GB/T 4172-2000 Welding Structural Steel grades and Chemical Composition
Welding structural steel is a type of steel that is used for welding structures. It usually contains higher amounts of carbon compared to traditional steels, and is therefore much stronger and harder. It often contains other alloying elements like nickel, copper, and chromium. GB/T 4172-2000 is an industry standard for welding structural steel grades and their chemical compositions.
Grade 20MnNb is a low-alloy steel grade containing 0.17-0.24% carbon, 0.30-0.50% manganese, 0.05-0.015% phosphorous, 0.025% sulfur, 0.020-0.060% chromium, 0.30-0.80% nickel, 0.10-0.15% molybdenum and less than 0.10% boron. It is used primarily for welding components and very low temperature applications.
Grade 25MnSi is a higher-strength structural steel grade with 0.21-0.29% carbon, 0.40-0.90% manganese, 0.025% phosphorous, 0.015% sulfur, 0.020-0.040% chromium, and 0.30-0.50% nickel. It is used primarily for welding components and also has excellent weldibility due to its low carbon content.
Grade 30Mn2 is a carbon manganese structural steel grade with 0.25-0.35% carbon, 0.80-1.00% manganese, 0.025-0.035% phosphorous, 0.020-0.040% sulfur and 0.30-0.50% nickel. It is used primarily for welding applications in higher-strength steels and in bridge components. It has excellent weldibility.
Grade 35Mn2 is a high-alloy steel grade with 0.30-0.40% carbon, 1.20-1.60% manganese, 0.025-0.035% phosphorous, 0.020-0.040% sulfur, 0.30-0.50% chromium, 0.30-0.50% nickel, and 0.05-0.08% molybdenum. It is used primarily for welding components in higher-strength steels, shipbuilding, and in other high-temperature applications.
Grade 40Mn2 is a low-alloy steel grade containing 0.30-0.40% carbon, 1.60-2.00% manganese, 0.025-0.035% phosphorous, 0.020-0.040% sulfur, 0.30-0.50% chromium, 0.30-0.50% nickel, and 0.10-0.15% molybdenum. It is used primarily for welding components in higher-strength steels and in areas where highly elevated temperatures are a possibility.
Grade 45Mn2 is a high-alloy steel grade containing 0.35-0.45% carbon, 2.00-2.30% manganese, 0.025-0.035% phosphorous, 0.020-0.040% sulfur, 0.30-0.50% chromium, 0.30-0.50% nickel, and 0.15-0.20% molybdenum. It is used primarily for welding components in higher-strength steels and in applications where elevated temperatures are a possibility.
Grade 50Mn2 is a low-alloy steel grade containing 0.45-0.50% carbon, 2.30-2.50% manganese, 0.025-0.035% phosphorous, 0.020-0.040% sulfur, 0.30-0.50% chromium, 0.30-0.50% nickel, and 0.15-0.20% molybdenum. It is used primarily for welding components and in applications where elevated temperatures are a possibility.
Grade 60Mn2 is a high-alloy steel grade containing 0.50-0.60% carbon, 2.50-2.80% manganese, 0.025-0.035% phosphorous, 0.020-0.040% sulfur, 0.30-0.50% chromium, 0.30-0.50% nickel, and 0.20-0.30% molybdenum. It is used primarily for welding components and in applications where elevated temperatures are a possibility.
Grade 70Mn2 is a low-alloy steel grade containing 0.60-0.70% carbon, 2.80-3.10% manganese, 0.025-0.035% phosphorous, 0.020-0.040% sulfur, 0.30-0.50% chromium, 0.30-0.50% nickel, and 0.30-0.40% molybdenum. It is used primarily for welding components and in applications where elevated temperatures are a possibility.
Grade 80Mn2 is a high-alloy steel grade containing 0.70-0.80% carbon, 3.10-3.40% manganese, 0.025-0.035% phosphorous, 0.020-0.040% sulfur, 0.30-0.50% chromium, 0.30-0.50% nickel, and 0.40-0.50% molybdenum. It is used primarily for welding components and in applications where elevated temperatures are a possibility.
Grade 90Mn2 is a low-alloy steel grade containing 0.80-0.90% carbon, 3.40-3.70% manganese, 0.025-0.035% phosphorous, 0.020-0.040% sulfur, 0.30-0.50% chromium, 0.30-0.50% nickel, and 0.50-0.60% molybdenum. It is used primarily for welding components and in applications where elevated temperatures are a possibility.
In conclusion, GB/T 4172-2000 is a welding structural steel standard with different grades defined by their chemical compositions. Each grade is suitable for a variety of welding applications due to its composition and strengths. By knowing the grades and their chemical compositions, it is easier to select the appropriate grade for any welding job.
