GCr15 precision seamless steel pipe knowledge introduction (Shandong Precision Seamless Steel Tube Factory) GCr15 precision seamless steel pipe is a kind of high carbon chromium bearing steel with less alloy content, good performance and wide application. After quenching and tempering, it has high and even hardness, good wear resistance, and high contact fatigue performance. The cold-worked steel has moderate plasticity, general cutting performance, poor welding performance, high sensitivity to formation of white spots, and temper brittleness. GCr15 precision seamless steel pipe chemical composition / element content (%) C: 0.95-1.05 Mn: 0.20-0.40 Si: 0.15-0.35 S: ≤ 0.020 P: ≤ 0.027 Cr: 1.30-1.65 The heat treatment system is: steel bar annealing, wire annealing or 830-840 degrees oil quenching. Heat treatment process parameters: 1. Ordinary annealing: 790-810 degrees heating, furnace cooling to 650 degrees, air cooling - HB170-207 2. Isothermal annealing: 790-810 degrees heating, 710-720 degrees isothermal, air cooling - HB207-229 3. Normalizing: 900-920 degrees heating, air cooling - HB270-390 4 high temperature tempering: 650-700 degrees heating, air cooling - HB229-285 5. Quenching: 860 degrees heating, oil quenching - HRC62-66 6. Low temperature tempering: 150-170 degrees tempering, air cooling - HRC61-66 7. Carbonitriding: 820-830 degrees of co-permeability 1.5-3 hours, oil quenching, -60 degrees to -70 degrees cryogenic treatment +150 degrees to +160 tempering, air cooling - HRC ≈ 67. Information Sources: