X20CrMoV11-1 vs 21CrMoV5-7: Both high-temp bolt/blade steels — different corrosion approaches
X20CrMoV11-1 vs 21CrMoV5-7
Side-by-side chemical composition and mechanical property comparison.
Overview
X20CrMoV11-1
1.4922
12% Cr martensitic creep-resistant steel for steam turbine applications. Operates to ~580°C continuous. Combines corrosion resistance of 12% Cr with creep strength from Mo+V. Used for steam turbine blades, bolts, discs, and high-pressure steam piping in fossil power plants.
21CrMoV5-7
1.7709
Cr-Mo-V high-temperature alloy steel for bolting at elevated temperatures up to ~550°C. Higher Cr and Mo than 15CrMoV5-9 for improved creep resistance. Used for turbine casing bolts, main flange bolts in steam power plants, and high-pressure/high-temperature petrochemical fasteners.
| X20CrMoV11-1 | 21CrMoV5-7 | |
|---|---|---|
| Material Number | 1.4922 | 1.7709 |
| Category | Alloy Steel | Alloy Steel |
| Standard | EN 10269 | EN 10269 |
Chemical composition (wt%)
| Element | X20CrMoV11-1 | 21CrMoV5-7 | Overlap |
|---|---|---|---|
| C | 0.17–0.23% | 0.17–0.25% | OK |
| Si | 0–0.5% | 0–0.35% | OK |
| Mn | 0.3–0.8% | 0.3–0.8% | OK |
| P | 0–0.025% | 0–0.02% | OK |
Mechanical properties
| Property | X20CrMoV11-1 | 21CrMoV5-7 | Unit |
|---|---|---|---|
| tensile_strength | 690–840 | 800–950 | MPa |
| yield_strength | ≥ 490 | ≥ 600 | MPa |
| elongation | ≥ 15 | ≥ 14 | % |
Compatibility Assessment
X20CrMoV11-1 has 12% Cr giving oxidation/corrosion resistance to ~580°C. 21CrMoV5-7 has only 1.3% Cr but higher Mo for creep strength to ~550°C. X20CrMoV11-1 for steam turbines (corrosion matters); 21CrMoV5-7 for non-corrosive high-temp bolting.
Frequently Asked Questions
Is X20CrMoV11-1 the same as 21CrMoV5-7?
X20CrMoV11-1 and 21CrMoV5-7 have a 40% composition overlap. Both high-temp bolt/blade steels — different corrosion approaches
Can I replace X20CrMoV11-1 with 21CrMoV5-7?
Generally not recommended. The compositions differ significantly (40% overlap). These materials have different alloying concepts and are intended for different applications.
What is the difference between X20CrMoV11-1 and 21CrMoV5-7?
The main differences are in the following elements: Cr, Mo. X20CrMoV11-1 is a Alloy Steel grade, while 21CrMoV5-7 is a Alloy Steel grade.
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