Hough-wall Bolts
Diameter
- Common diameters include M6, M8, M10, M12, M14, M16, M20, M24, etc.
- They can be selected according to factors such as the lateral pressure of the concrete, the thickness of the wall, and the strength of the formwork. For example, for the formwork fixing of small-scale building walls, M12 or M14 may be used.
- In the environment of thick walls and high pressure such as large-scale dams, those with a diameter of M20 and above will be used.
Length
- Generally, there are lengths such as 60mm, 80mm, 100mm, 120mm, 140mm, 160mm, etc., and custom lengths are also available.
- The length should take into account the thickness of the wall, as well as the dimensions of the formwork, wooden formwork, steel pipes and other reinforcement components.
- For example, for a 200mm-thick wall, with a formwork thickness of 15mm, and both the wooden formwork and the steel pipe having a thickness of 30mm, a through-wall bolt of about 300mm can be selected.
Materials of Hough-wall Bolts
- Ordinary Carbon Steel: Such as Q235, has a low cost, sufficient strength, and good processing performance, and is suitable for the formwork fixing of general building walls.
- High-strength Alloy Steel: Such as 40Cr, 35CrMo, etc., after quenching and tempering treatment, it has high tensile strength, yield strength, and fatigue resistance, and is used in projects with high requirements for the strength and reliability of bolts, such as high-rise buildings and long-span bridges.
- Stainless Steel: Such as 304, and 316, it has strong corrosion resistance and is used in environments with anti-corrosion requirements, such as coastal buildings, chemical workshops, food processing workshops, etc.
Surface Treatments of Hough-wall Bolts
- Galvanizing Treatment: It includes hot-dip galvanizing and electro-galvanizing. Hot-dip galvanizing is to immerse in molten zinc liquid to form a thick zinc layer, which has strong corrosion resistance and is suitable for harsh environments such as outdoors and humid areas; electro-galvanizing deposits a thin zinc layer by using the electrolysis principle, and is suitable for indoor occasions and those with lower requirements for service life.
- Blackening Treatment: Also known as oxidation treatment or bluing treatment, the bolt is put into a chemical solution containing oxidants and heated to form a black or bluish-black film of ferric tetroxide, which can improve corrosion resistance to a certain extent and has an aesthetic appearance.
- Phosphating Treatment: The bolt is soaked in a high-temperature solution containing phosphoric acid and dihydrogen phosphate, and a phosphating film composed of phosphate precipitates is formed. It is necessary to cooperate with the application of anti-rust oil to extend the service life.
Application Fields of Hough-wall Bolts
- Construction Field: Fixing the formwork during the construction of shear walls and columns in high-rise buildings; the construction of walls in hydraulic buildings such as dams and water tanks; fixing the formwork during the lining construction of tunnels and culverts.
- Equipment Installation Field: Used for fixing large-scale equipment such as elevators, outdoor air conditioning units, and water heaters to the wall; in industrial production, fixing the installation of large-scale machinery and pipelines passing through the wall.
- Other Fields: Connecting the embedded plate of the curtain wall and the wall structure in the curtain wall project; it is also used in the construction of some temporary facilities, such as prefabricated mobile houses and construction enclosures.
