8K Mirror Finish Stainless Steel: 201, 304, and 316 Grades Compared

What Is an 8K Mirror Finish

An 8K mirror finish is the highest reflectivity surface treatment applied to stainless steel sheet, produced by progressively finer polishing stages ending with a buffed mirror surface of very low roughness, typically below 0.1 micrometer Ra. The result is a highly reflective, decorative surface used where appearance matters as much as corrosion resistance, such as elevator panels, architectural cladding, and premium kitchenware.

Other Common Finishes

The No. 4 finish is a brushed satin finish produced with 120 to 180 grit abrasives, giving a uniform, low-reflectivity surface that hides fingerprints and scratches, and is the standard for food service and general architectural use. Mirror finishes above No. 8 are specified for decorative and reflective applications, while 2B and BA finishes serve industrial and appliance purposes.

Grade 201

201 is a cost-reduced austenitic grade in which manganese and nitrogen partially replace nickel, giving lower material cost but reduced corrosion resistance and formability compared with 304. It is used for interior decoration, tableware, and structural trim in dry environments, where its lower cost and good surface response are the deciding factors.

Grade 304

304, the 18-8 grade, is the standard choice for mirror-finished architectural and consumer products because it combines good corrosion resistance, formability, and polishability. It is used for elevator panels, handrails, decorative screens, and kitchenware, and performs well in atmospheric and indoor environments.

Grade 316

316 adds molybdenum for chloride resistance, making it the right choice for mirror-finished components in coastal, marine, or chemically aggressive environments where 304 would stain or pit. It is specified for seaside architecture, marine fittings, and food processing equipment.

Selection Guidance

Choose 201 where cost dominates and the environment is mild and indoor. Choose 304 for general architectural and consumer mirror-finish applications, and 316 where chlorides or humidity are present. Specify the finish grade, such as 8K or No. 4, the polishing direction, and protective film requirements for shipment.

Frequently Asked Questions

Q: What is an 8K finish?

A: A high-reflectivity mirror finish with roughness typically below 0.1 micrometer Ra.

Q: Which grade is best for coastal mirror-finish projects?

A: 316, for chloride resistance.

Q: What is a No. 4 finish?

A: A brushed satin finish with 120 to 180 grit abrasives.

Q: Why choose 201 instead of 304?

A: Lower cost, at the expense of corrosion resistance.

Q: What applications use 8K mirror stainless?

A: Elevator panels, architectural cladding, trim, and premium kitchenware.

Q: Can mirror finishes be applied to all three grades?

A: Yes, but corrosion performance in service differs by grade.

Contact us for 201, 304, and 316 stainless sheets in 8K mirror and No. 4 finishes with protective film.