within the acceptance limits of the relevant standards (detailed in the standards menu).
Defects are the general name given to discontinuities that will limit the use of the material or adversely affect its performance and are outside the acceptance limits of the relevant standards.
Discontinuities can be caused by 3 different stages:
- Discontinuities Arising from Design: Incorrect material selection, inappropriate product process and/or inappropriate process parameters, incorrect geometry and inappropriate material dimensions cause the most basic design discontinuities.
- Discontinuities Arising from Production: Casting, welded joining, plastic forming, machining, and powder metallurgy are the production methods. There are discontinuities specific to each production method.
- Casting Discontinuities: Gas cavity, shrinkage cavity, hot rupture, inclusion, and cold coalescence etc.
- Source Discontinuities: Cracks, pores, insufficient melting, insufficient penetration, and solid residues, etc.
- Plastic Forming Discontinuities: Lamination, grain, inclusions, elongated tensile voids, and cracks, etc.
- Machining and Heat Treatment Discontinuities: Grinding – machining cracks and heat treatment cracks are included in this group.
- Service Discontinuities: Fatigue cracks, stress corrosion cracks and intergranular crack formation starting with pitting corrosion are discontinuities in this group.
Crack control (NDT Control / NDT Test) in steel trading companies, heat treatment companies, plate / sheet trading companies, foundries, cement factories and crane manufacturers are done by ultrasonic crack control test, ultrasonic phased array crack control test, magnetic crack control test and penetrant crack control tests. Welding control (NDT Control / NDT Test) for steel construction companies, shipyards, pipelines, tank and storage companies are done by magnetic crack control test, ultrasonic crack control test and ultrasonic phased array crack control tests.
