1Cr13 vs 2Cr13 – Composition, Heat Treatment, Properties, and Applications
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Table Of Content
Table Of Content
Introduction
Engineers, procurement managers, and manufacturing planners routinely face choices between closely related stainless and alloy steels where small compositional differences have outsized effects on performance and cost. Two grades commonly encountered for wear‑resistant, martensitic stainless applications are designated 1Cr13 and 2Cr13. The practical selection dilemma typically centers on tradeoffs among strength and wear resistance versus toughness, weldability, and cost.
The primary distinction between these two commercial grades lies in their alloy balance—most notably the chromium and carbon levels—leading to different hardenability, achievable hardness, and corrosion performance. Because both grades are used in similar product families (valves, shafts, pump parts, blades, and tooling), engineers compare them to decide whether to prioritize higher strength and wear resistance or better toughness and fabrication ease.
1. Standards and Designations
- Common standards and cross‑references where grades with similar chemistry may appear:
- GB (China): 1Cr13, 2Cr13 (common Chinese designations)
- JIS (Japan): close equivalents often compared to SUS420 series (for martensitic stainless steels)
- EN / EN ISO: may be compared with parts of the X12Cr series (martensitic stainless family)
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ASTM/ASME: not direct 1:1 equivalents, but AISI 420 and other martensitic stainless specifications are functional comparisons
-
Classification:
- Both 1Cr13 and 2Cr13 are martensitic stainless steels (stainless, heat‑treatable). They are not low‑alloy HSLA nor tool steel in the traditional sense, although they are used for wear and cutting applications due to their hardenability.
Note: exact numeric ranges and naming vary by country and mill; always verify with the supplier’s material certificate.
2. Chemical Composition and Alloying Strategy
The following table shows representative composition ranges used in industry for the two grades. These are typical ranges—specific mill specifications and standards should be consulted for procurement or design calculations.
| Element | Typical 1Cr13 (wt%) | Typical 2Cr13 (wt%) |
|---|---|---|
| C | 0.08 – 0.20 | 0.15 – 0.30 |
| Mn | ≤ 1.0 (typ. 0.3 – 0.8) | ≤ 1.0 (typ. 0.3 – 0.8) |
| Si | ≤ 1.0 (typ. 0.2 – 0.8) | ≤ 1.0 (typ. 0.2 – 0.8) |
| P | ≤ 0.04 | ≤ 0.04 |
| S | ≤ 0.03 | ≤ 0.03 |
| Cr | ~12.0 – 13.5 | ~13.0 – 14.5 |
| Ni | ≤ 0.3 | ≤ 0.3 |
| Mo | ≤ 0.1 | ≤ 0.1 |
| V | ≤ 0.10 | ≤ 0.10 |
| Nb / Ti / B | trace / often <0.03 | trace / often <0.03 |
| N | trace | trace |
Explanation of how alloying affects properties: - Carbon increases strength, hardness, wear resistance, and hardenability but reduces ductility and weldability when raised. - Chromium provides corrosion resistance and contributes to hardenability and tempering response in martensitic stainless steels; incremental increases improve passive film stability and high‑temperature hardness retention. - Manganese and silicon are deoxidizers and influence hardenability; manganese in excess can reduce toughness. - Minor microalloying (V, Nb) may refine carbides and grain structure, improving toughness and creep resistance slightly.
The practical consequence: 2Cr13 tends to be specified to give higher as‑hardened hardness and wear resistance, while 1Cr13 is chosen where slightly better toughness and easier fabrication are needed.
3. Microstructure and Heat Treatment Response
Typical microstructures: - In the annealed condition both grades contain ferrite plus carbides; after quenching they form martensite with distributed chromium carbides (M23C6, M7C3, and cementite depending on C content and other elements). - 1Cr13 (lower C and slightly lower Cr) produces a martensitic matrix with fewer and smaller carbides at a given heat treatment, tending to give better toughness after tempering. - 2Cr13 (higher C and often higher Cr) forms a higher volume fraction of martensitic phase and more carbide precipitates, providing greater as‑quenched hardness and wear resistance but lower toughness.
Heat treatment response: - Common route: austenitize (typically 950–1050 °C depending on section size and composition), quench (oil or air for thin sections), then temper to target hardness/toughness. - Normalizing refines grain size and can improve machinability and toughness prior to final quench & temper. - Quench and temper: tempering temperature and time control the tradeoff between strength and toughness. Higher tempering reduces hardness but increases ductility and impact resistance. - Thermo‑mechanical processing (controlled rolling + cooling) is less common for these stainless martensitic grades but can refine microstructure and improve toughness.
Practical note: Because 2Cr13 has higher carbon/hardenability, it is more susceptible to hard, brittle martensite in thick sections and requires careful austenitizing and tempering cycles to avoid cracking.
4. Mechanical Properties
The table below shows representative achievable properties after typical quench & temper treatments. Values depend strongly on section size, heat treatment parameters, and exact chemistry; treat these ranges as guidance rather than guaranteed minimums.
| Property (typical after Q&T) | 1Cr13 | 2Cr13 |
|---|---|---|
| Tensile strength (MPa) | 600 – 900 | 700 – 1100 |
| Yield strength (0.2% offset, MPa) | 300 – 700 | 500 – 950 |
| Elongation (%) | 8 – 18 | 6 – 14 |
| Charpy impact (J, room T) | moderate (higher) | lower (reduced toughness) |
| Hardness (HRC) | 35 – 54 (process dependent) | 40 – 58 (can reach higher HRC) |
Interpretation: - 2Cr13 generally achieves higher tensile strength and hardness due to higher carbon and harder martensite, at the expense of ductility and impact toughness. - 1Cr13 is often selected when moderate strength with better toughness and fabricability are required.
