Forging ultrasound

There is no correlation between the ultrasonic grade of forgings and the grade of the forgings themselves; refer to the standards NB/T 47008–47010-2010 \"Forgings for pressure equipment\"...

Thank you, it only shows the quality assessment grade there, rather than the required ultrasound compliance level.

What does the quality assessment grade mean?

In NB/T47008, forgings are classified into three grades: II, III, and IV. For forgings of mechanical properties grades II and III, the requirement is that forgings from the same melting batch and subjected to heat treatment in the same furnace be grouped together, with one sample taken for inspection from each group. Grade IV forgings require individual inspection. Ultrasonic testing is not required for grade II forgings, while it is necessary to test each forging of grades III and IV individually. So what are the requirements regarding the quality grade of ultrasonic testing for forgings? For common forgings such as pipe flanges and manhole flanges, we usually specify in the drawings that such forgings should be manufactured, inspected, and accepted in accordance with NB/T47008-2010 grades II (III). Failing to specify specific ultrasonic inspection requirements means that the quality grade of the ultrasonic testing of the forgings shall be determined in accordance with the requirements of NB/T 47008. That is, Table 4 in the standard. The table lists three types of internal defects in forgings: individual defects, reduction in bottom wave amplitude, and defects in dense areas. For different categories of forgings, the acceptable levels for these three types of defects vary. For example, for cylindrical forgings, the acceptable level for individual defects is Grade II, the acceptable level for the reduction in the bottom wave is Grade I, and the acceptable level for defects in dense areas is Grade II. However, for some III and IV grade forging drawings that we consider to be relatively important, in addition to specifying the grade of the forgings and the requirements for manufacturing, inspection, and acceptance in accordance with NB/T47008, clear requirements are also set for ultrasonic testing. For example, after the rough machining of the forgings, ultrasonic testing is to be carried out in accordance with NB/T47013.3-2015, and a grade of II is considered acceptable. In summary, there is no correspondence between the forging grade and the grade that meets ultrasonic testing requirements. Generally speaking, the higher the grade of the forging, the higher the level required for successful ultrasonic testing.

Ultrasound is performed on each item, whether it is grade III or grade IV.

The grade of a forged part is related to the inspection items required for it. For parts with a higher grade, more inspection items and more detailed inspection requirements apply, and the inspection standards are stricter.

See NB/T 47008–47010-2010 \"Forgings for pressure equipment\"

Take a look at the specific non-destructive testing standards; NB/T 47013.3 covers the testing of forgings.