What does GOST 8239 specify for I-beams in Russia?

GOST 8239 defines I-beam dimensions (100-600mm depth) and grades (St235, St355) with yield strengths 235-355 MPa. It requires impact toughness of 30 J at -40°C for I-beams used in Siberian infrastructure, ensuring performance in extreme cold. The standard mandates phosphorus <0.045% and sulfur <0.050% to prevent brittleness. GOST I-beams are used in Russian oil pipelines and power plants, with strict quality controls (ultrasonic testing) for weldability-critical for field fabrication in remote regions.