Overview of SAW Flux-cored Wire Hardfacing Technology
Working Principle and Process Characteristics
2.1 Working Principle
When SAW hardfacing with flux-cored wire, the arc burns between the end of the wire and the substrate surface. The granular flux covering the arc area isolates the air from the molten pool and protects the molten metal from oxidation and nitriding. The flux-cored wire's metal sheath melts under the heat of the arc, while the alloy powder inside the core melts into the molten pool, adjusting the chemical composition of the surfacing layer. After cooling, the slag formed by the flux solidifies on the surface of the weld, which can be removed easily, leaving a smooth, high-hardness surfacing layer.
2.2 Key Process Characteristics
High Deposition Efficiency: SAW can use large current (typically 300~800A) for continuous welding, the deposition rate can reach 8~12 kg/h, which is 2~3 times higher than that of manual arc welding, suitable for mass production of large-area wear plates.
Controllable Alloy Composition: Flux-cored wire can add various carbide-forming elements such as chromium, molybdenum, vanadium, tungsten and niobium into the powder core, which can accurately control the hardness and wear resistance of the surfacing layer by adjusting the content of these elements, compared with solid wire, it has greater flexibility in alloy design.
Good Forming Quality: Under the protection of submerged arc flux, the surfacing layer is uniform and smooth, with no obvious splatter, and the post-welding processing workload is small. The penetration depth can be adjusted by changing welding parameters, which can effectively control the dilution rate of the substrate to the surfacing layer, ensuring the hardness and wear resistance of the surfacing layer.
Stable Automatic Operation: The whole process can be realized by mechanized and automatic operation, which reduces the requirements for workers' skills and ensures the consistency of the quality of each wear plate.
Common Alloy System Classification and Performance
SAW flux-cored wires for wear plate hardfacing are mainly classified according to their alloy composition, and different alloy systems correspond to different application scenarios and wear resistance. The common classifications are as follows:
| Alloy System | Main Alloy Elements | Hardness Range (HRC) | Main Performance Characteristics | Typical Applications |
| High Chromium Cast Iron Type | Cr 15~30%, C 2~5%, small amount of Mo, Ni, Nb | 55~65 | Excellent abrasive wear resistance, certain impact resistance, low cost, mature alloy system | General mining wear plates, crusher liners, cement mill liners, scraper conveyor plates |
| Chromium Carbide Composite Type | Cr 25~40%, C 3~6%, added V, W, Ti | 60~68 | High volume fraction of hard carbide, super abrasive wear resistance, slightly poor toughness | High wear requirement scenarios such as sand making equipment, ore crushing teeth, excavator bucket teeth plates |
| Low Carbon Alloy Martensite Type | Cr 4~10%, Mo 1~3%, Mn 1~2%, C 0.2~0.6% | 35~50 | Good impact toughness, good weld crack resistance, can bear large impact load, moderate wear resistance | Bulldozer blade, excavator bucket edge plate, large mining shovel surface that need high impact resistance |
| Niobium Vanadium Carbide Type | Nb 10~20%, V 5~15%, Cr 10~15% | 62~68 | Fine-grained hard carbide, excellent wear resistance and good high temperature performance | High temperature wear scenarios such as high temperature conveyor plates, sintering equipment liners |
| Composite Ceramic Reinforced Type | Added ceramic particles such as WC, TiC into the powder core | 65~72 | Extreme wear resistance, high cost | Extreme wear scenarios such as coal mining shearer drums, road milling machine pick holders |
Key Performance Indicators of Wear Plate
The performance of the hardfacing wear plate is mainly evaluated by the following key indicators:
4.1 Surfacing Layer Hardness
Hardness is the most basic indicator to measure wear resistance. Generally speaking, the higher the hardness, the better the abrasive wear resistance. The hardness of hardfacing wear plates on the market is mostly concentrated in 50~65 HRC, and special products can reach more than 70 HRC. It should be noted that hardness testing needs to be carried out after the surfacing layer is stabilized, generally after removing the surface 1~2mm slag and dilution layer to ensure that the test result is true.
4.2 Dilution Rate
Dilution rate refers to the proportion of the melted substrate components mixed into the surfacing layer. Too high dilution rate will reduce the content of alloy elements in the surfacing layer, resulting in decreased hardness and wear resistance. For SAW hardfacing with flux-cored wire, reasonable process control can control the dilution rate within 10~20%, and multi-layer surfacing can further reduce the influence of dilution.
4.3 Crack Resistance
Most high-wear hardfacing layers are high-carbon and high-alloy materials, which are prone to produce welding cracks during cooling. Reasonable formula design of flux-cored wire and preheating before welding (generally preheating to 150~300℃ according to different alloy systems) can effectively reduce cracking tendency. For applications that require no cracks on the surface of the wear plate, low-carbon alloy systems or special crack-resistant formulations can be selected.
4.4carbon steel, and the reinforced composite wear plate can reach more than 20 tim Wear Resistance
The most direct indicator to evaluate the performance of the wear plate is the relative wear resistance, that is, the mass loss ratio of the tested wear plate and the standard sample under the same wear test conditions. The wear resistance of high chromium cast iron hardfacing plate is generally 5~10 times that of ordinary low es.
