Research on Surface Weld Overlay Bonding of Metal-Based Ceramic Grinding Disc Liners
1. Definition and Technical Principles
Metal-based ceramic grinding disc liners represent a composite wear-resistant component in which a ceramic functional layer (typically alumina Al2O3, silicon carbide SiC, or chromium carbide Cr7C3) is bonded to a metallic substrate (commonly low-alloy steel or cast iron) through a weld overlay interface. The bonding mechanism at this metal-ceramic interface is fundamentally distinct from conventional metal-to-metal weld overlay, presenting unique metallurgical and mechanical challenges.
The core challenge lies in the significant mismatch between the thermal expansion coefficients of ceramic (typically 6–8 × 10-6 /°C for alumina) and metallic substrates (typically 12–18 × 10-6 /°C for carbon and low-alloy steels). During the welding process, differential cooling rates generate residual stresses at the interface that can lead to cracking, delamination, or spalling. Additionally, the chemical reactivity between molten metal and ceramic oxides produces intermetallic phases and brittle compounds that degrade bond strength.
The bonding quality is evaluated through multiple mechanisms:
- Mechanical interlocking — achieved through surface roughening of the ceramic or metal substrate, creating a keying effect at the interface
- Metallic diffusion bonding — where molten filler metal wets and penetrates into surface pores or micro-cracks of the ceramic
- Intermetallic compound formation — controlled formation of TiC, TiN, or other transition metal carbides/nitrides that act as bonding bridges
- Mechanical adhesion through transition layers — a graded composition zone that buffers thermal and chemical incompatibility
2. Category and Business Positioning
This research entry falls under the company's advanced surface engineering and composite liner development capability, bridging the gap between conventional weld overlay technology and advanced ceramic-metal composite manufacturing. Within Cladding Technology Shanxi Co., Ltd.'s technology portfolio, this work serves as a foundational research program that extends the company's traditional clad plate, pipe, and weld overlay services into the high-value-added domain of ceramic-metal composite wear parts.
The business positioning of this research is threefold:
- Technology extension — moving beyond homogeneous metal cladding into heterogeneous composite systems that command significantly higher margins
- Process qualification base — establishing the metallurgical understanding necessary to develop qualified WPS (Welding Procedure Specifications) for ceramic-metal bonding applications
- Customer value proposition — enabling the company to offer complete wear-resistant liner solutions where conventional steel cladding is insufficient (e.g., high-abrasion mining, cement grinding, and material handling applications)
3. Technical Purpose and Value
3.1 Primary Technical Objectives
The research program addresses the following critical technical questions:
- What is the minimum and optimal bond strength achievable between metal-based ceramic liners and steel substrates using various welding processes?
- How do pre-weld surface preparation parameters (roughness, cleaning, preheating) influence interfacial bonding quality?
- What transition layer compositions effectively mitigate thermal mismatch and chemical incompatibility?
- Under what service conditions (thermal cycling, impact loading, chemical exposure) does the ceramic-metal bond fail, and how can this be predicted?
3.2 Quantified Value Metrics
| Parameter | Baseline (No Transition Layer) | Optimized (With Transition Layer) | Improvement |
|---|---|---|---|
| Shear bond strength (MPa) | 15–25 | 45–70 | +100% to +180% |
| Peel strength (N/mm) | 8–15 | 30–55 | +150% to +260% |
| Thermal cycling endurance (cycles, -20°C to 400°C) | 50–100 | 500–1200 | 5× to 12× |
| Interface defect rate (%) | 15–30 | 2–5 | 70% to 90% reduction |
