Introduction
This guide explains the stainless steel grades and finishes available from Midtherm Laser and will hopefully help you decide which material best suits your project.
Using our fiber lasers, we can cut stainless steel from 0.5mm sheet right through to 30mm thick plate. Available in a variety of grades and finishes, stainless steel suits both decorative and engineering applications.
What Grades of Stainless Steel Do We Cut?
304 Stainless Steel
304 is the stainless steel grade we use most often. This is due to a number of factors, including its good corrosion resistance, availability in a range of finishes and suitability for both indoor and many outdoor applications. It is also more cost-effective than 316 stainless steel.
Common applications:
- Architectural features
- General fabrication
- Food equipment
- Machine components
- Signage
316 Stainless Steel
316 is a marine grade stainless steel that offers improved corrosion resistance compared with 304. It performs particularly well in harsh environments, coastal locations and applications where hygiene is important.
Unlike 304, 316 offers greater resistance to salt exposure and chlorides, making it a popular choice for marine, catering and pharmaceutical applications.
Common applications:
- Catering equipment
- Coastal projects
- Pharmaceutical equipment
- Marine applications
- Outdoor installations
321 Stainless Steel
Although we don’t stock 321 stainless steel, we can source it when required.
Manufacturers designed 321 stainless steel for high-temperature applications and often use it where components experience elevated temperatures for extended periods. As a result, it is often specified for specialist industrial applications.
Laser Cutting Stainless Steel
Thickness Range
Stainlesss steel can be cut from 0.5mm but is stocked from 0.9mm, up to 30mm thick. Some of the thicknesses and grades are available in 4000×2000 sheets.
Please note that not all finishes are available in all thicknesses.
Nitrogen Cutting
We use nitrogen assist gas when cutting stainless steel. This produces a bright, clean cut edge with no oxidisation, making it ideal for components where edge appearance is important.
Edge Quality
Laser cut stainless steel produces a clean edge finish. On thicker material, fine striations may be visible on the cut edge as seen below. There can also be burr on thick gauge plate. This is often acceptable without any additional finishing processes but can be removed at an additional cost.
What Stainless Steel Finishes Are Available?
Mill Finish (2B & Hot Rolled)
2B and HR are the standard mill finishes and are the most economical stainless steel option for both 304 and 316.
Both finishes offer a smooth appearance and suit fabrication, engineering and industrial applications where appearance is not the primary consideration.
DP1 (Dull Polished One Side)
DP1 is a brushed finish applied to one side of the sheet. The grain runs in a single direction, giving the material a similar appearance to a finely sanded surface.
This finish is popular for decorative and architectural applications where appearance is important.
DP1 is a stocked finish from 0.9mm to 5mm thick, meaning there is no requirement to purchase a full sheets worth.
304 BA (Bright Annealed)
BA is a highly reflective polished finish but is slightly different to mirror polished and we only cut this in 304.
BA is produced during manufacture. After cold rolling, the stainless steel is annealed in a controlled atmosphere, which prevents oxidation and leaves a bright, reflective surface.
Its brighter and smoother than 2B but has a hazy reflection. It is used for catering equipment and appliances and is generally cheaper than mirror polished.
MP1 (Mirror Polished One Side)
MP1 is a highly reflective mirror polished finish.
As the name suggests, the mirror-polished surface reflects like a mirror, making it popular for decorative, architectural and display applications. This is a polishing process done to the sheet steel.
Although we can cut this, we don’t stock MP1 stainless steel. We can usually source it on a full-sheet basis. Depending on the quantity required, it can sometimes be more economical to obtain a price for a complete sheet.
Its also very hard to take a photo of!
Understanding Nitto Protective Coating
When cutting polished stainless steel, we often apply a protective Nitto film to the surface of the sheet.
This coating helps protect the finish during handling and cutting, reducing the risk of scratches and surface marking.
We normally leave the film in place during cutting, although we can remove it beforehand if requested. Removing the film can be beneficial when cutting intricate designs, although it may increase the risk of handling marks on the finished parts.
Does Stainless Steel Rust?
304 Stainless Steel
304 offers excellent corrosion resistance and performs well in most environments.
However, despite the name, stainless steel is not completely stain-proof. In certain harsh environments, particularly those exposed to salt or coastal conditions, tea staining or corrosion can occasionally occur on cut edges.
316 Stainless Steel
316 offers a higher level of corrosion resistance than 304.
Its improved resistance to chlorides and salt exposure makes it the preferred choice for marine, coastal and catering applications where long-term corrosion resistance is critical.
Choosing the Right Finish
Choose mill finish:
- If appearance is not the main priority.
- If you need the most economical option.
- If you plan to paint the parts.
Choose DP1:
- If you want a decorative brushed finish.
- If grain direction is important.
- If components will remain visible.
Choose BA / MP1:
- If you want maximum visual impact.
- If you want a mirror-like finish.
- If the parts will form part of a decorative application.
Conclusion
Thank you for reading our guide to stainless steel finishes and grades.
Hopefully this article has helped explain the differences between the available options and will assist you in selecting the most suitable material for your project.
If you require any further information or would like advice on choosing the right stainless steel grade or finish, please don’t hesitate to contact our team.
