1. Differences in chemical composition
| Element | GR.B Upper limit | GR.C Upper limit | Influence |
|---|---|---|---|
| C | 0.26% | 0.23% | GR.C has lower carbon content and lower risk of cold cracking during welding |
| P | 0.035% | 0.030% | GR.C has stricter impurity control and better low temperature toughness |
| S | 0.035% | 0.025% | GR.C has lower sulfur content and better hot working performance |
2. Mechanical properties comparison
| Parameter | GR.B | GR.C | gap |
|---|---|---|---|
| Yield Strength | ≥235 MPa | ≥315 MPa | +34% |
| Tensile Strength | ≥400 MPa | ≥425 MPa | +6% |
| Elongation | ≥21% | ≥23% | +2% |
| Cold bending performance | Generally | Excellent | GR.C can bend to a smaller radius |
3. Differentiation of core application scenarios
| Type | Applications | Advantages |
|---|---|---|
| GR.B | Lightweight building frames, enclosure structures, general equipment supports | Low cost, meeting regular strength requirements |
| GR.C | Heavy machinery chassis, bridge load-bearing components, high-pressure pipeline supports | High yield strength + fatigue resistance, suitable for dynamic loads |
4. Key points of processing and cost
Welding process: GR.C has lower carbon equivalent (CET≤0.45%), loose welding preheating requirements, and reduced process costs; GR.B welding requires strict control of heat input to prevent embrittlement.
Economic efficiency: GR.B is about 15-20% cheaper and suitable for budget-sensitive projects; GR.C has a significant strength premium and lower unit load-bearing cost.