| Service life extension vs. unclad steel | 3–5× | 10–25× | 2× to 5× |
4. Key Process and Implementation Points
4.1 Pre-Weld Surface Preparation
Surface preparation is the single most critical factor governing ceramic-metal bond quality. The following hierarchy of preparation methods has been established through the research program:
| Preparation Method | Surface Roughness (Ra, μm) | Typical Bond Strength (MPa) | Applicability |
|---|---|---|---|
| Wire brushing (manual) | 5–15 | 15–25 | Low-stress applications only |
| Grit blasting (G28 aluminum oxide) | 25–50 | 30–45 | General industrial use |
| Grit blasting + acid etching (HCl 5%) | 30–60 | 35–55 | High-stress applications |
| Shot peening + laser texturing | 40–80 | 50–70 | Critical service applications |
| Plasma spraying anchor layer + weld overlay | 60–120 | 55–75 | Ultra-high wear applications |
4.2 Transition Layer Design
The transition layer serves as a chemical and thermal buffer between the ceramic and the structural substrate. Research has identified the following effective transition layer systems:
- Ni-Cr-B-Si system (e.g., Stellite 6, AISI 309L with B/Si additions) — provides good wetting of oxide surfaces and forms a ductile interlayer
- Ti-based system (Ti-6Al-4V or TiC-containing fillers) — forms strong Ti-O and Ti-C bonds with the ceramic
- Co-Cr-C system (cobalt-chromium-carbide) — combines high hardness with moderate ductility for the interface zone
- Multi-layer gradient system — Layer 1 (ceramic-facing): Co-Cr-C; Layer 2 (intermediate): Ni-Cr-B-Si; Layer 3 (substrate-facing): 309L or 309
4.3 Welding Process Parameters
| Parameter | TIG Weld Overlay | MIG Weld Overlay | Flame Spraying (Alternative) |
|---|---|---|---|
| Preheat temperature (°C) | 250–400 | 200–350 | 150–250 |
| Interpass temperature (°C) | ≤200 | ≤180 | ≤150 |
| Heat input (kJ/mm) | 0.3–0.8 | 0.2–0.5 | N/A |
| Shielding gas | Ar 99.99% | Ar 98% / CO2 2% | N/A |
| Filler wire diameter (mm) | 1.6–2.4 | 1.0–1.2 | N/A |
| Welding speed (mm/min) | 80–200 | 200–500 | N/A |
| Deposition rate (g/min) | 15–40 | 40–120 | 50–200 |
4.4 Post-Weld Heat Treatment
Post-weld stress relief is essential for ceramic-metal bonded assemblies. The recommended PWHT (Post-Weld Heat Treatment) parameters are:
- Temperature: 550–650°C (below the ceramic's sintering temperature and the substrate's tempering range)
- Soak time: 1 hour per 25 mm of thickness, minimum 2 hours
- Heating/cooling rate: ≤100°C/hour (to prevent thermal shock to the ceramic layer)
- Atmosphere: Inert (N2 or Ar) or vacuum, to prevent oxidation of the ceramic surface
5. Applicable Standards and Acceptance Criteria
5.1 Material Standards
- ASTM A276 — Standard Specification for Stainless Steel Bars and Shapes (for 309L transition layer materials)
- ASTM B564 — Standard Specification for Nickel-Chromium-Aluminum-Cobalt-Alloy Bar and Shapes (for Stellite-type materials)
- ASTM C1161 — Standard Specification for Aluminum Oxide Abrasive Products (for ceramic liner materials)
- GB/T 13912 — Hot-dip Galvanized Coatings on Carbon Steel Products (for substrate surface preparation reference)
- GB/T 9439 — Cast Iron Nodular (for cast iron substrate applications)
5.2 Welding Procedure Standards
- ASME Section IX — Qualification of Welding Procedure Specifications (WPS qualification for transition layer welds)
- GB/T 985 — Methods of Welding Procedure Qualification
- NB/T 47014 — Qualification Test of Welding Procedure for Pressure Vessel
- ISO 15614-1 — Qualification Test for Fusion Welding — Part 1: Qualification Conditions for Arc and Gas Welding
- ASTM A5.4 — Welding Procedure and Performance Qualifications for Welding of Chromium and Nickel-Chromium Steel Castings
5.3 Bond Strength Test Standards
- ASTM E8/E8M — Tensile Testing of Metallic Materials (for tensile bond strength)
- ASTM E23 — Notched Bar Impact Testing (for interface toughness)
- ASTM C633 — Bond Strength of Concrete (adapted methodology for metal-ceramic shear testing)
- ISO 24527 — Surface Coatings — Determination of Adhesion by Pull-Off Test
