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Weld‑joint anti‑corrosion capability is critical to the service life of Armario de distribución montado products. As a professional switchgear cabinet assembly line manufacturer, Chuanli applies ISO and AWS welding standards for Medium Voltage Assembled Switchgear Cabinet, Low Voltage Assembled Switchgear Cabinet, Indoor Assembled Switchgear Cabinet and Outdoor Assembled Switchgear Cabinet. This article sorts full‑process welding, polishing and inspection specifications, delivering practical process references for manufacturers and quality inspectors.
The core difference between the anti-corrosion welding of the switch cabinet frame and the ordinary structural welding is, Therefore, the long-term anti-rust of the weld is the primary evaluation index, and the differentiated process threshold is formulated according to the indoor and outdoor use environment of the set cabinet, so as to eliminate the corrosion hazard of the weld under high humidity, salt fog, and alternating temperature conditions, and the whole text is logical and smooth without fragmentation.
KYN28 medium-voltage cabinet and GCS low-voltage cabinet, as representatives of indoor complete switch cabinets, operate in closed distribution rooms, with mild salt spray and moderate humidity, with relatively moderate anti-corrosion welding threshold, but still need to strictly control welding thermal deformation and surface defects. The frame of the cabinet is mainly made of SPCC cold-rolled steel with MIG semi-automatic welding, the welds need to be fully fusion, without burrs and porosity defects, and the welding heat input is controlled to reduce the thickness of the oxidation layer on the weld surface; The bottom water collection chamber adopts continuous full welding to avoid the accumulation of condensed water in small gaps, and the side plate reinforcement ribs can be fixed by segmental spot welding under the premise of uniform stress. After welding, the surface oxide scale and welding slag must be completely removed, otherwise, the subsequent phosphating spraying coating will partially fall off, and rust will appear on the weld after 2-3 years of operation. The indoor cabinet does not need stainless steel welding wire, and ordinary solid welding wire can match the base plate to meet the anti-corrosion requirements.
XGW box transformers, outdoor ring network cabinets and other outdoor complete switch cabinets are subject to rain, dust, coastal salt fog and temperature difference shocks all year round. Compared with indoor models, the anti-corrosion welding process has been upgraded in all dimensions.
| Comparison Items | Indoor Switchgear | Outdoor Corrosion-Resistant Switchgear |
| Main Substrate | SPCC Cold-Rolled Steel Plate | SG Hot-Dip Galvanized Steel Plate / 304 Stainless Steel |
| Welding Method | Semi-Automatic MIG Spot Welding + Full Welding | Robotic Continuous MIG Full Welding / Stainless Steel TIG Welding |
| Matching Welding Wire | Ordinary Carbon Steel Solid Core Welding Wire | Corrosion-Resistant Alloy Welding Wire / ER308 Stainless Steel Welding Wire |
| Weld Defect Allowance | Allowable Single ≤0.5mm Micropores, Zero Porosity | Zero Undercut Mandatory Requirements |
| Water Collection Tank Welds | Intermittent Full Welding, Seamless Continuous Full Welding | No Micro-Gap |
| Post-Weld Treatment | Ordinary Grinding + Local Anti-Rust Primer | Overall Grinding + Zinc-Rich Epoxy Repair Primer |
| Post-Weld Salt Spray Standard | Neutral Salt Spray ≥500h | Neutral Salt Spray ≥1000h |
The outdoor cabinet assembly line of Chuanli uses robot welding to reduce the unstable defects of manual welding; All welds on the bottom water collection trough and cabinet door frame are continuous full welds, preventing rainwater from seeping into the welding seams.
Any water storage or gas-tight structure in the outdoor cabinet should not use segmented spot welding; The lap joint and the water-stopping edge must be fully welded without gaps. The coastal C4 severe corrosion 304 stainless steel outdoor cabinet adopts full TIG argon arc welding to avoid chromium loss and intergranular corrosion in the weld heat-affected zone. For the welding of hot-dip galvanized steel cabinets, the use of silicon-containing alloy welding wire can reduce the burning of the zinc layer during welding, and the welded area must be completely repaired with anti-corrosion coating later to form a complete anti-corrosion barrier.
Cleaning the surface of the sheet metal before welding and matching the anticorrosive welding wire are the source links to control the rusting of the welded seam. The integrated pre-treatment workstation of the automation switch cabinet assembly production line of Chuanli is equipped, and all the frames are processed uniformly before welding. The material hazards are eliminated from the source, and the paragraphs are continuous without small segments.
