Q550GJ building steel plate technical requirements

Q550GJ (C, D, E) is a building steel (construction steel) complying with the GB/T 19879 standard. Generally, TMCP, TMCP+tempering, Q+T (quenching and tempering) and other heat treatment processes are used.

Technical conditions of Q550GJ construction steel: Z-direction performance, flaw detection performance, tension, Charpy V-notch impact, bending test, elongation.

The thickness direction performance material of Q550GJ building steel plate shall be subject to ultrasonic testing one by one according to GB/T 2970, and the testing method and qualification level shall be indicated in the requirements.

Materials with thickness less than 12 mm shall be subject to Charpy (V-notch) impact test with small size specimen. When the thickness of Q550GJ steel plate is 8mm-12mm, the sample size is 7.5mm x 10 mm x 55 mm, the test result shall not be less than 75% of the specified value; When the material thickness is 6 mm-8 mm, the sample size is 5 mm x 10 mm x 55mm, the test result shall not be less than 50% of the specified value.