| Overlay Chemistry | Typical chromium carbide overlay compositions use approximately 3–5% carbon and 20–35% chromium by mass. Actual chemistry should be selected according to impact, abrasion, temperature, and corrosion exposure. | Heat analysis or product test report showing carbon, chromium, manganese, silicon, and other declared alloying elements. | Chemistry influences carbide formation, wear resistance, weldability, and resistance to high-temperature oxidation. | Required |
| Overlay Hardness | A common working range is approximately 55–65 HRC, often equivalent to about 600–750 HV depending on the test method and conversion basis. | Hardness map with test locations, test method, surface condition, and measured values. Vickers testing should identify the applied load. | Hardness is useful for screening wear resistance, but it should not be used as the only indicator of service life. | High |
| Carbide Morphology | Prefer a reasonably uniform distribution of primary chromium carbides in the matrix, with controlled cracking and no large areas of unmelted or poorly bonded material. | Metallographic cross-sections from production samples, including macro photographs and, where appropriate, microscopic images. | Carbide distribution and matrix structure affect crack propagation, chipping, and real abrasion performance. | High |
| Base Plate Material | Common backing plates include carbon or low-alloy steel grades selected for structural strength, forming, welding, and operating temperature requirements. | Base-metal mill certificate, grade designation, yield strength, tensile strength, elongation, and chemical analysis. | The backing plate carries loads and determines installation, bending, drilling, and welding limitations. | High |
| Thickness and Tolerance | Typical supplied constructions may combine a base plate of approximately 4–40 mm with an overlay of approximately 3–20 mm. Final limits must be agreed on the drawing and purchase order. | Approved dimensional drawing, thickness readings at defined points, flatness data, and tolerance statement. | Incorrect thickness or flatness can cause fit-up problems, premature cracking, and installation delays. | Required |
| Bond Integrity | The overlay should be continuously fused to the base material, without unacceptable delamination, lack of fusion, slag inclusions, or open defects. | Visual inspection records, cross-section examination, and an agreed non-destructive or destructive inspection plan where applicable. | Good bonding prevents spalling and extends service life under impact and vibration. | Required |
| Controlled Surface Cracking | Transverse stress-relief cracks are common in hardfaced overlay plates. Their spacing, width, and orientation should remain within the agreed technical specification. | Crack acceptance criteria, surface photographs, crack-spacing measurements, and written installation guidance. | Cracks may be normal for stress relief, but excessive or irregular cracking can reduce structural integrity. | High |
| Abrasion Testing | For comparative screening, request a standardized abrasion test such as ASTM G65 or an equivalent agreed method. Test conditions must be identical across samples. | Complete test report stating specimen preparation, abrasive type, load, wheel speed, test duration, mass loss, and laboratory identification. | Standardized mass-loss results provide more useful comparisons than hardness values alone. | High |
| Quality Management Certification | ISO 9001 certification from an accredited certification body is a useful baseline for documented quality processes. | Valid certificate, certification scope, issuing body, certificate number, and verification status. | Certification supports process control, traceability, corrective action, and auditability; it does not replace product inspection. | High |
| Environmental and Safety Systems | ISO 14001 and ISO 45001 may be relevant when environmental control, worker safety, and responsible supply-chain management are part of the procurement policy. | Current certificates with matching legal entity, manufacturing site, and certification scope. | These systems can reduce compliance risks and support customer sustainability requirements. | Medium |
| Inspection Documentation | For export orders, request a product certificate or inspection document consistent with EN 10204, commonly a 3.1 inspection certificate when contractually required. | Heat number, batch number, chemistry, dimensions, hardness, inspection results, and authorized sign-off. | Traceable documents make claims, incoming inspection, and future replacement orders easier to manage. | Required |
| Production Capability | Assess whether the facility controls plate preparation, welding parameters, consumables, heat input, cooling, cutting, straightening, and final inspection in-house or through qualified subcontractors. | Process flow chart, equipment list, welding procedure documents, operator qualifications, and sample quality records. | Stable process control is more important than nominal production capacity for consistent wear performance. | High |
| Custom Dimensions and Shapes | Confirm capability for cut-to-size plates, bolt holes, countersinks, bends, formed liners, segmented panels, and installation markings. | Approved CAD drawing, dimensional inspection report, cutting tolerance, bend-radius limitation, and packaging plan. | Accurate prefabrication can reduce field cutting, welding, downtime, and installation labor. | High |
| Welding and Installation Support | Supplier instructions should cover compatible welding consumables, preheating requirements, interpass temperature, cooling method, and precautions around carbide cracking. | Written welding procedure, recommended consumables, repair procedure, and technical support contact. | Incorrect welding can cause distortion, delamination, excessive cracking, or damage to the base plate. | High |
| Sample and Pilot Validation | Before bulk production, validate representative samples under the actual wear mechanism: sliding abrasion, impact abrasion, gouging, erosion, or combined service. | Pre-production sample, agreed acceptance criteria, laboratory or field-trial results, and signed approval record. | Application-specific validation reduces the risk of selecting a plate based only on generic catalog values. | Required |
| Lead Time and Delivery Control | Lead time should be confirmed separately for standard plates, custom-cut parts, samples, and repeat orders. Custom fabrication generally requires additional drawing approval and inspection time. | Production schedule, material reservation plan, inspection date, packing list, and shipment milestone updates. | Clear delivery controls help prevent shutdowns caused by missing liners or delayed replacement parts. | Medium |
| Packaging and Corrosion Protection | Use rigid support, separation between machined surfaces, moisture protection, lifting points, and clear identification of plate orientation and heat numbers. | Packing specification, loading photographs, gross and net weights, marking plan, and moisture-protection method. | Proper packaging reduces transport damage, rust, deformation, and identification errors at the installation site. | High |
| Commercial and Technical Transparency | Prefer quotations that clearly separate plate grade, overlay thickness, base thickness, custom processing, inspection, packaging, and shipping terms. | Detailed quotation, technical data sheet, drawing revision, warranty terms, claims procedure, and agreed Incoterms. | Transparent specifications make bids comparable and reduce disputes caused by ambiguous product descriptions. | Required |