JB/T 5000.14-2007General technical requirements for heavy machinery - Part 14: Non-destructive testing of steel castings (English PDF)

3.3 Cluster of defect indications

A cluster of defect indications happen when the distance between two adjacent defects is two times less than the length of the bigger one.

3.4 Array defect indications

An array defect indications are including at least three linear defect indications or nonlinear defect indications, and the distance by line connection between them less than 2mm.

4. General requirements

4.1 Application principles

4.1.1

The chosen of inspection method and quality inspecting grade should be based on the usage and type of forgings which should be accord with the requirements of relative technical documents.

4.1.2

For the ferromagnetic forgings which required surface inspection, the magnetic particle inspection should be prior to use. The penetrate inspection is used only when there are some limitations, for instance structural morphology or resource condition.

4.2 Inspection files

4.2.1

When inspecting wildings by using standards hereby, a nondestructive inspection specification which is according with relevant regulation can be made out by referring to the standards hereby when necessary.

4.2.2

The inspection procedure and result should be exact and integrity with a signature of the one responsible for. The storage period of inspection records and reports should be not less than 5 years .After 5 year, provided the user requiring, they can be given to the user self for reserving.

4.2.3

In the inspection files, the quality grade and validity term of relevant inspector who is responsible for a inspection should be recorded.

4.2.4 A regular inspection with a record should be taken on the inspection equipment and device’s performance, and only after qualifying, they can be used.

4.3 Inspector

4.3.1

All the inspectors work on the nondestructive inspection should hold a qualification certificate awarded by the national relevant department.

4.3.2

The inspector of nondestructive inspection is graded senior level, medium level and general level. The inspector with a leveled certificate should work on a relative inspection work on each level carrying a relative technical responsibility.

4.3.3

The inspector of nondestructive inspection should have a good physical condition; moreover the vision has to reach the following requirements.

4.3.3.1Corrected visual acuity should be no less than 5.0 (the decimal fraction is 1.0) and take a sight test every year.

4.3.3.2

The inspector work on the surface inspection should not be color blindness.

5.2 Choosing quality grade

5.2.1

The defects allowed on external or inner of steel castings can be regulated in material standard or according to the quality grading order in 5.1. The following items have to be considered according to magnitude of load, method and distribution.

5.2.1.1

For the different area on the castings, a different quality grade can be made .In this case a relative area should be specified as following.

—— indicate the place, length and width;

—— other depth should be given out to the welding seam’s each end and the special edge area in

5.2.3.

5.2.1.2

For the quality on external or inner, a same or different quality grade can be decided.

5.2.1.3

The quality grade 1 is only be used for welding or the special edge area in 5.2.3.

5.2.1.4

The shape of castings can affect its quality and inspectable .Moreover, the inspectable of castings is also concerning with the surface condition.

5.2.2

The grade 5 is applied when ordering provided a quality grade is not indicated and other requirements is also not specified in the material standard, center 15 15 15 15 15 15 ...