JB/T 9020-1999 JB/T 9020-1999 Ultrasonic testing of large forged crankshafts JB/T9020-1999 Standard download decompression password: www.bzxz.net

JB/T9020
This standard adopts ASTMA503+
一75 (reconfirmed in 1980) "Ultrasonic Testing Method for Large Crankshaft Forgings" in an equivalent manner. This standard is a revision of ZBJ32004·88 "Ultrasonic Testing for Large Crankshaft Forgings". There are several differences between this standard and the adopted standard in terms of main technical contents:
…- Specific requirements are made for the flaw detection period and surface condition;-- The qualification of flaw detection personnel is stipulated;
The supplementary requirements in ASTMA503一75 (reconfirmed in 1980) are not adopted. Compared with ZBJ32004-88, this standard has some changes in the following important technical contents:- This standard re-describes Chapter 5 of the revised standard and makes more comprehensive provisions for the inspection report in Chapter 10;- The flaw detection frequency is revised to 1~～5 MHz. This standard replaces ZBJ32004--88 from the date of implementation. This standard is proposed and managed by Deyang Large Castings and Forgings Research Institute. The responsible drafting unit of this standard is the Second Dongxing Machinery Group Corporation. The main drafters of this standard are Wang Zi and Zhong Huixian. 336
1 Scope
Machinery Industry Standard of the People's Republic of China
Ultrasonic examination of large forged crankshafts
Ultrasonic examination of large forged crankshaftsJB/T9020
Replaces ZB J32 004--88
This standard specifies the technical specifications for ultrasonic inspection of forged crankshafts with main bearing journals or crank journals with a diameter equal to or greater than 200mm.
This standard includes inspection equipment and inspection methods, and specifies inspection areas and acceptance rules. This standard is not applicable to ultrasonic inspection of forged crankshafts for diesel locomotives, but this standard may also be used when the manufacturer and the user agree.
2 Reference standards
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 will be revised, and the parties using this standard should explore the possibility of using the latest versions of the following standards. G13/T9445—1988 General Rules for Technical Qualification of Nondestructive Testing Personnel JB/T10061—1999 General Technical Conditions for Type A Pulse Reflection Ultrasonic Flaw Detector 3 Basis for the use of this standard
The use of this standard must be indicated in the order contract and drawings: The crankshaft is accepted according to this standard. 4 Flaw detection period and surface requirements
4.1 The first flaw detection is carried out after rough machining (i.e. after the first heat treatment) and before drilling and processing grooves, and the second flaw detection is carried out after the second heat treatment.
4.2 The roughness of the flaw detection surface should be Ra6.3um. 5 Equipment and personnel requirements
5.1 The performance of the flaw detection equipment shall comply with the provisions of JB/T10061. The flaw detection frequency is 1~5MHz. 5.2 The flaw detection personnel shall comply with the provisions of GB/T9445, and it is best to be a person with a qualification certificate of Level I or above. 6 Adjustment of instrument sensitivity 1)bZxz.net
The bottom wave reflection should be adjusted to 100% full screen height as the reference wave on the thickness of the workpiece to be inspected. This adjustment should be performed in an area without downward interference signals.
1) For instruments with good vertical linearity, 100% screen height can be used as the reference wave height. For saturated instruments with poor vertical point linearity in the 80%~100% screen height section, 80% full screen height can be used as the reference.
Approved by the State Bureau of Machinery Industry on June 28, 1999, and implemented on January 1, 2000
7 Inspection area
7.1 Main key area
7.1.1 Axle pin and bearing part
JB/T 9020—1999
The area from the surface of all main bearing shaft journals and crankshaft journals to the depth of 1/8 of the diameter from the surface (see Figure 1). Main key area
Secondary key area
Figure 1 Inspection area of ​​shaft pin and bearing part
7.1.2 Crank arm part
The crank arm area between the center plane of the main bearing shaft parallel to the three o'clock position and the center plane of the adjacent crankshaft parallel to the three o'clock position, and the area from the common center line outward to the point where the outer diameter exceeds the outer diameter by 1/8 of the outer diameter (see Figure 2). Figure 2 Inspection area of ​​the vertical arm of the crankshaft
7.2 Secondary critical area
The area from 1/8 diameter inward to 1/4 diameter of the main bearing shaft journal and the crankshaft journal (see Figure 1). 7.3 Non-critical area
Other parts not included in the primary critical area and secondary critical area. 338
8 Inspection method
JB/T9020--1999
8.1 Inspect the entire surface of the crankshaft and conduct a longitudinal scan of all areas that can be inspected from each end face of the main bearing shaft and each end face of the crankshaft journal.
8.2 Scan each crankshaft journal and the main bearing shaft journal in the circumferential direction. 8.3 The probe should have at least 15% overlap each time it is scanned. 8.4 The scanning speed shall not exceed 150mm/s. 8.5 Inspection can be carried out in a stationary state or when the crankshaft is placed on a bed or roller and rotated. If the user does not specify, the manufacturer can choose any method for inspection.
8.6 During the inspection process, pay attention to monitoring the attenuation of the bottom wave. If the bottom wave drops significantly, it may indicate the existence of defects, or it may indicate that the probe is in poor contact with the surface of the crankshaft forging, or that the transmittance of the sound beam has changed locally when passing through the forging. 9 Acceptance criteria
9.1 White spots, cracks or other crack-like defects are not allowed in the main critical area, secondary critical area and non-critical area. 9.2 The following defects are allowed to exist within the limits:
--In the main critical area, defect signals equal to or greater than 20% of the reference wave height are not allowed; - In the secondary critical area, defect signals equal to or greater than 50% of the reference wave height are not allowed; - In other inspection areas, defect signals equal to or greater than 100% of the reference wave height are not allowed. - Dense defects are not allowed.
Note: Dense defects refer to the presence of 5 or more defect signals equal to or greater than 10% of the basic wave height in a 50mm (including 50mm) cube.
9.3 When the bottom wave attenuation caused by non-geometric shapes exceeds 50%, other inspections should be carried out on the crankshaft forgings, such as magnetic particle inspection, dye penetrant inspection, radiographic inspection or metallographic inspection, to determine the cause and decide whether the crankshaft can be used. 9.4 For any defects exceeding those specified in 9.2, the use of the crankshaft should be decided by the design department, process department and relevant technical persons in charge. 10 Inspection report
10.1 A simple diagram of the crankshaft forging should be drawn in the report to indicate the location, range and direction of any recordable signals found. 10.2 The following items should be recorded in the report:
a) Crankshaft name (specification, type), material, workpiece number, drawing number, furnace number, quantity; b) NDT method, NDT instrument, NDT frequency, probe, NDT sensitivity, coupling agent type, surface condition of the crankshaft inspected surface; c) NDT date, NDT results, NDT conclusion, inspector, and reviewer; d) Defect signals equal to or greater than 10% of the reference wave height; e) Any bottom wave attenuation greater than or equal to 20%; f) Any other abnormal conditions.
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