Reasonable price for AISI 4340 Steel | 36CrNiMo4 | 1.6511 | EN24 | 817M40 | SNCM439 Factory in New Zealand
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.
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Carbon has the ability to form very long chains of interconnecting C-C bonds. This property is called catenation. Carbon-carbon bonds are strong, and stable. This property allows carbon to form an almost infinite number of compounds; in fact, there are more known carbon-containing compounds than all the compounds of the other chemical elements combined except those of hydrogen (because almost all organic compounds contain hydrogen too).
The simplest form of an organic molecule is the hydrocarbon—a large family of organic molecules that are composed of hydrogen atoms bonded to a chain of carbon atoms. Chain length, side chains and functional groups all affect the properties of organic molecules. By IUPAC’s definition, all the other organic compounds are functionalized compounds of hydrocarbons.
Carbon occurs in all known organic life and is the basis of organic chemistry. When united with hydrogen, it forms various flammable compounds called hydrocarbons which are important to industry as refrigerants, lubricants, solvents, as chemical feedstock for the manufacture of plastics and petrochemicals and as fossil fuels.
When combined with oxygen and hydrogen, carbon can form many groups of important biological compounds including sugars, lignans, chitins, alcohols, fats, and aromatic esters, carotenoids and terpenes. With nitrogen it forms alkaloids, and with the addition of sulfur also it forms antibiotics, amino acids, and rubber products. With the addition of phosphorus to these other elements, it forms DNA and RNA, the chemical-code carriers of life, and adenosine triphosphate (ATP), the most important energy-transfer molecule in all living cells.
Main article: Compounds of carbon
Commonly carbon-containing compounds which are associated with minerals or which do not contain hydrogen or fluorine, are treated separately from classical organic compounds; however the definition is not rigid (see reference articles above). Among these are the simple oxides of carbon. The most prominent oxide is carbon dioxide (CO2). This was once the principal constituent of the paleoatmosphere, but is a minor component of the Earth’s atmosphere today. Dissolved in water, it forms carbonic acid (H2CO3), but as most compounds with multiple single-bonded oxygens on a single carbon it is unstable. Through this intermediate, though, resonance-stabilized carbonate ions are produced. Some important minerals are carbonates, notably calcite. Carbon disulfide (CS2) is similar.
The other common oxide is carbon monoxide (CO). It is formed by incomplete combustion, and is a colorless, odorless gas. The molecules each contain a triple bond and are fairly polar, resulting in a tendency to bind permanently to hemoglobin molecules, displacing oxygen, which has a lower binding affinity. Cyanide (CN), has a similar structure, but behaves much like a halide ion (pseudohalogen). For example it can form the nitride cyanogen molecule ((CN)2), similar to diatomic halides. Other uncommon oxides are carbon suboxide (C3O2), the unstable dicarbon monoxide (C2O), carbon trioxide (CO3), cyclopentanepentone (C5O5) cyclohexanehexone (C6O6) , and mellitic anhydride (C12O9).
With reactive metals, such as tungsten, carbon forms either carbides (C4), or acetylides (C2−2) to form alloys with high melting points. These anions are also associated with methane and acetylene, both very weak acids. With an electronegativity of 2.5, carbon prefers to form covalent bonds. A few carbides are covalent lattices, like carborundum (SiC), which resembles diamond.
Main article: Organometallic chemistry
Organometallic compounds by definition contain at least one carbon-metal bond. A wide range of such compounds exist; major classes include simple alkyl-metal compounds (e.g. tetraethyl lead), η2-alkene compounds (e.g. Zeise’s salt, and η3-allyl compounds (e.g. allylpalladium chloride dimer; metallocenes containing cyclopentadienyl ligands (e.g. ferrocene); and transition metal carbene complexes. Many metal carbonyls exist (e.g. tetracarbonylnickel); some workers consider the carbon monoxide ligand to be purely inorganic, and not organometallic.
While carbon is understood to exclusively form four bonds, an interesting compound containing an octahedral hexacoordinated carbon atom has been reported. The cation of the compound is [(Ph3PAu)6C]2+. This phenomenon has been attributed to the aurophilicity of the gold ligands.
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