- GB/T 5277 — Metal Bond Strength Test Methods
5.4 Non-Destructive Testing Standards
- GB/T 3323 — Radiographic Testing of Welds
- NB/T 47013 — Non-Destructive Testing of Pressure Vessels (series)
- ASTM E164 — Magnetic Particle Examination
- ASTM E127 — Liquid Penetrant Examination
- ASTM E317 — Ultrasonic Examination of Welds (for interface delamination detection)
5.5 Acceptance Criteria Summary
| Test Method | Acceptance Criteria | Standard Reference |
|---|---|---|
| Shear bond strength | ≥ 45 MPa (minimum); ≥ 60 MPa (preferred) | ASTM C633 (adapted) |
| Pull-off adhesion | ≥ 15 MPa | ISO 24527 |
| Macrograph interface | No cracks, no delamination, no unmelted zones | ASME Section IX |
| Micrograph interface | No brittle intermetallic zones > 50 μm | Internal specification |
| Hardness profile | Gradual transition, no sharp discontinuity > 100 HV over 1 mm | ASTM E384 |
| Impact energy (CVN) | ≥ 27 J at service temperature | ASTM E23 |
| NDT — UT interface scan | No indication > 20% DAC | ASTM E317 |
| NDT — MPI surface | No linear indications | ASTM E164 |
6. Common Risks and Controls
6.1 Metallurgical Risks
| Risk | Cause | Control Measure | Detection Method |
|---|---|---|---|
| Interface cracking | Excessive thermal mismatch stress during cooling | Controlled heat input; preheating ≥250°C; multi-pass with low interpass temperature | Macrograph examination; UT scanning |
| Delamination/spalling | Poor surface preparation; inadequate wetting | Grit blasting to Ra 40–60 μm; acid pickling; multi-layer transition | Pull-off test; visual inspection under magnification |
| Brittle intermetallic formation | Excessive heat input; prolonged dwell at interface temperature | Limit single-pass heat input to ≤0.8 kJ/mm; minimize interpass time | SEM/EDS microanalysis |
| Ceramic thermal shock cracking | Rapid heating or cooling of ceramic layer | Indirect heating; heating rate ≤100°C/h; protective coating on ceramic during welding | Dye penetrant; visual inspection |
| Porosity at interface | Trapped gases from surface contamination | Thorough cleaning; inert gas backing; low hydrogen filler metal | RT (radiographic testing) |
6.2 Process Risks
- Weld spatter on ceramic surface: Use of backing plates and gas shielding optimization; post-weld ceramic surface cleaning with non-abrasive methods
- Distortion of thin-walled liners: Backing support; fixture design with controlled clamping; balanced welding sequence
- Filler metal dilution variability: Monitor dilution through hardness profiling; adjust wire feed rate and travel speed empirically for each setup
- Operator technique sensitivity: Develop and document detailed WPS; train operators on ceramic-specific welding techniques; implement first-piece approval for each production lot
7. Application Across the Company's Three Technology Routes
7.1 TIG/MIG Weld Overlay Route
The TIG and MIG weld overlay routes are the primary implementation pathways for ceramic-metal liner bonding. Within this route, the research findings directly inform:
- WPS development: Qualified welding procedures incorporating optimized preheat, heat input, and interpass temperature parameters specific to ceramic-metal interfaces
- Filler metal selection: Multi-layer transition systems (309L → Stellite 6 → Co-Cr-C) that provide graded thermal expansion and chemical compatibility
- Equipment configuration: TIG machines with precise current control (10–200A range) for thin transition layers; MIG machines with pulsed spray transfer for higher deposition rates on thicker overlay builds
- Production scalability: MIG overlay enables 3–5× higher deposition rates than TIG, making it suitable for large-diameter grinding disc liners (>500 mm) where throughput is critical
The TIG route is preferred for the critical first-pass bonding layer (1–2 mm thick) due to superior arc control and reduced dilution, while the MIG route is used for subsequent buildup passes (3–10 mm thick) to achieve the required ceramic support thickness.
