Overview

Q355FRWB, Q355FRWC, Q355FRWD, and Q355FRWE are new fire-resistant weathering steels. These materials have been developed for both strength and durability. Their properties make them suitable for structural applications exposed to harsh environments and fire risks.

1. Steel Grade Meaning

The name Q355FRWB can be broken down as:

Q: Yield strength (from Chinese “Qu”)

355: Minimum yield strength (355 MPa)

FRW: Fire-Resistant Weathering

B: Grade classification (A to E, with E being higher)

These grades share the same base performance, with differences in classification grade.

2. Weldability

The Carbon Equivalent (CEV) must follow the standard limits.

If carbon content is ≤ 0.12%, the welding crack sensitivity index (Pm) may be used instead of CEV.

Either CEV or Pm can be used to evaluate weldability, based on agreement between the buyer and seller.

If not specified, the supplier may choose which method to use.

3. Smelting Process

Steel must be produced by converter or electric furnace.

Refining outside the furnace is required.

The smelting method can be selected by the supplier unless the buyer requests otherwise.

4. Delivery Conditions

Steel in the Q355FRW series can be delivered in the following conditions:

AR (As Rolled)

N (Normalized)

NR (Normalized Rolled)

TMCP (Thermo-Mechanical Controlled Process)

For higher strength levels such as Q420FRW and above, QT (Quenched and Tempered) delivery is also allowed.

Note:

Normalizing includes both normalizing and tempering.

TMCP includes thermo-mechanical rolling and tempering.