Effect of cooling process on microstructure and properties of SA633 Gr E carbon steel plate sheet

The weldability of SA633 Gr E carbon steel plate sheet is good. It means that under certain process and construction conditions, SA633 Gr E carbon steel plate sheet can obtain good performance after welding. Weldability is a measure of the hot workability of steel. Weldability can be divided into weldability in construction and weldability in use. Weldability in construction refers to the sensitivity of cracking in weld metal and near seam zone, and hardening sensitivity of steel in near seam zone. Good weldability means that under certain welding process conditions, the weld metal and steel near the seam do not produce cracks. Weldability in use means that the mechanical properties of weld and HAZ steel are not lower than those of base metal.

The Brazil steel is facing a "crisis of demand" as the epidemic of new crown pneumonia spreads in Brazil. The demand for SA633 Gr E carbon steel plate sheet and so on steel will be reduced by 50% in April. The demand for the second quarter will be 40% lower than that in the first quarter. The demand for this year will be reduced by 20% compared with the same period this year. In 2019, Brazil's apparent steel consumption was 20.6 million tons, a year-on-year decrease of 2.7%; crude steel production dropped to 32.33 million tons, the lowest since 2016 (30.2 million tons).

Q550C steel belongs to low alloy high strength steel. Chemical composition of Q550C steel: C ≤ 0.18, Si ≤ 0.60, Mn ≤ 2.0, P ≤ 0.030, S ≤ 0.030, Nb ≤ 0.11, V ≤ 0.12, Ti ≤ 0.20, Cr ≤ 0.80, Ni ≤ 0.80, Cu ≤ 0.80, N ≤ 0.015, Mo ≤ 0.30, B ≤ 0.004, Al ≤ 0.015. Mechanical properties of Q550C steel: yield strength ≥ 550 MPa, tensile strength 600-780 MPa, elongation after fracture ≥ 16%, impact energy ≥ 55J. SA633 Gr E carbon steel plate sheet, Q550C steel is mainly used for manufacturing various large-scale engineering structural components and construction machinery. Due to its high strength, Q550C steel can meet the requirements of large-scale and lightweight construction machinery.