Se você procura aço inoxidável que combina durabilidade com elegância, visual moderno – pense em eletrodomésticos de cozinha, painéis arquitetônicos, or elevator cladding—304 4 brushed stainless steel is the answer. O “#4” refere-se à sua multa de assinatura, acabamento linear, enquanto “304” garante resistência confiável à corrosão. Este guia detalha tudo que você precisa saber para escolher, usar, and maintain this popular material.
1. 304 4 Aço inoxidável escovado: Material Overview & Propriedades
304 4 brushed stainless steel combines the strength of 304 grade with the aesthetic appeal of a brushed finish. Here’s what makes it stand out:
Propriedades do material principal
| Propriedade | Valor típico | Why It Matters for Your Projects |
|---|---|---|
| Composição Química | 18–20% Chromium, 8–10.5% Nickel, ≤0.08% Carbon | Chromium forms apassivation layer (rust-resistant film); nickel keeps itaustenitic (não magnético) |
| Força de rendimento | 205 MPa (29,700 psi) | Resists bending in high-use items (por exemplo, countertop edges) |
| Resistência à tracção | 515 MPa (74,700 psi) | Strong enough for structural parts (por exemplo, painéis de parede) |
| Resistência à corrosão | Excelente (resiste à água, ácidos suaves) | Won’t rust in kitchens, bathrooms, or indoor spaces—though less durable than 316 in saltwater |
| Propriedades Magnéticas | Não magnético (recozido) | Safe for electronics and medical equipment |
| #4 Brushed Finish | Linear texture, Ra 0.8–1.6 µm | Hides fingerprints and minor scratches (unlike mirror polish) |
304 contra. 316 Comparação: 304 4 brushed steel is ideal for indoor use, enquanto 316 (with molybdenum) is better for coastal/outdoor spaces. A café used 304 4 brushed steel for indoor countertops—they stayed scratch-free for 5 years—while outdoor tables (exposed to rain) needed 316 to avoid rust.
2. 304 4 Aço inoxidável escovado: Fabricação & Processos de Acabamento
O #4 brushed finish is created through a precise mechanical process that gives 304 steel its distinct look. Veja como é feito:
Etapa 1: Base Steel Preparation
Primeiro, 304 stainless steel is cold-rolled into sheets (starting with a 2B mill finish—smooth but matte). This base sheet is cleaned to remove oil, sujeira, and mill scale (a rough oxide layer) usandojato de areia or chemical cleaning.
Etapa 2: Creating the #4 Brushed Finish
- Grit Sequence Selection: The sheet passes through a stainless steel brushing machine fitted with abrasive belts. The process uses a specific grit sequence—typically 120-grit (to shape the texture) followed by 180–240-grit (to refine it into a fine, uniform line).
- Brushing Direction: The abrasive belts move in one direction (usually horizontal) to create parallel linear lines—this is what defines the #4 terminar.
- Ra Value Check: After brushing, the surface is tested for Valor Ra (roughness average). UM #4 finish requires an Ra of 0.8–1.6 µm—smooth enough to touch, textured enough to hide fingerprints.
Etapa 3: Post-Finish Protection
- Passivação: The brushed sheet undergoes a nitric acid bath to strengthen the passivation layer—critical for maintaining corrosion resistance (brushing can expose tiny areas of unprotected steel).
- Controle de qualidade: Inspectors check for consistent texture (no uneven lines) and confirm the Ra value meets standards (por exemplo, ISO finish #4).
Exemplo: A manufacturer once skipped the 240-grit step—their #4 finish had rough, visible scratches. Adding the final grit step fixed the issue and made the finish sellable.
3. 304 4 Aço inoxidável escovado: Aplicativos & Industry Use-Cases
304 4 brushed steel’s blend of aesthetics and durability makes it a staple in multiple industries:
1. Cozinha & Food Industry
- Eletrodomésticos: Refrigerator doors, oven fronts, and dishwasher panels use 304 4 brushed steel—its texture hides fingerprints from daily use. A major appliance brand reported 30% higher sales for fridges with #4 brushed finishes (contra. mirror polish).
