Management of Surfacing Welding Construction for Wear-Resistant Parts of Cement Plant Grinding Equipment

Literature Overview

Li Qiao, from Beijing Jiake Xinxing Technology Co., Ltd., published a paper in New Century Cement Herald (Vol. 20, No. 1, 2014) on the management of surfacing welding construction for wear-resistant parts in cement plant grinding equipment. The paper addresses the organizational and management aspects of surfacing welding projects, arguing that management quality is a critical determinant of project success. The author emphasizes the need for careful analysis of grinding mill conditions, appropriate selection of offline versus online welding approaches, and comprehensive management covering planning, personnel, coordination, documentation, and safety.

Technical and Management Context

Cement plant grinding equipment—including ball mills, vertical mills, roller presses, and classifiers—contains numerous wear-resistant parts that require periodic surfacing welding repair. These components include:

Mill liners and lifter bars
Roller press squeeze rolls
Vertical mill grinding table and roller surfaces
Classifier blades and wear rings
Feed chutes and discharge chutes

The unique challenges of surfacing welding in cement plants include:

Large component sizes that may not be removable for workshop repair
Production downtime costs that pressure repair schedules
Harsh operating environments with dust, moisture, and chemical contamination
Limited access to welding positions on installed equipment
Requirement for rapid turnaround to minimize production loss

Offline versus Online Surfacing Welding Comparison

Aspect	Offline (Workshop) Welding	Online (In-Situ) Welding
Component removal	Required	Not required
Production downtime	Longer (removal + transport)	Shorter
Welding position	Favorable (horizontal, flat)	Unfavorable (vertical, overhead)
Quality control	Excellent	More challenging
Equipment access	Full	Limited
Preheating control	Precise	Difficult
Post-weld treatment	Feasible	Often impractical
Cost	Higher (downtime + transport)	Lower (no removal)
Typical application	Critical, large components	Accessible, smaller components

Management Framework

The author proposes a comprehensive management framework for surfacing welding construction projects:

1. Planning Management

Condition assessment: Thorough evaluation of each grinding mill's wear pattern, operating parameters, and maintenance history
Timing determination: Selection of optimal repair timing based on production schedules, wear progression, and component criticality
Method selection: Decision on offline versus online welding based on component size, accessibility, and production constraints
Schedule development: Detailed work schedule with milestones, resource requirements, and contingency plans
Material procurement: Advance ordering of consumables, shielding gases, and auxiliary materials with quality certification

2. Personnel Management

Welder qualification: Verification of welder certifications for the specific process, position, and material
Training and briefing: Pre-job training on specific procedures, safety requirements, and quality expectations
Supervision structure: Assignment of qualified welding supervisors for each work area
Performance monitoring: Tracking of welder productivity and quality metrics

3. Construction Coordination

Interface management: Coordination with mechanical, electrical, and process teams for component isolation, gas-free certification, and hot work permits
Equipment staging: Arrangement of welding equipment, lighting, ventilation, and access scaffolding
Sequence planning: Logical welding sequence to minimize distortion and ensure quality
Inspection integration: Scheduling of in-process and final inspections within the work sequence

4. Technical Documentation

Welding procedure specification (WPS): Detailed parameters for each component and welding condition
Welding procedure qualification record (WPQR): Qualification evidence for the procedure
Inspection records: Documentation of all inspections including UT, MT, PT, hardness testing, and dimensional checks
Material traceability: Complete records of consumable lot numbers, heat numbers, and certification documents
As-built drawings: Updated drawings reflecting actual repair dimensions and geometry

5. Safety Management

Hot work permits: Formal authorization for welding in potentially hazardous environments
Confined space procedures: Gas testing and ventilation for work inside mills or hoppers
Fire prevention: Fire watch and extinguishing equipment for hot work near combustible materials
Electrical safety: Grounding, insulation, and lockout/tagout procedures
PPE requirements: Welding helmets, gloves, protective clothing, respiratory protection for flux fumes

Engineering Practice Considerations

The paper emphasizes that surfacing welding construction differs from other construction activities in several important ways:

Process sensitivity: Surfacing welding quality is highly sensitive to process parameters, making strict procedure adherence essential
Material matching complexity: The diversity of base materials and service conditions requires careful consumable selection for each application
In-process quality dependence: Unlike structural welding where final NDT catches defects, surfacing welding often requires in-process monitoring because defects may not be detectable after the overlay is complete
Thermal management: Large components with high thermal mass require careful preheating and heat input management to prevent cracking

Key Performance Indicators for Surfacing Welding Projects

KPI	Target	Measurement Method
First-pass quality rate	>95%	NDT results on first inspection
Rework rate	<3%	Number of repairs / total welds
Schedule adherence	±5% of planned duration	Actual vs. planned completion
Consumable utilization	>90%	Used / purchased quantity
Safety incidents	Zero	Incident reports
Client satisfaction	>90% score	Post-project evaluation

Study Insights

This paper represents a valuable contribution to the body of knowledge on welding project management, an area that is often underemphasized in technical literature. The author's observation that "management quality is a critical determinant of project success" is particularly relevant for surfacing welding, where the technical challenges are compounded by logistical, organizational, and scheduling pressures. The systematic approach to management—covering planning, personnel, coordination, documentation, and safety—provides a practical framework that can be adapted to any surfacing welding project regardless of scale or complexity.

The emphasis on the decision between offline and online welding is particularly practical. Many engineers default to offline welding for quality reasons, but the production cost implications of extended downtime may make online welding the more rational choice, provided adequate quality control measures are implemented. This decision should be based on a comprehensive cost-benefit analysis that includes both direct repair costs and indirect production loss costs. The paper's contribution to the professional community lies in elevating management considerations to the same level of importance as technical parameters in surfacing welding projects.