Impact Test Temperatures for S355K2G2W Weathering Steel Plates

If you’ve ever looked at a datasheet for S355K2G2W weathering steel, you’ve probably noticed the “K2” marking. That little code tells you something important: this steel is built to absorb impact at low temperatures. Specifically, it guarantees a minimum of 27J in Charpy V-notch tests at -20°C.

Why does this matter? Bridges, transmission towers, and outdoor structures don’t just face rain and sun—they face sudden winter freezes. A steel that turns brittle when the temperature drops is a risk no engineer wants to take. S355K2G2W offers a reliable safety net. It’s not the most extreme low-temperature grade out there (that would be something like -40°C or -50°C), but for most European climates and many moderate cold regions, -20°C hits the sweet spot between performance and cost.

What about the “G2W” part? That stands for weathering steel with improved atmospheric corrosion resistance. So you’re getting both toughness in the cold and the ability to form that protective rust patina over time.

One practical note: impact testing should always be done on finished plates as delivered. Don’t assume that heat from welding or cutting won’t alter the heat-affected zone’s low-temperature properties. For critical applications, post-weld impact verification is a smart move.

S355K2G2W gives you dependable toughness down to -20°C, combining cold-weather safety with the long-term benefits of weathering steel.