- Food-Grade Countertops: Restaurants and commercial kitchens use 304 4 brushed steel countertops—they’re easy to clean, resist food stains (por exemplo, tomato sauce), e conhecer NSF/ANSI 51 food-safety standards.
2. Arquitetura & Construção
- Architectural Wall Panels: Hotels and offices use 304 4 brushed steel for accent walls—its linear texture adds depth to spaces. A hotel lobby in Chicago used 500 sq. meters of #4 brushed panels—they still look new after 8 anos.
- Elevator Cabin Cladding: Elevator interiors rely on 304 4 brushed steel—its durability resists dents from luggage, and the finish hides scuffs from foot traffic.
3. Médico & Automotivo
- Equipamento Médico: Exam tables and instrument carts use 304 4 brushed steel—its non-porous surface is easy to sterilize (atende aos padrões da FDA).
- Automotive Trim: Luxury cars use #4 brushed steel for dashboard accents—its texture adds a premium look without showing dust.
4. 304 4 Aço inoxidável escovado: Fabricação & Forming Techniques
Fabricating 304 4 brushed steel requires care to avoid damaging the finish. Here are best practices:
Key Fabrication Methods
| Technique | Tips for Protecting the #4 Terminar | Use Case Example |
|---|---|---|
| Corte a laser | Use nitrogen assist gas (prevents oxidation) and cover the finish with a protective film during cutting. | Cutting decorative shapes for wall panels |
| Dobrando | Use a press brake with rubber-coated dies to avoid scratching. Keep the bending radius ≥1x the sheet thickness (por exemplo, 2mm sheet needs a 2mm radius). | Making countertop edges or panel frames |
| Soldagem | Use TIG welding with ER308L filler wire. Depois de soldar, remove discoloration using astainless steel brush (matching the #4 finish direction) and re-passivate. | Joining countertop sections |
| Colagem adesiva | Use a high-strength epoxy (por exemplo, 3M VHB tape) instead of drilling (drilling can chip the finish). Clean the surface with isopropyl alcohol first for better adhesion. | Attaching wall panels to studs |
Warning: A fabricator once used a steel brush to clean welds—this left crosswise scratches that ruined the #4 terminar. Using a brush that follows the finish’s linear direction fixed the problem.
5. 304 4 Aço inoxidável escovado: Surface Care, Cleaning & Manutenção
With proper care, 304 4 brushed stainless steel can last decades. Here’s how to keep it looking new:
Routine Cleaning Steps
- Daily Cleaning: Wipe with a soft, lint-free cloth (microfiber works best) and warm, soapy water. Avoid abrasive sponges (they scratch the finish).
- Tough Stains: For grease or food stains, use a stainless steel brush finish cleaner (por exemplo, Bar Keepers Friend) applied in the direction of the brushed lines. Rinse thoroughly and dry immediately.
- Fingerprint Removal: Use um 50/50 mix of water and vinegar—spray on, wipe with a cloth, and dry. For frequent use areas (por exemplo, fridge doors), apply a fingerprint-resistant coating (available at hardware stores) todo 6 meses.
Scratch Repair
- Minor Scratches: Use a 320-grit sanding pad, sand gently in the direction of the brushed lines, then wipe with a clean cloth.
- Deep Scratches: Hire a professional to re-brush the area (they have the right grit belts to match the #4 terminar).
Maintenance Schedule
| Frequency | Task |
|---|---|
| Daily | Wipe with soapy water and dry |
| Weekly | Clean with vinegar to remove fingerprints |
| Todo 6 Months | Apply fingerprint-resistant coating |
| Annually | Check for rust spots; re-passivate if needed |
6. 304 4 Aço inoxidável escovado: Padrões, Certificações & Conformidade
To ensure you’re getting high-quality 304 4 brushed steel, look for these standards and certifications:
Key Standards
| Standard Organization | Relevant Specs | Focus Area |
|---|---|---|
| ASTM (NÓS.) | ASTM A240 | Defines 304 steel quality and #4 finish requirements |
| ISO (Global) | ISO finish #4 | Sets Ra value (0.8–1.6 µm) for brushed finishes |
| EM (Europa) | EM 10088-2 nota 1.4301 | Equivalent to 304; ensures finish consistency |
Critical Certifications
- NSF/ANSI 51: Proves suitability for food-contact surfaces (por exemplo, countertops, eletrodomésticos).
