IS 40Ni6Cr4Mo3 Medium Carbon Steel, Low Alloy Steel, Round bars, Rods
IS 40Ni6Cr4Mo3 is a medium carbon, low alloy steel known for its toughness and strength in relatively large sections. IS 40Ni6Cr4Mo3 is also one kind of nickel chromium molybdenum steels. IS 40Ni6Cr4Mo3 alloy steel is generally supplied hardened and tempered in the tensile range of 930 – 1080 Mpa. Pre hardened and tempered IS 40Ni6Cr4Mo3 steels can be further surface hardened by flame or induction hardening and by nitriding. The IS 40Ni6Cr4Mo3 steel has good shock and impact resistance as well as wear and abrasion resistance in the hardened condition. IS 40Ni6Cr4Mo3 steel properties offer good ductility in the annealed condition, allowing it to be bent or formed. Fusion and resistance welding is also possible with our IS 40Ni6Cr4Mo3 alloy steel. IS 40Ni6Cr4Mo3 material is often utilized where other alloy steels do not have the harden ability to give the strength required. For highly stressed parts it is excellent choice. IS 40Ni6Cr4Mo3 alloy steel can also be machined by all customary methods.
IS 40Ni6Cr4Mo3 is a heat treatable, low alloy steel containing nickel, chromium, and molybdenum. It is known for its toughness and capability of developing high strength in the heat treated condition, while retaining good fatigue strength.
- IS 40Ni6Cr4Mo3 Steel Supply Range
40Ni6Cr4Mo3 Steel Round Bar: diameter 8mm – 1000mm
40Ni6Cr4Mo3 Steel Plate: thickness 10mm to 300 mm
40Ni6Cr4Mo3 Steel Square: 20mm – 300mm
40Ni6Cr4Mo3 Steel Flat : 20mm x 10mm to 3000 x 300 mm
Surface Finish: Black, Rough Machined, Turned or as per given requirements.
Due to availability the IS 40Ni6Cr4Mo grade steel is often substituted with European based standards 817M40, AISI 4340 and 1.6511/36CrNiMo4 or Japan based SNCM439 steel
- Different designation of Chromium Nickel Molybdenum Steels IS 40Ni6Cr4Mo3
- IS 40Ni6Cr4Mo3
- UNS G43400
- SAE/AISI 4340
- DIN 34CrNiMo6
- JIS SNCM8
- JIS SNCM 439
- Alloy 4340
- BS 817M40
- Werkstoff 1.6565
- JIS G4103
- En 10250 36CrNiMo4
- En 10250 1.6511
- IS 40NI6CR4MO3 Steel Grade Heat Treatment
- Stress Relieving
For pre-hardened steel stress relieving is achieved by heating steel IS 40Ni6Cr4Mo3 to between 500 to 550°C. Heat to 600 °C – 650 °C, hold until temperature is uniform throughout the section, soak for 1 hour per 25 mm section, and cool in still air.
A full anneal may be done at 844°C (1550 F) followed by controlled (furnace) cooling at a rate not faster than 10°C (50 F) per hour down to 315°C (600 F). From 315°C 600 F it may be air cooled.
IS 40NI6CR4MO3 alloy steel should be in the heat treated or normalized and heat treated condition before tempering. The tempering temperature for depends upon the strength level desired. For strength levels in the 260 – 280 ksi range temper at 232°C (450 F). For strength in the 125 – 200 ksi range temper at 510°C (950 F). And don’t temper the IS 40Ni6Cr4Mo3 steels if it is in the 220 – 260 ksi strength range as tempering can result in degradation of impact resistance for this level of strength.
Tempering should be avoided if possible within the range 250 °C – 450 °C due to temper brittleness.
- Flame or Induction Hardening
As mentioned above, pre-hardened and tempered IS 40Ni6Cr4Mo3 steel bars or plates can be further surface hardened by either the flame or induction hardening methods resulting in a case hardness in excess of Rc 50. IS 40NI6CR4MO3 steel parts should be heated as quickly as possible to the austenitic temperature range (830 °C – 860 °C) and required case depth followed by an immediate oil or water quenching, depending upon hardness required, workpiece size/shape and quenching arrangements.
Following quenching to hand warm, tempering at 150°C – 200°C will reduce stresses in the case with minimal effect on its hardness.
All de-carburised surface material must first be removed to ensure best results.
Hardened and tempered IS 40Ni6Cr4Mo3 alloy steel can also be nitrided, giving a surface hardness of up to Rc 60. Heat to 500°C – 530°C and hold for sufficient time (from 10 to 60 hours) to develop the depth of case. Nitriding should be followed by slow cooling (no quench) reducing the problem of distortion. The nitrided grade IS 40Ni6Cr4Mo3 materials can therefore be machined to near final size, leaving a small grinding allowance only. The tensile strength of the IS 40Ni6Cr4Mo3 steel material core is usually not affected since the nitriding temperature range is generally below the original tempering temperature employed.
Surface hardness achievable is 600 to 650HV.
Machining is best done with the alloy steel IS 40Ni6Cr4Mo3 in the annealed or normalized and tempered condition. It can be readily machined by all conventional methods such as sawing, turning, drilling etc. However in the high strength conditions of 200 ksi or greater the machinability is only from 25% to 10% that of the alloy in the annealed condition.
Welding of steel IS 40Ni6Cr4Mo3 in the hardened and tempered condition (as normally supplied), is not recommended and should be avoided if at all possible, because of the danger of quench cracking, as the mechanical properties will be altered within the weld heat affected zone.
If welding must be carried out, pre-heat to 200 to 300°C and maintain this while welding. Immediately after welding stress relieve at 550 to 650°C, prior to hardening and tempering.
If welding in the hardened and tempered condition is really necessary, then the work piece, immediately on cooling to hand warm, should be if possible stress relieved at 15 °C below the original tempering temperature.
- Applications of IS 40Ni6Cr4Mo3 Steel / 4340 Steel
AISI 4340 steel is used in most industry sectors for applications requiring higher tensile/yield strength than 4140 steel can provide.
Typically used for
- Aircraft Landing Gear
- Power transmission gears
- Power transmission shafts
- High duty engine connecting rods
- High temperature applications
- Parts of machine tools such as spindle gear
- Oil and Gas Drilling
- Warm and Cold Forming
- Machine Building
- Transfer Systems, like power transmission gears and shafts.
- General engineering industries and structural use applications, such as: heavy duty shafts, gears, axles, spindles, couplings, pins, chucks, molds etc.
- Other structural parts.
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