Methods for ultrasonic examination of steel forgings for valves
1 Scope
This standard specifies the general requirements, testing methods, defect classification and testing report for ultrasonic testing that adopts the A-mode ultrasonic fIaw detector using pulse echo technique to detect the defects of workpiece.
This standard is applicable to the ultrasonic testing of carbon steel and low alloy steel castings.
This standard is not applicable to ultrasonic testing for valve products or raw materials such as austenitic stainless steel forgings and pipes, steel plates and welds.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, or revisions, of any of these publications do not apply to this standard. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition applies.
GB/T 11259-1999 Standard practice for fabrication and control of steel reference blocks used in ultrasonic inspection (eqv ASTM E428:1992)
JB/T 9214-1999 Practice for evaluating performance characteristics of A scope ultrasonic pulse-echo testing systems
JB/T 10061-1999 Commonly used specification A-mode ultrasonic flaw detector using pulse echo technique (eqv ASTM E750:1980)
JB/T 10062-1999 Testing methods for performance of probes used in ultrasonic flaw detection
JB/T 10063-1999 Specification for No. 1 standard test block used in ultrasonic flaw detection
3 General requirements
3.1 Ultrasonic testing personnel
Ultrasonic testing personnel shall be those who have certain basic knowledge and forging testing experience and have obtained technical qualification certificates recognized and approved by relevant departments.
3.2 Testing equipment
3.2.1 Ultrasonic testing equipment shall be accompanied with product quality certificate or qualification documentation.
3.2.2 Flaw detector:
3.2.2.1 A-mode ultrasonic fIaw detector using pulse echo technique is adopted, and its operating frequency shall be 0.5 MHz ~ 10 MHz.
3.2.2.2 Instrument shall be displayed linearly within at least 80% of the full scale, and the vertical linearity error shall not be greater than 5%.
Foreword i
1 Scope
2 Normative references
3 General requirements
3.1 Ultrasonic testing personnel
3.2 Testing equipment
3.3 Test blocks
3.4 Couplant
4 Testing methods
4.1 Testing time and preparation
4.2 Scanning
4.3 Determination of attenuation coefficient of workpiece material
4.4 Determination of testing sensitivity
4.5 Compensation
4.6 Re-checking of testing system
4.7 Determination of equivalent of a flaw
4.8 Flaw records
5 Flaw grade classification
6 Test report
Figure 1 CS ǀ standard test block
Figure 2 CS II standard test block
Figure 3 CSIII standard test block
Figure 4 Scanning at perpendicular directions
Table 1 Dimensions of CS ǀ standard test block
Table 2 Dimensions of CS II standard test block
Table 3 Grade classification of single flaw
Table 4 Grade classification for an intensive flaw area
Table 5 Grade classification for loss of back reflection
