Yong Kim Steel Sdn Bhd
9, Jalan TPP 5/15,
Taman Perindustrian Puchong,
47100 Puchong,
Selangor Darul Ehsan, Malaysia.
+603-8063 1633
+603-8063 3984
+603-8063 1848

Machinery Steel 4140

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Machinery Steel 4140 Machinery Steel Machinery Steel 4140 Machinery Steel


AISI 4140 steel Manufacturer and Exporter, supplied with round, square, flat, block, and shaft etc. AISI 4140 is defined as a low alloy steel which has  1%  Cr-Mo as strengthening alloy elements.Compared with AISI 4130, it has a higher carbon content with good balance of strength, toughness, abrasion and impact resistance and heat treatment capabilities, but poor in weldability characteristics. AISI 4140 is generally supplied in quenched and tempered condition with hardness 28-32HRC.

1. Supply Form & Size & Tolerance

Supply Form Size(mm) Process Tolerance
Round Φ6-Φ100 Cold Drawn Bright/Black Best H11
Φ16-Φ350 Hot Rolled Black -0/+1mm
Peeled/ground Best H11
Φ90-Φ1000 Hot Forged Black -0/+5mm
Rough Turned -0/+3mm
Flat/Square/Block Thickness :120-800 Hot Forged Black -0/+8mm
Width:120-1500 Rough Machined -0/+3mm

Remark: Tolerance can be customized as per requests

2. Chemical Composition

Standard Grade C Si Mn P S Cr Ni Mo
ASTM A29 4140 0.38-0.43 0.15-0.35 0.75-1.00 ≤ 0.035 ≤ 0.04 0.8-1.1 0.15-0.25
EN10083 42CrMo4 0.38-0.45 ≤ 0.4 0.6-0.90 ≤ 0.025 ≤ 0.035 0.9-1.2 0.15-0.30
1.7225
JIS G4105 SCM440 0.38-0.43 0.15-0.35 0.6-0.85 ≤ 0.035 ≤ 0.04 0.9-1.2 0.15-0.30
GB 3077 42CrMo 0.38-0.45 0.17-0.37 0.5-0.80 ≤ 0.035 ≤ 0.035 0.9-1.2 0.15-0.25
BS 970 EN19 0.35-0.45 0.15-0.35 0.5-0.80 ≤ 0.035 ≤ 0.035 0.9-1.5 0.2-0.40

3. Physical Property

Density g/cm3 7.85
Melting point °C 1416
Poisson's ratio 0.27-0.30
Machinability (AISI 1212 as 100% machinability) 65%
Thermal expansion co-efficient µm/m°C 12.2
Thermal conductivity W/(m.K) 46
Modulus of elasticity 10^3 N/mm2 210
Electric resistivity Ohm.mm2 /m 0.19
Specific heat capacity J/(kg.K) 460
Modulus of elasticity 10^3 N/mm2 100 íŠ 200 íŠ 300 íŠ 400 íŠ 500 íŠ
205 195 185 175 165
Thermal expansion 10^6 m/(m.K) 100 íŠ 200 íŠ 300 íŠ 400 íŠ 500 íŠ
11.1 12.1 12.9 13.5 13.9

4. Mechanical Property

Mechanical Condition R S S T U V W
Ruling Section mm 250 250 150 100 63 30 20
Tensile Strength Mpa 700-850 770-930 770-930 850-1000 930-1080 1000-1150 1080-1230
Yield Strength Mpa Min 480 540 570 655 740 835 925
Elongation % 15 13 15 13 12 12 12
Izod Impact J Min 34 27 54 54 47 47 40
Charpy Impact J Min 28 22 50 50 42 42 35
Hardness Brinell HB 201-255 233-277 233-277 248-302 269-331 293-352 311-375

5. High Temperature Strength

For quenched and tempered heavy forgings
Diameter mm Yield strength MPa
20 íŠ 100 íŠ 200 íŠ 250 íŠ 300 íŠ 350íŠ 400íŠ
≤250 510 486 461 441 422 392 363
250-500 460 431 412 402 382 353 324
500-750 390 333 333 324 304 275 245

6. Forging

Forging temperature should be carried out between 900íŠ-1200íŠ,The lower the forging-ending temperature ,the finer the grain size .Hold the temperature till uniform before forge,minimum forging temperature 850°C,so don’t forge below 850íŠ.AISI 4140 steel  should be cooled as slowly as possible in still air or in sand after forged.

7. Normalizing

Normalizing is used to refine the structure of forgings that might have cooled non-uniformly after forged,and considered as a conditioning treatment before final heat treatment.Normalizing temperature for AISI 4140 steel should be carried out between 870íŠ-900íŠ. hold suitable time for the steel to be thoroughly heated to  complete the ferrite to austenite transformation.Cool in still air.

8. Annealing

After Forged,AISI 4140 steel  may be annealed .Annealing temperature should be carried out between 800íŠ-850íŠ, hold suitable time for the steel to be thoroughly heated. Cool slowly in the furnace.This treatment will form a structure suitable for machining.The maximum Hardness is 241 HB.

9. Hardening

This heat treatment will obtain martensite structure  after quenched.It should be carried out between 840íŠ-875íŠ, hold suitable time for the steel to be thoroughly heated, soak for 10-15 minutes per 25 mm section, and quench in oil, water, or polymer as required.Tempering should be followed  immediately after quenched.

10. Tempering

Tempering is usually carried out to relieve stresses from the hardening process, but primarily to obtain the required  hardness and mechanical properties. The actual tempering temperature will be chosen to meet the required properties.Heat the AISI 4140 carefully to a suitable temperature ,usually between 550íŠ-700íŠ, soak at the temperature for 2 hours per 25mm of ruling section, then cool in air.Tempering between 250íŠ-375íŠ is not avoided as tempering within this range will seriously reduce the impact value,result in temper brittleness .

11. Application

AISI 4140 steel finds many applications as forgings for the aerospace,oil and gas,automotive, agricultural and defense industries etc.
Typical applications for 4140 steel uses include:forged gears,spindles,fixtures,jigs,collars,Axles,conveyor parts,crow bars,logging parts,shafts,sprockets,studs,pinions,pump shafts, rams, and ring gears etc

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