Many infrastructure and solar projects fail earlier than expected not because of poor design, but because the wrong steel material was selected from the beginning.

We’ve seen highway guardrails rust through within a few years in coastal Southeast Asia, and solar mounting brackets deform under high wind loads in desert regions because low-grade steel was used to reduce initial cost. In reality, choosing unsuitable carbon steel often leads to higher maintenance expenses, structural risks, and shortened project life.

For projects in tropical, coastal, or high-temperature environments, hardness, galvanizing quality, and steel grade directly determine whether the structure can survive 20+ years outdoors.

About Beifang Group

Since 2010, Shandong Beifang Group has specialized in galvanized steel products for highway infrastructure and solar energy projects. With over 15 years of manufacturing experience, our factory in Liaocheng, Shandong operates multiple production lines for guardrails, galvanized pipes, and PV mounting systems.

Understanding Carbon Steel Hardness

Carbon steel hardness is mainly determined by carbon content and heat treatment process. Hardness affects strength, weldability, wear resistance, and forming performance. Common measurement standards include HB (Brinell Hardness), HRB, HRC, and HV.

Low Carbon Steel (≤0.25% Carbon)

Representative Grades: Q235, 10#, 20#

Hardness: HB 120–150 / HRB 60–75

Features:

▸ Good weldability

▸ Easy forming and bending

▸ Lower strength but better ductility

Typical Applications:

▸ Highway guardrails

▸ Solar mounting structures

▸ Steel structures and welded components

Low carbon steel is the most commonly used material for guardrails and PV brackets because it balances cost, processing performance, and structural stability.

Medium Carbon Steel (0.25%–0.60% Carbon)

Representative Grades: 35#, 45#, 40Mn

Normalized Hardness: HB 150–220

Quenched & Tempered Hardness: HRC 20–40

Features:

▸ Higher strength

▸ Better wear resistance

▸ Suitable for load-bearing mechanical parts

Applications:

▸ Shafts

▸ Gears

▸ Mechanical components

Medium carbon steel is usually not recommended for large-scale galvanized guardrails or solar brackets because higher hardness reduces forming efficiency and increases galvanizing difficulty.

High Carbon Steel (>0.60% Carbon)

Representative Grades: T8, T10, 65Mn

Quenched Hardness: HRC 55–65

Features:

▸ Extremely hard

▸ Excellent wear resistance

▸ Lower toughness and weldability

Applications:

▸ Cutting tools

▸ Springs

▸ Saw blades

High carbon steel is generally unsuitable for outdoor guardrail or solar mounting systems due to brittleness and welding limitations.

How to Choose Materials for Guardrails & PV Mounting Structures

For highway guardrails, low carbon steel such as Q235 or Q355 combined with hot-dip galvanizing is the most practical solution.

In coastal or tropical regions, zinc coating thickness should reach at least 85μm according to ASTM A123 to improve corrosion resistance. For government infrastructure projects, material traceability and MTC documentation are also essential.

Recommended Configuration:

▸ Q235/Q355 steel

▸ Hot-dip galvanized coating ≥85μm

▸ Compliance with AASHTO or local highway standards.

PV mounting systems require a balance between strength, corrosion resistance, and installation efficiency.

For Southeast Asia projects exposed to typhoons and salt air, galvanized low carbon steel provides better long-term durability and lower maintenance cost compared with untreated steel.

For Middle East desert projects, material expansion under high temperatures and sand abrasion resistance should also be considered.

Recommended Configuration:

▸ Low carbon structural steel

▸ Hot-dip galvanizing ≥85μm

▸ Wind load customization up to 60m/s

▸ Corrosion-resistant bolt assemblies

What Beifang Group Can Provide

▸ Mill Test Certificates (MTC) for raw materials

▸ Galvanizing thickness inspection reports

▸ ISO 9001 quality management certification

▸ Customized structural calculation reports

▸ OEM/ODM production support

▸ Standard lead time: 25–35 days

Talk to Our Engineering Team

If you are sourcing materials for highway guardrails or solar mounting systems, our engineering team can help recommend suitable steel grades and galvanizing standards based on your project environment, contact our export engineer Wendy Yang directly:

WhatsApp: +86 195 2695 8693

Email: xinhui@bfgroup-tomex.com

For active projects, we provide:

1. Free material recommendation and structural consultation

2.Sample production within 7 days

3. Third-party inspection support before shipment

—— Shandong Beifang Group | Manufacturer since 2010