Grade A ship steel is mainly used for the internal frame of the ship and the outer plate bearing general stress. Grade B, Grade D and Grade E ship steel RA32 oil supply vessel steel can be used for important structures in high stress areas such as hull outer plate and main deck. The Grade E ship steel has good low temperature performance, which is suitable for the hull outer plate, deck, etc. According to the minimum yield strength, the high-strength ship steel is divided into four grades: A, D, E and F. The commonly used high strength ship steels are AH32, DH32, EH32, etc.
The weldability of RA32 oil supply vessel steel is good. It means that under certain process and construction conditions, RA32 oil supply vessel steel 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 effect of nitrogen on steel performance is similar to that of carbon and phosphorus. With the increase of RA32 oil supply vessel steel nitrogen content, the strength of steel can be improved, plasticity especially toughness can be significantly reduced, weldability becomes worse, and cold brittleness is intensified. Nitrogen with aluminum, niobium, vanadium and other elements can reduce its adverse effects, improve the performance of RA32 oil supply vessel steel steel, can be used as an alloying element of low alloy steel.
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