5. Weldability
Weldability is influenced primarily by carbon equivalent and hardenability. Higher C and higher Cr increase the propensity to form hard martensite in the heat‑affected zone (HAZ), increasing risk of cold cracking.
Useful empirical indices include the IIW carbon equivalent and the Pcm formula: - $$CE_{IIW} = C + \frac{Mn}{6} + \frac{Cr+Mo+V}{5} + \frac{Ni+Cu}{15}$$ - $$P_{cm} = C + \frac{Si}{30} + \frac{Mn+Cu}{20} + \frac{Cr+Mo+V}{10} + \frac{Ni}{40} + \frac{Nb}{50} + \frac{Ti}{30} + \frac{B}{1000}$$
Qualitative interpretation: - 2Cr13, with its higher carbon and slightly higher chromium, has a higher carbon equivalent and greater hardenability, so it is more likely to develop hard martensite in the HAZ and therefore requires preheat, controlled interpass temperatures, and post‑weld heat treatment to avoid cracking. - 1Cr13 (lower C) welds more readily but still demands welding procedures appropriate for martensitic stainless steels (preheat, low hydrogen practice, and post‑weld tempering where necessary). - Use of filler metals: matching or lower hardenability filler wires, and weld post‑heating/tempering, are common practices.
6. Corrosion and Surface Protection
- Both grades are martensitic stainless steels with modest corrosion resistance compared with austenitic grades. Chromium provides passive film formation, but the lower overall chromium and carbon‑enriched carbide precipitation at grain boundaries can locally deplete Cr and reduce corrosion resistance.
- For typical environments:
- 1Cr13: adequate for mildly corrosive environments (atmospheric, mild water) when polished and passivated.
- 2Cr13: slightly improved pitting resistance if chromium is marginally higher, but increased carbide formation can reduce practical corrosion resistance unless heat treated and passivated correctly.
- PREN (Pitting Resistance Equivalent Number) is not particularly useful for these low‑Mo, low‑N martensitic grades, but the formula is:
- $$\text{PREN} = \text{Cr} + 3.3 \times \text{Mo} + 16 \times \text{N}$$
- For 1Cr13 and 2Cr13, PREN will be low compared to duplex or superaustenitic grades, because Mo and N are negligible.
- Surface protection: galvanizing, protective coatings, painting, and passivation are common strategies when higher corrosion resistance is needed. For wear parts, hard chrome or thermal spray coatings are often applied.
7. Fabrication, Machinability, and Formability
- Cutting and machining:
- 2Cr13 (higher hardness potential) is generally more abrasive on tools and more difficult to machine in the hardened state. Machining in the annealed condition reduces tool wear.
- 1Cr13 in annealed condition machines more easily; after hardening both require carbide tooling and rigid setups.
- Forming and bending:
- Cold forming is limited once material is hardened. Annealing before forming is standard practice.
- Finishing:
- Both grades can be ground and polished; 2Cr13 tends to require more aggressive grinding due to higher hardness and carbide content.
- Heat treatment distortion and cracking risks are higher for 2Cr13 during quench; fixturing and controlled cooling help manage distortion.
8. Typical Applications
| Typical uses of 1Cr13 | Typical uses of 2Cr13 |
|---|---|
| Shafts, valve components, pump parts, moderate‑wear blades, general hardware where toughness and reasonable corrosion resistance are required | Wear parts, leaf springs, higher‑load shafts, cutting elements, components requiring higher as‑hardened hardness and wear resistance |
| Fasteners, bolts, and moderately loaded components where fabrication ease is valued | Tools and dies for light duty, components subject to higher contact stresses where abrasion resistance is prioritized |
Selection rationale: - Choose 1Cr13 when the design emphasizes toughness, easier fabrication/welding, and moderate corrosion resistance at lower cost. - Choose 2Cr13 where higher hardness and wear resistance under load are dominant requirements and where application‑specific heat treatment and post‑weld procedures can be implemented.
9. Cost and Availability
- Cost: In general, baseline material cost for both is similar because chromium content difference is modest; 2Cr13 can be slightly more expensive due to tighter control of carbon/cr ranges and the potential for additional processing (e.g., tempering to high hardness).
- Availability: Both are common in regions where martensitic stainless steels are produced; specific product forms (bars, forgings, plate, precision‑ground stock) vary by mill. Lead times may be longer for special chemistries, special sizes, or certified lots.
- Process cost: Fabrication and welding for 2Cr13 may increase total part cost because of preheat/post‑weld heat treatment and additional machining time.
10. Summary and Recommendation
Summary table (qualitative)
| Attribute | 1Cr13 | 2Cr13 |
|---|---|---|
| Weldability | Better (lower C, lower CE) | More demanding (higher C, higher CE) |
| Strength–Toughness balance | Balanced toward toughness and ductility | Higher strength and hardness, reduced toughness |
| Cost (material + processing) | Lower to moderate | Moderate to higher (due to processing) |
Recommendation: - Choose 1Cr13 if you need a martensitic stainless steel that balances strength with better toughness, easier welding and fabrication, and cost‑effective processing—for example, shafts, valves, and general components that require corrosion resistance in mild environments and decent impact resistance. - Choose 2Cr13 if the priority is higher as‑hardened hardness, wear resistance, and higher tensile strength for components subjected to abrasion or contact fatigue—provided you can accommodate stricter heat‑treatment control, more demanding welding procedures, and potentially higher processing costs.
Final practical advice: always specify the exact mill/test certificate chemistry and required heat treatment, and perform application‑specific testing (hardness, impact, corrosion) on production lots where service conditions are critical.