As the core load-bearing component of heavy-duty trucks, the manufacturing process of steel wheels directly determines the mechanical properties, structural strength and service life of the product. Precision forging has become the mainstream manufacturing method for heavy-duty truck steel wheels due to its high material utilization rate, compact microstructure and excellent mechanical performance. Different from previous articles focusing on fatigue failure and operation and maintenance, this paper focuses on the whole process of precision forging of steel wheels without tire-related content, and conducts research from the perspectives of process difficulties, application of numerical simulation, process parameter optimization, defect control and intelligent forging development, so as to provide technical references for improving quality and efficiency in the manufacturing of heavy-duty truck wheels.

1. Core Characteristics of Precision Forging Process for Heavy-Duty Truck Steel Wheels

Heavy-duty truck steel wheels mainly consist of two core parts: rim and disc. The precision forging of the disc is the core of the process. Different from ordinary casting and stamping processes, precision forging is a near-net-shape forming process, in which pressure is applied to the blank through a die to produce plastic deformation in a closed cavity, directly forming a disc blank that meets the requirements of dimensional accuracy and performance.

This process is suitable for the heavy-load demand of heavy-duty trucks and has three core characteristics:

First, enhanced material structure and performance. The forging process can break the coarse as-cast structure inside the steel, eliminate microscopic defects such as porosity and shrinkage cavities, and make the metal fibers distribute continuously along the wheel contour, greatly improving the tensile strength, yield strength and impact toughness of the disc to meet the load-bearing requirements of more than 20 tons for heavy-duty trucks.

Second, high dimensional accuracy and less subsequent machining. Precision forging can realize near-net forming of bolt holes, center holes and spoke surfaces, reducing subsequent cutting processes, improving material utilization and reducing production costs.

Third, strong process continuity. It can form an integrated production line with pre-forging, final forging, trimming and calibration, suitable for large-scale industrial production.

Compared with light-duty wheel forging, heavy-duty truck wheel forging faces problems such as large blank weight, high deformation resistance and complex die stress, which easily lead to insufficient forming, dimensional deviation and uneven internal structure in traditional processes.

2. Difficulties and Common Defects in Steel Wheel Forging

Heavy-duty truck steel wheels are usually made of high-strength medium-carbon alloy steels such as 42CrMo and Q345B. The blank diameter is mostly 300–500 mm with a weight of 15–30 kg. In the high-temperature forging process, the process control is extremely difficult due to the influence of blank heating temperature, die temperature, forging pressure, deformation rate and other factors.

On the one hand, complex surface forming is difficult. The spokes are mostly curved with reinforcing ribs, resulting in a long metal flow path and easy insufficient local filling, which directly affects structural strength.

On the other hand, die loss under high deformation resistance is serious. High-strength steel still has high deformation resistance at high temperatures, leading to rapid die wear, deformation and cracking, which shortens die life and increases manufacturing costs.

Affected by the above difficulties, traditional forging processes are prone to three typical defects:

• Folding defects: Surface metals overlap to form closed gaps, destroying material continuity.

• Cracking defects: Including surface hot cracks and internal micro-cracks caused by excessive temperature or uneven deformation.

• Dimensional deviation: Caused by insufficient blank volume, low forging pressure or die springback.

3. Application of Numerical Simulation Technology in Wheel Forging

Numerical simulation is the core method to optimize the wheel forging process. Finite element analysis software such as DEFORM-3D and ANSYS is used to simulate the whole forging process, predict metal flow, stress-strain distribution, temperature field change and defect location in advance, greatly shortening the R&D cycle without repeated die testing.

In process preview and optimization, a 3D model is established to simulate the whole deformation process from pre-forging to final forging, intuitively observing the filling state and accurately positioning insufficient filling and folding defects.

In temperature and stress field analysis, numerical simulation monitors the temperature change of the blank and die in real time, determines the optimal heating temperature range (1150–1200°C), and optimizes die design to reduce stress concentration, increasing die service life by more than 30%.

In defect prediction and elimination, simulation identifies the causes of folding and cracking, adjusts deformation rate and lubrication conditions, and eliminates defects from the source, increasing the qualification rate from 85% to over 98%.

4. Optimization Path of Precision Forging Process for Heavy-Duty Truck Wheels

Combined with numerical simulation results and production practice, systematic optimization is carried out from four dimensions: blank preparation, process parameters, die design and heat treatment coordination.

Blank preparation optimization: Precision blanking ensures the weight and dimensional error within ±1%. Step-by-step heating furnaces are used to ensure the temperature difference inside and outside the blank does not exceed 50°C.

Process parameter optimization: A three-stage forging process is adopted:

• Pre-forging: low pressure and slow speed for preliminary forming;

• Final forging: high pressure and high speed for full cavity filling;

• Calibration: precise pressure control to eliminate dimensional deviation.

The die preheating temperature is optimized to 250–300°C, and graphite-based high-temperature lubricant is used to reduce flow resistance.

Die design optimization: A combined die structure is adopted for easy processing and replacement. The fillet radius of key parts is increased to reduce stress concentration. Cooling channels are set inside the die to control working temperature.

Heat treatment coordination optimization: Normalizing is carried out immediately after forging to refine grains and eliminate forging stress, improving the uniformity of hardness and strength.

5. Development Trend of Intelligent Forging Technology

With the popularization of intelligent manufacturing, precision forging of heavy-duty truck wheels is developing towards automation, intelligence and digitization.

Intelligent forging production lines integrate automatic feeding, temperature detection, closed-loop pressure control and online dimension detection, realizing unmanned production through industrial robots. Digital twin technology links virtual simulation with actual production, dynamically adjusting process parameters. Near-net isothermal forging further reduces deformation resistance and realizes the forming of more complex wheel structures.

Conclusion

Precision forging is the core technology in the manufacturing of heavy-duty truck steel wheels, directly determining the load performance and quality stability of products. Process optimization, numerical simulation application and intelligent upgrading are important research directions in the field of commercial vehicle parts manufacturing.

This paper focuses on the whole wheel forging process, avoids tire-related content and previous research directions, and provides practical technical solutions for forging process improvement and product quality improvement in the industry. In the future, with the integration of intelligent technology and new materials, the precision forging process of heavy-duty truck wheels will achieve greater breakthroughs to further meet the development needs of heavy load, high efficiency and safety of commercial vehicles.