... Steel3. Structural Hollow Sections 4. Angle (L-shaped cross-section) and Tee (T-shaped cross-section)5. Rail profile (asymmetrical I-beam ... engine, piston pin, inlet valve and exhaust valve, oil pump and oil burner, etc.Steel for oil field25CrNiMo, AISI4145, 37CrMnMoA, 23MnNiMoCr54, 15CrNi4Mo, 15CrNiMo, etc ...