What is the Q345NQR4 steel meaning?

TB/T 1979 Q345NQR4 weathering steel

Standard: TB/T 1979-2014

Material: Q345NQR4

Equivalent: 08CuPVRE hot rolling
Category: weathering steel, atmospheric corrosion resisting steel for railway rolling stock

Q345NQR4 steel meaning

The first charater “Q” is the first letter of Chinese Pinyin: “Qufu”, which means Yield Strength.

The number 355 is the minimum value of yield strength 355 MPa.

NQ means the first letter of Chinese Pinyi “NaidaQifushi”, which means atmospheric corrosion resisting.

R is short for as rolled.

4- Indicates the steel belongs to Cu, P, V (RE) series weathering steel.

Q345NQR4 steel shall be done low temperature impacting test at -40 °C with impact energy 27J for the plates thickness equal or above 12mm.