Submerged Arc Surfacing Repair of 2-Tonne Steam Hammer Anvil

Literature Overview

The paper by Zhou Hongbo, Li Zhisheng, and Yang Peizhen, published in Welding in 1990, documents the transition from manual metal arc surfacing to submerged arc surfacing for the repair of steam hammer anvils at Dalian Steel Works. The steam hammer is a primary forging equipment in steel production, and its anvil is subjected to severe conditions including high-temperature impact loading, thermal cycling, and cyclic stress. The authors describe the failure modes of the anvil dovetail section, the limitations of the traditional manual surfacing approach, and the significant productivity improvements achieved by switching to submerged arc surfacing. This paper represents an important case study in process optimization for heavy equipment repair.

Core Technical Points

The anvil of a steam hammer is one of the most heavily loaded components in a forging shop. The 2-tonne steam hammer delivers impact energy to the workpiece through the hammer head, which strikes the workpiece positioned on the anvil. The anvil dovetail section, where the anvil is secured to the frame, is subjected to alternating impact loads in combination with thermal loading from the hot forged workpiece. The authors identify two primary failure mechanisms: creep under sustained high-temperature impact loading and thermal fatigue caused by repeated heating and cooling cycles. The combination of these mechanisms leads to progressive damage, manifesting as cracking in mild cases and spalling of metal blocks in severe cases.

The repair challenge is compounded by the large volume of material that must be restored. The damaged area can be as large as 600 by 250 by 130 millimeters, representing a substantial volume of surfacing deposit. With the traditional manual arc surfacing approach, the repair required three to four welders working in rotation, with long repair times and high labor intensity. The authors report that switching to submerged arc surfacing improved productivity by more than five times while significantly reducing worker fatigue. This productivity improvement is achieved through the inherent advantages of submerged arc welding, including higher deposition rates, deeper penetration per pass, and the ability to operate with larger wire diameters.

Process Analysis and Engineering Practice

The submerged arc surfacing process for the anvil repair involves several key steps. First, the damaged area must be prepared by removing all cracked and spalled material through machining or grinding, exposing sound base metal. The surface must be cleaned to remove any oxide, scale, or contamination that could interfere with fusion. Preheating of the base metal to 200-300 degrees Celsius is typically required to reduce the cooling rate and minimize the risk of cracking in the surfacing deposit.

The selection of the submerged arc wire and flux combination is critical to achieving the desired properties in the surfacing layer. For steam hammer anvils, which are typically made of low-carbon steel or low-alloy steel, the surfacing material should provide adequate hardness and wear resistance while maintaining sufficient toughness to withstand the impact loading. Common wire compositions include low-carbon steel wire with alloy additions such as chromium, molybdenum, or vanadium to enhance wear resistance. The flux composition is selected to provide adequate arc stability, slag protection, and appropriate dilution characteristics.

The welding parameters for submerged arc surfacing of the anvil typically involve wire diameters of 2.4 to 3.2 millimeters, currents of 400 to 700 amperes, and voltages of 28 to 36 volts. The travel speed is adjusted to achieve the desired deposition rate and penetration profile. Multi-pass surfacing is required to build up the full thickness of the repair, with interpass temperature control to prevent excessive thermal input and maintain the mechanical properties of the deposited layers. The sequence of welding passes should be planned to minimize residual stress and distortion, particularly in thick sections where thermal contraction can generate significant stresses.

In my experience with heavy equipment repair, the transition from manual to automated surfacing processes is one of the most impactful improvements that can be made. The productivity gains are substantial, but the quality improvements are equally important. Submerged arc surfacing produces deposits with fewer defects, more consistent composition, and better mechanical properties than manual arc surfacing. The reduced labor intensity also improves worker safety and reduces the risk of fatigue-related errors. However, the transition requires investment in equipment, training, and process development, which must be justified by the volume of work and the availability of skilled operators.

Study Insights and Implications

This paper is a valuable example of process engineering applied to a specific repair application. The authors did not simply describe the problem and propose a solution; they quantified the improvements in productivity and labor intensity, providing the economic justification for the process change. This quantitative approach is essential in engineering practice, where decisions about process changes must be supported by data rather than intuition.

The paper also highlights an important principle in repair engineering: the selection of the repair process should be driven by the geometry and volume of the repair, not just by the material requirements. Manual arc surfacing is appropriate for small, irregular areas where access is limited and the volume of deposit is small. However, for large, regular areas requiring substantial material buildup, automated processes such as submerged arc surfacing offer significant advantages in both productivity and quality.

For engineers managing repair operations in heavy industry, this paper reinforces the importance of continuous process improvement. The steam hammer anvil repair application demonstrates that even well-established repair practices can be significantly improved through careful analysis and process optimization. The principles of PDCA (Plan-Do-Check-Act) apply directly to this situation: the authors identified the problem, implemented the process change, measured the results, and confirmed the improvement. This systematic approach should be adopted for all repair operations to ensure continuous improvement in productivity, quality, and safety.