Optimization of 1045 steel heat treatment process: How to improve strength and wear resistance?
As a representative of medium carbon steel, the mechanical properties of 1045 steel are highly dependent on heat treatment process. By scientifically adjusting the parameters of quenching, tempering and surface treatment, its strength and wear resistance can be significantly improved, and even reach the performance level of some alloy steels. This article systematically analyzes how to tap the potential of 1045 steel from three aspects: mechanism analysis, process optimization plan, and practical cases.
1. Core Objectives & Basic Principles of Heat Treatment
1.1 The underlying logic of performance improvement
- Strength: obtain martensitic structure through quenching and strengthen by lattice distortion.
- Toughness: tempering eliminates quenching stress and precipitates carbides to stabilize the structure.
- Wear resistance: surface hardening (such as high-frequency quenching) or carburization treatment (such as carburizing) reduces friction loss.
1.2 1045 Steel Process route selection
- High strength + high toughness —>Quenching and Tempering: quenching + high temperature tempering
- High surface hardness–>Surface quenching: high frequency/flame quenching
- Comprehensive optimization–>Compound process: quenching and tempering + surface treatment
2. Optimization Guide For Key Process Parameters of 1045 Steel
2.1 1045 Steel Quenching process: core control points of martensitic transformation
| Parameter | Recommended range | Deviation risk |
| Heating temperature | 830-850℃ | Too low → incomplete austenitization; too high → grain coarsening |
| Holding time | 0.8-1.2 min/mm | Insufficient time → uneven structure; too long → oxidation decarburization |
| Cooling medium | 10% brine solution | Water cooling is prone to cracking, oil cooling has insufficient hardness (see table for comparison) |
Cooling medium comparison
| Medium | Cooling rate | Hardness (HRC) | Deformation/cracking risk | Cost |
| Tap water | Fast | 50-55 | High | Low |
| 10% brine | Very fast | 55-58 | Very high | Low |
| Rapid quenching oil | Medium | 45-50 | Low | High |
| Polymer solution | Controllable | 48-53 | Medium | Medium |
Optimization suggestions:
- 1045 Steel For parts with complex shapes: use graded quenching (oil cooling to 300°C and then air cooling) to reduce the risk of cracking.
- 1045 Steel For parts with large cross-sections: use PAG (polyalkylene glycol) aqueous solution to balance cooling speed and safety.
2.2 1045 steel tempering process: a battle between strength and toughness
Relationship between tempering temperature and performance (taking 840℃ quenching as an example)
| Tempering temperature | Tensile strength (MPa) | Hardness (HRC) | Impact toughness (J/cm²) | Applicable scenarios |
| 200℃ | 1000-1100 | 50-55 | 40-50 | High hardness wear-resistant parts |
| 400℃ | 800-900 | 35-40 | 80-100 | Comprehensive performance structural parts |
| 600℃ | 600-700 | 25-30 | 120-150 | High toughness safety parts |
Tempering time: usually 1-2 hours, large pieces need to be extended to 3-4 hours (calculated based on thickness 25mm/h).
Note:
- Avoid tempering in the 250-350℃ range (first type temper brittleness zone).
- Water cooling or oil cooling is recommended after tempering to prevent second type temper brittleness.
2.3 Surface strengthening technology: improve wear resistance at low cost
| Technology | Depth of hardened layer | Surface hardness (HRC) | Cost | Applicable parts |
| High frequency quenching | 1-3 mm | 55-60 | Medium | Medium | Gears, journals |
| Carburizing | 0.5-1 mm | 58-62 | High | High-load friction pairs |
| Nitriding | 0.2-0.5 mm | 65-70 | Very high | Precision wear-resistant parts |
| Laser cladding | 0.5-2 mm | 60-65 | Very high | Local repair and strengthening |
Recommended solution for small and medium-sized enterprises:
- High-frequency quenching + self-tempering: cost controllable, suitable for mass production of shafts and gears.
- Hard chrome plating (0.05-0.1mm): corrosion resistance + wear resistance, lower cost than carburizing.
3. Actual Case: Optimization of Heat Treatment of A Certain Agricultural Machinery Gear
3.1. Problem background
- Parts: Corn harvester transmission gear (module 8, tooth width 50mm)
- Failure mode: Tooth surface wear is too fast, and the average life is only 800 hours.
- Original process: 860℃ water quenching + 200℃ tempering, surface hardness HRC52-54.
3.2. Optimization plan
Process adjustment:
- Quenching medium is changed to 10% salt water + 0.2% rust inhibitor, and cooling is more uniform.
- Tempering temperature is increased to 350℃ (avoiding the brittle zone), hardness is reduced to HRC48-50 but toughness is improved.
- High frequency quenching of tooth surface, hardened layer depth is 1.2mm, surface hardness is HRC58-60.
3.3. Effect comparison
| Index | Original process | Optimized process | Improvement |
| Tooth surface hardness | HRC52-54 | HRC58-60 | +12% |
| Core impact toughness | 45 J/cm² | 75 J/cm² | +67% |
| Average life | 800 hours | 1500 hours | +87.5% |
| Relative cost per piece | x1.0 | x1.082 | +8.2% |
4. Common misunderstandings and coping strategies for optimizing the performance of 1045 steel
1. Excessive pursuit of high hardness:
– Error: Blindly adopt low-temperature tempering (HRC55+), resulting in brittle fracture of parts.
– Correction: Select hardness according to load type, HRC40-45 is recommended for impact load parts.
2. Ignore decarburization control:
– Error: There is no protective atmosphere for quenching heating, and the surface decarburization layer is as deep as 0.3mm.
– Correction: Introduce nitrogen or apply anti-oxidation coating, and the decarburization layer is controlled within 0.1mm.
3. One-size-fits-all cooling medium:
– Error: All parts are quenched with water, and the cracking rate of complex parts exceeds 15%.
– Correction: Select the medium according to the thickness/shape of the parts (see the table in Section 2).
5. Summary: Four steps to achieve 1045 steel heat treatment optimization
1. Clarify performance requirements: distinguish between overall strength and surface wear resistance requirements.
2. Design process route: give priority to the composite solution of quenching and tempering + surface treatment.
3. Strictly control key parameters: quenching temperature ±10℃, tempering time accurate to minutes.
4. Verification and iteration: continuous optimization through metallographic detection + bench test.
Mastering these optimization rules can make the performance of 1045 steel parts brand new even without upgrading the material!
Interactive topic: What problems did you encounter when optimizing the performance of 1045 steel? Welcome to discuss with us.
OUR CORE 1045 STEEL PRODUCT
