What are “Direct Rolled Coil,” Hard Rolled Coil, and Medium-Thick Plate?

Direct Rolled Coil belongs to Hot Rolled Coil

Hot Rolled Coil is produced using continuous casting slabs or initial rolled slabs as raw materials. After progressive heating in a reheating furnace and descaling with high-pressure water, the material enters the roughing mill. The roughed material undergoes head and tail cutting before entering the finishing mill, where computer-controlled rolling is implemented. After final rolling, the product goes through laminar cooling (computer-controlled cooling rate), is coiled by a coiler, and becomes a Direct Rolled Coil. Direct Rolled Coils often have tongue and fish-tail shapes at the head and tail, with lower thickness and width accuracy. Defects like waves, edges, and tower shapes may exist at the edges. These coils are heavier, and the inner diameter of the steel coil is 760mm. (Commonly used in the pipe manufacturing industry.)

Hot-rolled products have excellent properties such as high strength, good toughness, easy processing, and good weldability. Therefore, they are widely used in manufacturing industries such as ships, automobiles, bridges, buildings, machinery, and pressure vessels.

Hot-rolled steel plate products include steel strips (coils) and steel plates cut from them. Steel strips (coils) can be divided into Direct Rolled Coils and finished coils (divided coils, leveled coils, and longitudinally cut coils).

Direct Rolled Coil
Direct Rolled Coil

Hard Rolled Coil

Hard Rolled Coil: Continuous rolling of hot-rolled pickled coils at room temperature.

Features: Because it has not undergone annealing treatment, its hardness is very high (HRB greater than 90), and its mechanical processing performance is extremely poor. It can only undergo simple directional bending processing (less than 90 degrees, perpendicular to the coiling direction).

Application Scope:

(1) Processed into ordinary cold-rolled after annealing;

(2) Processed into galvanized steel with a galvanizing unit equipped with pre-annealing treatment;

(3) Panels that basically do not require processing.

Medium-Thick Plate

Medium-Thick Plate Definition: Steel plate thickness greater than or equal to 5.0mm.

Classified into ordinary carbon plate, high-quality carbon plate, low-alloy plate, ship plate, bridge plate, boiler plate, container plate, etc.

Applications: Used in industries such as construction, machinery, shipbuilding, bridges, boilers, pressure vessels, etc.