Selection Guide for Different Application Scenarios
When selecting SAW flux-cored wire for wear plate hardfacing, it needs to be matched according to the main failure form of the wear part:
Abrasive wear of low impact: Such as cement raw material chute, ore screening plate, sand conveyor. It is recommended to select high chromium type flux-cored wire with 58~62 HRC, which has high cost performance and can meet the service life requirements.
Strong impact and abrasive wear: Such as bulldozer blade, engineering machinery bucket, mine hammer head. It is required that the wear-resistant layer has certain toughness while having wear resistance, and it is recommended to select martensitic alloy flux-cored wire with 40~50 HRC to avoid peeling and cracking of the surfacing layer under impact.
Extreme high wear conditions: Such as coal mining machinery working parts, road construction milling wear plates, iron ore crushing liners. It is recommended to select chromium carbide composite or ceramic reinforced flux-cored wire with 62~68 HRC, which can significantly extend the service life of parts, although the cost is high.
High temperature wear: Such as sintering machine pallets, coke oven conveyor plates, metallurgical slag processing plates. It is recommended to select niobium-vanadium alloyed flux-cored wire, which maintains high hardness and oxidation resistance at working temperatures up to 600℃.
Points for Attention in Welding Process
To obtain high-quality hardfacing wear plates, it is necessary to control the key points of the welding process:
Preparations before Welding: The substrate surface should be cleaned of oil, rust and oxide scale to avoid porosity and inclusion defects. For thick substrates and high-alloy wires, preheating to 150~300℃ in advance can reduce welding stress and avoid cracking.
Parameter Selection: For common 1.2mm~2.4mm diameter flux-cored wire, the welding current is generally 250~600A, the welding voltage is 28~38V, and the welding speed is 300~600mm/min. The larger the wire diameter, the higher the corresponding current. Appropriately reducing the welding current and increasing the welding speed can reduce the dilution rate of the substrate.
Surfacing Layer Design: The thickness of the wear-resistant layer is generally designed as 3~12mm. For multi-layer surfacing, the interlayer temperature should be controlled not exceeding 300℃ to avoid too large grain growth affecting performance. For wear plates that need bending and post-processing, the surfacing should be carried out on the substrate after pre-bending to avoid cracking caused by post-bending.
Post-welding Treatment: After welding, it should be slowly cooled, especially for high-alloy wires, to avoid cracking caused by rapid cooling. For parts requiring stress relief, stress relief annealing can be carried out at 200~300℃ after welding to eliminate residual welding stress.
Development Trend of the Industry
In recent years, SAW flux-cored wire for wear plate hardfacing has the following development directions:
First,high-performance alloy design, more and more applications require higher wear resistance and longer service life, so the development of composite reinforced wires such as WC and TiC is accelerating, and the proportion of high-alloy wires in the market is increasing year by year.
Second,crack-free and high-toughness improvement, many engineering applications require that the surface of the wear plate does not allow cracks, which promotes the development of low-carbon crack-resistant formulations, which balance hardness and toughness by optimizing alloy proportion and microstructure control.
Third,environmentally friendly production, the new generation of flux-cored wire reduces the content of harmful elements such as cobalt and radioactive elements, and the matched submerged arc flux also develops towards low-pollution and recyclable directions, which meets the requirements of green manufacturing.
Fourth,customized development, for different wear conditions of different industries, manufacturers have launched more segmented dedicated products, which can achieve more precise performance matching, avoiding the waste of performance or insufficient life caused by the use of general products.
Company Introduction
Tangshan Runxing Machinery Co., Ltd., a professional manufacturer located in Tangshan, Hebei Province that focuses on R&D, production and on-site construction service of hardfacing wear-resistant metal products, was founded in 2010.
Our main products include chromium carbide overlay (CCO) wear plates, custom processed wear liners, wear-resistant pipes and pipe fittings, hardfacing flux-cored welding wires, automatic hardfacing welding machines, and professional roller surfacing repair service. We follow the business idea of “Integrity, Superior Quality, Innovation & Sustainable Development” and own mature advanced metal surface hardfacing technology.
We provide customized wear-resistant solutions for cement, steel, mining, port and dredging industries around the world, and have gained good market reputation in Russia and Central Asia.
All export business is fully authorized and handled by Hebei Yuwan International Trade Co., Ltd. This trading company completes all export work including customs clearance, shipment, documents and payment collection. Our factory focuses on product development and production to ensure stable product quality and on-time delivery.
Runxing Machinery sincerely hopes to establish long-term cooperation and achieve mutual benefit with you!
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FAQ
Of course, we can provide customers with free samples but customer should pay the courier fee.
Please kindly provide the grade, width, thickness, surface treatment requirement and quantities you need to purchase.
Prices various according to periodic price changes of raw materials.
30% T/T in advance ,balance before shipment
Yes,if you have your own design , we can produce according to your specification and drawing.