Stainless Steel

Stainless Steel Product Use Cases

Stainless steel tubes

Steel & More is your supplier of stainless steel tubes according to ASTM A554. Our range of ASTM A554 stainless steel tubing includes welded mechanical tubes in austenitic, ferritic, and austenitic-ferritic duplex stainless steel for use in decorative, exhaust, structural, and other applications where mechanical properties, appearance, or corrosion resistance are required. ASTM A554 tubing is typically supplied without protective coating. The ASTM A554 specification for stainless steel tubing includes welded or cold reduced mechanical tubing in sizes up to 508 mm outside diameter and in wall thicknesses of 0.020 in. (0.51 mm) and more.

Stainless steel sanitary tubes

The stainless steel sanitary tube is polished inside and out to the highest quality standards. Sanitary tubes, sanitary fittings, sanitary valves and other products are manufactured for the food and beverage, pharmaceutical and biotechnology industries. Our products are designed to reduce the inclusion areas where bacteria can form and dock. Sanitary valves in clamp form are designed to be disassembled, cleaned and reassembled for the optimal sanitary product line.

Stainless steel pipes

Stainless steel pipes are used in construction, food industry, pharmaceutical industry, petrochemical industry, automotive industry, municipal and decorative purposes.

Stainless steel pipes are offered to customers in various specifications (different sizes, dimensions, grades, lengths and thicknesses) according to their needs.

Overview Stainless Steel Grades

Grade 304

Grade 304, with its chromium-nickel and low carbon content, is the most versatile and widely used of the austenitic stainless steels. Its alloys are all modifications of the austenitic alloy with 18% chromium and 8% nickel. Grade 304 proves to be resistant to oxidation, corrosion and durability. All of them offer easy fabrication and cleaning, the avoidance of product contamination offers a variety of surfaces and appearances. Type 304 stainless steels are used in corrosion resistant electrical enclosures, car shapes and panels, wheel covers, kitchen appliances, hose clamps, exhaust manifolds, stainless fittings, storage tanks, pressure vessels and piping.

Grade 304L

Grade 304L is a T-300 series austenitic stainless steel containing a minimum of 18% chromium and 8% nickel. Grade 304L has a maximum carbon content of 0.030. It is the standard “18/8 stainless steel” which is usually found in pans and cooking tools. Grade 304L is the most versatile and widely used alloy in the stainless steel family. Ideal for a variety of domestic and commercial applications, 304L has excellent corrosion resistance, ease of fabrication and excellent formability. The austenitic stainless steels are also considered the most weldable of the high-alloy steels and can be welded using all fusion and resistance welding processes.

Grade 316

The second most common grade (after 304); for food and surgical stainless steel; alloy addition of molybdenum prevents specific forms of corrosion. Also known as “Marine Grade” stainless steel because of its increased resistance to chloride corrosion compared to Grade 304. SS316 is widely used in the construction of nuclear reprocessing plants. Most watches made of stainless steel are made of this grade. Rolex is an exception in that they use type 904L. 18/10 stainless steel often corresponds to this grade. Also known as “A4” in accordance with the International Organization for Standardization ISO 3506.

Grade 316L

The grade 316/316L is a molybdenum containing austenitic stainless steel. The higher nickel and molybdenum content in this grade allows it to show better overall corrosion resistance properties than 304, especially with regard to pitting and crevice corrosion in chloride environments. In addition, grade 316/ 316L offers excellent tensile strength, creep and creep rupture strength at elevated temperatures as well as excellent formability and weldability. 316L is the lower carbon version of 316 and is insensitive to sensitization; therefore it is very often used in heavy welded components.

Grade 409

Grade 409 stainless steel is a ferritic steel that offers good mechanical properties and high temperature corrosion resistance. It is generally regarded as a chromium stainless steel, with applications in automotive exhaust systems and applications requiring weldability.

Grade 409 steels are also available in highly stabilized forms, such as grades S40930, S40920 and S40910. The stability of these steel grades is ensured by the presence of niobium, titanium or both in the composition of the steels.

