Introduction:
AISI 4130 steel is defined as a low alloy steel which contains 1%Cr and 0.2%Mo as strengthening alloy elements.it offers good strength,toughness, corrosion resistance and machinability.Compared with AISI 4140,It has lower carbon,0.28-0.33%,so it can be welded easily. AISI 4130 is commonly supplied in the hardened and tempered condition with a hardness range 207-235HB.
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 |
Mo |
| EN10083 |
25CrMo4 |
0.22-0.29 |
≤0.4 |
0.6-0.9 |
≤0.025 |
≤0.035 |
0.9-1.2 |
0.15-0.3 |
| 1.7218 |
| ASTM A29 |
4130 |
0.28-0.33 |
0.15-0.35 |
0.4-0.6 |
≤0.035 |
≤0.04 |
0.8-1.1 |
0.15-0.25 |
| JIS G4105 |
SCM430 |
0.28-0.33 |
0.15-0.35 |
0.6-0.85 |
≤0.035 |
≤0.04 |
0.9-1.2 |
0.15-0.3 |
| GB 3077 |
30CrMo |
0.26-0.33 |
0.17-0.37 |
0.4-0.7 |
≤0.03 |
≤0.03 |
0.8-1.1 |
0.15-0.25 |
3.Physical Property
| Density g/cm3 |
7.85 |
| Melting point °C |
1432 |
| Poisson's ratio |
0.27-0.30 |
| Machinability (AISI 1212 as 100% machinability) |
70% |
| Specific Gravity |
7.8 |
| Thermal conductivity W/(m.K) |
46 |
| Modulus of Elasticity Tension |
29 |
4. Mechanical Property
| |
Tensile Strength Mpa |
Yield Strength Mpa |
Elongation % |
Hardness HBW |
Impact Charpy-V, -18ºC,J |
| 60K |
≥ 586 |
≥ 414 |
≥ 18 |
174-237 |
≥ 42 |
| 75K |
≥ 655 |
≥ 517 |
≥ 17 |
197-235 |
≥ 42 |
5.Forging
Forging temperature of AISI 4130 steel should be carried out between 950ºC-1200ºC,The lower the forging-ending temperature ,the finer the grain size .Hold suitable time for the steel to be uinformly heated before forge, but don't forge below 950ºC.AISI 4130 steel should be cooled as slowly as possible after forged.
6.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 4130 steel should be carried out between 880ºC-900ºC. hold suitable time for the steel to be uniformly heated to complete the ferrite to austenite transformation.Cool in still air.
7.Annealing
AISI 4130 steel can be annealed to relieve stress after forging ,and obtain a good structure suitable for machining,Annealing temperature should be carried out between 800ºC-850ºC, hold suitable time for the steel to be heated uniformly. Cool slowly in the furnace.
8.Hardening
This heat treatment will obtain martensite structure after quenched,it will increase the surface hardness and strength.AISI 4130 steel should be carried out between 870ºC-890ºC, hold suitable time for the steel to be thoroughly heated, then quench in oil, or water.Tempering should be followed immediately after quenched.
9.Tempering
Tempering is usually carried out to relieve stresses from the hardening process, and will optimize hardness and mechanical properties. The actual tempering temperature will be chosen to meet the required properties.Heat the AISI 4130 carefully to a suitable temperature ,usually between 400ºC-570ºC, soak at the temperature for 2 hours per 25mm of ruling section, then cool in air.The lower the tempering temperature the greater the strength. However, Tempering between 250-375°C is not advised as tempering within this range will seriously reduce the impact value.
10.Application
AISI 4130 steel finds many applications as forgings for the aerospace,oil and gas,automotive, agricultural and defense industries etc.
Typical applications for 4130 steel uses include:forged valve bodies, pumps,Aircraft engine mounts,Welded tubing,fittings,Hydraulic tools,etc
IS AISI 4130 SAME AS 30CRMO?