Regardless of the medium-voltage or low-voltage cabinet steel plate, it must complete the complete surface cleaning before entering the welding station, remove the oil film, rust spots, oxidation skin, and dust on the plate, otherwise, welding will easily produce slag and porosity, and residual oil stains will cause poor adhesion of the coating after welding, and the weld seam will peel off and rust.River production line standardization cleaning process: laser cutting burr removal → alkali washing degreasing spray multi-stage rinsing → oxidation plate grinding rust removal → drying to ensure no water film on the plate before welding.The welding position of the outdoor cabinet hot-dip galvanized steel plate should be ground to remove the local zinc layer in advance to prevent the formation of zinc slag in the weld seam and electrochemical corrosion.
| Cabinet Raw Materials | Cleaning Key Control Points | Acceptance Criteria |
| Ordinary SPCC Cold-Rolled Steel Sheet | Thoroughly degreased and dust-free | No oil film, passes continuous water spread test |
| SGCC Hot-Dip Galvanized Sheet | Zinc layer polishing in welded areas | Local zinc layer removal, no residual zinc dross |
| 304 Stainless Steel Sheet | Surface oxidation and fingerprint removal | Uniform metallic luster, no dark oxide spots |
The residual oil on the surface of the plate before welding will produce hydrogen pores inside the weld, which will become a hidden rust spot after the cabinet is sprayed.
The matching degree between the welding wire and the substrate directly determines the electrochemical corrosion resistance of the welded area, and the mismatch of dissimilar metal welding materials will form electrochemical corrosion, and the wet environment will accelerate the rusting of the welded area. River production line sets up fixed material matching specification: indoor carbon steel cabinet frame matches ER50-6 carbon steel solid wire; The hot-dip galvanized outdoor cabinet uses silicon alloy MIG welding wire to reduce the burning of the zinc layer; The 304 stainless steel outdoor corrosion-resistant cabinet is equipped with ER308 stainless steel argon arc welding wire, ensuring that the chromium and nickel elements of the weld are consistent with the base plate, and eliminating intergranular corrosion. All welding materials are stored with material inspection reports, and the production line strictly prohibits the mixing and mismatching of different cabinet baseboards and welding wires.
Combined with the ISO 384 Welding Process Qualification (WPS) document, Chuanli is dedicated to medium-voltage complete switchgear, The low-voltage complete switch cabinet sets different standard welding parameters, and the robot welding station is locked in a fixed program to prevent the operator from adjusting it arbitrarily, ensuring that the corrosion-resistant quality of the welded seam of the batch cabinet is uniform, and the whole text is continuous without being divided into points.
KYN28 and other medium-voltage cabinet frames are mostly made of 2.0-2.5mm thick cold-rolled steel. The welding robot on the production line uses MIG welding with fixed WPS standard parameters: welding current 180-210A, arc voltage 24-26V, welding speed 350-400mm/minute, and mixed gas flow rate 18-22L/minute. Heat input should be strictly controlled to prevent the oxidation layer from thickening on the welded seam due to high temperature; The welding gun should swing evenly during the full welding process to avoid local undercutting. The bottom water tank is fully welded, which reduces the welding speed by 15% and ensures that there are no small gaps in the welded seam. The welding position of the medium-voltage cabinet frame is clearly marked on the process drawing, and only non-water-retentive and non-sealed strengthening ribs are allowed for intermittent spot welding. The continuous full welding is required for all joints along the water barrier, the door frame, and the busbar room to eliminate the hidden danger of corrosion gaps.
Low-voltage switchgear cabinets represented by GCS/MNS drawer cabinets often use 1.2– 1.5mm thin plates,Applying medium-voltage welding parameters is easy to burn through and cause excessive thermal deformation; the production line adopts a low-input pulse MIG welding low-voltage frame; the W parameter is adjusted to 120-150A current and 20-22V voltage; the high-frequency pulse mode is concentrated to control heat. Drawer compartment frame 50mm spacing segmented spot welding control overall deformation; The base and the cable inlet sealing frame still use continuous full welding to ensure the airtight and waterproof performance. The control of the width of the thin plate weld seam is uniform, which reduces the area of the heat-affected zone that is prone to oxidation and corrosion.
Welding seam polishing and repair coating is the core process of repairing welding damage and rebuilding the continuous anti-corrosion layer. Any missing process will break the overall anti-corrosion system of the cabinet, and the rusting and failure of the welding seam in the later period. Chuanli production line sets up independent post-weld grinding and repair spraying workstations, and performs closed-loop inspection before entering the overall phosphating workshop. The paragraph logic is smooth and there are no small segments.