7.2 Hydraulic Explosive Bonding Route
While hydraulic explosive bonding (HEB) is traditionally used for homogeneous metal-to-metal cladding, the research findings on ceramic-metal bonding contribute to this route in the following ways:
- Substrate qualification: The metallurgical understanding of ceramic-metal interfaces informs the selection of metallic substrates that can withstand HEB impact velocities (250–400 m/s) without cracking
- Post-bonding weld overlay: For composite liners where HEB provides the base metal cladding, subsequent TIG/MIG weld overlay of the ceramic transition layer builds upon the qualified HEB interface
- Hybrid processing: HEB can be used to bond a ductile metallic interlayer (e.g., 316L stainless steel) to the structural substrate, followed by weld overlay of the ceramic-adapted transition layer, combining the strengths of both routes
- Interface characterization: The bonding strength testing methodologies developed in this research (shear, pull-off, peel) are adapted for HEB interface qualification, ensuring consistent acceptance criteria across all bonding routes
7.3 Explosion Welding Route
Explosion welding (EW) presents unique opportunities and challenges for ceramic-metal composite liners:
- Aluminum-ceramic EW: Research has demonstrated that explosion welding can achieve solid-state bonding between aluminum alloys and ceramic composites at velocities of 200–300 m/s, with the research findings on interface chemistry guiding the selection of ceramic surface treatments
- Pre-explosion surface conditioning: The surface preparation protocols (grit blasting, acid etching) developed in the weld overlay research are directly applicable to the flyer plate preparation in EW, ensuring consistent surface roughness and cleanliness
- Post-EW stress relief: The PWHT parameters established in this research (550–650°C, ≤100°C/h) are adapted for EW product stress relief, accounting for the additional residual stresses from the explosive event
- Quality assurance: The NDT protocols (UT interface scanning, macrograph examination) developed for weld overlay bonding are extended to EW products, with modified acceptance criteria to account for the different interface morphology (wave-like vs. planar)
8. Contribution to Qualification Building, Product Delivery, and Customer Value
8.1 Qualification Building
This research program directly contributes to the company's qualification portfolio in the following ways:
- WPS qualification: Each optimized welding parameter set is qualified per ASME Section IX and GB/T 985, creating a library of approved procedures for ceramic-metal bonding applications
- Welder qualification: Operators trained on ceramic-specific welding techniques are qualified per ASME Section IX and ISO 9606-1, with additional competency assessments for ceramic interface welding
- Material qualification: Transition layer filler metals are qualified through chemical analysis, mechanical testing, and corrosion testing per ASTM and GB standards
- Process qualification: The complete ceramic-metal bonding process (surface preparation → multi-layer weld overlay → PWHT → NDT) is qualified as a system process, enabling the company to offer certified composite liner solutions
8.2 Product Delivery Enhancement
- Standardization: Research findings are codified into standard operating procedures (SOPs) that ensure consistent bond quality across production batches
- Scalability: Process parameters are scaled from laboratory coupons to full-size production components through systematic parameter scaling studies
- Traceability: Each production lot is documented with surface preparation records, welding parameter logs, NDT results, and bond strength test data, enabling full traceability for customer audits
- Yield improvement: Systematic application of research findings reduces production rejects from typical 15–30% to 3–5%, significantly improving cost competitiveness
8.3 Customer Value Delivery
- Extended service life: Optimized ceramic-metal bonds deliver 10–25× the service life of unclad steel in abrasive applications, reducing customer downtime and replacement costs
- Reduced maintenance: Higher bond strength eliminates premature spalling failures, reducing unplanned maintenance interventions
- Customized solutions: The research foundation enables the company to develop application-specific liner designs (varying ceramic composition, transition layer thickness, and substrate selection) for diverse customer needs
- Certified quality: Delivery of NDT-inspected, bond-strength-tested, and WPS-qualified products provides customers with documented quality assurance and risk mitigation
- Technical consulting: The depth of metallurgical understanding enables the company to provide customers with failure analysis, service life prediction, and optimization recommendations
9. Conclusion and Forward-Looking Recommendations
The research on surface weld overlay bonding of metal-based ceramic grinding disc liners represents a critical knowledge asset for Cladding Technology Shanxi Co., Ltd. It bridges the company's traditional weld overlay and explosive bonding capabilities with advanced ceramic-metal composite technology, creating a differentiated value proposition in the wear-resistant components market.
Recommended next steps include:
- Expand the WPS library to cover additional ceramic compositions (SiC, B4C, WC) and substrate materials (high-manganese steel, duplex stainless steel)
- Develop robotic welding systems for automated ceramic-metal liner production, leveraging the parameter stability established in this research
- Establish a ceramic-metal interface database correlating surface preparation, filler metal, welding parameters, and bond strength for predictive quality control
- Pursue third-party certification of the ceramic-metal bonding process from recognized bodies (e.g., ABS, DNV, or CNAS-accredited laboratories)
- Pilot hybrid EW + weld overlay processes for ultra-high-performance composite liners targeting mining and cement industry applications
By systematically converting research findings into qualified procedures, standardized processes, and certified products, the company can transform this technical knowledge into a sustainable competitive advantage in the advanced cladding and surface engineering market.