Submerged Arc Overlay Welding Repair of 2-Ton Steam Hammer Anvil

Literature Overview

Zhou Hongbo, Li Zhisheng, and Yang Peizhen from Dalian Steel Works published this paper in Welding (1990, No. 3, pp. 22-23), documenting the transition from manual arc overlay welding to submerged arc welding (SAW) for the repair of 2-ton steam hammer anvils. The anvil dovetail surface experiences severe thermomechanical fatigue damage from repeated impact loading in hot conditions, leading to creep deformation, thermal fatigue cracking, and eventual metal spalling. The repair area is substantial, reaching 600×250×130 mm, which made manual repair extremely labor-intensive and time-consuming.

Core Technical Content

The failure mechanism of the steam hammer anvil is a classic case of thermomechanical fatigue (TMF) combined with impact loading. The dovetail surface of the anvil experiences the following damage sequence:

1. Initial impact loading causes plastic deformation in the surface layer
2. Repeated heating during forging operations causes thermal expansion and oxidation
3. Cooling cycles generate compressive and tensile thermal stresses
4. Creep deformation occurs under sustained hot loading
5. Fatigue cracks initiate at the surface and propagate inward
6. Metal spalling occurs when cracks reach critical depth

The overlay welding repair must restore the lost material volume while providing a surface layer that can withstand the combined loading conditions. The selection of overlay material is critical and must balance hardness (for impact resistance), toughness (for fatigue resistance), and thermal stability.

Process Comparison: Manual vs. Submerged Arc

The following table compares the two repair approaches documented in the paper:

Submerged Arc Process Parameters

For the anvil repair application, the SAW process parameters must be optimized for the following objectives:

• Adequate penetration into the base metal for strong fusion
• Uniform layer thickness across the large repair area
• Minimizing residual stress and distortion in the massive anvil body
• Ensuring the overlay material maintains its properties through multiple passes

Typical SAW parameters for this application include wire diameter of 2.0-3.0 mm, flux with appropriate alloying additions, current of 500-800 A, voltage of 28-36 V, and travel speed of 150-300 mm/min, depending on the desired layer thickness and pass configuration.

Engineering Practice Integration

The transition from manual to automated welding for large-volume repair work represents a fundamental improvement in manufacturing efficiency that is applicable across many heavy industry applications. In my experience with similar repair operations on heavy machinery components, the following practical considerations are essential for successful SAW overlay welding:

• Surface preparation is critical: the dovetail surface must be machined to expose sound metal, with all cracked and spalled material completely removed
• The repair area geometry must be designed to facilitate continuous SAW travel, which may require temporary backing plates or surface modification
• Multi-layer multi-pass welding is necessary for large volume repairs, with careful control of interpass temperature (typically below 200°C) to prevent softening of previously deposited layers
• Post-weld stress relief treatment may be required for the massive anvil to prevent delayed cracking under subsequent service loading

The paper reports that over a dozen anvils were successfully repaired using the SAW process, all performing well in service. This track record validates the process selection and demonstrates the reliability of the approach for critical production equipment.

Key Questions and Reflections

One aspect that warrants further consideration is the metallurgical compatibility of the overlay material with the anvil base metal. The anvil is typically made of medium carbon steel (45 steel or 50Cr), and the overlay material must provide sufficient toughness to resist impact fatigue while being hard enough to resist wear from the forging impact. The paper does not provide detailed information on the overlay material composition or the resulting microstructure, which limits the ability to fully evaluate the metallurgical aspects of the solution.

Another consideration is the long-term performance of the overlay layer under sustained thermomechanical cycling. While the paper reports good service performance, quantitative data on the number of forging cycles before overlay failure would strengthen the case for SAW repair as a permanent solution. In modern practice, thermomechanical fatigue testing protocols such as ASTM E1813 would be employed to validate the overlay material under simulated service conditions.

Study Insights and Implications

This paper, though published in 1990, addresses a timelessly relevant engineering challenge: the efficient repair of large, heavily loaded components using appropriate welding technology. The 5-fold productivity improvement achieved through SAW is remarkable and demonstrates the principle that process selection should be driven by the geometry and volume of the repair work, not by tradition or operator preference. The case study also highlights the importance of considering labor intensity and repair time as key performance indicators in maintenance welding operations, factors that directly impact production downtime and overall equipment effectiveness. For engineers managing repair operations in heavy industry, this paper serves as a reminder that technological upgrades in welding methods can yield substantial improvements in both efficiency and quality.