- Conformidade com a FDA: Mandatory for medical equipment and food-processing parts.
- RoHS Compliance: Ensures no harmful substances (por exemplo, lead) for consumer goods.
- Mill Test Certificate (EM 10204 3.1): Confirms chemical composition, propriedades mecânicas, and finish quality—always ask suppliers for this.
7. 304 4 Aço inoxidável escovado: Supply Chain, Preços & Aquisições
Buying 304 4 brushed steel efficiently means understanding costs, lead times, and supplier requirements. Here’s what you need to know:
Preços (2024 Estimates)
| Product Type | Price per kg | Price Difference vs. 2B Finish |
|---|---|---|
| 304 #4 Brushed Sheets (1mm de espessura) | $4.00–$4.80 | 15–20% higher (brushing adds labor/cost) |
| 304 #4 Brushed Coils (1mm de espessura) | $3.80–$4.50 | 10–15% higher than 2B coils |
Cost Driver: Nickel prices (304 has 8–10.5% nickel) affect costs—if LME nickel rises 10%, 304 #4 brushed steel prices typically rise 8–9%.
Procurement Tips
- Quantidade mínima (Minimum Order Quantity): Most suppliers require 100kg for sheets, 500kg for coils. Smaller orders (por exemplo, 50kg) are possible but cost 25% mais.
- Tempo de espera: 2–3 weeks for stock sizes (por exemplo, 1x2m sheets); 4–6 weeks for custom sizes/coils.
- Supplier Selection: Choose suppliers who specialize in brushed finishes (general steel suppliers may have inconsistent texture). Ask for a sample before ordering to check the finish.
- Embalagem: Request sheets/coils wrapped in VCI film (evita ferrugem) and separated by foam (avoids finish damage during shipping).
Exemplo: A restaurant owner ordered 200kg of 304 #4 brushed steel sheets (stock 1x2m size). They received the order in 2 weeks and saved $300 contra. custom sizes.
Yigu Technology’s Perspective
Na tecnologia Yigu, 304 4 brushed stainless steel is our top choice for clients needing both aesthetics and durability. We supply ASTM A240/EN 1.4301 304 #4 brushed sheets (0.5–3mm thick, 1x2m/2x3m stock sizes) and coils, with Ra values strictly between 0.8–1.6 µm. We offer custom cutting/ bending and provide samples for finish approval. All our products come with EN 10204 3.1 certificates and NSF/ANSI 51 compliance for food-grade use. We also track nickel prices daily, helping clients lock in rates. For one hotel project, we supplied 1,000 sq. meters of #4 brushed panels—our consistent texture made installation seamless and the client’s space look cohesive.
Perguntas frequentes
- Can 304 4 brushed stainless steel be used outdoors?
It’s not recommended for long-term outdoor use (por exemplo, patio furniture). Rain, sal, and humidity will cause rust within 2–3 years. If you must use it outdoors, apply a marine-grade clear coat every 6 months and cover it during bad weather. - How do I tell if my stainless steel is 304 #4 brushed or a cheaper grade?
Use a magnet—304 is non-magnetic (recozido), while cheaper grades (por exemplo, 430) are magnetic. Também, check the finish: 304 #4 brushed steel has uniform, fine lines (Ra 0.8–1.6 µm), while cheaper grades may have uneven or rough texture. - Will welding 304 #4 brushed stainless steel ruin the finish?
Welding can cause discoloration (bluing) near the weld, but it won’t ruin the finish. Fix it by gently sanding the discolored area with a 240-grit pad (in the direction of the brushed lines) and then re-passivating with a stainless steel cleaner. This restores the finish and corrosion resistance.