Martensitic stainless steel is a kind of stainless steel whose properties can be adjusted by heat treatment (quenching and tempering), and it is a kind of hardenable stainless steel.
Type Cr13 (1Cr13, 2Cr13, 3Cr13, 4Cr13) is a typical grade, which is mainly used for general corrosion resistance conditions (such as atmosphere, seawater, nitric acid, etc.) and components requiring certain strength.
It is widely used.
What is the difference between 1Cr13 and 2Cr13? What are the differences between the four similar Cr13 grades?
In this article, the data of chemical composition, heat treatment system and final mechanical properties of four stainless steel grades are listed for comparison and reference.
|
Chemical composition |
||||
|
Standard |
GB/T1220-2007 Stainless Steel Bars |
|||
|
Steel grade |
1Cr13 |
2Cr13 |
3Cr13 |
4Cr13 |
|
C |
0.08~0.15 |
0.16~0.25 |
0.26~0.35 |
0.36~0.45 |
|
Si |
≤1.00 |
≤1.00 |
≤1.00 |
≤0.60 |
|
Mn |
≤1.00 |
≤1.00 |
≤1.00 |
≤0.80 |
|
P |
≤0.040 |
≤0.040 |
≤0.040 |
≤0.040 |
|
S |
≤0.030 |
≤0.030 |
≤0.030 |
≤0.030 |
|
Ni |
（<0.60） |
（≤0.60） |
（≤0.60） |
（≤0.60） |
|
Cr |
11.5~13.5 |
12.0~14.0 |
12.0~14.0 |
12.0~14.0 |
|
Heat treatment schedule |
|||
|
Grade |
Annealing |
Quenching |
Tempering |
|
1Cr13 |
800-900 ℃ slow cooling or about 750 ℃ fast cooling |
950~1000 ℃ oil cooling |
700~750 ℃ fast cooling |
|
2Cr13 |
920~980 ℃ oil cooling |
600~750 ℃ fast cooling |
|
|
3Cr13 |
920~980 ℃ oil cooling |
600~750 ℃ fast cooling |
|
|
4Cr13 |
1050~1100 ℃ oil cooling |
200~300 ℃ fast cooling |
|
Mechanical property
| Grade | 1Cr13 | 2Cr13 | 3Cr13 | 4Cr13 |
| Annealing hardness | ≤200 | ≤223 | ≤235 | ≤235 |
| After quenching and tempering | 1Cr13 | 2Cr13 | 3Cr13 | 4Cr13 |
| Specified non-proportional extension strength Rpo.2/(N/mm2) | ≥345 | ≥440 | ≥540 | – |
| Tensile strength Rm/(N/mm2) | ≥540 | ≥640 | ≥735 | – |
| Elongation after fracture A/% | ≥22 | ≥20 | ≥8 | – |
| Reduction of area Z/% | ≥55 | ≥50 | ≥35 | – |
| Impact absorbing energy Aku2/J | ≥78 | ≥63 | ≥24 | – |
| Hardness HBW | ≥159 | ≥192 | ≥217 | HRC50 |
1Cr13 and 2Cr13 are different.
It can be seen from the above table that they are different in chemical composition, mechanical properties and heat treatment system.
From the chemical composition alone, the average content of Cr element of four grades (1Cr13, 2Cr13, 3Cr13, 4Cr13) is more than 12%, which also determines their basic corrosion resistance.
From 1Cr13 to 4Cr13, the carbon content increases gradually, and the strength increases, while the plasticity and toughness decrease correspondingly, which is verified by the mechanical property data after heat treatment.
So, which is hard, 2Cr13 or 1Cr13?
2cr13 is harder than 1cr13, and 3Cr13 is harder than 2Cr13.
From the perspective of heat treatment system, 1Cr13, 2Cr13 and 3Cr13 can be narrowly classified into one category, while 4Cr13 is quite different.
In the final analysis, the metallographic structure is different with different carbon content, and the heat treatment method is different.
This factor should be fully considered when replacing materials.
