Carbon Steel Plate Description

Carbon steel plates have many uses and a large amount. They are mainly used in railways, bridges, and various construction projects to manufacture various metal components that bear static loads, and unimportant mechanical parts and general welded parts that do not require heat treatment.

Product Parameters

1. Chemical Composition of Q235 Carbon Steel Plate (%)

Element Q235A Q235B Q235C Q235D

Carbon (C) ≤0.22% ≤0.20% ≤0.17% ≤0.17%
Manganese (Mn) ≤1.40% ≤1.40% ≤1.40% ≤1.40%
Silicon (Si) ≤0.35% ≤0.35% ≤0.35% ≤0.35%
Sulfur (S) ≤0.050% ≤0.045% ≤0.040% ≤0.035%
Phosphorus (P) ≤0.045% ≤0.045% ≤0.040% ≤0.035%
Deoxidation Rimmed (F)/Killed (Z) Killed (Z) Killed (Z) Killed (Z)

Notes:

Quality Grade Improvement: From A to D, sulfur and phosphorus content decreases progressively, enhancing low-temperature toughness and purity.

Deoxidation Methods:

Q235A: Can be rimmed steel (low cost, good surface finish, but with segregation).

Q235B/C/D: Must be killed steel (uniform composition and stable performance).

Trace Elements: Q235D may contain small amounts of vanadium (V), titanium (Ti), or niobium (Nb) to improve low-temperature toughness.

2. Mechanical Properties of Q235 Carbon Steel Plate

Property Q235A/B (Thickness ≤16mm) Q235C/D (Thickness ≤16mm)

Yield Strength (σₛ) ≥235 MPa ≥235 MPa
Tensile Strength (σ₆) 375~500 MPa 375~500 MPa
Elongation (δ₅, 50mm) ≥26% (longitudinal) ≥26% (longitudinal)
Impact Energy (-20°C) Not required Q235D: ≥27 J
Hardness (HB) 120~160 (as-rolled) 120~160 (as-rolled)

Notes:

Thickness Effect: Yield strength slightly decreases with increasing thickness (refer to standard classification tables). For example, Q235B with 40~60mm thickness requires a yield strength of ≥225 MPa.

Low-Temperature Toughness: Q235D offers impact resistance at -20°C, suitable for cold-region structures.

Cold Bending Performance: Q235 exhibits good cold bending properties, ideal for folding and stamping.

3. Typical Applications

Construction: Building frames, steel workshops, bridge supports.

Mechanical Manufacturing: Shafts, bolts, brackets, and non-high-strength components.

Containers & Piping: Low-pressure storage tanks, ventilation ducts (requires rust prevention).

General Hardware: Angle steel, channel steel, sheet piles.

4. Comparison with Q195 and Q345

Parameter Q195 Q235B Q345B (Low-Alloy Steel)

Yield Strength ≥195 MPa ≥235 MPa ≥345 MPa
Tensile Strength 315~430 MPa 375~500 MPa 470~630 MPa
Carbon Content ≤0.12% ≤0.20% ≤0.20%
Low-Temperature No requirement No requirement (Q235D: available) -20°C Impact ≥34 J
Cost Lowest Moderate Higher