Grade 420

Stainless steel grade 420 is a high carbon steel with a minimum chromium content of 12%. Like any other stainless steel, grade 420 can be hardened by heat treatment. It offers good ductility in its annealed condition and excellent corrosion resistance properties when the metal is polished, surface ground or hardened. This grade has the highest hardness – 50HRC – among all stainless steels with 12% chromium.

Stainless steels similar to 420 grade stainless steels include martensitic steels like the other 420 grade versions, which have vanadium, sulphur and molybdenum in their composition, and grade 440. The non-standard 420C grade has a carbon content only slightly higher than that of 420 grade.

Martensitic stainless steels are steels with high hardness and high carbon content. These steels are generally produced by methods that require hardening and tempering treatment. The operating conditions of martensitic steels are affected by the loss of material strength at high temperatures and the decrease in ductility at negative temperatures.

Grade 430

Stainless steel grade 430 is a non-hardenable steel containing straight chromium and belongs to the group of ferritic steels. This steel is known for its good corrosion resistance and formability, combined with practical mechanical properties. Due to its resistance to nitric acid it can be used in certain chemical applications.

Stainless steel grade 430F is normally supplied in bar form for use in automatic screw machines.

Grade 434 has similar properties to grade 430, although it is a molybdenum containing version. The molybdenum content increases its corrosion resistance.

Grade 439

Type 439 is a ferritic stainless steel stabilized with 18% chromium and titanium with a corrosion resistance similar to that of 304/304L stainless steel. This grade can be used in the annealed, cold formed or welded condition in applications where other stainless steels such as Type 304/304L and Type 430 are used. Type 439 has good weldability and excellent resistance to stress corrosion cracking due to titanium stabilization. Type 439 outperforms Type 409 in both oxidation and corrosion resistance, and typical applications include tubular elbows and exhaust system components.

Grade 441

Stainless steel grade 441 is a ferritic stainless steel with niobium, which gives the steel good resistance to oxidation and corrosion. This steel offers good high-temperature strength at high temperatures in exhaust gas environments and has good deep-drawing properties, good ductility, good weldability and good gloss. It is easy to polish. Flat-rolled 441 stainless steel has magnetic quality in all conditions.

Grade 444

Grade 444 corresponds to grade 304 in many corrosion environments and has a lower coefficient of expansion and better thermal conductivity. It has superior 304 and 316 grade chloride stress corrosion cracking resistance and is resistant to oxidation and creep at elevated temperatures, making it a preferred material for the most demanding automotive exhaust applications. Applications requiring high quality corrosion resistance and resistance to chloride stress corrosion cracking are ideal for this alloy. Current applications include food processing, brewery and wine production plants, hot water tanks, heat exchanger tubes and automotive components.

The choice of stainless steel grades is not exhaustive. It is only intended to provide an overview.

Stainless Steel Finishes

Stainless steel sheet is produced in many different types due to the different uses and applications in which stainless steel can be used. It has become popular in kitchens due to its low maintenance, cleanliness, appearance and corrosion resistance to food acids and water.

For example, the most commonly used surface for most stainless steel appliances is the No. 4 “Brushed” surface. This surface provides a nice bright brushed appearance that withstands daily use and hides fingerprints, scratches, scrapes, etc.

No. 0 Surface

Also known as Hot Rolled Annealed (HRA) The sheet is hot rolled to the required thickness and then annealed. No pickling or passivation processes are carried out, which results in a scaled black surface.

As a result, the fully corrosion resistant film on the stainless steel is not developed and, with the exception of certain high temperature applications, this surface is not suitable for general end uses.

No. 1 Surface
Sheets are hot rolled, annealed, pickled and passivated. This results in a dull, slightly rough surface; well suited for industrial applications, generally in the sheet thickness range. Grinding marks may be visible in isolated areas.

Some of the thinner thicknesses within the sheet thickness range are cold rolled; however, sheet, coil and strip thicknesses are produced by cold rolling, i.e. without rolling and heating the material. Cold rolling hardens the material and the thinner dimensions may need intermediate annealing and pickling or bright annealing while reducing the thickness to the final dimension.

The starting material for cold rolling always has surface No. 1. Cold rolled material is supplied with the following standard rolling mill surfaces.

