665M17 – 2% Ni – Mo Case Hardening Steel

665M17 is a 2% Nickel – Molybdenum case hardening steel, characterised by high core strength, good toughness and fatigue resistance, with case hardnesses up to 60HRC when carburised, hardened and Tempered.

Material is usually supplied in the annealed/Normalised condition upto 207HB
General applications include all industry sectors for applications requiring high surface wear resistance, high shock resistance, high core strength & impact properties. Typical uses include transmission components, steering mechanisms and shafts.

RELATED SPECIFICATIONS 665M17 – 2% Ni – Mo Case Hardening Steel
				BS970-1955 EN34 DIN 15NiMo8
TYPICAL CHEMICAL COMPOSITION
				Carbon	0.17%
				Silicon	0.25%
				Manganese	0.50%
				Phosphorous	<0.040%
				Sulphur	<0.040%
				Nickel	1.75%
				Molybdenum	0.25%
MECHANICAL PROPERTY REQUIREMENTS – On Blank Carburised Test Piece – BS970 Part 3 1991 665M17
Test Bar Diameter	Tensile Strength Mpa	Elongation %	Charpy Impact J	Izod Impact Ftlbs	Hardness HB
19mm	770min	12	35	40	207
FORGING
Forging Temperature for this material should be 850 – 1150oC Soaking times should be kept to a minimum to avoid heavy scale and excessive grain growth, suggest 15minutes per inch (25mm) of ruling section.
HEAT TREATMENT
Annealing – Heat to 830 – 850oC ensuring sufficient time is allowed for the centre to achieve furnace temperature and hold for a time commensurate with the ruling section, followed by furnace cooling.
Carburizing – Pack, salt or gas carburizing at 900 – 950oC, hold for time commensurate with required case depth, followed by suitable hardening and tempering to optimise core properties.
Hardening – Heat to 830 – 880oC and hold for time commensurate with the ruling section, quench as required in Water, Oil or Air. Note: This treatment is used for core refinement and should be followed by Tempering
Case Hardening: Following core refining, re-heat to 760 – 800oC, hold for time commensurate with ruling section and quench in oil. Note: Material should be tempered immediately whilst still hand warm.
Tempering – Heat to 150 – 200oC for sufficient time to allow centre to achieve furnace temeperature, and hold for 2Hrs minimum, cool in still air.
MACHINING
Material in the annealed condition is readily machinable by milling, drilling, turning, tapping as required
WELDING
In the annealed condition the material is readily weldable using low hydrogen electrodes, however following cooling the material should be stress relieved at 600-650oC. Note: Welding in the Carburized or Heat Treated condition is not recommended