No.4 Stainless Steel: Agree the Grain Before Ordering
A No.4 name points to a directional polished surface, but it does not guarantee one appearance across batches or fabrication routes. Define the grain on the finished part and retain an agreed sample before comparing offers.
- Finish
- No.4
- Process route
- Directional abrasive-belt polish; confirm the producer route and sample
Visible face
Mark the surface that will be seen
Grain direction
Show orientation after cutting and bending
Reference sample
Agree colour, texture and viewing conditions
Receiving
Inspect the delivered form against that sample
Define the Appearance Requirement
Start with the part that the end user will see: the visible face, its adjacent panels, the direction of the surface lines and the amount of later fabrication. A finish name alone does not specify how several panels should look together.
Mark the orientation on the drawing and describe the service environment. Ask the supplier to identify the proposed form and surface process, then compare a physical or approved reference sample with the expected final part. The specific coil offer, if relevant to the order, is bounded separately below; this page does not imply an in-house polishing service or stock.
Set Grain Texture and Direction
ASSDA describes No.4 as an abrasive-belt-produced directional polished surface. Because appearance can vary with the abrasive process, name the desired texture by reference to an agreed sample rather than only an assumed grit or roughness number.
On drawings and sample labels, use an arrow for grain direction and identify the acceptable visual range on the visible face. If a project needs a very close match across parts, specify how the samples will be viewed and accepted before the order is placed.
Carry the Grain Through Cutting and Bending
Confirm whether the surface is delivered as coil, sheet or another exact form. Plan cutting, bending and joining with the grain arrow mapped to each finished panel; rotation of a blank can change how adjacent faces look. Ask which face must remain protected and which operations might alter the polish.
ASSDA notes that direction matters when matching fabricated surfaces. It does not prove that a later weld can always be blended to the original finish. Approve a representative fabricated sample when that result is critical, and keep the process responsibility on the order.
Have a Specification Ready?
Send what you already know, such as grade, finish, size or quantity. Inquiries are answered within 2 hours.
Agree Sample, Batch and Viewing Conditions
Retain a labelled sample or approved panel showing the finish, grain arrow and visible face. Agree light, viewing distance and angle, inspection stage, acceptable variation and who decides a mismatch. If material for adjacent parts comes from separate batches, ask how those batches will be compared before fabrication.
Do not substitute an unagreed roughness or gloss number for the approved visual result. ASSDA recommends reference samples viewed under stated conditions when visual matching matters. Keep the sample identifier with the purchase order and receiving documents; do not claim every batch will be visually identical.
Turn the Visual Decision into an Order Line
Your enquiry should state grade and standard, exact form and dimensions, finish name, sample ID, grain orientation, quantity, protective-film requirement and intended fabrication. Ask the supplier to confirm each field in the quotation and identify any proposed alternative.
At receipt, compare the delivered face and grain with the retained sample under the agreed method. Photograph disputed areas in context, preserve lot identification and resolve differences against the order rather than an image chosen afterward. This checklist does not set a universal numerical surface limit.
Keep the Finish Claim Within Its Evidence
ASSDA provides an industry description of No.4 abrasion, directionality and appearance variation on stainless flat products. That technical description does not establish a universal appearance target or a guaranteed corrosion outcome.
ZIVO has one confirmed 304 cold-rolled No.4 stainless steel coil configuration: 0.3–3 mm thickness, standard widths 1219 / 1500 mm, coil ID 508 / 610 mm and coil weight 2–10 t. This is an exact coil offer boundary, not a sheet offer, stock commitment or claim that ZIVO polishes it in-house. For a quote, confirm the producer, this exact form and size, and an agreed appearance sample. If the end use has corrosion, cleanability or weld-appearance requirements, ask the responsible designer to approve the finish in that service context.
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Send the product form, grade, finish, thickness, width, length and quantity. Inquiries are answered within 2 hours.
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