Are there any examples of stainless steel being used as lightning protection and grounding material in chemical plants by the sea?

There are no specific cases; nowadays, copper-clad steel is most commonly used, followed by galvanized flat steel. In coastal areas where the soil is saline-alkaline, copper-clad steel is a better choice.

Stainless steel is used very rarely, with few cases available for analysis. When using copper-clad steel, considering the level of corrosion, it is recommended to use copper-clad steel with a copper layer thickness of 0.5 mm. Copper-clad steel with a thickness of 0.254 mm is not suitable for environments with high corrosion levels, while copper-clad steel with a copper layer thickness of over 0.8 mm has a cost that is close to that of pure copper products, making it less cost-effective.

We have some grounding wires made of stainless steel flat bars on site; as long as they can achieve the desired purpose and there are no major economic issues, that’s fine

Specifications for Grounding System Materials in Weiming Construction Plant Area I. Specifications for grounding electrodes (rods): Continuous casting zinc-coated steel Test items Required standards Raw materials: The steel material shall comply with the requirements for medium-carbon steel specified in GB/T700-2006; the zinc coating shall meet the requirement of a zinc content of ≥99.995% as specified in GB/T470-2008. Appearance: The surface shall be free of oxidation residues, burrs, or cracks, and the depth of shrinkage holes shall be less than 10% of the thickness of the anode. Adhesion: As per adhesion tests, the zinc layer shall not separate from the steel core. Specifications and allowable tolerances: Diameter ±0.2 mm; zinc coating thickness ≥5 mm; length ≥2.5 M. Mechanical properties: steel core strength ≥370 N/mm2. Contact resistance: R ≤0.5 Ω. Electrochemical properties: with a saturated Cu/CuSO4 reference electrode, the value is ≤-1.12; with a saturated calomel (SCE) reference electrode, the value is ≤-1.05. Current efficiency: ≥95%. Diameter of the grounding electrode: >ψ24 mm. Manufacturers recommended: Hangzhou Zhongshi Electrical, Jiangsu Junyao Electrical, Jiangsu Yinruitong Electrical. II. Specifications for grounding main wires: For continuous casting zinc-coated steel grounding wires, hot-dip galvanized steel grounding wires should be used for those buried in soil. (II) The minimum specified size for the grounding wire of continuous casting zinc-clad steel is Φ15. (III) The thickness of the zinc layer is ≥ 2 mm. (IV) In accordance with the specification requirements, the burial depth of the horizontal grounding main wire shall be no less than 0.8 meters. III. Specifications for grounding branches: Continuous casting zinc-clad steel grounding wires (1) The vertical grounding branches that lead from the grounding main line in the soil to the equipment shall use continuous casting zinc-clad steel grounding wires. (2) The minimum size of the continuous casting zinc-clad steel grounding wires used for these branches is determined based on the requirements of the equipment. (III) The thickness of the zinc layer is ≥ 2 mm. (IV) The vertical ground branch is connected to the equipment; a yellow-green grounding wire is used, either by welding or crimping, and secured at the equipment’s grounding point. IV. Specifications for exothermic welding (clamps) of continuous casting zinc-clad steel: (1) For exothermic welding, welding molds, welding powder, and welding procedures are used. (II) Constructed according to exothermic welding procedures. (III) After welding, remove surface residues and apply an undercoat as well as a zinc powder topcoat to prevent rust and corrosion. V. Key Points for the Monitoring of Weiming Petrochemical’s Grounding System (1) Inspection of materials upon arrival: 1. When grounding system materials supplied by manufacturers arrive at the site, they must be accompanied by factory inspection reports, which must be carefully verified. 2. The manufacturer shall provide, or our company’s thickness gauge shall be used, to conduct on-site random tests for the thickness of the zinc coating as well as its diameter; a visual inspection of the surface is also required. Work can only proceed once these checks show satisfactory results. 3. For the installation of zinc-coated steel grounding electrodes, use an electric rammer to drive them in slowly; a hammer should not be used to avoid damaging the grounding electrode as well as its surface. 4. After all work on the grounding system is completed, the grounding resistance must be tested; the value of this resistance should be ≤ 4Ω, or as specified in the contract. (II) Procedure for heat-release welding of grounding systems: 1. Mold selection: Choose a mold that corresponds to the welding method, and select the appropriate welding powder as well ； 2. Operation procedure: (1) Clamp the mold using a mold clamp in order to open and close it ；   (2) Bake the mold to remove moisture ； (3) Bake the materials to be welded in order to remove moisture and oil ； (4) Place the material to be welded into the mold and clamp it (hold the welding material horizontally without any stress). (5) Use a tool to insert the spacer gasket into the mold and seal the flow channels ； (6) Put the welding powder into the mold, add igniting powder on top of it, and leave some space at the opening of the mold ；  (7) To ignite the primer with a lighting gun, one must stand on the side of the mold opening ； (8) After 20–30 seconds, open the mold and remove the residues on the surface of the weld points (the mold must be cleaned after each welding operation). Note: Proper personal protection must be used during operation; wear gloves and protective clothing, and do not face the mold’s exhaust port! (III) Safety precautions: Heat-generation welding has a very high ignition point; it will not catch fire due to friction or impact. No gases that expand rapidly are produced during combustion, so it is non-explosive and easy to store and transport.    Safety protective equipment must be worn before welding ；  Before welding for the first time (or after cooling), cleaning and baking are required to remove any dirt and moisture inside the mold.  The part of the welding material that goes into the mold must be straight, and once the mold is clamped, there should be no stress between the main and secondary materials and the mold, to prevent damage to the mold ；  When using mold clamps and auxiliary fixtures, the tightening force of the bolts should not be too high to prevent damage to the mold ；  If the mold cannot close completely, seal the gaps with fire-sealing putty (suitable for small gaps) to prevent leakage during welding ；  When lighting the ignition powder, the operator must stand on the side of the mold opening; at the same time, there must be no people or flammable or explosive materials in the direction opposite to the mold opening ；  Do not open the mold immediately after the welding flux has completed its reaction; allow it to cool naturally for 30 seconds before opening the top cover to check the welding quality. Open the mold only after the weld has set, to prevent the solder joints from cracking ；  After each welding operation (or before welding), the mold must be thoroughly cleaned. All cavities within the mold need to be cleaned to avoid affecting the quality of welding. (IV) Key construction tips: 1. If the top of the grounding electrode/rod becomes deformed after being driven deep, the deformed part must be cut off or polished to avoid affecting the closing performance of the mold ； 2. After welding, allow the mold to cool naturally; do not use water to force cooling. VI. Acceptance criteria for grounding system materials: (1) When the manufacturer’s grounding system materials arrive at the site, they must be accompanied by a factory inspection report. (II) The manufacturer shall provide, or our company’s thickness gauge shall be used, to conduct on-site random tests of the zinc coating thickness; work can proceed only if the results are satisfactory. (III) After the construction is completed, the manufacturer must test the grounding resistance, which should be ≤ 4Ω, in accordance with GB standards or the provisions of the contract. VII. Reference diagrams for construction: Grounding system diagram using steel coated with zinc (1) Grounding system diagram using steel coated with zinc (2)

Using steel coated with zinc is ideal; stainless steel is not suitable for use by the sea.