First of all, if we want to clarify this question, let's take a look at their respective origins.AISI 4130 is a grade from ASTM A29 American standard, while 30CrMo comes from Chinese GB 3077 standard. They can be said to be similar grades. Let's take a look at their specific composition differences, please see the table below.
| Standard |
Grade |
C |
Si |
Mn |
P |
S |
Cr |
Mo |
| ASTM A29 |
4130 |
0.28-0.33 |
0.15-0.35 |
0.4-0.6 |
≤0.035 |
≤0.04 |
0.8-1.1 |
0.15-0.25 |
| GB 3077 |
30CrMo |
0.26-0.33 |
0.17-0.37 |
0.4-0.7 |
≤0.03 |
≤0.03 |
0.8-1.1 |
0.15-0.25 |
From the above table,we can intuitively see their small differences, which are so small that they can be ignored.In actual use, we can completely replace each other, of course, the premise is to carefully check whether their chemical composition is in the overlapping range.
Other Equivalent Grade
Europe/EN10083 &EN10250:25CrMo4/DIN 1.7218
Japan/JIS G4105:SCM430
UK/BS970:708A25/708M25
QUICK FAQS FOR AISI 4130 STEEL
Is AISI 4130 Steel Low-Carbon Low-Alloy Steel?
From the above content,we can clearly see that AISI 4130 has carbon content with range 0.28-0.33%.According to the classification of carbon content, it belongs to the Medium-carbon series( 0.25%≤ C<0.6%).With Alloy elements below 5%,we can define AISI 4130 as low alloy steel.
Can AISI 4130 Steel be Cold Drawn?
Yes,AISI 4130 steel can be cold drawn with high-precision size and smooth surface.After cold drawn process,AISI 4130 steel has good mechanical properties and can be directly applied without further processing.
In addition to cold-drawn round steel, AISI 4130 can also be processed into other shapes, such as square steel, flat steel, hexagonal steel, and even special-shaped steel.
AISI 4130 Steel vs AISI 4135 Steel
As a Cr-Mo series alloy structural steel,AISI 4130 and AISI 4135 belong to the ASTM A29 standard.First of all, let's take a look at their specific composition differences.
| Grade |
C |
Si |
Mn |
P |
S |
Cr |
Mo |
| 4130 |
0.28-0.33 |
0.15-0.35 |
0.4-0.6 |
≤0.035 |
≤0.04 |
0.8-1.1 |
0.15-0.25 |
| 4135 |
0.33-0.38 |
0.15-0.35 |
0.7-0.9 |
≤0.035 |
≤0.04 |
0.8-1.1 |
0.15-0.25 |
From the above table,the carbon content of AISI 4135 is higher than 4130, so the hardness, tensile strength and yield strength of AISI 4135 are relatively better for the two materials after heat treatment. However, AISI 4130 is better in terms of toughness.
According to the classification of API temperature grade, 4135 and 4130 steel are often applied to P-U grade, which is -29ºC-+121ºC. However, due to the slightly lower carbon content of 4130 steel, its low temperature performance is slightly better than that of 4135 steel.(the difference is also relatively speaking, basically the difference is not very large).
AISI 4130 STEEL VS AISI 4140 STEEL
We analyze AISI 4130 and AISI 4140 from the naming rules of American steel grades.The most sure thing is that they belong to Chromium-Molybdenum Steel.Then let's take a concrete look at their performance differences in various aspects.
| Grade |
C |
Si |
Mn |
P |
S |
Cr |
Mo |
| 4130 |
0.28-0.33 |
0.15-0.35 |
0.4-0.6 |
≤0.035 |
≤0.04 |
0.8-1.1 |
0.15-0.25 |
| 4140 |
0.38-0.43 |
0.15-0.35 |
0.75-1.0 |
≤0.035 |
≤0.04 |
0.8-1.1 |
0.15-0.25 |
From the above table,we can clearly see that, as Cr-Mo series alloy steels, AISI 4130 and AISI 4140 have the same content of Cr and Mo elements, but the difference is obvious in C and Mn elements.
| |
4130 |
4140 |
| Normalizing,ºC |
870-900 |
850-900 |
| Annealing,ºC |
830-850 |
850 |
| Quenching,ºC |
860-890 |
840-880 |
| Tempering,ºC |
540-570 |
220-650 |
| Quenching Medium |
Oil/Water |
Oil/Water |
| Hardness,HRC |
32-38 |
28-58 |
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