After the welding of the cabinet frame is completed, all welds and the surrounding heat-affected zone must be fully ground to remove welding slag, oxide skin, burrs, and residual zinc slag on the galvanized plate. The indoor carbon steel cabinet adopts 120 sandpaper plane polishing; Outdoor galvanized and stainless steel cabinets require 240 fine sand belt polishing to smooth the transition of the weld seam and the base plate, without bumps, water accumulation, and crevices. The grinding range extends 15mm outward from both sides of the weld, completely removing the oxidation heat-affected zone; After polishing, compressed air should be used to blow away dust and metal shavings to avoid the formation of blisters and rust under the coating.
After polishing, all welded areas are subjected to targeted rust prevention treatment before the cabinet is phosphated and sprayed, to compensate for the damage to the corrosion-resistant layer caused by the high temperature of welding.
| Cabinet Substrate | Weld Repair Coating Process | Dry Film Thickness Requirements | Salt Spray Performance Improvement |
| Ordinary Carbon Steel Indoor Cabinet | Single-Layer Epoxy Zinc-Rich Primer | ≥40μm | 30% Improvement in Salt Spray Performance |
| Hot-Dip Galvanized Outdoor Cabinet | Zinc-Rich Primer + Intermediate Anti-Rust Paint | ≥70μm | Complete Repair of Damaged Zinc Layer |
| 304 Stainless Steel Outdoor Cabinet | Passivation Treatment + Transparent Anti-Corrosion Varnish | ≥25μm | Inhibits Intergranular Corrosion in Welds |
If the weld repair primer is omitted, the weld coating will peel off easily after 1-2 years of outdoor cabinet spraying, and rust will spread along the weld.
After the local repair and painting of the weld seam is completed, the entire cabinet enters the full process phosphating and electrostatic powder spraying production line, forming a complete three-layer anti-corrosion system of repair primer + phosphating conversion film + outdoor weather-resistant powder, and the weld seam and substrate are integrated and continuously anti-corrosive without interruption.
Chuanli has formulated a three-level inspection standard for the anti-corrosion welding of cabinet frames: initial inspection at the welding station, re-inspection after polishing and repair, and salt spray sampling inspection of finished cabinets. The visual inspection of the first inspection covers the appearance indicators of the weld seam: no porosity, no bite, no fusion, no welding slag residue, no grinding dead angle; The re-inspection includes magnetic particle inspection of key welds such as the full weld of the water tank to detect internal micro-cracks. The finished cabinets are randomly subjected to neutral salt spray tests according to indoor/outdoor standards. If rust spots appear on the welds in advance, the welding parameters and post-treatment processes will be traced and rectified for the entire batch. All inspection records are combined with cabinet batch filing, and welding anti-corrosion quality is fully traced in the intelligent switch cabinet assembly production line, with key spot inspection of corrosion-prone welds such as the water collection compartment, cabinet door sealing frame, and outdoor cabinet chassis.
Q1: What matching standard is used for the welding wire of the indoor and outdoor anti-corrosion switch cabinet frame?
A1: Indoor carbon steel: ER50-6 solid wire; Hot-dip galvanized outdoor cabinet: silicon alloy MIG welding wire; 304 stainless steel outdoor cabinet: ER308 argon arc welding wire.
Q2: What is the core difference between the welding WPS parameters of the medium-voltage and low-voltage cabinet frames?
A2: Medium pressure thick plate adopts continuous full welding with large heat input; Low-voltage thin plate adopts pulse low heat input welding to prevent burning through deformation.
Q3: Why must the seam of the outdoor cabinet water tank be seamless and continuous?
A3: Segmented spot welding will form small gaps and accumulate rainwater, and the weld seam will corrode quickly in a high-humidity environment with high salt spray.
Q4: How far should the welded seam of the anti-corrosion switch cabinet be extended?
A4: 15mm outward extension on both sides of the weld, grind, and completely remove the oxidation heat-affected zone.
Q5: Which three-level inspection system does the welding of the cabinet body of the production line of Chuanli implement?
A5: Welding station initial inspection → polishing and repair re-inspection → salt spray sampling inspection in the finished cabinet.
Improper welding parameters and incomplete post‑weld treatment bring permanent corrosion risks to various Armario de distribución montado. Supported by mature switchgear cabinet assembly line, Chuanli implements full‑range anti‑corrosion quality control for indoor and outdoor cabinets. Manufacturers should avoid cost‑driven process simplification. Standardized welding workflows effectively restrain weld‑seam rust and guarantee reliable operation for high‑humidity and salt‑fog application scenarios.
