YULIN Welding — 48,000 TPY SAW Flux Plant
Lincoln & ESAB OEM Supplier

Client Background

YULIN Welding Materials Co., Ltd. is a specialized manufacturer of submerged arc welding (SAW) fluxes serving the global welding consumables supply chain. With established OEM supply agreements for Lincoln Electric and ESAB — two of the world's largest welding equipment and consumables companies — YULIN needed to scale production dramatically to meet growing international demand while maintaining the strict quality specifications required by its brand-name partners.

Prior to engaging FUMI, YULIN operated several smaller production lines with a combined capacity under 15,000 TPY. The lines were semi-manual, struggled with batch-to-batch consistency, and could not accommodate the throughput volumes Lincoln and ESAB were projecting in their multi-year forecasts.

The Challenge

YULIN's brief to FUMI was ambitious on multiple fronts — scale, quality, and speed — all of which carried significant technical risk:

• Unprecedented Scale. The target of 48,000 TPY on a single line was roughly triple YULIN's existing total capacity. No off-the-shelf equipment configuration existed for this throughput in the SAW flux sector.
• OEM-Grade Consistency. Lincoln Electric and ESAB impose exacting particle-size distribution, moisture content, and chemical uniformity standards. Any deviation risked rejection of entire shipments.
• High-Temperature Material Demands. SAW flux calcination runs above 800°C under mildly corrosive conditions. Standard carbon steel kilns degrade within 12–18 months at these parameters.
• Compressed Timeline. YULIN required first commercial output within 18 months of contract signing to align with a supply agreement renewal window.
• Full Automation Mandate. To eliminate human error and reduce per-ton labor cost, the client required automation from raw-material batching through finished-product packaging.

FUMI Solution

FUMI deployed a multi-disciplinary engineering team spanning process design, mechanical engineering, automation & controls, and QA/QC to deliver an integrated turnkey plant. The approach was grounded in FUMI's proven SAW flux reference designs, scaled and customized for YULIN's capacity target and quality requirements.

Process Flow

The plant operates on a continuous, closed-loop material flow from intake to dispatch:

1. Automated Batching & Mixing. Raw minerals — silica sand, manganese ore, fluorite, limestone, and proprietary binders — are received into segregated silos. A PLC-controlled weighing and dosing system meters each ingredient to within ±0.5% of the recipe target and feeds a high-shear mixer.
2. Drum Granulation. The blended powder is conveyed to a custom-designed rotating drum granulator where controlled water spray produces uniform green granules. Granule size distribution is monitored in real time via laser diffraction.
3. 310S Stainless Steel Rotary Kiln Calcination. Green granules enter a direct-fired rotary kiln fabricated from AISI 310S (25Cr-20Ni) stainless steel. The alloy provides superior oxidation resistance and creep strength at sustained operating temperatures above 850°C. Zoned temperature control — preheat, calcination, and cooling sections — ensures complete mineral phase transformation without over-firing.
4. Cooling & Classification. Calcined granules pass through a counter-flow air cooler and multi-deck vibrating screen to achieve the target particle size distribution (typically 10–60 mesh for SAW applications). Overs and unders are recycled to the granulator.
5. ABB Robotic Packaging. Finished flux is stored in conditioned surge bins and packaged by an ABB IRB 460 palletizing robot into 25 kg multi-wall bags and 1,000 kg bulk bags. The packaging cell includes automatic bag placement, filling, heat-sealing, palletizing, and stretch-wrapping — operating lights-out on third shift.
6. QC Laboratory Integration. An in-line auto-sampler diverts product to an on-site laboratory every 30 minutes for XRF chemical analysis, sieve testing, and moisture determination. Results feed back to the batching PLC for closed-loop recipe adjustment.

Key Technical Highlights

Several design decisions set this plant apart from conventional SAW flux installations:

Quantified Results

The plant achieved commercial acceptance on the first qualification batch submitted to Lincoln Electric and ESAB — a milestone that typically requires 2–3 adjustment cycles. Key performance metrics at 12 months of operation:

FUMI didn't just deliver equipment — they delivered a partnership. The team's willingness to co-engineer the process around Lincoln and ESAB's exacting flux specifications, rather than force-fit a standard design, was the single biggest reason we achieved first-pass qualification. Eighteen months later, the plant is still running at over 90% utilization and our OEM partners have praised the batch-to-batch consistency. This project transformed our competitive position in the global SAW flux market.

— YULIN Welding Management