Hot Selling for AISI 4340 Steel | 36CrNiMo4 | 1.6511 | EN24 | 817M40 | SNCM439 Factory from Karachi
AISI 4340 steel is a medium carbon, low alloy steel known for its toughness andstrength in relatively large sections. AISI 4340 is also one kind ofnickel chromium molybdenum steels. 4340 alloy steel is generallysupplied hardened and tempered in the tensile range of 930 – 1080 Mpa.Pre hardened and tempered 4340 steels can be further surface hardened by flame or induction hardening and by nitriding. The 4340 steel has goodshock and impact resistance as well as wear and abrasion resistanc...
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is a medium carbon, low alloy steel known for its toughness and
strength in relatively large sections. AISI 4340 is also one kind of
nickel chromium molybdenum steels. 4340 alloy steel is generally
supplied hardened and tempered in the tensile range of 930 – 1080 Mpa.
Pre hardened and tempered 4340 steels can be further surface hardened by
flame or induction hardening and by nitriding. The 4340 steel has good
shock and impact resistance as well as wear and abrasion resistance in
the hardened condition. AISI 4340 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 4340 alloy steel. ASTM 4340
material is often utilized where other alloy steels do not have the
hardenability to give the strength required. For highly stressed parts
it is excellent choice. AISI 4340 alloy steel can also be machined by
all customary methods.
Due to availability the ASTM 4340 grade steel is often substituted
with European based standards 817M40/EN24 and 1.6511/36CrNiMo4 or Japan
based SNCM439 steel. You have the detailed data of 4340 steel below.
1. AISI 4340 Steel Specification and Relevant Standards
|Standard||EN 10250||JIS G4103|
2. ASTM 4340 Steels And Equilvalents Chemical Composition
|JIS G4103||SNCM 439/SNCM8||0.36-0.43||0.60-0.90||0.030||0.030||0.15-0.35||1.60-2.00||0.60-1.00||0.15-0.30|
3. AISI Alloy 4140 Steel Mechanical Properties
(Heat Treated Condition )
|Tensile Strength MPa||Yield Strength
|Thermal expansion co-efficient (20°C/68°F, specimen oil hardened, 600°C (1110°F) temper||12.3 µm/m°C||6.83 µin/in°F|
|Thermal conductivity (typical steel)||44.5 W/mK||309 BTU in/hr.ft².°F|
4. Forging of 4340 Alloy Steel
the steel 4340 first, heat up to 1150°C – 1200°C maximum for forging,
hold until temperature is uniform throughout the section.
Do not forge
below 850 °C. 4340 has good forging characteristics but care must be
taken when cooling as the steel shows susceptibility to cracking.
Following forging operation the work piece should be cooled as slowly as
possible. And cooling in in sand or dry lime is recommended etc.
5. AISI 4340 Steel Grade Heat Treatment
pre-hardened steel stress relieving is achieved by heating steel 4340
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.
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.
4340 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 4340 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 4340 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. AISI 4340
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.
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.
and tempered 4340 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 4340 materials can therefore be machined
to near final size, leaving a small grinding allowance only. The tensile
strength of the 4340 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.
is best done with the alloy steel 4340 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.
of steel 4340 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.
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.
8. Application of 4340 Steel
4340 steel is used in most industry sectors for applications requiring
higher tensile/yield strength than 4140 steel can provide.
Some typical applications such as:
Aircraft Landing Gear
Oil and Gas Drilling,
Warm and Cold Forming,
Transfer Systems, like power transmission gears and shafts.
engineering industries and structural use applications, such as: heavy
duty shafts, gears, axles, spindles, couplings, pins, chucks, molds etc.
At Brooks Forgings Ltd we have the manufacturing capabilities to hot forge hammerhead bolts to DIN 186, DIN 188, DIN 261 and DIN 7992. Sizes up to M100 and lengths of 6000MM are achieveable.
Our range of in house manufacturing capabilities enables us to rapidly manufacture specialist components and non-standard items to our customer’s exact specifications.
Die Sinking, Upset Forging, Machining, Roll Threading, Finishing and Packing.
Quality to QC1, QC2 and QC3. ISO 9001, ISO 14001 and OHSAS 18001 approved.
Contact us today with your requirements.
An insight into how our NSK Super Precision Bearings are manufactured at our plant in Newark –UK and in which industries and applications these high quality products are best applied.
In order to meet market demands for higher speeds, reliability and individual product traceability, NSK has invested consistently in new materials and production techniques at its Newark UK manufacturing plant. NSK is proud to show customers its facilities and has released a virtual tour that provides viewers with a real insight into the production environment without coming to the plant.
Products manufactured at the Newark plant, which has been a site of bearing manufacture for over 100 years, include a wide range of Super Precision bearings that enable machine tools to operate at higher speeds and help deliver greater accuracy and performance.
The new virtual plant tour takes the viewer on a journey through a state-of-the-art production facility producing Super Precision Robust bearings for the international market. The process begins with steel bar and tube, which is then cut, machined, ground, hardened, finish ground and assembled, tested and lubricated, then marked and packaged. The change from raw steel through increasingly fine processing stretches from traditional mechanical metal cutting and heat treatment processes to outstanding clean room environment assembly areas and 2D laser marking.
Tim Constantine, Manufacturing Director of the Newark plant comments, ‘We are extremely proud of our plant, the investment that has gone into it and the products it produces, however, not all of our customers and partners can readily visit the plant. What we wanted to do with this movie was to be able to take viewers through the process of manufacturing a precision bearing and at the same time allow visual access to the plant itself from anywhere in the world.’ Simone Albayrak, European Marketing Manager for NSK Europe adds, ‘Not everyone knows what a crucial role precision bearings play in industrial applications, hence we go further than just the manufacturing process and show where the bearings are used in machine tool spindles and explore some of the products made by those machines. If the viewer is interested in ‘how things are made’ from an engineering point of view we feel a few minutes spent watching the movie should prove both informative and an enjoyable watch.’
The recent investment in the NSK plant in Newark UK was dedicated to improve workflow following lean principles, create new clean production areas and implement the latest warehousing technology.
For more details on the Super Precision bearings or to discuss the specification of bearings for all applications, contact NSK.