Hot-rolled plate: frame longitudinal beam (thickness 4-8mm）

Hot Rolled Steel process: the billet is heated to more than 1100℃ (austenitic state), and then cooled naturally after rough rolling and finishing rolling. Core features: the surface oxide is obvious, blue-gray, need to be removed by pickling or sandblasting; Wide thickness range (1.2-200mm), but large tolerance (±0.1-0.5mm); The internal grain is coarse, the residual stress is low, and the ductility is excellent.

Mechanical properties

Hot rolled plate: yield strength is usually 235-355 mpa (such as Q235B), suitable for impact resistance, high deformation scenarios (such as building trusses, shelf support).

Surface quality

Hot rolled plate: the surface oxide layer needs Pickling or shot peening treatment, which is mostly used for concealed structures (such as steel structure beams and columns);

Common misunderstanding "cold rolling must be higher than hot rolling" : cold rolling process costs are high, but not all scenarios need its high precision (such as hot rolled plate for underground pipeline support is more economical). "The same thickness can be replaced" : cold-rolled plate due to work hardening, welding need to control the heat input, otherwise easy to crack. Selection decision tree Step 1: Clarify the demand priority strength/precision requirements → select cold rolling; High cost/toughness requirements → selective hot rolling. Step 2: Evaluate processing conditions No surface treatment equipment → purchase cold rolled sheet directly; Complex bending/stretching → Cold rolled sheet to be annealed. Step 3: Calculate the total cost Small batch: cold rolled plate (eliminate post-processing); High volume: Hot rolled plate + autonomous surface treatment (lower cost). Supplier cooperation points require material certificates (such as JIS G3141 cold-rolled plate standard, ASTM A1011 hot-rolled plate standard); Verify thickness tolerances (micrometer sampling for cold-rolled plate, ultrasonic thickness gauge for hot-rolled plate); Preferred choice can be customized annealing process of steel mills (such as Baosteel, Angang Steel).