2B (Light, cold rolled)

A bright, cold-rolled surface is the most common “mill” surface for thin stainless steel sheet. It resembles a very hazy mirror, with some reflection. It is achieved by a final light rolling pass of the sheet through polished rolls. This is the most common cold-rolled surface that can be used as a preliminary stage for polishing. 2B sheets do not normally have a protective coating and may therefore contain slight traces of handling and shearing operations.

No. 3 (brushed, grain 120)

A polished intermediate surface obtained by finishing with a 120 grit abrasive. A unidirectional, directional “grain”. Used in areas subject to heavy wear or can be further polished after manufacture. Our No. 3 polished stainless steel sheets are supplied with a peelable protective cover on one side, which can be removed after the material has been installed.

No. 4 (brushed, 150 grit)

A polished surface obtained by finishing with an abrasive with 150 meshes. This is a glossy general purpose surface with a visible, directional “grain” that prevents mirror reflection. Often found in kitchen applications. We stock a variety of sizes and finishes in polished stainless steel sheet no. 4. Like the version no. 3, these sheets are also provided with a peelable protective coating on one side.

No. 8 (mirror)

It is produced by polishing with increasingly fine abrasives and extensive buffing until all grain lines are removed from the preparatory grinding operations. It is used for cosmetic applications such as mirrors and reflectors.

BA (bright annealed)

Is sometimes confused with paint no. 8, although it is not as “clear and flawless” as the high gloss paint no. 8. This is achieved by annealing the material under an atmosphere so that no scale is formed on the surface. This results in a highly reflective, mirror-like finish, without the need for further polishing.

The right way to store and handle stainless steel

Stainless steel contamination occurs when the thin passive layer on the surface of the metal is permanently damaged, leading to corrosion. This surface contamination not only negatively affects the aesthetics of the steel, but can also affect its performance, so prevention should always be a primary objective.

There are many possible sources of stainless steel contamination, including manufacturing methods, chemical environment, temperature, product design, carbon steel particles, paint, grease, oil, dust, dirt, salt and free metals such as copper, zinc, lead, brass and aluminum. Errors can be costly and difficult to correct, so prevention is always a far better course of action.

In the steel processing industry, fabricators must follow very careful storage and handling practices to prevent contamination of stainless steel, and it goes without saying that there is a correlation between the possibility of contamination and the quality, expertise and experience of the steel fabricator.

Here are some important ways that processors can avoid stainless steel contamination:

Careful storage

Mixed” production halls bear a high risk of contamination. Manufacturers should have dedicated areas for their stainless and carbon steel inventory and manufacturing processes. These areas should be kept separate – preferably by physical means such as a wall.

Adequate protection

The stainless steel should be protected by plastic or other covering to prevent iron filings and other impurities from settling on the surface and causing damage.

Eliminate the possibility of iron or steel dust particles

Loose and embedded iron particles are one of the most common sources of contamination. Many workshop operations such as grinding, blasting, welding and machining produce splashes, chips or dust, and these debris can land on and contaminate the stainless steel. It is therefore essential that carbon steel is always handled far away from stainless steel.

Keep tools separate

Processors should ensure that there is no contamination from shared tools, equipment and storage facilities.

Special tools for stainless steel processing and handling are essential and fabricators should only use tools suitable for stainless steel handling, e.g. carbon-free cut-off wheels and hammers made of hardened chrome sheet.

Good handling practices

When handling stainless steel, plastic-coated or plastic-sheathed belts or ropes are preferable. If carbon steel straps are used (which is often the case), cardboard pads or other suitable packaging material (e.g. wood) should be placed on top of the stainless steel to prevent contact with the carbon steel.

Stainless steel sheets should be stored horizontally in a wooden box and covered to prevent contamination from airborne debris, while sheets should be stored vertically in a dry, covered area. This also avoids the possibility of impregnating or damaging the surface of the material with corrosive particles (such as iron filings) by walking on it.

Keep it clean

A high standard of cleanliness in the working environment is essential. Fingerprints, chalk marks, paint, oil, grease can also cause damage and the stainless steel should be kept as clean as possible. It is best to use a cleaning agent or acid that has a corrosive or passivating effect (i.e. that helps the surface layer to regenerate itself), but these agents must be handled with care and caution as they can be aggressive.