Seamless Steel Tubes / Rolled Rings

Description

Ovako 280 are made of pure steel and are seamless. They are available in many dimensions up to a maximum outer diameter of 256.5 mm.

Properties

Are usually supplied as rolled tubes. This results in the following mechanical properties:

Welding: Good welding properties, suitable for all common welding processes.

Normalising: 900-920°C, cooling in still air.

Stress-relief annealing: 550-600°C, holding time 1-2 hours, cooling in the oven or in the air.

Tempering: 900-920°C, quenching in water and tempering at 500°C for approx. 1 hour.

Case hardening: Carburising at 850-950°C, hardening at 780-830°C, quenching in oil or stepped quenching, tempering at 150-200°C for 1 hour, normal surface hardness 58-63HRC.

Nitriding: 500-520°C, surface hardness approx. 650HV. Also suitable for plasma nitriding.

Description of rolling bearing steel tubes Ovako 803 (100Cr6)

Characterised by high resistance to fatigue and wear. The tubes are supplied in annealed condition and are easy to machine. Up to 60-65HRC can be achieved by martensitic hardening/tempering.

Properties

Usually supplied as soft-annealed tubes. The following mechanical properties can be achieved:

Forging: 800-1100°C, cooling in still air.

Soft annealing: Heat up to 820°C /1 hour, hold at 820°C for 2 hours, cool down from 820°C to 740°C / 1 hour, cool down from 740°C to 690°C /10 hours, cool down in still air.

Stress-relief annealing: 550-650°C, holding time 1 hour, cooling in air.

Martensitic hardening: 830-870°C / 10-60 minutes, quenching in oil and tempering within 2 hours to min. 160°C according to data sheet.

Bainitic hardening: 850-875°C / 10-60 minutes, quenching in salt bath 220-250°C /3-7 hours according to data sheet.

Tempering: 160-570°C according to data sheet, cooling in still air.

Rolling bearing steel tubes and Ovako® 824 (100CrMo7)

Suitable for through-hardening thicker wall thicknesses. This steel also has high fatigue strength, excellent wear resistance and good toughness. This grade is suitable for martensitic and bainitic hardening.

Properties

Usually supplied as soft-annealed tubes. The following mechanical properties can be achieved:

Forging:                             800-1100°C, cooling in still air

Soft annealing:                 Heat up to 820°C /1 hour, hold 820°C 2 hours, cool down from 820°C to 740°C / 1 hour, cool down from 740°C to 690°C /12 hours, cool down in still air.

Stress-relief annealing:  550-650°C, holding time 1 hour, cooling in still air.

Martensitic hardening:   830-870°C / 10-60 minutes, quenching in oil and tempering within 2hours.
 
Bainitic hardening:         850-875°C / 10-60 minutes, quenching in salt bath 220-250°C/3-8 hours

Tempering:                     160-500°, cooling in still air.

For dimensions for which no tubes are produced, it is possible to roll rings. Ovako® can roll profiled rings, which can be up to 50% lighter than cylindrical rings. At the same time, the profile can be rolled very closely to the finished dimension.
can be rolled, thus reducing machining costs. All grades produced by Ovako® can be supplied as rings. Delivery is ex works with corresponding delivery times.

The rings can be finished with the following additional process steps:
• Shot peening
• Pre-turning, finish turning, ultrasonic testing
• Heat treatment (normalising, soft annealing, stress relief annealing, isothermal annealing, quenching and tempering)