Management of Surfacing Construction for Wear-Resistant Parts of Cement Milling Equipment

Literature Overview

This paper, authored by Li Qiao from Beijing Jiake Emerging Technology Co., Ltd., was published in New Century Cement Herald in 2014 (Vol. 20, No. 1, pp. 41–45). The study addresses the management aspects of surfacing construction for wear-resistant parts in cement milling equipment, particularly vertical mills. The paper emphasizes that surfacing construction, like other construction projects, requires careful organization and management to ensure quality. Key management areas include planning, personnel management, coordination, technical documentation, and safety management.

Technical Background

Cement milling equipment, including vertical mills, ball mills, and roller mills, is subjected to severe wear due to the abrasive nature of the material being processed. The wear-resistant parts include:

• Vertical mill grinding rollers and table: Subject to abrasive wear and impact.
• Ball mill liners: Subject to abrasion and impact from steel balls.
• Roller mill grinding rolls and table: Similar to vertical mill.
• Separators and classifiers: Subject to erosive wear from material and air.

The surfacing of these parts is a critical maintenance activity that requires careful planning and execution.

Management Framework for Surfacing Construction

The paper proposes a comprehensive management framework that encompasses the following areas:

1. Planning Management

Planning is the foundation of successful surfacing construction. The planning process should include:

• Scope definition: Identify all parts requiring surfacing, including wear-resistant parts and structural components.
• Schedule development: Develop a realistic schedule that accounts for preparation, surfacing, inspection, and reassembly.
• Resource allocation: Allocate personnel, equipment, materials, and space.
• Risk assessment: Identify potential risks (e.g., schedule delays, quality issues, safety hazards) and develop mitigation plans.

2. Personnel Management

The quality of surfacing construction depends heavily on the skills and experience of the personnel involved:

• Welder selection: Select welders with appropriate qualifications and experience for the specific surfacing application.
• Training: Provide training on the specific surfacing process, materials, and quality requirements.
• Supervision: Assign experienced supervisors to monitor the surfacing process and ensure compliance with procedures.
• Performance evaluation: Evaluate welder performance based on quality metrics (e.g., defect rate, rework rate).

3. Construction Coordination

Surfacing construction often requires coordination with other maintenance activities and production schedules:

• Production scheduling: Coordinate with production to minimize downtime.
• Equipment availability: Ensure that the surfacing equipment (welding machines, gas supplies, etc.) is available and functional.
• Material availability: Ensure that the surfacing materials (wires, electrodes, fluxes) are available and stored properly.
• Site preparation: Prepare the work area to ensure safe and efficient surfacing operations.

4. Technical Documentation and Records

Comprehensive documentation is essential for quality control and traceability:

• Welding procedure specifications (WPS): Document the welding parameters, sequence, and inspection requirements.
• Welder performance qualifications (WPQ): Document the welder's qualifications and experience.
• Material records: Document the source, composition, and inspection status of all surfacing materials.
• Inspection records: Document all inspection results, including visual, PT, MT, UT, and hardness testing.
• As-built records: Document the actual surfacing parameters and results for future reference.

5. Safety Management

Safety is paramount in surfacing construction, particularly in industrial environments:

• Hazard identification: Identify all potential hazards (e.g., arc flash, fumes, burns, falls).
• Risk assessment: Assess the likelihood and severity of each hazard.
• Control measures: Implement control measures (e.g., PPE, ventilation, hot work permits).
• Emergency preparedness: Prepare emergency response plans for potential incidents.

Online vs. Offline Surfacing: Decision Criteria

One of the key decisions in surfacing construction is whether to perform the surfacing online (on the installed equipment) or offline (after removal from the equipment). The decision depends on several factors:

The paper recommends that the decision between online and offline surfacing should be made based on a careful analysis of the specific situation, considering factors such as equipment criticality, production schedule, and available resources.

Quality Control in Surfacing Construction

Quality control is a critical aspect of surfacing construction management. The following quality control measures should be implemented:

1. Incoming inspection: Inspect all surfacing materials upon receipt to verify composition, dimensions, and quality.
2. Pre-weld inspection: Inspect the base material for defects, hardness, and geometry before surfacing.
3. In-process inspection: Monitor welding parameters and inspect each layer for defects during surfacing.
4. Post-weld inspection: Inspect the completed surfacing for defects, hardness, and dimensional accuracy.
5. Final acceptance: Verify that the surfacing meets all specified requirements before returning the equipment to service.

Study Reflections

This paper makes a valuable contribution to the field of surfacing construction by emphasizing the importance of management. While technical aspects (welding parameters, materials, processes) are critical, the management aspects (planning, personnel, coordination, documentation, safety) are equally important. In my experience, many surfacing projects fail not because of technical issues but because of poor management. The paper's emphasis on systematic management is a reminder that surfacing construction is a complex project that requires careful planning and execution.

The paper also highlights the importance of the decision between online and offline surfacing. This decision has significant implications for production, cost, and quality, and should be made based on a thorough analysis of the specific situation. The paper's recommendation to analyze each case individually is sound engineering practice.

In conclusion, this paper provides a comprehensive management framework for surfacing construction that can be applied to any industrial setting. The emphasis on planning, personnel, coordination, documentation, and safety is essential for ensuring the quality and safety of surfacing operations. The paper should be read by all engineers and managers involved in surfacing construction, as it provides practical guidance on how to manage these projects effectively.