Understanding the Aesthetic of Galvanized Steel
To find out why the aesthetic of our Boltless Racks may be inconsistent from batches to batches, we must first understand the two key processes involved in the production of SWL Boltless Racks:
- Hot-dip Galvanization to produce the high-tensile Galvanized Steel coils
- Cold Roll Forming of the steel coils into all the Boltless Rack components
Hot dip galvanizing is the process of protecting iron or steel with a layer of zinc by immersing the metal in a bath of molten zinc at a temperature of around 450 °C (842 °F). During the process, a metallurgically bonded coating is formed which protects the steel from harsh environments, whether they be external or internal. It is considered to be the most environmentally friendly process available to prevent corrosion.
Aesthetic repercussion of Galvanization
Galvanization often results in a surface texture known as "spangles" on the coated metal. These spangles are crystalline structures formed during the galvanization process and are a characteristic feature of hot-dip galvanized coatings. The presence of spangles is due to the way the zinc coating solidifies as it cools after being immersed in the molten zinc bath. Here's why spangles form:
- Crystalline Structure: The zinc coating that forms during hot-dip galvanization has a crystalline structure. As the molten zinc adheres to the surface of the steel or iron and then cools, these zinc crystals start to solidify.
- Natural Variation: The formation of these zinc crystals is not uniform across the entire surface of the coated metal. Instead, it occurs in a somewhat random or natural pattern. This variation in the size and distribution of crystals gives rise to the spangle pattern.
The presence of spangles does not affect the protective properties of the galvanized coating; in fact, they are an indicator of a properly galvanized surface. Spangles are a sign that the zinc coating has adhered well to the metal substrate and that the metallurgical bond between the zinc and the steel or iron is strong, which is essential for corrosion protection.
It's important to note that while spangles are a natural outcome of the hot-dip galvanization process, the appearance of the spangle pattern can vary based on factors such as the composition of the steel, the specific galvanizing process used, and the cooling rate of the protected metal.
Cold Roll Forming
Cold roll forming is a manufacturing process used to shape flat metal sheets or strips into various profiles, sections, and shapes while maintaining the material at or near room temperature. This process is called "cold" roll forming because it does not involve heating the metal to a high temperature, as is done in hot rolling processes.
The key three advantages of cold roll forming are:
- High Efficiency and Cost-Effectiveness: Cold roll forming is highly efficient and cost-effective, especially for high-volume production. It allows for continuous processing of metal strips or sheets with minimal interruptions. This leads to reduced labor costs, lower material waste, and increased overall productivity, making it a cost-efficient choice for manufacturing large quantities of parts or profiles.
- Precise Tolerances and Consistency: Cold roll forming offers excellent control over dimensional tolerances. The process produces profiles with consistent cross-sections and tight tolerances, ensuring that each part meets precise specifications.
- Strength and Structural Integrity: Cold roll-formed parts often exhibit excellent strength and structural integrity, making them suitable for applications that require load-bearing or structural components.
Aesthetic repercussion of Cold Roll Forming
Cold roll forming involves bending and shaping metal strips or sheets by passing them through a series of rollers. During this process, the metal experiences significant deformation, leading to strain hardening. Strain hardening causes localized stresses within the material, especially at points where the metal undergoes significant bending or forming. These stresses can become visible as stress marks on the surface.
In some cases, the seams or joints where different sections of the cold-formed profile are joined together can be visible. The appearance of these seams can depend on the design and precision of the cold roll forming process. Any surface imperfections, or inconsistencies in the material can become more pronounced after cold roll forming. These imperfections may include stress marks, dents, or variations in color. It is important to note that these imperfections do not affect the tensile strength properties of the metal components.