1045 steel is a medium carbon steel (carbon content is about 0.45%), which is a high-strength carbon structural steel with good strength, hardness, machinability and moderate toughness. Its typical mechanical properties are: tensile strength 570-700 MPa, yield strength 310 MPa, elongation 12-20%. The following is its specific application and analysis in the machinery manufacturing industry:
1. Shaft parts
- Application scenarios:
– Drive shaft: used to transmit torque and rotational motion, such as agricultural machinery and small machine tool transmission systems.
– Support shaft: such as conveyor roller shaft, light-load gearbox main shaft. - Advantages:
– Medium strength is sufficient to withstand conventional loads, and fatigue resistance can be improved through quenching and tempering (quenching + tempering).
– Low cost, suitable for standardized mass production.
2. Gears & Sprockets
- Application scenarios:
– Low-speed gears: such as agricultural machinery gearbox gears and non-precision gears in industrial reducers.
– Sprockets: used in conveyor belts and chain drive systems, requiring surface wear resistance. - Machining points:
– Surface hardening: Through high-frequency quenching or carburizing treatment, the surface hardness can reach HRC 50-55, and the core remains tough.
– Limitations: Not suitable for high-speed or high-impact gears (requires alloy steel such as 4140).
3. Fasteners
- Application scenarios:
– Bolts and nuts: used for mechanical structure connection, such as equipment base and frame fixing.
– Pins and washers: require a certain hardness and shear strength. - Advantages:
– Good cold heading forming performance, suitable for mass production.
– After heat treatment, it can reach Grade 8.8 bolt standard (tensile strength ≥ 800 MPa).
4. Structural parts & brackets
- Application scenarios:
Frames and bases: such as machine tool support structures and conveyor frames.
– Connecting plates and flanges: used for pipe or equipment fixing. - Advantages:
– Good weldability (need to be preheated to 150-200°C), stress relief annealing after welding can reduce deformation.
– The cost is lower than low alloy steel, suitable for non-high precision scenarios.
5. Tools & wear-resistant parts
- Application scenarios:
– Agricultural tools: such as plow blades and lawn mower blades.
– Die inserts: wear-resistant parts in simple stamping dies or fixtures. - Main points for processing:
– After surface quenching, the hardness is increased to HRC 55-60 to enhance wear resistance.
– Regular maintenance is required to avoid long-term high wear environment (such as switching to tool steel).
6. Hydraulic & pneumatic components
- Application scenarios:
– Cylinder piston rod: low-pressure hydraulic system (working pressure ≤20 MPa).
– Cylinder housing: requires certain strength and sealing surface accuracy. - Limitations:
– Poor corrosion resistance, chrome plating or protective coating is required in humid environments.
– High-pressure scenarios need to be upgraded to alloy steel (such as 4140) or stainless steel.
Comparison With Other Materials
| Materials | Advantages | Applicable scenarios |
| 1045 steel | Low cost, good processability, moderate strength | Medium and low load shafts, fasteners, structural parts |
| Q235B steel | Lower cost, but weak strength (yield 235 MPa) | Lightweight structures such as non-load-bearing brackets and shells |
| 4140 steel | High strength, fatigue resistance (tensile strength ≥850 MPa) | High stress gears, crankshafts, aviation parts |
| 304 stainless steel | Strong corrosion resistance, but high cost and low strength | Food machinery, chemical environment |
1045 Steel Processing & Heat Treatment Recommendations
- Machining:
– Annealed hardness is about HB 170-210, suitable for turning and milling, carbide tools are recommended. - Welding:
– Preheat to 150-200°C, use low-hydrogen electrodes, and slowly cool or temper after welding (600-650°C). - Heat treatment:
– Normalizing: Improve the uniformity of the structure, hardness HB 180-220.
– Quenching and tempering: quenching (water cooling or oil cooling) + tempering (500-600°C), hardness HRC 25-35.
– Surface hardening: low-temperature tempering after high-frequency quenching, surface hardness HRC 50-55.
Typical Application Cases of 1045 Steel
- Agricultural machinery transmission shaft:
– After quenching and tempering, the tensile strength of 1045 steel reaches 700 MPa, and the cost is 30% lower than that of alloy steel, which meets the needs of field operations. - Conveyor sprocket:
– After high-frequency quenching on the surface, the wear resistance is improved, and the service life is extended by 2 times compared with ordinary carbon steel. - Industrial bolts:
– After cold heading and heat treatment, it reaches the 8.8 grade standard and is used for equipment assembly.
Summary
1045 steel is widely used in mechanical manufacturing for shafts, gears, fasteners and structural parts due to its low cost, easy processing and medium strength. Although its performance is not as good as alloy steel, it has significant cost-effectiveness in medium and low loads and non-extreme environments. When selecting materials, it is necessary to comprehensively consider the working conditions (load, corrosion, impact) and cost, and improve performance through heat treatment or surface treatment when necessary.
