What is the chemical composition of S235JRH steel pipe?
S235JRH is a non-alloy structural steel. Its chemical composition primarily consists of carbon (C ≤ 0.17%), manganese (Mn ≤ 1.40%), silicon (Si ≤ 0.035%), phosphorus (P ≤ 0.030%), and sulfur (S ≤ 0.030%). This steel also contains trace amounts of nitrogen (N ≤ 0.012%) to ensure weldability. Compared to other S235 series steels, the JRH suffix indicates that it is cold-formed and exhibits higher impact toughness. This compositional design enhances weldability and formability in architectural and mechanical structures.
What are the mechanical properties of S235JRH?
S235JRH has a minimum yield strength (ReH) of 235 MPa, a tensile strength (Rm) between 360 and 510 MPa, and an elongation (A5) of at least 26%. This steel grade has an impact energy (KV) of at least 27 J at room temperature, indicating good toughness. These properties make it suitable for structural components subject to moderate loads, such as building frames and mechanical supports. Furthermore, its low carbon equivalent value (CEV) ensures good weldability.
What is the difference between S235JRH and other S235 series steels, such as S235JR and S235J0?
The primary difference between S235JRH and S235JR is the impact test temperature. JRH requires testing at 0°C, while JR can be tested at room temperature (20°C). S235J0 requires a lower impact test temperature (-20°C). JRH steel is typically used for cold-formed structures requiring higher toughness, while JR is suitable for general welded structures. Furthermore, JRH has more stringent controls on phosphorus and sulfur content to reduce cold brittleness.
What is the carbon equivalent value (CEV) of S235JRH steel? How does it affect welding? S235JRH typically has a carbon equivalent value (CEV) below 0.36%, which means it has good weldability and requires minimal preheating. This low CEV reduces the risk of hardening in the heat-affected zone (HAZ), making it suitable for a variety of welding methods, including arc welding and gas shielded welding. However, when welding thick plates or in extreme environments (such as low temperatures), appropriate welding procedure specifications (WPS) must be followed.
Is S235JRH corrosion-resistant? Does it require surface treatment?
S235JRH is an unalloyed steel with moderate inherent corrosion resistance. It is susceptible to rusting in humid or corrosive environments. Therefore, surface protection measures such as hot-dip galvanizing, spray coating, or painting are generally required. For use in marine or chemical environments, stainless steels (such as 304) or weathering steels (such as S355J2WP) are recommended as alternatives.
