Screws can be made of either steel or iron, depending on the application and performance requirements. In terms of material properties, steel screws are typically made of carbon steel or alloy steel, offering higher strength and corrosion resistance.
They are suitable for applications requiring heavy loads or exposure to humid environments, such as machinery, the automotive industry, and building structures. Iron screws (usually gray cast iron or malleable cast iron) are less expensive but have lower toughness and are often used in light-load applications where strength requirements are lower, such as furniture assembly or low-stress fixing.
In terms of industry standards, international standards (such as ISO and DIN) and national standards (GB) clearly classify screw materials. For example, screws below grade 4.8 often use low-carbon steel or iron, while high-strength screws above grade 8.8 must use alloy steel.
In terms of processing technology, steel screws can have their hardness increased through heat treatment (such as tempering and quenching), and their surfaces are often treated with galvanizing or Dacromet coating for corrosion protection. Iron screws, due to their brittleness, typically only undergo simple electroplating or blackening treatments.
In terms of application selection, steel screws must be used in high-load scenarios such as automotive engines and bridge connections; while iron screws can be used in low-stress environments such as indoor furniture and appliance housings to reduce costs. We currently have these products in stock. Our Phillips head screws are made of high-strength steel, with a nominal diameter of 3mm, suitable for precision applications such as communication equipment, and have a performance rating of 5.6.
