Construction vehicle wheel hub support shafts are crucial components used in driving axles on construction vehicles such as road rollers, excavators, and loaders. Welded at both ends of the axle housing, they connect the drive axle housing to the internal gear ring, with half-axles passing through the axle tubes. These parts must not only bear the weight of the vehicle but also withstand the impact and counter-impact forces from the road surface during operation. Therefore, high mechanical performance is required, particularly in terms of stiffness, wear resistance, and seismic resistance, making them essential safety components for construction vehicles.

The technical specifications for this product are as follows: 1. Fatigue bench testing must exceed 500,000 cycles; 2. Heat treatment hardness: 24-32 HRC; 3. Metal flow lines: Full fiber metal flow lines distributed along the axial direction without any fractures or disorder; 4. Mechanical properties: Reh ≥ 630 N/mm2, Rm ≥ 750 N/mm2, A ≥ 18%, Z ≥ 52%, aku2 ≥ 60 J/cm.

Currently, domestic enterprises commonly employ free forging or die forging processes for production. While these methods meet product requirements, they exhibit low material utilization, high energy consumption, and severe environmental pollution. With the rapid growth of the national economy and the construction machinery industry, there has been a significant increase in demand for these important safety components. The existing outdated processes cannot meet the current market and technological development needs.

In response to this, the company has independently developed an advanced manufacturing process for construction vehicle full fiber wheel hub support shafts, achieving near-net shape through a hot extrusion process. This process utilizes solid round steel bars, subjected to medium-frequency heating and extrusion on a high-precision hydraulic press. The key steps include cutting, heating, extrusion, upsetting, internal hole extrusion, and final precision machining. This innovative process results in full fiber metal flow lines along the axial direction, significantly improving the shaft's fatigue life and load-bearing capacity. The production efficiency and product quality have also seen notable improvements.

Compared to traditional die forging processes, this method offers several advantages and innovations:

1. No need for machining of the internal hole;
2. Over 2 times increase in production efficiency;
3. 15.5% raw material savings, over 30% energy savings, and 50% reduction in processing time;
4. Reduction in environmental pollution;
5. Attainment of full fiber metal flow lines along the product's axial direction.

The development and application of the construction vehicle full fiber wheel hub support shaft near-net shape technology have not only provided significant economic benefits to the company but also yielded notable social benefits. The clean medium-frequency heating reduces energy consumption, and the extrusion-formed internal hole eliminates subsequent machining processes, saving production equipment, manpower, and resources. The near-net shape production also saves a substantial amount of metal material while greatly improving production efficiency. This product's achievement of full fiber metal flow lines along the axial direction marks a qualitative breakthrough in mechanical performance compared to products produced through traditional forging methods.

The traditional forging process, known for its high energy consumption and environmental pollution, is gradually being phased out. This transition will save a considerable amount of valuable energy for the country while enhancing the overall reliability of construction vehicle drive axles in China. It has laid a solid foundation for the development of the construction machinery industry in China, narrowing the gap between the drive axle technology of Chinese construction vehicles and international advanced levels. This advancement plays a positive role in promoting technological progress within the industry.

Award Level: Third Prize

Completing Unit: Nanyang Hongyang Forging Co., Ltd.