M4 M16 Carbon steel L & J Hook Bolt with nut washer Class4.8 grade 8.8 Zinc plating

• One Time Burying Method: Bolts are embedded during concrete pouring, ideal for tilt-controlled towers.
• Pre-reserved Hole Method: Bolts placed after equipment positioning, using non-shrinkage concrete.

Proper bolt placement and reinforcement techniques are crucial. Solutions include welding reinforcement bars for loose bolts, adjusting bolt length through cutting or elongation, and correcting position mismatches.

Equipment fixing, steel structure foundations, street lamps, traffic signs, pumps, boiler installation, heavy equipment pre-embedded fixing.

Brinell hardness (HB) and Rockwell hardness are primary measurement methods, each with specific testing procedures.

Grade 8.8 Zinc plating" usually refers to High strength bolts or fasteners of strength class 8.8 with an electro galvanised surface.
1. Grade 8.8 (8.8)
Indicates the mechanical property grade of the bolt, where:
‘8’ denotes tensile strength ≥ 800 MPa
‘.8’ indicates that the yield strength is 80% of the tensile strength
The material is generally medium carbon steel or low carbon alloy steel, and after heat treatment (quenching + tempering).
2. Zinc plating
It is an electroplated zinc finish used to improve corrosion resistance.
Commonly labelled as:
‘8.8 Galv’ or ‘8.8 Zinc plated’.
The thickness of the coating is usually 5-12 μm, depending on the standard or the environment in which it is used.

Steel properties can be enhanced through alloy mixing:

• Carbon increases hardness/rigidity but decreases toughness
• Chromium increases hardness with less impact on toughness
• Titanium increases both hardness and toughness

• Quenching: Rapid cooling increases hardness but decreases malleability
• Tempering: Slow cooling increases both strength and toughness

Carbon steel and alloy steel bolts have multiple performance levels (3.6 to 12.9), with 8.8+ being high-strength bolts requiring heat treatment.