Why are
20Mn2 seamless steel pipes both loved and hated? 20Mn2 seamless steel pipe is a "backbone material" in fields such as machinery manufacturing and hydraulic equipment. Many engineers have mixed feelings about it—they love its high strength and wear resistance, but worry about the pitfalls they encounter when purchasing it. Here are some common pitfalls:
- Material Confusion: Often confused with 20# steel and 45# steel, leading to substandard performance.
- Price Confusion: Price differences of up to 30% for the same specifications can be confusing, making it difficult to distinguish between quality differences and inflated prices.
- Processing Challenges: Prone to cracking during welding, and the heat treatment process is difficult to control accurately.
Key Points for Purchasing 20Mn2 Seamless Steel Pipe
First, Identify the Material of the 20Mn2 Seamless Steel Pipe
- Look for the "20Mn2" marking in the GB/T 8162 standard.
- Simple Identification Method: When polishing 20Mn2 seamless steel pipes with a grinding wheel, the sparks will be bright yellow with a red tail (brighter than the sparks of 20# steel).
- Essential Testing Report: Request the supplier to provide a spectral analysis report, focusing on the Mn content (1.60-1.90%) of the 20Mn2 seamless steel pipe.
Second, Guide to Avoiding Pitfalls in 20Mn2 Seamless Steel Pipe Specification Selection
- Clearly Define the Wall Thickness Tolerance of 20Mn2 Seamless Steel Pipes: Ordinary Grade ±12.5%, High Grade ±10%
- Special Scenarios with Additional Benefits:
- High-Pressure Environment: Choose hot-rolled + cold-drawn secondary processing steel pipes.
- Low Temperature Conditions: Require an impact energy ≥27J at -40℃.
Third, Price Negotiation Techniques for 20Mn2 Seamless Steel Pipes
Market Anchor: The current mainstream price for φ50×5mm is approximately 6500-7200 RMB/ton.
Secrets to Using 20Mn2 Seamless Steel Pipes
First, the key to preventing cracking during the welding of 20Mn2 seamless steel pipes:
- The preheating temperature of the 20Mn2 seamless steel pipe must reach 150-200℃ (confirmed with an infrared thermometer).
- J507 welding rods are preferred, and the welding current should be 10% lower than usual.
- Immediately after welding, the 20Mn2 seamless steel pipe should be wrapped with an asbestos blanket for slow cooling.
Second, the golden parameters for heat treatment of 20Mn2 seamless steel pipes:
- Quenching: 880℃±10℃ water quenching (thin-walled steel pipes) or oil quenching (thick-walled steel pipes)
- Tempering: 450-500℃, holding time calculated at 1.5min/mm.
Threeway Steel is known as a professional supplier engaged in manufacturing and distributing a wide range of steel pipe, and our headquarter located the central part of China – Hunan and six associated factories throughout China.
Threeway Steel is known as a professional supplier engaged in designing, manufacturing and distribution of a wide range of steel products with the headquarter located the central part of China – Hunan and six associated factories throughout China.
Threeway Steel is known as a professional supplier engaged in designing, manufacturing and distribution of a wide range of steel products with the headquarter located the central part of China – Hunan and six associated factories throughout China.
Threeway Steel is known as a professional supplier engaged in designing, manufacturing and distribution of a wide range of steel products with the headquarter located the central part of China – Hunan and six associated factories throughout China.
Threeway Steel is known as a professional supplier engaged in designing, manufacturing and distribution of a wide range of steel products with the headquarter located the central part of China – Hunan and six associated factories throughout China.
