From the perspective of market conditions, today S355ML plate spot prices are operating smoothly, futures are volatile, and market acceptance is average. Merchants have a wait-and-see attitude. Low-price transactions are average, while high-price transactions are poor. Most merchants have daily transactions of 200-300 tons. between. For the market outlook, most merchants adopt the mode of selling more and lowering the warehouse, and are cautious about the later market.
Chemical composition of Q420 steel: C ≤ 0.20, Si ≤ 0.50, Mn ≤ 1.70, P ≤ 0.035, S ≤ 0.035, Nb ≤ 0.07, V ≤ 0.20, Ti ≤ 0.20, Cr ≤ 0.30, Ni ≤ 0.80, Cu ≤ 0.30, N ≤ 0.015, Mo ≤ 0.20. The mechanical properties of Q420 steel are: yield strength ≥ 340 MPa, tensile strength 500-680 MPa, elongation after fracture ≥ 18%, impact energy 34J.S355ML plate, Q420 steel has good mechanical properties and weldability, good cold and hot workability. Q420 steel is mainly used for manufacturing mining machinery, heavy vehicles, ships, bridges, medium and high pressure boilers, vessels and other large welding and structural parts.
S355ML plate controlled rolling is that, on the basis of adjusting the chemical composition of S355ML plate, by controlling the heating temperature, rolling temperature, deformation system and other process parameters, the change law of austenite structure and the microstructure of phase transformation products are controlled, so as to achieve the purpose of refining the structure and improving the strength and toughness of S355ML plate.
Expression method of pressure coefficient of seamless steel pipe: pressure P 17.5, coefficient S-4 seamless pipe production and manufacturing: tube blank -- Inspection -- peeling -- Inspection -- Heating -- perforation -- pickling -- grinding -- lubrication and air drying -- welding head -- cold drawing -- solution treatment -- pickling -- pickling and passivation -- Inspection -- cold rolling -- degreasing -- air drying -- internal polishing -- one external polishing -- Inspection -- identification of finished S355ML plate product packaging.