Steel Grating Manufacturing Process & Strict Quality Control Standards | NJMM Manufacturing Guide

High-performance Steel Grating relies on standardized manufacturing workflows and rigorous quality control, which directly determine load capacity, anti-corrosion performance and service life. For global distributors and EPC contractors, choosing products with mature production techniques and full inspection systems means fewer after-sales risks and stronger competitiveness in industrial, petrochemical and power plant projects. As a 33-year professional steel grating manufacturer, NJMM fully follows international norms including ISO 1461, ASTM A123 and YB/T4001. 

Our production flow covers raw material handling, forming, welding, surface treatment and finishing, with every step operated by automated equipment to guarantee consistent output.

We mainly adopt premium Q235 carbon steel for regular products and 304/316 stainless steel for corrosive working environments. All raw materials are sourced from qualified large steel mills with complete Mill Test Certificates (MTC) to verify chemical composition and mechanical strength. Automatic cutting machines process bearing bars and twisted cross bars into specified sizes. Common specifications include 25×3mm to 50×5mm bearing bars, with 30mm or 40mm bearing bar pitch and 100mm cross bar pitch, meeting mainstream global project demands.

We use fully automatic hydraulic press-welding production lines. Each intersection of bearing bars and cross bars is forged tightly under high pressure, eliminating virtual welding and loose joints. This integrated structure delivers excellent structural rigidity for long-term heavy-load use. After welding, workers weld edge banding plates around panels to enhance overall stability and prevent deformation during installation and transportation. For anti-slip requirements, we process serrated edges on bearing bars to boost surface friction.

Hot-dip galvanizing is the key procedure to extend grating lifespan. Before galvanizing, all panels go through degreasing, pickling and fluxing to remove oil, rust and surface oxides thoroughly. Then gratings are immersed in molten zinc at around 450°C to form a firm zinc-iron alloy layer. We strictly control the zinc coating thickness at no less than 85μm for standard products, and provide 120μm thick coating for coastal areas with severe salt fog erosion. Finally, products are cooled and subject to anti-rust treatment to avoid white rust during storage.

For customized orders such as pipeline cutouts and irregular shapes, our CNC cutting equipment ensures the dimensional tolerance within ±0.5mm for seamless on-site assembly. Finished products are bundled with protective materials to prevent scratches on the galvanized layer during long-distance sea transportation.

Quality control runs through every production link, implementing multi-layer inspections to ensure all products comply with global industrial standards.

Our QC team checks the appearance, size and mechanical properties of each batch of steel materials. Unqualified raw materials are rejected directly to avoid quality risks from the source. Complete material certificates are archived for customers’ customs clearance and project bidding.

During welding, technicians regularly check welding pressure and parameters to ensure uniform welding quality. For galvanizing, we monitor liquid temperature and immersion time in real time to keep the zinc layer even and adhesive. Any abnormal process will be adjusted immediately.

This is the most critical inspection stage. First, inspectors measure overall dimensions, bar spacing and flatness. Second, use professional thickness gauges to test zinc coating thickness one by one. Third, conduct sampling load tests and anti-slip tests to verify structural safety. All qualified products will be marked, while defective goods are reworked or scrapped.

All our steel gratings are certified by ISO 9001 quality management system and CE. They fully meet ANSI/NAAMM and EN standards, adapting to market requirements of Europe, Southeast Asia, the Middle East and other regions. We can provide all inspection reports and certification documents for every shipment.

Standardized production and strict quality control bring solid benefits to our partners. Our stable product quality reduces customer complaints and return risks. Diversified specifications and custom capabilities support various project scenarios ranging from factory platforms, drainage trenches to petrochemical and power plant walkways. Large ready stock of mainstream models ensures fast delivery, while reliable packaging lowers damage rates in transit.

With mature manufacturing technology and a sound quality management system, NJMM maintains stable product performance even in harsh high-temperature, humid and corrosive environments.

Advanced automated production and all-round quality control are the core competitiveness of NJMM steel grating. Every panel is manufactured and inspected in accordance with international standards, delivering durable, safe and cost-effective products for global industrial projects. Whether you need standard stocked products or customized solutions for special engineering projects, we can meet your demands.

Welcome global distributors and contractors to contact us for factory visits, free samples and detailed technical parameter documents. We look forward to establishing long-term win-win cooperation with you.