Characteristics and development history of China Q345R (HIC) steel

This article is about Characteristics and development history of China Q345R (HIC) steel. The steel for hydrogen induced cracking produced abroad is mainly SA516G r (60 ~ 70) (H) steel, and has been widely used. In china, Q345R (HIC) steel and Q345R is widely used.

Since the 1990s, China has developed Q345R (HIC) steel, 20R (H IC) steel and SA 516Gr70 (HIC) steel on the basis of 20R, Q345R and SA516Gr70, and has been widely used in China. . However, due to the limitations of equipment conditions, there is nomajor breakthrough in the development of large thickness (not less than 120 mm) HIC steel. Therefore, large thickness and large single heavy moisture resistant hydrogen sulfide corrosion steel plates have long relied on imports. In recent years, with the continuous updating and transformation of equipment, in 2006, large-scale high-performance anti-hydrogen sulfide corrosion steel was developed. In 2007, SA516 Gr70 (HIC) and Q345R (HIC) steel plates with a thickness of 110-132 m were supplied to the Sichuan Puguang project for 6 427 t. 2008-09 , combined with the manufacturing needs of Tianjin Bluestar cold high pressure separator equipment, according to the technical requirements of the user, the SA516 Gr65 (HIC) extra thick plate with a thickness of 165 mm was produced, and its quality has reached the same level as France's Arero. The level of the product.

The Q345R(HIC) steel produced in China is not a new steel grade. Instead, it adds some additional steels with certain hydrogen-resistant cracking resistance to the smelting requirements of the Q345R steel plate. Q345R(HIC) steel is smelted in an electric furnace + LF / VD vacuum refining process, and calcium is processed during the smelting process to control the shape of the inclusions. The steel is an intrinsic fine-grained killed steel having an actual grain size of 5 or more.

Q345R steel cracks rapidly due to stress corrosion cracking and hydrogen induced cracking under severe H2 and wet H2S environmental conditions. Studies have shown that the sensitivity of hydrogen induced cracking is closely related to the mass fraction of S element in steel and the band structure, and the sensitivity of S mass fraction and band structure is also reduced. The mass fraction of S element in Q345R (HIC) steel smelted by special methods has been reduced to an ultra-low level of 0.004, which not only has the ability to resist hydrogen-induced cracking, but also improves the resistance to H2S stress corrosion. In recent years, Q345R (HIC) steel pressure vessels have been used more and more. In the refining and chemical industry, Q345R (H IC) steel has a tendency to replace Q345R steel.