What are the precautions for using stainless steel as the main frame of the transfer window?

When the main frame of the transfer window is made of stainless steel, attention should be paid to details in the material selection, processing, installation, and maintenance links to ensure its corrosion resistance, cleanliness, and service life. The following are the specific precautions:
I. Precautions for Material Selection
Select the stainless steel model according to the usage scenario
304 stainless steel: Suitable for ordinary clean environments (such as food and electronic workshops), avoid contact with strong acids, alkalis, or high salt spray environments.
316 stainless steel: If the transfer window is used in scenarios with strong corrosiveness such as medicine and chemical industry (such as contact with disinfectants, acid, and alkali solutions), 316 stainless steel containing molybdenum should be selected, as it has a stronger resistance to chloride ion corrosion.
Be vigilant against material counterfeiting: Confirm the material certificates provided by the supplier (such as spectral test reports), and avoid using inferior 201 stainless steel (with poor corrosion resistance and prone to rust).
Requirements for sheet thickness
The thickness of the main frame is usually ≥1.2mm to ensure structural strength and avoid deformation (especially for large transfer Windows). If it needs to bear weight (such as passing heavy equipment), the thickness can be increased to 1.5-2mm.
Ii. Precautions for Processing Technology
Surface treatment process
Polishing treatment: The surface of the frame needs to undergo mirror polishing (roughness Ra≤0.8μm) or matte sandblasting treatment to reduce dust adhesion and bacterial growth, meeting the GMP requirements for clean surfaces.
Welding process: Argon arc welding is adopted. The weld seam should be ground smooth and free of burrs (to avoid dust accumulation), and undergo acid washing and passivation treatment (to remove the welding oxide layer and enhance corrosion resistance).
Structural design details
Rounded corner transition: The inner corners and edges of the frame should be treated with rounded corners of R≥5mm to prevent dust accumulation at right angles and facilitate cleaning.
No blind spot design: Avoid grooves and gaps on the frame (such as using an embedded door panel design), and reduce the risk of pollutant residue.
Iii. Installation and Sealing Precautions
Install environment adaptation
When installing, avoid excessive gaps with the wall (it is recommended that the gap be ≤5mm), and fill it with silicone sealant to prevent dust from seeping in.
If it is installed in an area with a large temperature difference (such as between a cold storage and a normal temperature area), the thermal expansion and contraction of stainless steel should be taken into account, and an expansion gap should be reserved.
Sealing component matching
The sealing strip of the door frame should be made of silicone rubber or ethylene propylene diene monomer (EPDM) rubber, which should be closely attached to the surface of stainless steel to avoid contamination of the clean area due to poor sealing.
When installing the sealing strip, avoid twisting and folding. At the interface, use hot melt welding (instead of glue bonding) to prevent it from falling off.
Iv. Precautions for Cleaning and Maintenance
Daily cleaning Specifications
Do not use steel wool balls or strong acid and alkali cleaners (such as hydrochloric acid, or nitric acid) to avoid scratching the surface or corroding the material. It is recommended to wipe with 75% ethanol or neutral detergent.
After cleaning, it is necessary to dry the surface water stains in time to avoid local corrosion caused by the residue of chloride ions (such as residual chlorine in tap water), especially for 304 stainless steel.
Key points of regular maintenance
Check whether there are cracks or rust spots at the welding points. If slight rust is found, wipe it with a special stainless steel rust remover paste and re-passivate it.
For areas that are in long-term contact with disinfectants (such as pharmaceutical workshops), check the material surface for discoloration or peeling every quarter. If necessary, carry out surface coating repair.
V. Precautions for Special Scenarios
High-temperature environment
If the transfer window is used in high-temperature sterilization scenarios (such as wet heat sterilization), it is necessary to confirm the heat resistance of the stainless steel (304 stainless steel can withstand temperatures ≤800℃, 316 stainless steel ≤1200℃), and avoid the aging of the sealing parts due to high temperatures (replace with fluoro rubber sealing).
Anti-static requirements
When used in the electronics industry, the stainless steel frame needs to be grounded (with a resistance of ≤10^9Ω) to prevent static electricity accumulation. If necessary, an anti-static coating can be sprayed on the surface.
Vi. Suppliers and Acceptance Criteria
Qualification review
Select suppliers with the production qualifications for clean equipment and require them to provide the factory certificates of stainless steel plates and surface treatment inspection reports (such as roughness and passivation film thickness).
Acceptance test
Visual inspection: No scratches on the surface, flat weld points, and smooth rounded corners.
Functional tests: Frame load-bearing capacity test (such as no deformation after loading a 100kg load for 24 hours continuously), air tightness test (smoke method to detect the sealing effect).
Summary
The stainless steel transfer window frame needs to be strictly controlled throughout the entire process from "selection - processing - installation - maintenance", with the core being to ensure corrosion resistance, cleanliness, and structural strength. Especially in industries such as medicine and food, GMP standards must be strictly followed to avoid the risk of contamination caused by material defects. If the usage environment is complex, it is recommended to communicate with the supplier about a customized solution (such as explosion-proof stainless steel frames).