42cr Seamless Steel Pipe

42Cr and 42CrMo seamless steel pipes both belong to the medium-carbon chromium-based quenched and tempered alloy seamless pipe category. The core difference lies in the addition of molybdenum. They differ significantly in heat treatment characteristics, mechanical properties, applicable scenarios, and procurement costs, adapting to different levels of working conditions.

Chemical composition and heat treatment performance are the core differences between the two. 42Cr uses only chromium as the core alloying element, with no mandatory molybdenum content requirement; 42CrMo adds an additional 0.15%~0.25% molybdenum, fundamentally optimizing its heat treatment performance. 42Cr has limited hardenability, resulting in significant core strength reduction in thick-walled pipes after tempering, and exhibits marked high-temperature temper brittleness. Rapid cooling after tempering is necessary to control cracking risk, leading to a low process tolerance. 42CrMo, on the other hand, has significantly improved hardenability, resulting in uniform internal and external properties in thick-walled pipes after tempering. Furthermore, molybdenum effectively suppresses temper brittleness, lowering the heat treatment process threshold and leading to better finished product performance stability and yield.

The mechanical properties and adaptability to operating conditions differ significantly. Under the same specifications and tempering conditions, 42CrMo has tensile strength and yield strength more than 15% higher than 42Cr, exhibiting superior fatigue and impact resistance. Simultaneously, molybdenum imparts excellent high-temperature creep resistance, maintaining stable load-bearing capacity below 500℃, while 42Cr is only suitable for room-temperature conditions, experiencing severe strength degradation at high temperatures.

In terms of application and cost, 42Cr seamless steel pipes are mostly used in ordinary mechanical applications such as normal temperature drive shafts, conventional gear sleeves, and medium-strength fasteners. The spot circulation volume is small, and the unit price is slightly lower. 42CrMo is suitable for high-end heavy-duty applications such as large-tonnage hydraulic cylinders, heavy machinery spindles, wind power components, and high-pressure high-temperature fasteners. The spot specifications are comprehensive, and the purchase price is 15%~20% higher than that of 42Cr. It has significant advantages in overall service reliability and service life.